The relay protection device is an equipment that realizes the relay protection function, which refers to an automatic device that can react to the failure or abnormal operation of the electrical components in the power system and act on the circuit breaker to trip or send a signal. It mainly contains the following main links: ①Signal acquisition, that is, the measurement link; ②Signal analysis and processing link; ③Judgment link; ④The output link of the function signal.

In the power system, if there is no fault in the primary system and the protection malfunctions, it will affect the reliable power supply to the user. If the heavy load line malfunctions and trips, it may also cause system oscillation accidents and undermine the safe and stable operation of the system. ; If a short-circuit fault occurs in the system, but the protection refuses to operate, the scope of the accident will be expanded and even the power equipment will be damaged. In order to make the protection really play a role in the protection and control of the power system, the protection as a whole must be in a good operating state, so that the characteristics of the relevant components and equipment are good, the circuit wiring is correct, the fixed value and the action characteristics are correct. Therefore, the inspection quality of protection must be strengthened.

Test principle

When testing in manual mode, first output the initial voltage or current value, and then controlled by the user, press the up and down cursor keys to increase or decrease the value of the variable until the protection device and relay contacts are activated, and then press the cursor key to increase or decrease the value of the variable until the protection device , The relay contact returns.

When testing in automatic mode, first output the initial voltage or current value, and then change the variable forward step by step by a step length (plus step length) until the protection device and relay contacts act, and record the action value; if the return method is " When "start→end→begin", the program will reverse the variable step by step (minus the step length) until the protection device and the relay contact return, and record the return value.

After the test is completed, the test results are displayed on the screen, and the user can save the result file.

The line connection is based on the type of protection device under test and relay (voltage protection, current protection; voltage type, current type), and the coil winding is connected to the corresponding voltage or current output terminal of the device. Connect the action contact of the tested protection device and the action contact of the tested relay to the contact input of the device.