There was a 5 MVA newly installed isolation transformer having ABB make REF615 relay connected to it.
The problem was whenever the transformer was charged Relay SEF protection operated.
When DR files were investigated, there was a huge unbalance current flowing during the charging of the transformer for a duration of 5 sec. Since there was a residual connection of SEF (Io setting was 10% FLC) so unbalance current flow is neutral. Therefore recommendation was to increase the timing of SEF to 6 sec. Is this recommendation correct?

-SEF connected in the residual connection? Also, ask them to block inrush current.
– You can block SEF for the first 5 sec from transformer charging then you can unblock to avoid nuisance tripping due to unbalance inrush current, making 6 sec is not correct as you are permanently increasing the operating time of SEF
By SEF u mean to stand by earth fault or sensitive earth fault?
– Stand by earth fault. Stand by earth fault by definition and philosophy should be connected to neutral CT. What is the difference between normal earth fault and SEF if u connect it to a residual connection of phase CT?
I am never in favor of giving 10% pickup to a residual connected earth fault relay. Had it been a SEF connected to neutral CT 6s delay is ok. SEF is the last level of tripping for an uncleared earth fault and hence this time delay is ok. If NGR is present, you need to check the NGR current withstand time and make sure that the delay is less than this. Generally NGR fault current withstand time is 10s, But, by the name itself don’t u think that must be kept sensitive to residual connection pickup setting?
– To detect fault close to the neutral point..that too for impedance grounded system Stand by earth fault is not sensitive earth fault.
– The main idea behind using SBEF is that, in the DY transformer, there is no backup protection available for the Y side earth fault relay. SBEF provides that backup protection. To give a sensitive setting to relay, u need to consider the error n CT dynamic characteristics into account. There is a very interesting section in NPAG that explains this.
-If any low setting can be given to a residual connected earth fault relay, then y do u think we use CBCT ??
U have to be pretty sure about your CT dynamic response before giving low setting to a residual connected earth fault relay.
– But SEF will be used at the neutral of the transformer, right? Do we still have to consider CT dynamic characteristics if ALF is ok?
But in this case, they have not used neutral CT. My understanding is for a residual connection we generally go with a 10-30% of CT ratio as a pickup. To protect the transformer winding which is not converted by the residual connection we will go for SEF at neutral and keep pickup sensitive.
– I presume here they have SEF means they must be connected to the neutral of the transformer. Even if it is not the case they can increase the pickup of the relay momentarily using the inrush detection function instead of increasing the TOP is what I feel.
– In which conditions NGT secondary voltage should be increased above 500 V instead of 240 V?
– see As per the manual they assumed their secondary is 500V but over NGT is 240V so according to that u need to use a resistor to 0.2 ohms to get the stable and accurate measurement for the earth fault
– it depends on ur NGT secondary voltage. In ur Case for the Transformer Protection, u didn’t have Differential Protection in Any new transformer or Running Transformer if u Energize for the first time or u Energize after Shutdown the windings will definitely conduct a minimum current that we called as Inrush current at the time we need some protection to block this inrush so in ur case u didn’t have differential protection only u have Earth fault so what they recommend for 6s is ok but After energized it should return back to 5s.
– Actually, there was an existing 13800/240V. NGT connected to a generator. For some reason, it requires to redesign resistor which came around 0.256ohm but the problem is it was asked to increase the NGT secondary voltage giving reference to the manual. Are there any standards for this ??
– if there is 240v in ur design then u should correct it according to NGT if u need it as per manual then ur NGT should be 500V no PBS for 240V u can use as mentioned 0.256 ohm
– as I know I didn’t come to cross standard it always depends on our System voltage. But the relay ABB REF615 has an inrush blocking feature in the current module I guess. it’s enabled
– NO REF only has Feeder protection, Current and Earth fault
– the function is off
-Yes. when it is enabled it will block the tripping. u need to configure the Function block in ur IED. But keep it 10% it will not exceed more than that I think Remove Hindi Type Vv Add Chandan Kumar Singh India added J 1000 Sys 95
What is the blown-out time for SFU fuse of 60/100 A ?? Is it 20ms Or even less ??

-If fuse and relay were to co- originate What time discrimination should be given between SFU fuse (100A) and EM relay ( CAG 14)?

Dear engineers, you can share your related issues in our discussion groups to find out the solutions. Please text on WhatsApp to join: +989129613659

– A single-phase 105MVA, 400/220/33kv single-phase ICT has been replaced in a three-phase delta star connected unit, and above is the issue when they are charged? Please share ur views or possible reasons for this what is the status of voltages ?? Are they balanced ??

-If there is unbalance in the phase then there’ll be voltage generated in the open delta circuit.
– They are balanced it is working with the spare transformer the issue is when they are replacing with the new one
Better to simulate the scenario in software and see the results.
– Are you trying to do it online or offline? If online, then PCM will retrieve the model automatic from the front port. If offline, then recheck the complete model which you want to configure. The yellow mark shows hardware items invalid with the complete model. When I’m trying to do this offline then I’m not able to put the correct code in the yellow section.
– Online means the PCM will retrieve the code from the relay itself, Check whether the relay is showing online or offline in PCM. May the communication has an issue. The best is to create a complete relay connection again. I prefer to reinstall the Connectivity Package file of RET615 again With its current software version which is in the relay…
I install the REF615 recently with the PCM 2.0 version. It worked.

-can u please discuss
How relay Sensing CT saturation?
How could we Protect from CT saturation?
If CT saturation Occurs, what’s the Real-time status of the Diff relay?
How could we test the CT saturation scenarios in another make relay
Except Siemens.? (Add on Stability) is there in siemens user x: Resistive reaches are same for all zones?
user x: Yes
Mostly in bus bar differential relay CT saturation is taken care of by an inbuilt algorithm/program ..when we open one secondary of one phase CT. tripping gets a block Also, there is another philosophy of bus zone and check zone where CT saturation or CT secondary problem is taken care of by comparing both current statuses of two core.
Actually high resistive fault can take place at any distance may be zone 1, zone 2, zone 3. So we are maintaining the highest resistive reach for all zones.

-Anyone aware most of Micom P44X relay resistive reach are same for phase and ground?R3G, R2G, R1G -33 ohm
R3P, R2P, R1P – 25 ohms. Why these values are same in most of the Micom settings ??
-As per the theory in the p44× handbook of Alstom maximum resistive, reach for ground fault is 80 % and for phase, the fault is 60 %. The faulty resistance is calculated by expecting a 120 % rise in current and a 20% drop in-phase voltage.
– Resistive ph reaches 60 percent of maximum load impedance and ground reach is 80 percent of load impedance is for Zone 3 I think, Again Zone 2 resistive reaches are taken as 80 Of zone 3 resistive reaches I guess. I think 15 percent drop in-phase voltage, And 1.5 times rise in current But taking voltage 0.85pu and current 1.5 times of conductor capacity either for zebra/ panther taking cos angle in emergency loading Zloadmin
R3G-80% of Zloadmin
R3P – 60% of Zloadmin
We were not able to achieve resistive reach 33 ohm for ground and 25 ohms for phase.
-So On what basis French are proposing these settings ??
user x: As per my calculation R=V/I
V=0.8 ×63.5 v
I=1.2 A
R=(0.8×63.5 )/1.2
Rg=0.8 R=33 ohms
Rp=0.6R=25 ohms

But the concern is R=V/I * cos phi. The calculation is given in Alstom P44x book.

– A 11Kv, 2.2MW synchronous motor tripped on-field failure. As per customer excitation is healthy. What could be the possibilities of a field fail trip? It’s running for 1 year.
user x:
LOE will operate when the impedance trajectory passes the offset mho scheme.

