Motor Protection

• Trainer: Dr. Saeed Roostaee (Profile)
• Online
• Date: 19 and 20 August 2023
• Platform: Google Meet & Online player
• Last update: 6 August 2023
• Contact us

Course content:

• Basics of Synchronous and Asynchronous Motors
• Motor Nameplate
• Motor Connections
• Motor Faults, Faults, and Protection Functions
• Overview of the Motor Protection Functions
• Motor Overcurrent Protection
• Motor Earth fault protection
• Motor Overload protection
• Motor Voltage protection
• Negative Sequence Protection
• Motor Lock Rotor & Mechanical Jam protection
• Motor Undercurrent protection

Modern numerical motor relay protection technology must be sufficient to meet the protection requirements of any of the vast range of motor designs. A motor protection relay providing sufficient protection will have the following set of characteristics such as extended start relay protection, loss-of-load relay protection, number of starts limitation, stalling relay protection, short circuit relay protection, thermal relay protection, Earth fault relay protection, negative sequence current detection, winding RTD measurement/trip, under-voltage relay protection, auxiliary supply supervision, …

• 14 Speed Switch
• 27 Undervoltage*
• 37 (P,C) Underpower/Undercurrent
• 38 Bearing Temperature*
• 46 Current Unbalance
• 47 Phase Reversal
• 49P PTC Overtemperature*
• 49R RTD Thermal*
• 49T Thermal Model
• 50 (P,G,Q) Overcurrent (Phase, Ground, Neg. Seq.)
• 50P LR Locked Rotor
• 50P LJ Load Jam
• 50N Neutral Overcurrent
• 51 (P,G,Q) Time-Overcurrent (Phase, Residual, Neg. Seq.)
• 55 Power Factor*
• 59P Phase Overvoltage*
• 60 Loss-of-Potential*
• 66 Starts-Per-Hour
• 81 (O,U) Over-/Underfrequency
• 87 Current Differential*
• 90 (P,I,T) Load Control (Power, Current, Thermal Capacity)
• 50/51 Adaptive Overcurrent
• 85 RIO SEL Mirrored Bits® Communications
• DFR Event Reports—Motor Starts, Motor Operating
• Statistics
• ENV Optional SEL-2600 RTD Module*
• HMI Operator Interface
• LDP Load Data Profiling
• LGC SELogic® Control Equations
• MET Metering
• RTU Remote Terminal Unit
• SDTM Slip-Dependent AccuTrackTM Thermal Model
• SER Sequential Events Recorders

• Stator overload protection 49
• Starting time supervision, locked rotor protection 48
• Restart inhibit 66,49R
• Negative-sequence current protection I2> 46
• Thermal unbalanced-load protection I2 2(t) 46
• Temperature measurement 1 38
• Undercurrent protection 37
• Active-power protection (P<) 32U
• Sensitive ground-fault protection 59N,
• non-directional 51Ns
• directional 67Ns
• Overcurrent protection 50, 51
• Current-differential protection 87
• Undervoltage protection 27
• Overvoltage protection 59
• Underexcitation protection 40
• Rotor ground-fault protection 64R
• Frequency protection 81
• Circuit-breaker failure protection 50BF
• User-programmable logic (CFC)
• Control functionality
• Graphic display (large)
• Flexible interfaces
• Frequency operating range (10 Hz – 70 Hz)
• Operational measured values and
• functional measured values

• Three-phase non-directional overcurrent protection, low-stage PHLPTOC 3I> 51P-1
• Three-phase non-directional overcurrent protection, instantaneous stage PHIPTOC 3I>>> 50P/51P
• Non-directional earth-fault protection, low-stage EFLPTOC I0> 51N-1
• Non-directional earth-fault protection, high stage EFHPTOC I0>> 51N-2
• Non-directional earth-fault protection, instantaneous stage EFIPTOC I0>>> 50N/51N

