GE SR745-W3-P5-G5-HI Transformer Protection Relay

GE SR745-W3-P5-G5-HI Transformer Protection Relay

Product Overview

GE SR745-W3-P5-G5-HI is a high-precision, multifunctional digital transformer protection relay launched by General Electric (GE), designed specifically for power transformers in power systems. It undertakes the core responsibilities of transformer fault detection, protection action triggering, and operation status monitoring. This relay integrates advanced microprocessor technology and digital signal processing algorithms, which can quickly identify and accurately judge various types of faults such as short circuit, overload, grounding, differential, and gas in transformers. At the same time, it has complete communication functions and data recording capabilities, and can seamlessly connect to the power system automation network, providing comprehensive guarantees for the safe and stable operation of transformers. It is widely used in scenarios such as power stations, substations, and industrial distribution networks, and is compatible with various types of power transformers such as oil immersed and dry-type.

Core functions and advantages

1. Comprehensive protection function coverage

SR745-W3-P5-G5-HI integrates various core functions required for transformer protection, forming a complete protection system: firstly, differential protection function, which quickly identifies internal short-circuit faults by comparing the current difference on both sides of the transformer, with an action time of ≤ 10ms; secondly, overcurrent protection (including timed and inverse time limits), providing graded protection for overload, external short-circuit and other faults; The third is grounding protection, which is suitable for high current grounding systems and low current grounding systems, and can accurately detect single-phase grounding faults; The fourth is the gas protection interface, which can be connected to gas relay signals to achieve dual protection against internal faults in oil immersed transformers; In addition, it also has auxiliary functions such as overvoltage, undervoltage, and temperature protection, covering the operational risks of transformers in all aspects.

2. High precision signal acquisition and fast response

The relay adopts a 16 bit high-precision ADC (Analog to Digital Converter) and a high-speed digital signal processor, with current and voltage measurement accuracy of ± 0.2% and frequency measurement accuracy of ± 0.01Hz, which can accurately capture subtle changes in the operating parameters of the power grid. For fault signals, it has excellent fast response capability, with differential protection action time as fast as 5ms, far superior to traditional relays, effectively shortening the duration of faults, reducing the degree of transformer equipment damage, and reducing the risk of fault expansion.

3. Flexible fixed value configuration and adaptive capability

This relay supports multiple sets of protection setting group storage and switching, and can quickly call the corresponding protection setting according to different operating conditions of the transformer (such as no-load operation, load operation, maintenance status), adapting to complex power grid operation requirements. At the same time, it has adaptive function, which can automatically compensate for the impact of factors such as grid frequency fluctuations and CT (current transformer) saturation on protection accuracy, avoid protection misoperation or refusal to operate, and improve protection reliability.

4. Improved communication and data management capabilities

Relays are equipped with rich communication interfaces, supporting various communication methods such as RS485 and Ethernet, and compatible with mainstream power communication protocols such as IEC 61850, Modbus, DL/T 645. They can be directly connected to SCADA systems and substation integrated automation systems to achieve real-time uploading of protection action information and operating parameters, as well as receiving remote control commands. In addition, it has a built-in large capacity data storage that can record key operational data (such as current and voltage waveforms) and protection action events before, during, and after faults, with a recording capacity of over 1000 records, providing strong basis for fault analysis and tracing.

5. Industrial grade reliability and environmental adaptability

The product adopts industrial grade high stability components and modular design, with strong anti-interference ability. It has been certified by electromagnetic compatibility standards such as GB/T 14598.10 and can resist interference such as grid harmonics and electromagnetic radiation. Its working temperature range covers -25 ℃~70 ℃, and its relative humidity adaptation range is 5%~95% (without condensation). It can operate stably in high temperature, humid, and dusty substation environments. At the same time, the relay has a complete self checking function, which can monitor the real-time running status of hardware circuits and software programs, and issue alarm signals in a timely manner when abnormalities are detected.

6. Convenient operation and maintenance design

The relay is equipped with a Chinese LCD display screen and user-friendly operation buttons. Operators can intuitively view operating parameters, protection settings, and fault information, and complete operations such as setting value modification and protection switching through buttons. It supports local or remote configuration and firmware upgrades through dedicated software, simplifying maintenance processes. In addition, the relay adopts a standardized drawer type installation structure, which is easy to install and disassemble, and convenient for on-site maintenance and replacement.