This tripping seems to be due to transient swing or low-frequency disturbances.
: Do u have the Comtrade file?
: And settings of the relay
user x: Comtrade file customer can’t able to retrieve as he does not have a laptop and expertise to retrieve data. Settings I will provide

user x: One 20 MVA transformer has frequent trippings by REF… in LV side… What will be the probable reason….
user x: LV side feild CT and NCT has same ratio 600/1
The stabilizing resistor value for a through fault current need to be checked
Eee Deepak Kindly add in protection relay and IEC 61850 India: Do u have any DR.
user x: The polarity of the lv neutral ref ct may be reversed. The s1 and s2 to be reversed and connected and than checked
Eee Deepak Kindly adds in protection relay and IEC 61850 India: As CT3 is measuring fault current similar to neutral current there may be single-phase fault at the remote outside of zone..
Eee Deepak Kindly add in protection relay and IEC 61850 India: Had u observed any other fault or pickup in lines
user x: That REF operates when there is a 33kv feeder tripped
user x: Wiring diagram
Fault angle for both LV CT ILN and LV CT IL3 both are same and magnitude also similar
user x: Is it tripping during charging or in running?
This proves there is no internal fault ..

Yes.. once check pre fault current angle of IL2 and IL3 one is -142 & -108 deg..
user x: Thank you.
user x: Running
user x: Please forward original post.
user x: One 20 MVA transformer has frequent trippings by REF… in LV side… What will be the probable reason….
user x: LV side feild CT and NCT has same ratio 600/1
user x: It’s the problem
user x: This message was deleted
user x: I will check
user x: Is it connected to the local grid? Any external system trip during that time.
user x: Yes
Eee Deepak Kindly add in protection relay and IEC 61850 India: Once check with polarity only I doubt with the polarity of IL3
user x: While posting such cases it is useful to the members if a brief note on trips is given and details of fault record are mentioned.
Eee Deepak Kindly add in protection relay and IEC 61850 India: Or check relay setting and test if for any commissioning mistakes
Eee Deepak Kindly adds in protection relay and IEC 61850 India: Whenever There is fault on the 33kV side transformer is tripping on REF fault
user x: 33Kv is HV or lb. I presume that it is D/y TRX with LV 33Kv. Right?

user x: Yes
user x: It is a polarity issue of CT. If u see in this screen short the magnitude of current in IL3 and neutral are almost same, which confirms there is an external fault (resistive grounded system).

Then if u observe angle there are same..but if there is an external fault it must be in opposite direction. So if one is -108Deg the other should be 72Deg.

So i feel polarity should be checked once by doing stability test of transformer.
user x: Thanks
user x: Added few people from different organization. Hope will discuss well in power system field.
user x: Thank you sir.
user x: Many participants are asking me about profession and organisation of other group participants so wat type of query could be posted.

So I thought of sharing this to all group members.

We have participants who are from design, engineering, R&D, system studies, relay testing, testing commissioning, operation maintaince , automation etc

Gov Organisations :

Private Organisations:
PRDC, TCE,GE,schneider electric, SIEMENS, ABB, Tata stee,Tata Power, aadhunik power, sterling Wilson,reliance power,Voltech engg,Navabharat Group,Generator Consultants., etc

Kindly share your troubleshoot story, practical facing issues, any new R&D topic etc. We will share the documents and will try to resolve issues.

Thank you all.
user x: Thank you Srikanth
user x: Thank you sir
user x: Sure …
user x: Thank you sir. This group is really helping us to get along. Thanks to all the members 🙏🏻
user x: This type of groups are very useful for serving engineers in solving problems they face , updating knowledge and also to help co-members if they have solved similar problem earlier. For senior engineers who are not in service to share their experience and in touch with subject.
user x: This message was deleted
user x: YUP
– AA 5447 Bb Remove Hindi Type Vv Addd Chandan kumar singh iindia added J 1000 Sys 20
user x: It is a good initiative, thank you sukant for adding me in this group.
user x: Thank you sir for adding me in knowledge sharing group.
user x:
user x: Dear all..

I was carrying out load flow analysis on a simple network… With the shown parameters
user x: However the load flow parameters does not seem to be in agreement with the expected values..

Can anyone guide me where can be the probable mistake
user x: Can you capture the transformer’s input data modelling window…
user x: Sir I think cables parameters I have put wrongly
user x: Voltages?
user x: Why generator is being overloaded?
user x: That is my question..

It is a slack bus.. But it should come near to 6 MW including losses ..

But here it is 24MW
user x: Generator is rated of 5MW, but it’s is delivering 24 MW
user x: Absolutely sir..
user x: My question is that only
user x: Yes kindly check cable parameters may be the extra mw is getting lost
user x: Load is of mva only
user x: Load is 4 MW
user x: With 0.85 pf
user x: Can you capture the load input data modelling window
5user x: But it is drawing 15 mw
user x:
user x: Load data sir
user x: Cable parameters
user x: It is erroneous but I am unable to spot where it Went wrong
user x: Can you once increase the transformer’s capacity and rerun the load flow…
user x: Sir please find the results
user x: In load parameters, check the operating load data…
user x: Sir actually it was some absurd values over there..

However I have corrected and re run..

Results are the same.. When again opening the window.. Previous garbage values are coming
user x: How to make my data save sir?
user x: Give me 30 min…

I will build the same network
user x: After correction, can you send those results and input data
user x: Sure sir. Thank you for your help and support
user x: Yes sir.. Definitely
user x: Because cable will not draw active power…
user x: Transformer is over loaded
user x: And the load element is drawing more than its rated capacity…
user x: It has to be checked first…
user x: Sir also one thing I want to model simple transmission line.. With 132kV panther conductor .. Is that possible here!
user x: Below check operating load
user x: No sir.. Why cable will not draw reactive power
user x: You can model your own lines and cables…

If it’s parameters are known…
user x: It is getting changed after running after running the load flow
user x: Make operating load 4 mw
user x: And re run load flow
user x: Cable will draw reactive power and there will be active power drop…
user x: Already done
user x: And it’s very high voltage cable…
user x: Achha ok. That’s why bus voltages are rising
user x: Let me try with high load
user x: So that the over voltage can be compensated
user x: If voltage 132 kV…

Then try to replace a over head transmission line in place of cable…
user x: There would be capacitive effect too…
user x: Yes yes.. Correct sir
user x: But distance is only 50 kM
user x: Transformer secondary winding – delta?
user x: But yes as load is less capacitive effect is substantial
user x: It’s too high sir…
user x: Star sir
user x: Grounded?
user x: Yes
user x: Load configuration?
user x: It’s simple..fixed load of 4 MW
user x: I think ur load flow is not converging
user x: Yes.. My question is how to debud the mistake
user x: Yes..just run short circuit once
user x: Also no error reports coming
user x: I have not put the short circuit parameters sir
user x: Once open the branch report of power flow
user x: You run short circuit ..fault current ll not appear
user x: Check branch node in manager
user x: I have identified the thing..

Please find the operating load data….

Load is drawing this much.. And not the 4MW

user x: Capacitive effect is dependent on voltage…
user x: ETAP doesn’t show pop up for convergence
user x: Please some one tell me how to change and save operating load data correctly
user x: This message was deleted
user x: Please check Bus voltage
user x: Operating load is automatically generated after load flow analysis
user x: Operating Load can be updated from the Load Flow Study Case Editor. The operating load option is available if your ETAP key has the online (ETAP Real-Time) feature. When the operating load box is checked in the load flow study case editor, the calculation results are updated to sources, loads, and buses, so that they can be utilized as input for later studies. If your ETAP key does not have the online feature, you can see the operating P and Q data in the element editor; however, this data cannot be used in a later study.
user x: I am doing system study for the expansion of existing plant. During short circuit studies bus bar rating exceeds the 50kA. Please suggest me solution is need to increase bus bar size or any other fault current reduction devices in LV side.
user x: O.415 kV level
user x: Selecting the transformer’s with high percentage impedance…

Or verifying the availability of laying another bus in parallel with existing bus…
Keeping the spacing clearances in consideration…
user x: Hence it is the existing transformer increasing percentage impedance is not possible now and only one transformer in the system.
user x: What is the transformer’s through fault current?
user x: Spilting of the main buses may also be done for lowering fault level .
user x: 43kA
: It’s not only about changing bus bar. You should also check the associated switchgear rating
user x: Yeah
user x: Busbar short circuit current withstanding capacity of >50kA is recommended by…..?
user x: That’s way i need cost effective solution to reduce fault current
user x: What is the available fault mva given at your source point of the network….?
user x: Source fault current not given I have considered 25 kA it is HT side bus fault current .
user x: You considered 25kA at what voltage level?
user x: If you can know the details of upstream transformer’s at 22kV…