• Directional earth-fault protection, low stage DEFLPDEF I0> -> 67N-1
• Directional earth-fault protection, high stage DEFHPDEF I0>> -> 67N-2
• Rotor earth-fault protection MREFPTOC Io>R 64R
• Negative-sequence overcurrent protection for machines MNSPTOC I2>G/M 46G/46M
• Phase-reversal protection PREVPTOC I2>> 46R
• Three-phase thermal overload protection for motors MPTTR 3Ith>M 49M
• Motor startup supervision STTPMSU Is2t n< 48,66,14,51LR Motor load jam protection JAMPTOC Ist> 51LR
• Emergency start ESMGAPC ESTART ESTART
• Loss of load supervision LOFLPTUC 3I< 37 High-impedance or flux-balance based differential protection for machines MHZPDIF 3dIHi>G/M 87GH/87MH
• Stabilized differential protection for machines MPDIF 3dI>G/M 87G/87M
• Three-phase overvoltage protection PHPTOV 3U> 59
• Three-phase undervoltage protection PHPTUV 3U< 27 Positive-sequence overvoltage protection PSPTOV U1> 47O+
• Positive-sequence Undervoltage protection PSPTUV U1< 47U+ Negative-sequence overvoltage protection NSPTOV U2> 47OResidual
• overvoltage protection ROVPTOV U0> 59G
• Reverse power/directional overpower protection DOPPDPR P> 32R/32O
• Frequency gradient protection DAPFRC df/dt> 81R
• Over frequency protection DAPTOF f> 81O
• Under frequency protection DAPTUF f< 81U Three-phase underexcitation protection UEXPDIS X< 40 Circuit breaker failure protection CCBRBRF 3I>/I0>BF 51BF/51NBF
• Tripping logic TRPPTRC I -> O 94
• Multipurpose analog protection MAPGAPC MAP MAP

• Bay control QCCBAY CBAY CBAY
• Interlocking interface SCILO 3 3
• Circuit breaker/disconnector control GNRLCSWI I <-> O CB/DC I <-> O CB/DC
• Circuit breaker DAXCBR I <-> O CB I <-> O CB
• Disconnector DAXSWI I <-> O DC I <-> O DC
• Local/remote switch interface LOCREM R/L R/L
• Single point control (8 signals) SPC8GGIO
• Double point indication DPGGIO
• Single point indication SPGGIO
• Generic measured value MVGGIO
• Logic Rotating Switch for function selection and LHMI presentation SLGGIO
• Selector mini switch VSGGIO
• Pulse counter for energy metering PCGGIO
• Event counter CNTGGIO
• Supervision and monitoring
• Runtime counter for machines and devices MDSOPT OPTS OPTM
• Circuit breaker condition monitoring SSCBR CBCM CBCM
• Fuse failure supervision SEQRFUF FUSEF 60
• Current circuit supervision CCRDIF MCS 3I MCS 3I
• Trip-circuit supervision TCSSCBR TCS TCM
• Station battery supervision SPVNZBAT U<> U<>
• Energy monitoring EPDMMTR E E
• Measured value limit supervision MVEXP
• Three-phase current measurement CMMXU 3I 3I
• Three-phase voltage measurement (phase-to-earth)
• VPHMMXU 3Upe 3Upe
• Three-phase voltage measurement (phase-to-phase) VPPMMXU 3Upp 3Upp
• Residual current measurement RESCMMXU I0 I0
• Residual voltage measurement RESVMMXU U0 U0
• Power monitoring with P, Q, S, power factor, frequency PWRMMXU PQf PQf
• Sequence current measurement CSMSQI I1, I2 I1, I2
• Sequence voltage measurement VSMSQI U1, U2 V1, V2

• Current Protection: Phase Overcurrent (67, 51, 50)
• Directional Control of Overcurrent Protection (67)
• Overcurrent Protection (50)
• Current Protection: Undercurrent (37)
• Phase Unbalance (46)
• Time Delayed Overcurrent Protection (51)
• Current Protection: Measured Earth Fault (50/51G)
• Directional Control of Measured Earth Fault Protection (67G)
• Measured Earth Fault Protection (50G)
• Time Delayed Measured Earth Fault Protection (51G)
• Current Protection: Derived Earth Fault (50/51N)
• Directional Control of Derived Earth Fault Protection (67N)
• Time Delayed Derived Earth Fault Protection (51N)
• High Impedance Restricted Earth Fault (87REF)
• Voltage Protection: NPS Overvoltage (47)
• Earth Fault Protection (50N)
• Voltage Protection: Under/Over Frequency (81)
• Power Protection – 32
• Sensitive Power Protection – 32S
• Break Capacity Limit (50BCL)
• Phase Reversal (46 PH REV)
• Temperature Monitoring
• CT Supervision (60CTS)
• Power Factor – 55
• Trip Circuit Supervision (74TCS)
• Close Circuit Supervision (74CCS)
• Circuit Breaker Failure (50BF)