With the continuous development of the power system, the requirements for relay protection and automatic devices are becoming increasingly high. The relay protection device is located at the end of the power grid and is directly connected to high-voltage equipment, playing a crucial role in the safe and stable operation of the power system. Based on the understanding of the current operation of relay protection devices, there is a high possibility of accidents caused by operating conditions and production quality issues, especially when there are phase problems with voltage and current, the harm is even greater. Phase and frequency errors are important indicators of power quality, and phase angle is an important physical quantity that reflects the magnitude and direction of alternating current. For asymmetric short circuits and single-phase short circuits, correct indication of phase is particularly important.

　　

1Jibao InstrumentThe function and function of

　　

Relay protection calibrator is a testing instrument that ensures the correct operation of relay protection and automatic devices, and improves the operational level of relay protection devices. Its main functions include: testing the static and dynamic characteristics of relay protection and automatic devices; Check and verify secondary protection devices such as transistors, integrated circuits, and microcomputers; Conduct corresponding simulation experiments to check and verify the setting schemes, logic circuits, etc. of relay protection and automatic devices. Through the testing of relay protection devices, problems with relay protection and automatic equipment can be identified, and preventive measures and improvement plans can be proposed to avoid similar accidents. For example, the accident of partial collapse of the 220kV system and power outage caused by the refusal of 220kV busbar differential protection in a certain factory is a good example. Although the factory has undergone multiple technological transformations and equipment upgrades, the occurrence of this accident indicates serious problems in the management of relay protection and automatic devices.

　　

2. The concept of phase

　　

Phase is an important physical quantity that reflects the magnitude and direction of alternating current. For asymmetric short circuits and single-phase short circuits, correct indication of phase is particularly important. Phase measurement is an important component in the testing of relay protection devices. Use a phase meter to test the phase during testing, and use a relay protector to test the magnitude and phase of voltage and current. The values measured by the voltage transformer and the three current transformers differ by 180 degrees in phase. The voltage phase is recorded as 0 degrees from the phase point to the midpoint, with a current difference of one power angle indicating lead and a current difference of one negative angle indicating lag. For various protections, a phase difference of 90 degrees between voltage and current is required to accurately reflect the fault type and trigger tripping.

　　

3. Phase angle range

　　

For testing various relay protection devices, in addition to testing according to the requirements of the testing guidelines, it is also necessary to conduct simulated constant value testing based on actual operating conditions. For example, selective debugging and testing of fault types; Perform setting value verification on changes in system operation mode; Simulate and verify the action process of the device under certain operating modes; Verify the range of variation for some important parameters; and so on. In practical operation, it is necessary to carefully check the operating status of various faults generated under various operating modes, as well as the various signal displays and position statuses of the device after the occurrence of various types of faults, in order to verify their correctness.

　　

In short, the phase testing of the relay protection calibrator plays an indispensable role in the power system.