You can calculate the through fault of those Transformers and arrive at correct value…
user x: Selection of 50kA rated switchgear for 3 secs withstanding time, would give you higher short circuit current withstanding capacity for 1 sec…

And the fault isolation (relaying action) will be done in below 1 sec…
user x: Is there any ACB or current limiting devises
user x: To reduce the fault current at LV side like reactors
user x: Current limiting reactors – I don’t know
user x: Current limiting breakers.
user x: No, I don’t have knowledge of them…
user x: Ok thank u i will check for the upstream fault details once again.
user x: Yeah…
user x: Please check the Is-limiter of ABB.
user x: Sir aap idhar.. 😂 😂
– J 1000 Sys 146 added J 1000 1824 Introduced Durai PP, J 1000 1824 Introduced Vijayan PP, J 1000 Sys 107, J 1000 Sys user x:
user x: Might be useful for performing short circuit studies.,
– J 1000 Sys 6 added J 1000 Sys 10

user x: Originator of the post didn’t give the details of the expansion proposed. During chatting single line diagram(SLD) was given not at the begining. Expansion can be either power generation or motor loads etc., As per SLD source short circuit MVA is 165MVA. It has to be confirmed whether it is the same now or there is any increase. Circuit breakers CB1, 2 and CB 203 to be obtained. Buses short circuit ratings also to be gathered. Proposed expansion SLD to be added to existing SLD. As per obtained data it is to be verified whether existing breakers breaking capacities are having any margin or not. It is to be noted that when we are adding generation to existing buses we have to verify existing breakers breaking capacity, as it will effect short circuit currents magnitudes.
user x: Expansion in the load side and transformer rating is 2MVA . i am also checked that source fault MVA reduced to 1OKA the fault current still exceeded the 50 kA In the LV side . So the requirement is reduce fault current at LV side of transformer.
user x: Your source fault level is 4.33kA at 22kV level. What is your transformer impedance and vector group.
user x: 5.87 percentage
user x: Dyn11
user x: Your 0.415Kv bus fault level is 47.393kA considering infinite source at primary of your transformer. But fault at primary of your TRX is only 4.33kA.
user x: Thumb rule to calculate fault current at l.v terminals of the TRX. (considering infinite source at primary) is TRX. FLA(l.v)/ TRX. per unit impedance. Here it is 2782/ 0.0587 = 47.393kA.
user x: Yes your right we need to consider the fault current from the load side it is almost 11 kA
user x: It will increase the total iK” value to near 60 kA
user x: It’s the through fault current of a transformer, which will have negligible change in the calculated fault current w.r.t increasing source fault MVA….
user x: We have considered source fault at 22 kV level is 25kA
user x: So it will cause the faut current at transformer sec nearly 44 KA and also as per IEC 60909 We need to consider 1.05 c factor.
user x: What is that 11kA where from you got it? In your SLD source MVA (22kv level) is 165 MVA meaning 4.33kA then why 25kA? Worst case is consideration of infinity source at primay
user x: With that your l.v fault level calculated and is 47.393. I informed your source fault level is not that much.
user x: Source fault MVA IS 1002.165 MVA SC
user x: Assumption on this available fault level is based on??

Incoming breaker Isc?
user x: Yes
user x: The selection of breaker rating will always be higher than the calculated value….

In this methodology, the calculated will be much more, while in actual it will be lower than your calculated value…
user x: Please check correct source fault level. Do you want to replace the TRX by 2.5 MVA capacity? In SLD it is 2MVA.
user x: As long as your TRX capacity is 2MVA fault level will not be more than 47.393.
user x: Ok i will check it once again.
user x: If you consider 25kA as fault level then you cannot get actual fault level moreover fault level at incomer also should be less than 80% of the breaker rating.. you can get actual fault level from utility. In studies accurate data can only will give accurate results so don’t assume any major data
user x: Deepak this 25kA worked out from SLD. Because of closeness of symbol and figure I mistook it as 165. It is 1002.165 M.V.A. At 22Kv voltage level it works out to be around 25kA.
user x This is a simple circuit for short ckt studies and hence manual calculation is not difficult. If one wants to review existing breakers and buses short circuit capabilities HV side source data is necessary. L.v side, first rough calculation can be done assuming TRX H.V side fault level infinity. If it is more than existing breakers rupturing capacity then finer calculations necessary. Originator has to confirm whether expansion requires TRX. capacity enhancement or not.
user x: It is concluded from load flow study transformer capacity 2MVA is enough for expansion load so the problem in the short circuit study. Transformer SC contribution itself nearly 44 kA and fault current from the load side is nearly 15 kA so the requirement is fault current limiter at LT side.

user x: I don’t think that any current limiter is needed if you keep actual fault level it doesn’t cross 50kA
user x: Definitely
user x: Please fill missing information.
user x: In short circuit studies it is important to furnish details of fault current capabilities of breakers and bus bars. In spread sheet I left some cells with ? mark. Please provide that information then we can review in a better way.
user x: ok sir i will update
user x: What is this ,can you suggest this one connect worng or right ?
user x: Correct only.

When u will give the 3 phase then across the windings the Flux gets developed and with that EMG the rotor gets rotated
user x: It is star connected motor
user x: Wrong
user x: Wrong Delta connections
user x: Correct connection-A1B2, B1C2 AND C1A2
user x: Thanks for giving me suggestions
user x: Which software is suitable for preparing the electrical drawing ?
user x: Auto-CAD is the world wide used software for any type of drawings. However all big companies having their own softwares.
user x: Ok ,
but it’s not support in window -8.
user x: It will. You have to use licenced software. If using licenced one then contact to autocad engineers for proper installation. Also check the compatibility of Autocad alongwith service pack and type of bit of operating system. Window 8 mean Cad 14,15 and 16 will support. I am not sure above this will support or not. The best practice change the operating system either lower than 8 or higher. Coz Window 8 has lots of issues.
user x: Ok sir,
user x: I will not suggest for pirated software. But if you are using then need to install in correct way with proper key generated by Keygen.
user x: Actually operating system i.e., Windows 8, failed to support many softwares and was accepted and withdrawn back very soon by Microsoft…
user x: Yes. Better to upgrade to 10
user x: Yes sir
user x: Live in 10 minutes
user x: sizing calculation for High resistance grounding for 4.16 kV system. Please provide the calculation format.
user x: Please give some details. Your question is very vague. You would have give simple SLD of the scheme.
user x: You need NGR sizing calculation ??
user x: This message was deleted
user x: sir I need high resistance grounding calculation format this is for medium voltage system
5user x: NGR Calculation ???
user x: for a 4.16 kV System Neutral Grounding Resistor rated at 400 A. The line to Neutral Voltage will be 4.16 kV /√(3) = 2400 V. The required resistance will be 2400 / 400 = 6 Ohms.
user x:
user x: sir this is for the low resistance grounding calculation sir. for high resistance grounding system current should be less than 10AMPS
user x: It’s an example
user x: You can go through this link
user x: Yes sir i also viewed this link, we need to specify the charging current of the equipment connected in the network and the we need to calculate the Required current sir for that only if anyone done this for their project please share me sir
user x: Why high resistance grounding for 4.16kv distribution system?
user x: is the requirement of project specification sir.
user x: On what basis it is recommended. Normally for this voltage system low resistance grounding is used.
user x: Will try it.
user x: it is recommend by IEEE 142 sir. and ieee transaction paper , it is mention like following
2.4 and 4.16 kV. The primary reasons for this trend can be briefly recounted as follows.
1) A feeder circuit is not automatically tripped on the occurrence of the first line-to-ground fault; thus the continuity
of service is maintained.
2) The fault can be detected, and its location pinpointed while the system remains energized so that an orderly shutdown
for maintenance can be scheduled.
3) The buildup of destructive overvoltages caused by restriking (or spitting) line-to-ground faults is prevented.
user x: You have any project to be executed with this grounding system. Probably it is about advantages of high resistance grounding. System grounding itself big subject in Elect engineering. As far as my knowledge goes , after so many discussions now generally used grounding dusts are for 415 V system (LV) solid grounding, medium voltages low resistance grounding and in high voltage systems Trxs
user x: i have not worked for the high resistance grounding till now sir, this first time.
user x : neutrals solid grounding system is used. In case of high capacity generators to limit currents in case of core faults High resistance grounding is used. Depending on system grounding protection has to be chosen. In some cases equipment insulation has to be chosen.
user x: in our project they asking high resistance grounding for the 4.16kV System.
user x : You have any project on hand. If so give details and it’s complete SLD. Protection especially E/f protection has to suit it.
user x : It is a design stage sir here after only we need to identify protection based on our conclusion
user x: What is your productio process and what are loads connected to 4.16Kv system?
user x: It is air blower sir connected at 4.16 kV
user x: Unless there is some strong reason this H.R grounding is selected. Because of cost and other reasons distribution TRX earthing used for gen. neutral earthing
user x: There TRX 4.16kv winding capacitance connecting bus duct or cable capactance, if any surge arrestors etc are required to size sec. resistance that will be connected in secondary of earthing distribution TRX.
user x: I feel resistance grounding is require only when there high SLG fault current is above 80% of breaker capacity in LV swbd
user x: Breaker rated normal current rating selected basing on load connected
user x: Basic considerations in distribution grounding system are Economics, Control of over voltages, control of fault current magnitude and ground fault protection.
user x : Sir, I think that the place where ground faults are common, and place where grounding potentials play significant role, and place where ground conductors are exposed to humans…..will require righ resistance grounding…
user x: Can you give example of such places or application where is being implemented??
user x: Underground mines, airports, data centers etc
user x: As far underground coal mines (eg. dhanbad,jharkhand ) are concerned there is blower motor, lift and water pump motors with lightning system..all 11/0.433kv distribution system there is solidly ground neutral ..

