Power System Protection for Beginners

• #100 @Course Code
• Power System Protection for Beginners
• Course Creation: December 2025
• Instroctor: Dr. Saeed Roostaee
• Total time till now: 3 hours 25minutes
• This course is under recording, please join our WhatsApp group for updates: https://elec-engg.com/updates/

Chaper 1: HV

A: Power Generation and Transmission

• Basic overview of Generation and transmission
• Power System components
• World electricity generation
• Single Line Diagram (SLD)
• Power Generation Technologies
• Hydro-Electric Power
• Hydeo Power Plant in India
• Fossil fuel power
• Coal Power Station in India
• Nuclear power generation
• How does a Thermal power plant work?
• Wind energy
• Solar power
• Power Grid Infrastructure
• Electrical grid
• India National Grid Map (N, NE, S, W, E)
• European-wide synchronous grid
• National Grid

B: Substation and Its Components

• HV substation in India
• Type Of Substations
• Elements of Substation
• Power Line
• Ground wire
• Wave trap
• Potential transformer
• Disconnect switch
• Earth switch
• Circuit breaker
• Current transformer
• Lightning arrester
• Main transformer
• Substation Layout
• 400/63/20 kV substation layout
• General Single Line Diagram (SLD)
• Protection Single Line Diagram (PSLD)

C: Type of Busbar Configurations

• Single Bus-Bar Arrangement
• Single Bus-Bar Arrangement with Bus Sectionalized
• Main and Transfer Bus Arrangement
• Double Bus Double Breaker Arrangement
• Double Bus Single Breaker Arrangement
• One and a Half Breaker Arrangement

D: GIS substation

• GIS history
• GIS Vs. AIS
• GIS installation
• Maintenance
• GIS elements

E: Instrument transformers

• Why are instrument transformers needed
• Voltage/Potential Transformers (VT/PT)
• Current Transformers (CTs)
• Basic working principle
• Bushing CT
• Free-standing CT
• Pass-through CT
• Window-type CT
• Bar-type CT
• Wound type CT
• High voltage CT
• Tank type CT
• Top-core CT
• CT Ratio
• CT Polarity
• Excitation
• CT circuits
• VT circuits
• Metering Core
• Protection Core
• CT classes
• CT shorting block

Chaper 2: LV

A: Control & Protection Panel

• Introduction to Control Protection & Metering System
• Type of Panels & their usage
• Panel Construction & Components
• Control Panel
• Synch check
• Panel Accessories and Components
• Terminal Blocks
• Metering Components
• Wiring Components
• Control Switches
• Protection Relays
• Automation Components
• Protection Panel
• TCS Relay
• Trip Relay
• Lockout Relay
• Annunciator
• Electromechanical Relays
• Static Relay
• Numeric Relays
• BI/BO, AI/AO, CT/PT, NO/NC, Communication Ports.

B: Schmeatic Diagram

• Introduction to Electrical Drawing
• Typical Electrical Drawing Symbols
• One-Line Diagrams (Single-Line Diagrams)
• Overview of CRP Schematics
• Connected line or wires
• Wattmeter
• Varmeter
• Opened contact
• Closed contact
• Current transformer
• Current transformer with marked polarity
• Ammeter
• Voltmeter
• Thermal relay
• Three-winding three-phase transformer
• Overlap Line or wire
• NO contact
• NC contact
• Coil
• Emergency switch
• Contactor
• Changeover
• Selector Switch
• Push button
• Power factor meter
• Frequency meter
• Therma OL relay
• Timer
• Terminal
• Auxilary contactor
• Panel and Equipment Layout

C: Protection Classification, Types & ANSI Codes

• Common Acronyms
• ANSI Standard Device Numbers
• 21 Distance Relay
• 21G Ground Distance
• 21P Phase Distance
• 24 Volts-per-Hertz Relay / Overfluxing
• 25 Synchronizing or Synchronism-Check Device
• 27 Undervoltage Relay
• 27P Phase Undervoltage
• 32R Reverse Power
• 46 Reverse-Phase or Phase Balance Current Relay or Stator Current Unbalance
• 49 Machine or Transformer Thermal Relay
• Thermal Overload 50 Instantaneous Overcurrent Relay
• 50BF Breaker Failure 50N Neutral Instantaneous
• Overcurrent 51 Time Overcurrent Relay
• 51N Neutral Time Overcurrent
• 51V Voltage-Resistant Time Overcurrent
• 59 Overvoltage Relay
• 67 Directional Overcurrent Relay
• 67N Neutral Directional Overcurrent
• 79 Ac Reclosing Relay / Auto Reclose
• 81O Over Frequency
• 81U Under Frequency
• 86 Locking-Out Relay
• 87 Differential Protective Relay
• 87B Bus Differential
• 87G Generator Differential
• 87GT Generator/Transformer Differential
• 87L Line Current Differential
• 87RGF Restricted Ground Fault

D: PSLD (Protection Single Line Diagrams)

• Transformer protection single line diagram
• Line protection single line diagram
• Busbar protection single line diagram
• Feeder protection single line diagram

