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_at_L-3.com 770
565-1556
2
Outline

• Overview
• Theory
• Wiring
• Security

3
Generator Protection
What a Generator looks like
4
Generator Protection
5

• Overview

6
Why Upgrade? Generator and Transformer

• 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

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
Generator Protection

• Internal and External Short Circuits

11
Generator Protection Review

• 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

12
Generator Protection

• Abnormal Operating Conditions

13
IEEE PSRC Survey

• Conducted in early 90s, showed many areas of
  protection lacking
• Unwillingness to upgrade
• Lack of expertise
• To recognize deficiency
• To perform the work
• Generators dont trip (wrong)
• Operating procedures will save the day

PSRC Power System Relay Committee
14
ANSI/IEEE Standards

• 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

These are created/maintained by the IEEE PSRC
IAS They are updated every 5 years
15
Small Machine Protection IEEE Buff Book
32 Reverse Power 40 Loss of Excitation 51V
voltage restraint 51G Ground overcurrent 87
Differential

• Small up to 1 MW to 600V, 500 kVA if gt600V

16
Small Machine Protection IEEE Buff Book
32 Reverse Power 40 Loss of Excitation 46
Negative Sequence 51V voltage restraint 51G
Ground overcurrent 87 Differential

• Medium up to 12.5 MW

17
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

• Large up to 50 MW

18
Large Machine ProtectionIEEE C37.102

• Unit Connected,
• High Z Grounded

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
Desirable Attributes - Generator

• 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

26
Desirable Attributes - Generator

• 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!

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

33
(No Transcript)
34
(No Transcript)
35
(No Transcript)
36
(No Transcript)
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
39
Questions?