As far airport is concerned you can check in chennai airport distribution network .. all neutrals are solidly ground

You can find resistance grounding in 33/6.6 kv trx where 6.6kv swbd has motors which increases the fault current..
user x: But there could be resistance grounding in special cases ..
user x: What type of plant is it ??
user x: It is sewage plant
user x: In IEEE 142 they mention high resistance can be used in the 2.4 and 4.16 kV
user x: How much SLG current you are getting wid all motor contribution??
user x: What Saieesh referring are the isokeraunic areas where there will be many lightning strokes. To such areas recommendation is to use an overhead shield wire for direct stroke lightning protection. Another ethos of providing lightning protection that is effected by the type of grounding is the use of surge arrestors installed on each Conductor at intervals. The voltage rating of the arrestor is directly rated to the effectiveness of grounding employed on the system. That means system grounding is designer choice depending on industry process requirement and other factors.
user x: In Hyderabad GMR’s RGI Airport, all high voltage neutrals are of resistive grounding…
user x: Standard says H.R grounding system occasionally used on 2.4 or 4.16Kv system. It is nowadays used for medium and high capacity generators neutral earthing. It can be used where service continuity is required. I saw a case where cables failed because of wrong calculation of charging currents thereby secondar resistance of H.R earthing system.
user x: Yes sir…

It is as per IEEE Std 142 right???
user x: Sir,

Can we decode like this…
user x: After analysing earlier problems experienced generally followed earthing systems I posted. But some process industries depending on process requirement adopt other than generally adopted ones. For example unearthed systems. System designer will consider all the factors including protection. Earlier some Medium voltage systems used to have unearthed systems but later low resistance earthing system being followed. IEEE standard discusses different neutral earthing systems in C62.92 different parts different equipment.
user x : Thank you sir…
user x:

Live in 10 minutes
user x : Four quadrant power flows. Electrical system power flows can be represented in Cartesian co-ordinate system. Active power plotting on x-axis and reactive power on y-axis. During steady state operation synchronous generator operates in Ist quadrant delivering active and reactive powers into grid, in IVth quadrant delivering active power and recieving reactive power. Similarly synchronous motor operates in IInd and IIIrd quadrants. Now it is used in EHV transmission system power measurements. Voltage and current signals are digitised and their fundamental components are evaluated. Using these components and phase angle, the active and reactive power in four quadrants computed. To take care of variable power tariff, multiplication factors are changed depending upon frequency and voltage. Active power drawn over and above schedule when frequency is low and same for reactive power drwan when voltage is low.
user x: Yes sir….
Thanks a lot…

Yesterday I have gone through this document…
user x : 👆
user x: Chandan can u send it once again
user x:
user x: Hai anybody tested 3 end differential in T60 relay?because i have doubt..
user x : Anybody having standards regarding flicker calculation/constants ??
user x: Flicker?
user x: Yes ..if anybody having any standard document ..kindly share ..
user x: I’m not sure about this, once check it…@918809302443
user x : Shall we use NGTR instead of high resistance
user x: In sec side of 5MVA Transformer at 4.16 kV
user x:
user x: live in 10 minutes
user x:
user x: What is the protection requirement/ guidelines for connection of grid substation to solar power generating Station.
user x: In 132kv level
user x: Like CEA
user x: Hi
user x: Anybody knows pscsd
user x: *pscad
user x: Insulation coordination for direct lightning strike studies
user x: Y is it taken in ratio… I mean while modeling by default in one arrster it is 0. 0625 and another is 0 .9375
user x: There is no specific protection guidelines have been framed for solar generating power station.

Normal philosophy could be adopted from CBIP
user x: IEEE model … Kindly refer PSCAD Application Manual Page 32 of 115. And also PSCAD example – Lightning ..
user x: Already went through the manaul but its not clear
user x: Had gone through many examples they have also taken same ratio
user x: Ieee model if someone having plz share
user x: Dear all,
Anyone have details Documents about transformer Explosion prevention and fire extinguishing system?
N2 injection system ..
Delepan S
user x: Thanks.. I need details about N2 pressure maintenance and periodic condition..
user x: Please refer SERGI company website you may find some articles.
user x: Noted and thanks
user x: Check out the Youtube Session on Grid Connected and Standalone Solar Plant Design using PVSyst at 10.30 A.M. by our Expert Lakshmipathi.
user x:
user x: Public Attention!!!!!

Your BANK Account could be Emptied without an Alert
Dear All, Please let’s be very careful.. There is a new HIGH TECH FRAUD in town called the SIM SWAP FRAUD, and hundreds of persons are already VICTIMS.

How does it work?
1 A new fraud called SIM SWAP has started. Your phone network will momentarily go blind / zero (No Signal / Zero Bars) and after a while a call will come through.

2 The Person on the other end of the call will tell you that he is calling from (your cell phone company) depending on your network and that there is a problem in your mobile network.

3 He will instruct you to Please press 1 on your phone to get the network back.

  • Please at this stage don’t Press anything, Just cut or END the call.

If you press 1, the network will appear suddenly and almost immediately go blind again (Zero Bars) and by that action, your phone is #HACKED.

Within a second they will empty your bank account, and you won’t receive any alert.

What you will experience.
It will appear as though your line is without Network, meanwhile your SIM has been SWAPPED.
The danger here is that, you will not get any alert of any transactions, so please those of us doing USSD Banking and Mobile Banking BEWARE. Let’s be very careful.

Please, forward to your contacts, loved ones and friends. The fraud is increasing day by day.