Chaper3: Faults

A: Faults

• Normal Operation of Power System
• Abnormal Condition of Power System
• What is the fault
• Abnormalities
• Types of faults
• Faults in Windings
• Symmetrical fault
• Unsymmetrical faults
• Fault statistics
• Transmission Line Faults
• Earth Fault on H.V. External Connections
• Phase-to-Phase Fault on H.V. External Connections, Internal Earth Fault on H.V. Windings
• Internal Phase-to-Phase Fault on H.V. Windings Short Circuit Between Turns H.V. Windings
• Earth Fault on L.V. External Connections
• Phase-to-Phase Fault on L.V. External Connections, Internal Earth Fault on L.V. Windings
• Internal Phase-to-Phase Fault on L.V. Windings Short Circuit Between Turns L.V. Windings
• Faults in Generators
• Generator Stator Earth Fault
• Generator internal faults
• Faults due to the load
• Overload
• Unbalance Load
• Loss of field

B: Fault Simulation and Studies

• Fault calculations
• Symmetrical Components
• ETAP
• DIgSILENT PowerFactory
• PSCAD
• Single-phase fault simulation
• Three-phase fault simulation
• Earth fault simulation

C: Criteria for fault detection

• Overcurrent I>
• Earth-current IE>
• Current unbalance (negative sequence current I2>)
• Undervoltage U<
• Overvoltage U>
• Over- and Under-frequency
• Leakage (Differential) current
• Underimpedance Z<

Chapter 4: Protection

A: Protection Introduction

• Importance of the Protection System
• What do we want to protect?
• Function of protection systems
• Requirements for system protection
• Elements of a Protection System
• Primary Protection
• Backup Protection
• Zones of Protection
• Primary and Backup Protection
• Protection Relay History
• Electromechanical Relay
• Static Relays
• Numerical Relays

B: Numerical Relays

• Numerical Relays
• Advantages of Numerical Relays
• Structure of Numerical Relays
• How do Numerical Relays work?
• Analog to Digital Conversion
• Digital Phasor Measurement
• Example Feeder protection
• Numerical Relay Manufacturers

C: Relay Selection Guide

• Available Device Types
• Fields of Application
• Medium-Voltage Application
• Transformer Protection
• Generator Protection
• Line Protection
• Busbar Protection

Chapter 5: SIPROTEC 5 Online Mode

A: Online Mode

• Relay Offline Vs. Online Mode
• Device Information
• Config Information
• Process Mode
• Commissioning Mode
• Simulation Mode
• Edit device time
• Copy the online device to the project
• Assign an online device to the project
• Change the assigned device
• Create a backup from a device
• Load the Configuration to the device
• Retrieve Device Data

B: SIPROTEC 5 Web UI

• Device Information
• Relay Hardware and order code
• Set the relay date and time in the web UI
• Monitor Relay Displays
• Monitor binary inputs
• Monitor Binary outputs
• Monitor LEDs
• Access to all LOGs and download LOGs
• Runtime Data
• Monitor the recorded fault in the web UI
• Manual Recording trigger
• Download relay fault records
• Measurements
• Check the relay setting values
• Change settings
• Apply settings

C: Relay measurements

• Operational measured values
• Fundamental Components
• Symmetrical Components
• Function-specific measured values
• Energy metered values
• Statistical values
• Primary values
• Secondary values
• Snapshot
• Inject the three-phase values into the relay and monitor the relay measurements

D: Logs and Indications

• Reading Indications from the PC
• Operational Log
• Fault Log
• Ground-Fault Log
• User-defined Logs
• Config Logs in the matrix
• Download Logs
• Time stamp
• Relative time
• Entry Number
• Function Structure
• Signal name
• Signal Value
• Signal Quality

E: Fault Recorder

• Fault Recorder Function
• Fault recording with Pickup
• Fault recording with Pickup & AR cycle
• Storage settings
• Pre-fault time parameter
• Post-fault time parameter
• Sampling Frequency
• Fault recorder config
• Download fault records
• Comtrade format
• COMTRADE Viewer
• Time signals
• Harmonic signals
• Binary signals
• RMS and Instantaneous values

Chapter 6: OC Protection Functions

A: Overcurrent 50/51

• SIPROTEC 5 Over current config
• Overcurrent DT element (ANSI 50)
• Overcurrent IT element (ANSI 51)
• Threshold parameter
• Operate the delay parameter
• Overcurrent curves
• Method of measurement
• Time dial parameter
• OC logic in SIPROTEC 5
• Block OC

B: Overcurrent Earth 50N/51N

• Introduction to the Earth fault protection function
• IE calculation
• IE measurements
• Config earth fault protection
• Logic Diagram
• Threshold
• Operate delay

C: Directional Overcurrent 67

• Why Directional overcurrent protection
• How to configure Directional overcurrent protection ANSI 67 in SIPROTEC 5
• Voltage Connection
• Forward direction
• Reverse direction
• Blk. by meas.-volt. failure

D: Directional Overcurrent Earth 67N

• How does 67N work?
• How to configure 67N?
• IN measured
• 3I0 calculated
• Forward direction
• Reverse direction

Supplementary files:

We’ve gathered a library of helpful resources (PDFs, diagrams, videos, and more) for this course and attached them as free resources to support your study.

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