GE Multilin SR489-P5-LO-A20-E Generator Protection Relay
- Product Description: The GE Multilin SR489 is a sophisticated, microprocessor-based Generator Protection Relay. The model SR489-P5-LO-A20-E specifically provides comprehensive protection for medium to large generators (typically 25 MVA and above). It integrates multiple protection functions, metering, monitoring, control, and communication capabilities into a single compact unit. It features a user-friendly LCD interface (LO suffix) for local access and configuration. Its primary role is to detect abnormal operating conditions on a generator and generator step-up (GSU) transformer, initiating a trip signal to isolate the generator quickly to prevent catastrophic damage.
- Product Series: SR Series (Protection Relays) -> SR4xx Series (Generator Protection Relays) -> SR489 Series (Specifically designed for large generator protection).
- Key Features:
- Comprehensive Protection: Integrates numerous generator protection functions (see table below).
- Advanced Differential Protection (87G): High-speed, percentage-restrained differential protection for stator windings.
- Loss of Field (40): Two-zone impedance characteristic protection.
- Stator Ground Fault Protection: Includes 59G (Fundamental neutral overvoltage), 27TN (Third harmonic neutral undervoltage), and optional 64G (Sensitive directional power or subharmonic injection for 100% stator ground).
- Rotor Ground Fault Protection (64F): Field ground detection.
- Overexcitation (24): Volts/Hz protection for generator and step-up transformer.
- Negative Sequence (46): Unbalanced current (I₂) protection for rotor overheating.
- Backup Impedance (21): Distance protection for backup.
- Multifunction Metering: Measures volts, amps, MW, MVAR, MVA, Hz, power factor, energy, etc.
- Sequence of Events Recorder (SER): Timestamped log of events and trips.
- Oscillographic Fault Recorder: Captures waveforms during disturbances.
- Multiple I/O: Configurable contact inputs/outputs, analog outputs.
- Communications: Standard serial ports (RS232/RS485), optional Ethernet (10/100Base-T) and multiple protocol support (Modbus RTU/TCP, DNP 3.0, IEC 60870-5-103/104, IEC 61850 GOOSE/MMS).
- LCD Human-Machine Interface (HMI): Local display for settings, metering, event viewing, and diagnostics (
LOsuffix). - Flexible Logic (FlexLogic™): Allows custom logic equations for advanced control and interlocking.
- Robust Design: High immunity to electrical noise and harsh environments.
- Purpose / Function: To continuously monitor the electrical parameters (current, voltage, frequency, power, impedance, harmonics) of a generator and its associated circuits. Upon detecting a fault condition (e.g., internal short circuit, loss of field, overexcitation, ground fault, unbalanced load, abnormal frequency) or potentially damaging abnormal operating state, the relay will activate its output contacts to trip the generator circuit breaker (GCB) and/or initiate alarms, isolating the generator to prevent severe mechanical and electrical damage.
- Applications & Use Cases:
- Protection of large utility generators in thermal power plants (coal, gas, oil).
- Protection of generators in nuclear power plants.
- Protection of large industrial generators (e.g., pulp & paper, chemical plants, refineries).
- Protection of hydroelectric generators.
- Protection of combustion turbine generators.
- Protection of synchronous condensers.
- Primary protection for the stator windings and backup protection for system faults affecting the generator.
- Application Fields:
- Electric Power Generation (Utilities)
- Independent Power Producers (IPPs)
- Oil & Gas Industry (Offshore/Onshore Platforms, Refineries)
- Heavy Industry (Steel, Cement, Chemical, Pulp & Paper)
- Large Data Centers (Backup Generation)
- Water/Wastewater Treatment Plants
- Mining Operations
- Marine Applications (Large Vessels)
- Product Specifications & Parameters (SR489-P5-LO-A20-E):
|
Category
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Parameter
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Specification (SR489-P5-LO-A20-E)
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Notes
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|---|---|---|---|
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Model Identification
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SR489-P5-LO-A20-E
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P5: Size 5 Case; LO: LCD Operator Interface; A20: 0.5-20A AC Input; E: 120V AC/DC Power
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Power Supply
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Rated Voltage
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120 V AC/DC
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(±15%, 50/60Hz Nominal for AC)
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|
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Power Consumption
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Typically ≤ 25 VA / 20 W (Max)
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Current Inputs
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Phase CT Inputs (Ia, Ib, Ic)
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5A or 1A Nominal (Configurable)
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A20 suffix denotes 0.5-20A AC (Continuous / RMS) input rating. |
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Neutral/Ground CT Input (In, Ig)
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5A or 1A Nominal (Configurable)
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0.5-20A AC input rating.