Received from a #CybersecurityGroup

Don’t forget to share this post…… I repeat don’t forget to share this post. Many people’s Account as been emptied!
user x: Hi All..
Can anyone give me line parameters of 33kV and 66kV Coyote conductor and 33kV Rabbit conductor (Rp, Xp, Bp, Ro, Xo and Bo) values
user x:
user x: Thanks a lot
user x: 🤝🏻🤝🏻👍🏻
user x: Erpc available impedance chart👆🏻
user x: This do not have Coyote and Rabbit conductor details
user x: 👌👌👌👌👌
user x: 👆🏻2×20 Mva trf at Gss kudra in Bsptcl are tripping simultaneously on differential fault. Both the trf are separated on 33 kv Main bus. Above is the fault record of todays tripping. Any suggestions please
user x: Can you post SLD and brief history.
user x: In brief the substation is radially charged by a single source the 132 kv bus is single and feeding both the trfs but in 33 kv side the high level switch is opened so they are feeding 33 kv feeders separately. The trfs are in service for more than 10 years now and have Ret 670 as differential relay. A few more tripping records are as follow👇🏻
user x: Tripping of both the transformers at same time on differential protection could be due to fault on remote GSS.
Fault magnitude is around 15A

I feel slope 2 setting could be checked once by simulating through fault current.

Kindly share Trans. name plate details, RET setting file with fault MVA of the 132kv bus.
user x: Both the relays might have D.C supply from common source. Please check common area wiring including fuses or mcbs
user x: From data it is obaerved that tranaformer differentialnhas seen ground fault
user x: It may happen the ground fault would be outside the differential zone
Please check if zero sequence compensation is provided in differential relay for star side
user x: Thanks .
user x: These two trxs are not in parallel. LV fault currents magnitudes are not high like those of HV. Therefore these are not through fault Mal operations. Both relays operating simultaneously except in one trip data given. I talked to originator of posting and asked to check common D.C ckt wiring of these relays. On his feedback it can be further discussed.
user x: 👍
user x: 👍👍
user x: 👍

May I know, who is gopala krisha…
user x: *krishna
user x: He is senior expert in my another technical whatsApp group
user x: He is ADE in TS Transco.. and used to give technical trainings to new engineer
user x: 👌
user x: 👌
user x: Good
user x: 👍
user x: Good for learner
user x: Yeah
user x: Yes ..many of his slides are there , if you do a Google search
user x: Transco means Abu dhabi ? Transmissiin and dispach company
user x: No.. Andhra Pradesh Transmission company.. presently in Telangana after state division he had blog too..
user x: If any one have GIS or power grid pre commissioning procedure please send …
user x:
user x: Join the session for wind turbine basics and ETAP modeling
user x: Anyone having fiber optic cable commutation knowledge. I want a confirmation, whether I can use multimode FO cable with single mode relays or not. If yes, what are the impacts in communication.
user x joined using this group’s invite link
user x: Good morning Everyone.

Today’s webinar topic is Grid integration of wind energy system.

Modelling of wind turbine in DIgSILENT power factory. Session will be handled by DIgSILENT Expert Durairaj …Join the session at 10.30 am
user x:
user x: For Overcurrent & Earth Fault coordination, whether the following points need to be considered?

1) stabilising resistance calculation for REF, EF & sensitive E/F.
2) Opening of one pole.
3) E/F mal operation during motor starting.
4) sensitive E/F (CVCT based) pickup & time should be calculated.
user x: One 20mw generator tripping on 51N during synchronize with grid. What could be the reason ?
user x: Sir,
What is the 51N Protection, pick up magnitude?
user x: IDMT E/F ( Ansi code 51N)
user x: Current settings applied in that protection sir?
user x: Can I know magnitude of fault current
user x: 0.97 Amp secondary (CT : 100/1 connected in neutral side of generator)
user x: What is the voltage sir?
user x: Then there may be some high resistive fault
user x: During synchronisation?
user x: Tripping immediate during sync
user x: Earlier information is that it first tripped while in service. Afterwards tripping while synchronising. Hope that it is correct. As they are able to buildup voltage, let them measure Neutral C.T current after building rated voltage and before synchronising with clipon meter hooking in C.T wire.
user x: Relay terminal nos. 52,53 for neutral c.t connection.
user x: What is the magnitude recorded in fault event log?
user x: If there is a fault in genrator then it should trip even before synchronization

But it is tripping the moment genrator connected to grid

So the problem might be in grid but there will be a delta star transformer between genrator and grid so earth fault in grid will not seen as earth fault in gentrator side but it will be seen in ph ph fault

So the given input may not sufficient as we need to know what is the type of earthing , is there any other earth fault protection
user x: Will the unbalance in grid cause such tripping in generator, due to lower magnitude compared to the grid settings?
user x: Unbalance is not earth fault
user x: Does unbalance result in current flow in neutral…
user x: Never
user x: Sukantaji it is better incharge engineer join the group and participate in chatting. Otherwise it is like blind people identifying elephant in a moral story.
user x: Earlier we faced this type of problem. During switching on the BFP the unit is tripping on 95% earth fault protection. Even we are having UAT. The problem is loose connection at HV side of UAT. due to BFP starting currents because of loose connection at HV side of UAT power termination at one phase causing flash over. Then the same is rectified. So I am suspecting these type of problem may be there. In our case the generating voltage level is 11 kV and BFP is of 6.6 kV. Generator capacity is 50 MW. Generator Neutral earthing is with NGT.
user x: This message was deleted
user x: Thanks
user x: Thanks
user x: Thank you
user x: Thank you
user x: Is there any amount which we need to pay?
Can we join it online?
user x: It’s free for all.
user x: But registration is mandatory
user x: Thank you.. But can i join online?
user x: Yes. Its a webinar, so online only
user x: We need to mail to the email provided?
user x: Saying we want to join the webinar??
user x: Click on the “registration link” text and follow the steps
user x: Ok ok.. Thank you

I think concerned person will send us the link after we mail him
user x: Right?
user x: U should register by clicking on the “registration link” text
user x: In the registration page it will ask for IEEE membership number. That’s optional, so just ignore and fill everything else.
user x: I am very much looking forward to my wedding
user x: Congratulations 💐👏🏻
user x: Congratulations 👏
user x: Congratulations
user x: Congrats…
user x: Congratulations💐💐
user x: Congratulations ।।
user x: Congratulations dear
user x: Congratulations 💐
user x: All the best👍👍👍
user x: Congratulations 💐
user x: Congrats
user x: Congratulations
user x: Congratulations 💐
user x: In 5P20 , 5P10 what is basic difference
user x:
user x: 👆
user x: Thanku
user x: 👍
user x: Where is the catch?
user x:
user x: Can anyone provide iec 60071 part 4
user x: Thank you, for giving me these documents.
user x: I guess this is in german
user x: I think, It’s in English.
user x: Guys request to all. Please don’t share IEC document to each other. It’s a copyright issue.
user x: Okay, thanks for alerting.
user x: IEC Standards one page will be in English and one in European language. Further please note that it is not a good practice to post standards in public domains as they are copyright material. Group administrator responsible to see such materials are not posted. You can see the print from which the material is officially downloaded.
user x: Good morning,
Can any one pls share the IEEE standard-
ANSI/Ieee C37.91-2008

Title: guide for protective relay application for power transformers
user x: Or else pls provide any standard regarding applicable protections for power transformer.
user x: Will send it in private, text me…
user x:
user x: Thank you so much
user x: please help me solve the equation in the 19th page. for the K factor calculation of transformer.
user x: Its a wonderful document , thanks
user x: WC
user x: Can anyone resend this pdf pls
user x: And this as well
user x: Thank you
user x: Hi all….
Can someone tell me why motor behaves as constant impedance load while starting and as constant power load while running?
user x: What is the minimum loading of transformer one of my project it is loading only 13%. Is this cause any problem are it is ok.
user x: Sir kindly refer to the equivalent circuit diagram of motor.. I think that can be explained
user x: Hi all… Just one doubt.. Regarding star delta transformer if there is a single line to ground fault in secondary side of transformer is it possible that earth fault relay will not see any current
user x: For a star Delta transformer. L g fault on star side will be seen as L L fault on Delta side
user x: If no grounding trf is in delta side no earth fault will rise
user x: But Hv star side will operate on earth fault
user x: No I was asking in lv side
user x: I was asking for earth fault current on lv side delta configuration
user x: Yes.. In LV side earth fault relay will not operate
user x: Y is it so
user x: Line to ground fault on star side will be reflected as line to line fault on Delta side…

Zero seq currents will not flow on the Delta side..
user x: Zero sequence y it will not flow on delta side
user x: How will it flow if no ground connection is there?
user x: I think u didn’t understand my question… My question was there is a single line to ground fault in delta side secondary so if relay is there for earth fault protection
user x: Ok ok..

