How to debug relay protection

Relay protection is an extremely important part of the power system. Its main function is to quickly and reliably remove the faulty part from the power system when the power system fails or runs abnormally, so as to ensure the safety of power equipment and people and maintain the stability and normal operation of the system. In order to ensure that the relay protection device can play its role accurately and quickly, the debugging of relay protection is particularly important. This paper will introduce the debugging methods and steps of relay protection in detail.

First, the significance of relay protection debugging

As the "security guard" of power system, the correct action of relay protection device is directly related to the security and stability of the whole system. Debugging is a key link before relay protection is put into operation. Through debugging, it can verify whether the performance of the protection device meets the design requirements, ensure that it can act accurately when faults occur, and prevent misoperation or refusal.

Second, the preparatory work before relay protection debugging

1. Data preparation: including schematic diagram, setting list, instruction manual and relevant technical specifications of the protection device.
　　. Tools and instruments preparation: such as relay protection tester, multimeter, insulation resistance tester, DC power supply, etc.

3. On-site inspection: confirm that the protection device is installed correctly, the wiring is correct, the grounding is good, and the secondary circuit is firmly connected.

4. Setting value check: preliminarily set the protection setting value according to the setting value list issued by the dispatcher.

Third, the main content of relay protection debugging

1. Appearance and wiring inspection

-Check whether the outside of the protection device is intact and there is no obvious damage.

-Check whether the secondary wiring meets the requirements of the drawings and whether the terminals are fastened.

2. Insulation test before electrification

-Use a megger to measure the insulation resistance between each circuit of the protection device to ensure that it meets the insulation requirements.

-Measure the insulation between DC circuit and ground to prevent ground fault in operation.

3. AC loop test

-Connect rated voltage and current, and check whether AC sampling is correct.

-Verify that the polarity of current transformer (CT) is correct and the transformation ratio is matched.

4. Fixed value setting

-Input the setting value according to the setting value list issued by the dispatcher.

-Check after input to avoid input errors.

5. Protection function test

-Using relay protection tester to simulate various fault types (such as short circuit, overcurrent, quick break, grounding, etc.).

-Observe whether the protection device acts correctly according to the set value, and record the action time and value.

-For the microcomputer protection device, it is also necessary to check whether its communication function and wave recording function are normal.

6. Linkage test

-After the protection action, check whether the switch can trip correctly.

-Verify whether the signal loop and alarm loop respond correctly.

7. Records and reports

-All test data shall be recorded in detail during debugging.

-Prepare the commissioning report and submit it to relevant departments for filing.

Fourth, matters needing attention

-During debugging, safety regulations should be strictly observed and safety measures should be taken, especially to prevent equipment damage or personal injury caused by misoperation.
　　-Debuggers should have corresponding professional knowledge and work experience to ensure the accuracy of the test.

-If any abnormality is found, it shall be handled in time, and relevant tests shall be conducted again until the requirements are met.

tag

Relay protection debugging is a highly technical and professional work, which is related to the safety and stability of the whole power system. Only by carefully debugging in strict accordance with the regulations can we ensure that the relay protection device "does not refuse to move, does not move well" at critical moments and truly plays its role as a "safety line". With the continuous improvement of the automation level of power system, the relay protection technology is also improving, and the debugging method should also keep pace with the times to continuously improve the scientificity and effectiveness of debugging.