Generator protection system by Nicholas Naing
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This document outlines the agenda and topics to be covered in a generator protection system seminar taking place on January 13, 2016 from 1-3pm at the YTU Electrical Power Department. The seminar will include welcome and introduction sessions followed by presentations on generator protection systems, protection functions and their details, and a question and answer section. Protection topics to be covered include generator differential protection, distance protection, ground protection, unbalance protection, loss of excitation protection, inadvertent energization protection, and breaker failure protection. Sample generator protection relay wiring diagrams and configurations for small, medium, and large generators will also be discussed.
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Generator protection system by Nicholas Naing
- 1. Index This Seminar is Proudly Sponsored by : TRUST SYNERGY INTERNATIONAL
- 2. by Nicholas Naing GENERATOR PROTECTION SYSTEM
- 3. Index 1.00 p.m : Welcome Speech by YTU Electrical Power Department Head 1.10 p.m : Introduction to the Speaker 1.15 p.m : Generator Protection Systems 1.50 p.m : Tea Break 2.00 p.m : Protection Functions Detail 2.40 p.m : Question and Answer Section 3.00 p.m : End of Presentation Agenta : 13th JAN 2016 , 1 p.m ~ 3 p.m , YTU
- 4. IndexOverview Generator Abnormal Operating Conditions Loss of Synchronism Abnormal Frequency Over excitation Field Loss Inadvertent Energizing Breaker Failure Loss of Prime Mover Power Blown VT Fuses Open Circuits
- 5. Index The "Wild" Power System G Exciter Loss of Field Loss of Field Overexcitation Overexcitation Overexcitation Open Circuits Loss of Synchronism Inadvertent Energizing, Pole Flashover Abnormal Frequency Abnormal Frequency Breaker Failure Reverse Power Over Power What Really happened ?
- 6. IndexWhat Really happened ? The "Wild" Power System G Exciter Stator Ground Stator Phase System Ground System Phase
- 7. Index Protection Functions • 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
- 8. Index Small Generator Protection (IEEE) 32 Reverse Power 40 Loss of Excitation 51V voltage restraint 51G Ground overcurrent 87 Differential Small Size – up to 1 MW
- 9. Index Medium Generator Protection (IEEE) Medium Size – up to 12.5 MW 32 Reverse Power 40 Loss of Excitation 46 Negative Sequence 51V voltage restraint 51G Ground overcurrent 87 Differential
- 10. Index Large Generator Protection (IEEE) Large Size – Up to 50 MW 32 Reverse Power 40 Loss of Excitation 46 Negative Sequence 49 Thermal Overload 51V voltage restraint 51G Ground overcurrent 64 Ground Relay 87 Differential
- 11. Index Large Generator Protection (IEEE) Large Size – above 50 MW 32 Reverse Power 40 Loss of Excitation 46 Negative Sequence 49 Thermal Overload 51V voltage restraint 51G Ground overcurrent 64 Ground Relay 87 Differential
- 12. Index Sample Generator Protection Relay Wiring
- 13. Index Sample Generator Protection Relay Wiring
- 14. Index Sample Generator Protection Relay Wiring
- 15. Index Sample Generator Protection Relay Wiring
- 16. Index binary w. cable supervision inputs Three-phase V AC (110-690V AC) Three-phase I AC MPU pickup/ Dig. running/ Ana. running Crank Start prepare Run/stop coil Three multi inputs: PT 100/1000, (0)4..20mA, VDO, 0..40V Emergency stop Start enable Sample Generator Protection with Relay
- 17. Index 16 diesel generators15 diesel generators & 1 emergency generator8 bustie breakers2 shaft generators2 shore connectionsWrapped busbar possibillity Sample Generators Parallel Setup
- 18. Index Break
- 19. Index Desirable Attributes of Generator Protection ANSI number Levels Standard Phase sequence voltage 47 1 × Generator reverse power (2×) 32 2 × Generator overcurrent (4×) 50 4 × Voltage-dependent overcurrent 51V 1 × Fast overcurrent (2×) 51 2 × Generator overvoltage (2×) 59 2 × Generator undervoltage (3×) 27 3 × Generator overfrequency (3×) 81 3 × Generator underfrequency (3×) 81 3 × Busbar overvoltage (3×) 59B 3 × Busbar undervoltage (4×) 27B 4 × Busbar overfrequency (3×) 81B 3 × Busbar underfrequency (4×) 81B 4 × Generator overload (5×) 32 5 × Current/voltage unbalance 60 1 × Over excitation 24 1 × Loss of excitation 40 1 × Alarm relay 74 1 × Trip of non-essential load 3 3 groups
- 20. Index Generator Management Relay Sample
- 21. Index Protection Functions Generator Stator Differential (87) • Stator Phase Differential • Dual Slope Percent Restraint Operating Characteristic • Directional Supervision under saturation conditions Distance Protection (21/21N) • set based in percentages of the line impedances • zone 1 is 80% of the impedance of the line in order to not reach the remote end, the • zone 2 can be set at 120% of the impedance of the line in order to dependably overreach the line, • zone 3 sometimes are disabled or set to cover an adjacent line.
- 22. Index Protection Functions Voltage Protection (59) • Phase Overvoltage • Phase Undervoltage • Neutral Overvoltage (fundamental) • Neutral Undervoltage (3rd Harmonic) • Voltage Phase Reversal Voltage Restraint Overcurrent Undervoltage Trip Curves
- 23. Index Protection Functions Current Protection (50) • Phase, Ground and Negative Sequence Overcurrent Tripping • IEC, ANSI , IAC and Customizable Overcurrent Curves • Voltage Restraint increasing sensitivity under low voltage conditions
- 24. Index Protection Functions Frequency Protection (81) • Overfrequency (81O) • Underfrequency (81U) 100% Stator Ground Protection (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
- 25. Index Protection Functions 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
- 26. Index Protection Functions Volt/Hertz (Overexcitation) (40) • Detects changes in the Volts/Hertz ratio of the generator or associated transformer Loss of Excitation Loss of Excitation (24) • Uses Impedance Circle for loss of excitation detection • 2 Zones for fault detection and control
- 27. Index Protection Functions Thermal Protection (49 ) • Generator Thermal Model • RTD Alarming and Tripping • RTD Biased Thermal Model Thermal Model – Voltage Dependen Overload Curves
- 28. Index Protection Functions Inadvertent Energizing (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!
- 32. Index Contact Detail : Nicholas Naing naingwhbiz@gmail.com #KoNaingYIT Electrical Notes by Ko Naing YIT
- 33. Index
- 34. Index THANK YOU