Den also it will not trip because current will not have any return path..
user x: My question is why it is not possible to see earth fault current by relay on delta side
user x: Because there is no return earth path in delta formation. For earth fault current to flow there should be an earth current return connection.
user x: In auto Transformer or Star star winding mostly we have open Delta or Delta which reduce or circulate fault current ..
user x: 👍🏻
user x: When earth fault occurs star side phase that reflected current circulates internally among phase windings and will not enter in line terminals of delta connected windings. Hence it will not be detected. For that open delta protection is one solution.
user x: Yes
user x: Can anyone give me the actual value of current magnitude and time of tripping with this setting with CT 600/5 in 33KV incoming line
user x: If 450 amps comes in primary means it will trip @ 100 ms
user x: Anybody know how to transfer real time values of MW, MVAr, kV, Amp from siemens 7UM6 to DCS.
user x: 7UM62 and DCS both are support Modbus communication protocol.
user x:
user x: Chief Guest Debmalya Sen joining and delivering guest Lecture on Microgrid and Energy Storage: The Gen Z of ENergy Sector
user x: Hi all… For 3 phase fault current in a transformer can we calculate single line to ground fault
user x: And how can we convert that in per unit values
user x: Can anyone help me on this
user x: What is your doubt exactly
user x: Can we calculate single phase to ground fault current if 3 phase fault current is provided
user x: And how to take it in p.u
user x: Is it clear
user x: Answer is NO. since in a transformer sequence impedances are not same with each other

If current =V/Zp (Zp = positive seq impedance)
Then for unbalanced fault

Current= V/(Zp+ Zn + Z0)..
user x: For a transformer seq impedances are not same
user x: Yeah these are the sequence impedance formulas
user x: Positive and negative are same
user x: Only zero sequence is different
user x: Yes yes
user x: How to convert fault current in p.u then
user x: Unbalanced fault calculation is a tedious job If you want to do it by hand
user x: Coz generally we convert impedance in p.u
user x: Best method is to calculate the entire thing into PU

And den multiply it with the base value to get the current..

Reverse is not a general mathematical practice
user x: Is there any method to convert current in p.u also
user x: Why you will express current in pu
user x: Calculate that in pu first and den give tje actual value
user x: Namaste, May be useful.
user x: Join at 10 am to better understand power system simulation software’s and their capabilities. It is Q&A session where your question are answered with simulation results
user x: Circulate to your friends, juniors and students
user x: 46 negative sequence
user x: 79 auto reclose
user x: 37 under current
user x: 37 under current
user x: Thank you..👍🏻
user x: How to calculate operating fwd&rev region angle for directional earth fault protection in GE L90 relay if current polarization is used,
ECA-60 deg lag
FWD limit angle – 80 deg
user x: For current polarization method,if anyone know please let me know the explanations…
user x: This method is used in power transformer if ct is in the neutral or tertiary
user x: Ur which case??
user x: Also share the transformer configuration.. Delta-star grounded like tha
user x: Hello Everyone,

Hope you all are doing well,

I am Sameer Parmar From Gujarat India.

Unfortunately, this covid 19 pandemic I lost my job from Kuwait.

hereby I attached my CV for the further application process.

any recommendations or suggestions will be great help and appreciated.

Profile – Electrical Engineer (T & C / System Study / O & M)

user x

user x :Immegiate

Note: If you don’t have any vacancies please share it if any.
user x: yes you are right it’s for power transformer which step up from generator voltage…Reference Ig CT we took from neutral of this trafo.
user x: It is grounded right?
user x: yes
user x: Actually i have read in theory only… No practical knowledge
user x: I can share u the same
user x: Okay
user x: May be this can help you
user x: Thank you so much
user x: Regarding GE L 90 relay settings, please check whether directional E/f module set for Voltage polarisation or current polarisation. For current polarisation mode ECA 0 deg is fixed as per this relay manual. In case of Voltage polarisation ECA – 60 deg generally used.
user x: but in settings they give 60 deg
user x: current polarization
user x: Please check adopted strings file.
user x:
Session on Evolution of E-Mobility by Demalya Sen Live at 10 am today
user x:
user x: Great session by Krishnan rajagopalan on Microgrid is live now
user x:
user x:
user x: 10 am today
user x: Anyone from state transmission utility.. Do you have solar power plant connectivity at 132kv level or above.. ???
user x: If anyone please share the CERC Or CEA or any government🙏 guidelines for connectivity of above

user x changed their phone number to a new number. Tap to message or add the new number.
user x: Hi team,
Anyone have Motor current signature analysis study material / explain about it functions ..
user x: This is for technical discussions not for advertisement..
user x: Act like educated.. Not like illiterate
user x: Hi Good Morning Dear Sukanth Kumar Sir
user x: Please Look in to this
user x: We are getting good technical things in the group but inbitwin this kind of the messages are not good for our group
user x: Sorry
user x: Won’t repeat again.. By mistake it sent later i came to know
user x: Lets make a rule that only technical related things only should be posted here and no promotion related avtivity even it is electrical or in our domain. If anyone cross these admin can take action like blocking that person or even removing from group like that.
user x: Namaste, sorry to say that I am also very much disappointed the way by which some of the questions are posted. While posting a problem at least a brief note on the incidence has to be given so that other members understand the problem and give their suggestion. For ex. posting that relay tripped on some TRX protection what the reason. Then a member asks what is its capacity and voltage. Another asks it’s vector group. Like this time being wasted in auxiliary questions. Instead they have to give equipment details and the circumstances under which it is tripping. This type of note improves one’s technical drafting capabilities. Another thing is the initiator suddenly withdraws from discussion on that problem. By that members who participated will not be able whether their view is correct or not. Not only that, other members get knowledge on that if a solution is obtained. With such type of casual behaviour group looses it’s impotance. Hope that things will be taken in right spirit.
user x: In this regard ppl can give a minimum information like what we can have in first or flash incident report
user x: My view is that originator has to post some basic information and must be serious in getting correct solution. With basic information members can prepare required material and solution.
user x: Can anyone tell me about harmonics
user x: I have one question
user x: Why if the short circuit impedance is less the THD is high
user x: Please any one provide details regarding stringing tools and uses

user x: Anyone have DC volt battery and charger manuel ?
user xa: This message was deleted
user x: When members are of different mothertounges particular mother toInge postings have to be avoided.
user x: Hi guys.. I have one query… Is there any other method to limit the fault current other than NGR
user x: Kindly note NGR will not limit the fault current (It limits only the Single Line to ground fault Current).
user x: (Hope this helps and you will get the answers at 51:00)
user x: OK sir
user x: NGT is also possible
user x: U can use series reactor and Is limiter even.. If it is a green field project we can limit fault current with transformer impedance at engineering stage.
user x: Which ever method is cost effective and efficient: Is limiter OR Introducing Transdermal?
user x: What is mean by LDCM in line differnential relay ?
user x: line differential communication module
user x: Thank u
user x: Hai friends
user x: why have to use high impedance option for REF protection and why not in normal transformer differential?
user x: If we use the low impedance method to REF what would happen?
user x: If a CT got saturated in that case the current will not be balance hence it will try to through the instrument… And that will make unnecessary tipping and also to protect the Protective relay High impedance option used…
user x: Ok then Why not used high impedance method in normal TRF differential?
user x: See normal transformer differential basically compare the current between the 2 winding of the same phase… So if there is any internal fault in that case the current will not be same hence it will trip…. But if a through fault occurs in that case the same current will flow through the haig voltage as well as low voltage side… In this condition relay should not trip… As it is a out side fault…! The same thing is for REF as it is zone protection scheme..! In case of ref the relay has to be more sensitive as the relay trips in very low current…! That is why REF uses high impedance scheme..!
user x: In normal differential protection the allowable current is much higher compared to REF… the setting of REF usually 5% in most of the cases..!
user x: Ok. Thank you, dear.
user x: Always welcome..!
user x: Nothing will happen. We have many low impedance REF protection across the globe working fine
user x: Which type of differential is good for Motor? High Impedance differential or Biased Differential?
user x: What is the condition to choose the type of differential?
user x: Guys please watch the video and Subscribe the channel
user x: Admin pl. Advice this Business men.not post this type add.
user x: Both high impedance and biased differential could be used
Advantage/disadvantage of biased differential is