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Voltage Inputs
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Phase VT Inputs (Va, Vb, Vc)
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67-140V L-N or 120-240V L-L (Nominal) Configurable
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Continuous: 150V L-N / 300V L-L; Max Survive: 250V L-N / 500V L-L RMS
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|
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Auxiliary VT (Vx)
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67-140V L-N or 120-240V L-L (Nominal) Configurable
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Same as Phase VT ratings.
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Frequency Rating
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|
45 – 65 Hz (Nominal Range)
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Operates down to DC for some measurements.
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Protection Functions
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Generator Differential (87G)
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✔ (High-Speed, % Restrained)
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Core protection function.
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|
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Loss of Field (40)
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✔ (Two-Zone Impedance Characteristic)
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|
|
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Stator Ground Fault (59G / 27TN / 64G Option)
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✔ (Fund Overvolt (59G) + 3rd Harm Undervolt (27TN))
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Sensitive Directional Power (64G) or Subharmonic Injection optional.
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|
|
Rotor Ground Fault (64F)
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✔
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Field ground detection.
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|
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Overexcitation (24)
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✔ (Volts/Hz)
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Protects generator & transformer.
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|
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Negative Sequence (46)
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✔ (I₂ Overcurrent / Thermal)
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|
|
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Backup Impedance (21)
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✔
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|
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Over/Under Voltage (59/27)
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✔
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|
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Over/Under Frequency (81O/U)
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✔
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|
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Breaker Failure (50BF)
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✔
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Thermal Overload (49)
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✔
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Reverse Power (32)
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✔
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Phase Overcurrent (51V/51)
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✔ (Voltage Restrained/Restricted)
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|
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Instantaneous Overcurrent (50)
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✔
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|
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Sync Check (25)
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✔ (Optional)
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Output Contacts
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Trip Outputs (Form-C)
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5 (Minimum)
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P5 Case Standard Configuration. Assignable via logic.
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|
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Alarm/Status Outputs (Form-C)
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4 (Minimum)
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P5 Case Standard Configuration. Assignable via logic.
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Output Contact Rating
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250V AC/DC, 5A (Make), 0.3A (Continuous Carry)
|
Resistive Load. See manual for inductive load derating.
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Input Contacts
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Binary Inputs (Status/Control)
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8 (Minimum)
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P5 Case Standard Configuration.
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|
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Input Voltage Rating
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Configurable for 24-250V DC (Opto-isolated)
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Communications
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Serial Port 1
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Front RS232 (Service)
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|
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Serial Port 2
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Rear RS485 / RS232 (Configurable)
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Modbus RTU / IEC 60870-5-103
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Ethernet Port (Optional)
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Rear RJ45 (10/100Base-T)
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Modbus TCP, DNP3.0 TCP, IEC 60870-5-104, IEC 61850 (MMS/GOOSE)
|
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Physical
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Case Size
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Size 5 (
P5) |
Dimensions (H x W x D): ~ 355mm x 160mm x 180mm (14″ x 6.31″ x 7.1″)
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Mounting
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Panel Mount
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Environmental
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Operating Temperature
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-40°C to +70°C (-40°F to +158°F)
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Storage Temperature
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-40°C to +85°C (-40°F to +185°F)
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Humidity
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95% RH Non-condensing
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Standards
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Compliance
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IEEE C37.90, C37.90.1, C37.90.2, C37.91, IEC 60255
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Includes EMI/RFI Immunity, Surge Withstand, etc.
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Approvals
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|
UL 508, CSA C22.2 No. 14, CE Mark
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Important Note: This table provides the core specifications for the SR489-P5-LO-A20-E model. Specific ranges, settings, and availability of optional functions (like Sync Check 25 or specific 64G methods) should always be verified against the latest official GE documentation (GEH-6420 Manual for SR489) and datasheets relevant to the specific hardware and firmware version of the relay. The A20 current input rating (0.5-20A AC continuous) is a key identifier for this model variant.
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