GWPR300-GRE Generator Rotor Earth Fault Protection Relay

Product Functions

Core Protection Functions (ANSI 64R: Rotor Earth Fault Protection)

(ANSI 64R Element 1) Rotor Single Earth Fault Protection (Alarm or Trip Selectable)

• This element adopts the standard ping-pong injection measurement principle to continuously calculate the rotor insulation resistance to earth and the fault position percentage in real time. The protection function is enabled when the excitation voltage exceeds 12 V. Both the earth resistance threshold and the operating time delay support continuously adjustable setting ranges, enabling persistent monitoring of gradual insulation degradation in the excitation winding. Users can select alarm or trip as the output mode.

(ANSI 64R Element 2) Rotor Double Earth Fault Protection (Trip Fixed)

• This element is automatically activated after the single earth fault protection operates. It continuously tracks variations in the fault position percentage. When the position deviation exceeds the preset threshold, the relay outputs a trip signal to stop the generator, avoiding critical faults including rotor winding short-circuit and rotor shaft magnetization.

Measurement & Digital Input Acquisition Functions

• Real-time measured values: Excitation voltage Ue, rotor earth resistance R, and fault position percentage AK;
• Digital input loops: 21 channels of wet contact digital inputs; three rated voltage levels available upon order: AC/DC 220 V, DC 110 V, or DC 48 V;
• Digital output loops: 13 independent dry contact relay outputs, plus one dedicated device power failure signal output; Contact rating: 8 A @ 250 V AC / 8 A @ 30 V DC; Relay operating time ≤ 8 ms, reset time ≤ 5 ms.

Communication & Time Synchronization Functions

• Communication interfaces: Dual Ethernet ports (IEC 104 as default, IEC 61850 MMS optional), one RS485 serial interface (Modbus-RTU protocol);
• Multi-mode time synchronization: Compatible with IRIG-B code synchronization, SNTP network synchronization, and message-based synchronization;
• Print output: Serial port compatible with dot-matrix printers for local printing of protection setting values and fault event records.

Fault Waveform Recording & Analysis Function

• Upon fault occurrence, the relay automatically captures full-process data, recording real-time analog waveforms including excitation voltage, earth resistance and fault position. Waveform data is stored locally in the buffer and can be uploaded to the background SCADA system via communication links or printed locally. This function supports accurate post-fault analysis of earth fault progression and significantly shortens the fault troubleshooting cycle.

Multi-level Access Control Function

• The relay incorporates a two-tier access authority design with independent passwords for user level and administrator level.
• User authority: Only supports data viewing and event query;
• Administrator authority: Allows modification of protection settings, adjustment of communication parameters, and switching of protection function blocks, preventing unit safety hazards caused by misoperation from unauthorized personnel.

Online Self-diagnostics & Early Warning Function

• Continuous full-loop hardware self-diagnostics run after power-on, covering sampling loops, power supply modules, communication ports and relay output circuits. An immediate alarm signal will be triggered once hardware abnormality, loop disconnection or communication interruption is detected. It delivers early warning of equipment faults and prevents failure to operate or maloperation of the protection system.

Technical Parameters

Environmental Parameters

• Operating temperature: −40 °C ~ +70 °C; Storage and transportation temperature: −40 °C ~ +80 °C; Relative humidity: 5 % ~ 90 % (non-condensing).
• 3.2 Rated Electrical Parameters
• Excitation voltage measuring range: 10 V ~ 500 V;
• Auxiliary power supply: Universal AC/DC 100 V ~ 264 V;
• Power consumption: ≤ 10 W under normal operation, peak ≤ 15 W during protection operation.

Measurement & Operating Accuracy

• Protection delay error: ≤ ±5 % or ±35 ms; Digital input state change resolution: ≤ 1 ms;
• Insulation resistance between all conductive circuits to ground and electrically isolated circuits: ≥ 100 MΩ.

EMC Performance

• Compliant with Class A industrial immunity level specified in the IEC 60255 series standards.
• Withstands ±8 kV contact electrostatic discharge, ±15 kV air electrostatic discharge, 4 kV fast transient burst, 4 kV line-to-earth surge, 10 V/m radiated radio frequency electromagnetic field, Class 5 damped oscillatory magnetic field and pulse magnetic field interference.
• Conducted and radiated emission limits meet international standard requirements.

 Insulation & Mechanical Performance

• Circuits with different rated insulation voltages withstand corresponding power frequency dielectric withstand voltage and 1.2/50 μs lightning impulse withstand voltage tests without breakdown or flashover.
• The relay complies with Class I vibration, shock and bump tests per IEC 60255-21. No structural loosening or component detachment occurs after testing, and all protection logic functions remain fully operational.

Product Features

• High-speed & high-precision acquisition and calculation;Simultaneously computes all analog and digital quantities within a single sampling cycle. Equipped with a 16-bit independent ADC and sampling glitch filtering algorithm, providing high measurement accuracy and strong immunity to intense electromagnetic interference in power plants.
• Standardized modular architecture;Independent modular protection function units and hardware plug-ins with flexible optional functions. Convenient for future expansion, on-site maintenance & spare part replacement.
• Full-condition environmental adaptability;Fully sealed enclosure with physical separation of power and signal circuits. Dual-layer EMC design at both hardware and software levels, wide operating temperature range, suitable for humid, dusty and high-magnetic-field power plant sites.
• Multi-link intelligent communication;Dual Ethernet plus RS485 multi-channel communication, compatible with mainstream international power communication protocols. Multiple time synchronization schemes ensure stable and reliable data transmission.
• Convenient local operation & maintenance;Visual human-machine interface with comprehensive test routines, data printing and parameter management functions, greatly improving efficiency of on-site troubleshooting and setting configuration.
• Complete series-matched protection solution;When paired with the GWPR300-GD differential relay (ANSI 87G) and GWPR300-GB backup relay, the whole series adopts unified hardware, communication and operation logic, simplifying model selection for generator protection matching.

Application Scenarios

• Hydro-generator units with ratings ≤ 10 MW and turbo-generator units with ratings ≤ 100 MW;
• Captive power plants, distributed energy stations and main control rooms of medium/small generator units;
• Centralized generator protection panels, local unit protection cabinets and protection systems for prefabricated substations;
• All power generation projects requiring real-time monitoring of excitation circuit insulation and protection against rotor single & double earth faults. Full-range unit fault protection can be realized when matched with the complete GWPR300 series generator protection relays.