  1. They can operate having CTs with lower knee point
  2. They are not as sensitive as high impedance
  3. They can compensate for inaccurate or saturated CTs
  4. Their relay are of low impedance type
  5. Their circuit is bit complex compared to high impedance type
  6. Their relay setting is less complex compared to high impedance type

In my view you should go with high impedance differential protection as it is highly sensitive.
user x: Sorry to say it was sent by mistake… I will ensure it from next onwards this kind of things will not repeat.!
user x: Thank you dear
user x: Thank you
user x: What is difference between h terminal and h section ,if you have any idea please suggest me
user x: Wish all the members Happy Independence day.
user x: Wish you the same sir…
user x: Please anyone send 400kv one and half scheme, primary injection and busbar stability format.
user x: If anyone has ANSI C37 short ckt standard?
user x: This message was deleted
user x: Standards cannot be shared in public domain as they are rights protected. It can be a problem to group administrator. Please understand.
user x: Can anyone give the idea/requirements for bus Sectionalizer for 220kv single main bus scheme in 220/132 grid sub station.
user x: Do u require protection requirments or logics sirr
user x: Both
user x: And also physical arrangements of bay equipment ( c.t, pt, breaker, isolater etc.
user x: As of now its seems like short circuit happen in side the 11kv panel that is the reason behind the transformer failure…!
user x: The ultimate question is why transformer didn’t tripped..?
To me it seems like dc failure might has happened..!
user x: If anyone has some idea what may be the cause behind this please share your opinion..!
user x: This message was deleted
user x: Hello everyone,
I need IEC&ANSI standard for Short circuit calculation(To know the manual calc) for Etap if anyone have share with me…
Thanks in advance…
user x: For short circuit kindly follow iec 60909
user x: Manual calculation u can do ut as per unit basis thevins method
user x: M telling only for etap
user x: Standard i dont have
user x: Oh okay
user x: thank you
user x: Can anyone answer this with explanation..plz
user x: A
user x: Me too guessing the same.. Any explanation available?
user x: Any theory..
user x: B and D out because it’s delta
user x: A and C possible
user x: I went for A
v: Ha ha.. nice explanation..😁
user x: If for explanation the interviewer will ask this question then I can’t answer him in this way..
user x: This message was deleted
user x: This question is for Protection Engineers.
7 question’s answer.
user x: You can refer this…..
user x: For 5th question
user x: Whenever a SLG fault at star connected secondary of the transformation, in only one phase fault current will be flowing this has to reflect in the same way in the primary phase winding, but in delta each phase connected to two lines so……SLG in secondary will reflect as LL fault in the primary
user x: But if u take a transformer then there will be chances of 3phase unbalanced flow due to core Impedance.. right…
user x: Yeah in other phases current will be there but it is negligible
user x: It will be close to load current
user x: Hmm. But the burden will be on all 3 phases on delta side right..
user x: Ok
9user x: By drawing reactance diagram u will get the exact Idea….u can check once
user x: Thank you 🙂👍🏼
user x: 😊
user x: Can anyone answer 7th question?
9user x: 2nd Harmonic
user x: Seems like u r giving some test.
user x: I think this will be selected by user in relay… right?

I don’t know the reason u they select this perticular harmonic.
user x: Ha ha. It’s a material for getting aprovals in Oman
user x: Second harmonic
user x: Hi just a basic doubt,
Supposing there is a “3 phase to ground ” fault at some point on a long transmission line connecting two buses A and B.
Would the voltage at the buses A and B and their interconnected buses drop or increase?
user x: If they r ring made system then there will be chances of increasing at both buses. .
Or else we can find the increased voltage at the source only..
user x: This message was deleted
user x: This group is pure system and science.. so pls don’t text ths type msg..
user x: 👍 right
user x: Agree👍🏻
user x: Hello friends,
Is there anybody have C57.13 standard please share with me…thanks…
user x: Hello Everyone
Is there anybody have Battery commissioning report .
Please share
user x: Yes
user x: We are facing issue with kit software
user x: While opening that software from internal should unable to find test set
user x: send me private message so that we wouldn’t disturb this group professionals unnecessarily….
user x1: This message was deleted
user x:

Project : Uttar Pradesh, Duration will be around 6 months.
user x: Company name is
user x: The project could be from 6 months to 1 year..
user x: Project?
user x: Location?
user x: 🙄🙄
user x: Is it a technical group or business add group?
user x: This group is meant only for technical discussion/query.
Posting anything apart from these will result in removal from the group .
user x: 👍
user x Remove Hindi Type Vv Addd Chandan kumar singh iindia removed AA 8740 Thoufeeq Ahamed
user x: 👍🙏
user x: Dear Sir
Anyone guide me or send me any study materials for busbar sizing according to ANSI standards
user x: Hi

Please provide a detail about below issue.

1) How to take a data for profibus Communication of 7 SJ 8042 Relay through Digsi4.93?

2)How to Configure 7 SJ 8042 Relay for profibus Communication through Digsi4.93?
user x: Hi Good Evening
user x: Sir, CGL make 132/33kV 50MVA Transformer drawing needed, please share if possible.
user x: Can any one have sample setting calculations for SEL 487B?
user x: Hi,
Is there any standard for modeling of LV motors of least size?
user x: Does anyone know what is the problem with it?
user x: Check firmware version.
user x: Even I could not communicate by laptop
user x: You have to download firmware update software for relay
Please check a detail of firmware in relay abs update for the same in it.

For the communication you have to check template file or version of firmware in Digsi
user x: Ok. Thank you, dear
user x2: Indias first 1,200-Kv Substation.

India’s power sector will witness a new era in the transmission segment when state-run Power Grid Corp will launch a 1,200-Kv ultra-high voltage (UHV) test station along with experimental lines in Bina, Madhya Pradesh. The investment for the project is estimated at Rs 800 crore. The company is also setting up a 1,200-Kv transmission line for commercial purpose, which will be constructed between Wardha and Aurangabad in Maharashtra.

Till now, the power is transmitted on 765Kv /800Kv lines. The existing 400Kv line can transfer about 600 Mw power, 800Kv line can do between 1,200 Mw and 2,400 Mw and 1,200-Kv transfer 6,000-8,000 Mw, according to experts from the Indian Electrical and Electronics Manufacturers Association (IEEMA), which is associated with the project. With the government’s plan of adding over 100,000 Mw capacity in the coming 12th Plan coupled with the challenges put up by environment hurdles, right of way and transmission losses, there is a need to develop a more sound transmission system.

About 35 manufacturers, including BHEL, Areva, Siemens and Sterlite have joined hands with PowerGrid to establish the 1,200kV test station. The test line in Bina is being constructed with two 1200kV test bays in which the leading manufacturers are providing main equipment such as transformers, surge arresters, circuit breakers, transformers among others. These test bays and test lines shall be used for various field trials initially. “This will usher a new phase in the transmission sector as with a limited right of way (RoW), bulk power will be evacuated from the point of generation to the load centre. The transmission capacity, thus, will be fulfilled with one such line only catering to the capacity of several generators,” PowerGrid Chairman and Managing Director S K Chaturvedi told Business Standard.

According to IEEMA, the first 1,200kV system field was tested and commissioned in the former Soviet Union in 1985 after 12 years of research, which was discontinued after the disintegration of the Union. Then, Japan started developing a 1,000kV UHV system in 1978 and tests are still on. China started developmental work on a 1,100 kV UHV system in 2005 and a pilot project is presently under testing.