Key technical parameters

Product Model

SR745-W3-P5-G5-HI

Applicable transformer types

Oil immersed and dry-type power transformers (capacity ≥ 100kVA)

Rated current (CT secondary side)

5A or 1A (configurable)

Rated voltage (PT secondary side)

100V (line voltage), 57.7V (phase voltage)

rated frequency

50Hz/60Hz (adaptive)

measurement accuracy

Current and voltage: ± 0.2%; Power: ± 0.5%; Frequency: ± 0.01Hz

Differential protection action time

≤ 10ms (internal fault)

Overcurrent protection action time

Time limit: 0.05s~10s (adjustable); Inverse time limit: compliant with IEC 60255-3 standard

Ground protection sensitivity

Small current grounding system: ≤ 5A (primary side); High current grounding system: ≤ 10A (primary side)

communication interface

1 RS485, 2 Ethernet (RJ45)

communication protocol

IEC 61850, Modbus RTU/TCP, DL/T 645

working power supply

DC 220V/110V or AC 220V (optional, allowing ± 20% fluctuation)

power consumption

≤ 15VA (AC power supply); ≤ 10W (DC power supply)

Working environment temperature

-25 ℃~70 ℃ (operating); -40 ℃~85 ℃ (storage)

humidity range

5%~95% (no condensation)

Output contact capacity

AC 250V/5A, DC 30V/5A (passive contacts)

Installation method

Drawer style installation (compliant with IEC 60255-23 standard)

Applicable scenarios

SR745-W3-P5-G5-HI, with its comprehensive protection function, high-precision detection capability, and good compatibility, is widely used for transformer protection in various power systems and industrial scenarios. Typical applications include:

-Power plants: Main transformers and auxiliary transformers for thermal power plants, hydropower plants, photovoltaic power plants, etc. are protected to ensure the safe and stable connection between the power generation system and the power grid;

-Substation: Protection for distribution transformers and contact transformers in 110kV, 35kV, and 10kV substations to prevent the spread of faults and their impact on power supply in the grid;

-Industrial enterprises: self-produced power plant transformers and workshop power transformers for large industrial enterprises such as steel, chemical, metallurgical, etc., to ensure the continuity of production electricity supply;

-Rail transit: traction transformers and step-down transformers for subway, light rail and other rail transit systems, adapted to the characteristics of large load fluctuations in rail transit;

-Commercial and civil buildings: Protection of distribution transformers in large shopping malls, office buildings, and residential areas to ensure electrical safety for both civilian and commercial use.

Installation and usage precautions

Before installation, it is necessary to confirm that the relay model SR745-W3-P5-G5-HI matches the transformer parameters (capacity, voltage level, wiring method), and verify that the product nameplate information is consistent with the design requirements;

2. The installation location should be chosen in a ventilated and dry area, away from strong magnetic fields (such as large transformers and reactors) and high-temperature heat sources, avoiding direct sunlight and ensuring good heat dissipation of the relay;

3. Before wiring, the power supply of the relevant primary equipment and secondary circuit must be cut off. CT, PT circuits, power circuits, trip circuits, and communication circuits must be strictly connected according to the wiring diagram to ensure that the wiring is firm and the phase is correct. Open circuits are strictly prohibited on the CT secondary side, and short circuits are strictly prohibited on the PT secondary side;

4. Shielded cables should be used for CT and PT circuit wiring, with the shielding layer grounded at one end to reduce the impact of electromagnetic interference on measurement and protection accuracy; The tripping circuit wiring needs to undergo insulation testing, and the insulation resistance should be ≥ 10M Ω;

Before putting into operation, it is necessary to configure the protection settings through the operation panel or configuration software, including differential current, overcurrent settings, action time limits, grounding protection sensitivity, etc. The setting configuration must strictly follow the power system protection regulations;

After completing the fixed value configuration, protection function testing is required to verify the accuracy and reliability of relay protection actions by simulating various fault signals (such as differential current, overcurrent);

During operation, it is necessary to regularly check whether the operating parameters (current, voltage, power, etc.) displayed on the relay display screen are normal, check the status of the indicator lights, and confirm that there are no alarm signals; Regularly (recommended every six months) check the fixed value of the relay, conduct functional testing, and inspect the communication link;

8. During maintenance, it is necessary to first disconnect the working power supply and related secondary circuits of the relay. It is forbidden to plug or unplug modules with power on or modify the settings; When handling faults, the fault information (such as alarm codes and action events) should be recorded first, and then troubleshooting should be carried out to avoid arbitrary changes to the configuration.