Generator Management Relay

1. Generator Management Relay Protection, metering, and monitoring functions for generators. Presented by: John Levine, P.E. Levine Lectronics and Lectric, Inc. John@L-3.com 770 565-1556

2. Overview Theory Wiring Security Outline

3. What a Generator looks like Generator Protection

4. Generator Protection

5. Overview

6. Existing generator and transformer protection (more than 5 years or non-digital) may: Cause protection security issues Tripping on through-faults, external faults, swings, load encroachment and energizing May lack comprehensive monitoring and communications capabilities Not provide valuable forensic info that can lead to rapid restoration Not be up to ANSI/IEEE Standards! Insurance, Asset Reliability and Personal Liability Issues C37-102: Guide for the Protection of Synchronous Generators C37.91: Guide for Transformer Protection Why Upgrade? Generator and Transformer

7. Generator Management Relay Product Overview • Ideal Protection for Induction and Synchronous Generators at 25, 50 and 60Hz • Complete Generator Protection including: • Generator Stator Differential • 2 or 3 Zone Distance Backup • 100% Stator Ground • High speed sampling, 12 samples per cycle • Drawout Case Installation • Powerful Fault Recording: Waveform, Sequence of Events • Ethernet and Serial Communications • Metering of all important parameters

8. Theory

9. Show Generator Theory General Overview and Typical System from Training CD

10. Internal and External Short Circuits Generator Protection

11. Abnormal Operating Conditions Loss of Synchronism Abnormal Frequency Overexcitation Field Loss Inadvertent Energizing Breaker Failure Loss of Prime Mover Power Blown VT Fuses Open Circuits Generator Protection Review

12. Abnormal Operating Conditions Generator Protection

13. Conducted in early ’90s, showed many areas of protection lacking Unwillingness to upgrade: Lack of expertise To recognize deficiency To perform the work “Generators don’t trip” (wrong) Operating procedures will save the day IEEE PSRC Survey PSRC = Power System Relay Committee

14. Latest developments reflected in: Std. 242: Buff Book C37.102: IEEE Guide for Generator Protection C37.101: IEEE Guide for AC Generator Ground Protection C37.106: IEEE Guide for Abnormal Frequency Protection for Power Generating Plants ANSI/IEEE Standards These are created/maintained by the IEEE PSRC & IAS They are updated every 5 years

15. Small – up to 1 MW to 600V, 500 kVA if >600V Small Machine Protection IEEE Buff Book 32 Reverse Power 40 Loss of Excitation 51V voltage restraint 51G Ground overcurrent 87 Differential

16. Medium – up to 12.5 MW Small Machine Protection IEEE Buff Book 32 Reverse Power 40 Loss of Excitation 46 Negative Sequence 51V voltage restraint 51G Ground overcurrent 87 Differential

17. Large – up to 50 MW Small Machine Protection IEEE Buff Book 32 Reverse Power 40 Loss of Excitation 46 Negative Sequence 49 Thermal Overload 51V voltage restraint 51G Ground overcurrent 64 Ground Relay 87 Differential

18. Unit Connected, High Z Grounded Large Machine ProtectionIEEE C37.102 32 Reverse Power 40 Loss of Excitation 46 Negative Sequence 49 Thermal Overload 51V voltage restraint 51G Ground overcurrent 64 Ground Relay 87 Differential

19. HYBRID SYSTEM

20. Protection Functions • Protection Functions Include: • Generator Stator Differential • Backup Distance Protection • 100% Stator Ground • Generator Unbalance • Loss of Excitation • Accidental Energization • Breaker Fail • Phase Overcurrent – Voltage Restraint • Neutral Inst. / Timed Overcurrent • Neg. Sequence Overcurrent • Under / Over Voltage • Under / Over Frequency • Generator Thermal Model • RTD Temperature • Overexcitation – Volts/Hertz

21. Generator Protection

22. Generator Protection with GSU Wrap PTs on Low Side

23. Generator Protection with GSU Wrap PTs on High Side

24. Generator Protection PTs on Low Side

25. Reverse Power (32) Should be sensitive to 0.05 pu to properly detect motoring in large steam turbines Existing E/M and Static relays not sensitive enough May cause shutdown difficulties Negative Sequence (46) Should be sensitive to low values to detect open poles/conductors on system after GSU Existing E/M and Static relays not sensitive enough Long time low level events may cause excessive rotor heating, thermal tripping and damage rotor 100% Stator Ground (59N / 59D) Protects all of the stator winding Existing schemes typically only see 90% Stop low level fault near neutral from degrading into a high level fault and causing large amounts of damage Very secure Desirable Attributes - Generator

26. Inadvertent Energizing (50/27) High speed tripping of unit after breaker accidentally closed on dead machine, also pole flashover prior to syncing Most existing schemes do not incorporate Many schemes fail due to complexity (reliance on breaker auxiliary switches, yard distance relays, etc. If breaker is not tripped rapidly, mechanical and electric damage can occur to machine in fractions of a second! Pole flashovers must be cleared by high speed breaker failure, as the breaker is open! Desirable Attributes - Generator

27. Line – Ground faults – Delta Connected Generator

28. Line – Ground faults – Wye Connected Generator

29. Protection Functions Generator Stator Differential • Stator Phase Differential • Dual Slope Percent Restraint Operating Characteristic • Directional Supervision under saturation conditions Distance Backup Protection • 2 or 3 Zone Mho Distance Protection • Backup for primary line protection • Configurable Reach and Angle Distance Characteristic Dual Slope Phase Differential 100% Stator Ground Protection • 95% Fundamental OverVoltage • 15% Third Harmonic UnderVoltage Two Zone Distance Backup

30. Protection Functions Voltage Protection • Phase Overvoltage • Phase Undervoltage • Neutral Overvoltage (fundamental) • Neutral Undervoltage (3rd Harmonic) • Voltage Phase Reversal Current Protection • Phase, Ground and Negative Sequence Overcurrent Tripping • IEC, ANSI , IAC and Customizable Overcurrent Curves • Voltage Restraint increasing sensitivity under low voltage conditions Voltage Restraint Overcurrent Frequency Protection • Overfrequency • Underfrequency Undervoltage Trip Curves

31. Protection Functions Thermal Protection • Generator Thermal Model • RTD Alarming and Tripping • RTD Biased Thermal Model Inadvertent Energization • Prevents Accidentally Closing a Stopped Generator onto a Live Line • Armed when Generator is Offline and Voltage is below a pre-set level Thermal Model – Voltage Dependant Overload Curves Loss of Excitation (show Training CD) • Uses Impedance Circle for loss of excitation detection • 2 Zones for fault detection and control Volt/Hertz (Overexcitation) • Detects changes in the Volts/Hertz ratio of the generator or associated transformer Loss of Excitation

32. Wiring

37. Example

38. Enhanced Security Prevents Unauthorized Access and Provide Traceability • Security Audit Trail • Date and time of hardware, firmware or setting changes to your relays • Logging of the MAC address of computers and users making settings changes • Track method of how settings changes were made (i.e. keypad, serial port, ethernet) • Date/time security report was generated • Description of the GE Multilin Relay • Summary of the last time the configuration was changed • History of last 10 occurrences the configuration was changed Security strategy – conforms to industry and regulated guidelines