IEEMA’s Senior Director Operations Anil Nagrani said, “This will be an experimental line. There are many advantages of setting up a 1,200 Kv line. With unavailability of RoW, space crunch and various environmental issues, the existing power network can be upgraded to 1,200 Kv lines within the same space or little higher space.”
user x: Good information.
user x: 👍👍
user x: Good Use Full Information 👍👍
user x: 👍
user x: This substation is in existence from the last 10 years
user x: Reply
user x5: Funding agency of transmission line in india )
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user x:
user x: Check out this job at Tata Consultancy Services:
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user x: Dear All,
May the millions of lamps of Diwali illuminate your life with happiness, joy, peace and health. Wish you and your family a very happy prosperous Diwali.🎆🎇🌹🌹💐
user x: Same on yuhh….
user x: आदरणीय एवं परम स्नेही ,
आपको और आपके परिवार को धनतेरस, दीपावली, गोवर्धन पूजा, भाईदूज एवं छठ पूजा की अनेकानेक शुभकामनाएं !
यह दीपोत्सव अपनी रोशनी से आपके और आपके परिवार मे सुख, समृद्धि, सुख-शांति, सौहार्द एवं अपार खुशियों की जगमगाहट भर दे !

॥शुभम करोति कल्याणम,
आरोग्यम धन संपदा,
शत्रु-बुद्धि विनाशायः,
दीपःज्योति नमोस्तुते॥
Monu Singh and Family
user x: It will follow the inrush current characteristics such as 2 nd harmonics and 5 th harmonics
user x: Relay testing at site at bihar is available continuous work, are you ready to join?
user x: This message was deleted

If anyone interested they can contact to this number..
1user x: Any opening for freshers?
user x: Nope..😕
user x: 3 years experience required.
user x: Anybody know what is the formula for 1- phase pickup and 3phase pickup for T60 GE relay
user x1: This message was deleted
user x1: Actually according to the given details CT is 5A but In Caluculated pickup formula u kept it as 1200..
May I know why this difference?
user x: Check 240
user x: CTR 1200/5A
user x: Oh. Primary rating. OK OK.
user x: Hi, Anyone knows how to communicate Toshiba GRL 200 relay ?
user x: I have GR-Tiems software, but it need authenticated user and password. , please guide us if anyone knows .
user x: Anyone having idea regarding AVR installation at Wind TG. Can we use AVR for voltage regulation at wind TG end.??
user x: Dear sirs
Can anyone please explain about advantages/disadvantages/limitations of AFAS(Automatic fault analysis system)
user x: Happy to share as we developed this from scratch
user x4: Very good
user x:
user x: Anyone have NGR test report soft copy, if have send me
user x: I just need as small information about this code which is showing in this Micom relay.

I have already downloaded the Code list but this code is not mentioned in that.

Do u have any idea what this code represents?
user x: Please send that code list ji.
user x: U can find the error in manual of the specific relay..
user x: This message was deleted
user x:
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user x: Wishing all my friends a very happy and productive new year. May 2021 erase all the bad memories we had and make the upcoming year an eventful one.🎇🥂🎂🍾😊😊
user x: Happy new year
user x

🌾☘️🌺🌅सुप्रभात 🌺🌿🌾

🚩जय श्री राम🙏🙏

🌾१ जनवरी २०२१🎉
🌾 आपको एवं आपके परिवार के सभी सदस्यों को नव वर्ष की अनंत शुभकामनाएं💐
🌾नव वर्ष मंगलमय हो🌾
user x

: 🤗🎉🎊आपकी जिंदगी में आए खुशियों की बारात🥳💐मुबारक हो आपको नव वर्ष बार-बार
Happy New Year 2021😁♥️
नई उम्मीदों😇नई आशाओं से भरा हो यह नया साल 2021🤩
नई खुशियों😁नई तरंगों से भरा हो यह नया साल
Happy New Year 2021🎊🎉💐🥳✨♥️
user x: ईश्वर आप सभी को प्रातः काल की प्रथम किरण से प्रारंभ होने वाले नूतन वर्ष में सुख , शांति, शक्ति, सम्पत्ति, स्वरुप, संयम, सादगी, सफलता, समृध्दि, साधना, संस्कार, और स्वास्थ्य प्रदान करें ।

नये साल की अनेक शुभकामनाओं के साथ आप ओर आपके परिवार को हमारी तरफ से नये वर्ष की हार्दिक शुभ कामनाएं ।

user x: You’re invited to join a Microsoft Teams meeting

Title: Power System Analysis – Why, What & When?
Date & Time: 1st January 2021, 10.30 am (IST)
Join the meeting on your computer or mobile app
user x: Dear all

Happy new year to all.!!

Please provide a suggestion for below case,

Line Length :10 KM
Relay Specification :Micom P442
Relay setting : D/S- 0.300 ohm
U/P-1.2 ohm

Below problem occur in Pumping station,

1) Line was tripped at 8.3 KM away from UPSTREAM and 1.7 KM Away from Our pumping station.
Which side relay will operate ?
2) what’s the recommended setting for the operation of line ?
3) which relay operate first for above case ?

user x: I wish your life will be full of surprise and joy in the new year that’s about to begin. May you be blessed with everything you want in life.

Happy New Year to you and your family! Wishing you 365 days of good luck

🙏Ankit kumar singh 🙏
user x: Answer

  1. Pumping station relay has seen the fault in zone 1 and as per standard operating procedure relay at pumped storage should have tripped earlier
  2. Subjected to short circuit calculations.
    3.relay at pumped storage should have operated first.

user x: Line length is too small so go with line differential
user x: Distance relay operational is not much desired for less than 11kms line
user x: As per above pumping station will trip 1st and upstream will trip in zone2 if plcc is there then you can trip it faster
user x: Thank you for the response But sir
But in our this case
Upstream was tripped.

What’s the reasons ?
user x: Ok sir
It’s really helpful for the further process.
user x: Sir..

Upstream will feed because of the fault infeed.. In fact two relays only operate if there is a fault infeed from that particular direction
user x: Are you trying to say upstream tripped first?
user x: No sir
But due to some reason in actual case upstream was tripped instead of downstream
user x: Ok upstream should operate for the reason already explained above

user x: Actually it seems fault is on boundary case and if there is strong feed from upstream then there was a chance for both relays to see in zone1. As line is short CT and PT errors too play major issue

  1. Cable construction is similar to bunch of capacitances interconnected as inter-electrode conductors.
  2. So during voltage application in the used conductor and because of capacitance effect, certain voltage gets develop on the metallic sheath.
  3. Now the development of voltage depends upon the orientation/ geometry of cable like laying, pattern of voltage application etc..
  4. Now to avoid this effect we should follow the following PRACTICES.

A. If cable length is less than 1kms and application of voltage is less than 33kv, then earth the sheath on both side for strengthen of the earth connection.
B. If more than 1kms and less that 3to 4 km, then earth the sheath at one side and use SVL(sheath Voltage Limiter) at the other end.
C. If length more than 4 kms, use cross bonding like transposition of sheath earthing at equal interval of 1/3rd length of total length.

NOTE: Maximum utilities use the practice of sheath EARTHING at one end and use of SVL at the other end. This usually becomes the regular practice.

Others utilities do use can interact on this.
user x: Sir
Can any respected member verify the above facts as true and feasible for Hv cable earthing
user x: Namaste, When sheath is earthed at both ends, there will be flow of sheath current and generation of heat. Because of it, higher capacity cable has to be used. This problem becomes predominant when cable lengths are more. To avoid going for higher capacity cable, sheath currents will be eliminated by keeping other end of sheath unearthed. To limit that other end voltages SVL used. If you have sufficient capacity cable considering sheath currents, you can earth both ends also and it needs no SVL.
user x:
user x: It’s for NIT TRICHY candidates only
user x: Free for NIT students and Paid for others
user x: This message was deleted
user x: This message was deleted
user x: -Is your transmission line stranded and underutilized because power continues to take other parallel routes in the network ?

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-Know about this power flow controller which is modular, scalable, voltage agnostic, easy to install and relocate

On behalf of Sterlite Power, it is my pleasure to cordially invite you to attend our Webinar –

user x : New member from FACTS family”

Date : 4th Feb
Time : 4:00 pm to 5:30 pm

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