During the use of power detection equipment, there are certain precautions that need to be noted. Below, experts from Guodian Xigao provide examples to introduce the precautions for the microcomputer relay protection tester.
Important points to note during the communication test assessment
When testing conventional relays, the “switch position change confirmation time” should be set to a larger value, such as around 20ms. If the returned value error is too large during the test, it might be due to excessive contact jitter of the relay. In such cases, the “manual” mode can be selected to complete the test. When testing the action time of the relay, the AC quantity output by the tester should be greater than the startup value of the protection to ensure reliable operation of the protection.
When testing multi-stage overcurrent protection, it is usually done segment by segment. That is to say, when setting the value for stage I, stage II and stage III are all deactivated, and then the current is gradually increased until the protection is triggered. In this way, the measured action time is often inaccurate. When measuring the action time, it is better to directly output the set action value (1.2 times or more for low-voltage protection and below 0.8 times) from the test instrument to ensure that the protection can be activated and triggered. In this way, the measured action time will be more accurate.
When testing the distance protection, the short-circuit impedance must be less than the set value for the protection to trip. Therefore, for the test, the value is generally set at 0.95 times the set value to ensure that the protection can trip reliably. When simulating a grounding distance fault, the zero-sequence compensation coefficient must be set correctly.
When verifying the zero-sequence current setting value, it is necessary to distinguish whether the setting value given in the setting value sheet is for 3I0 or I0. If it is the setting value for I0, there will be a display in the lower left corner of the test module. If it is the setting value for 3I0, then multiply the I0 value displayed in the lower left corner by 3 to see if it is the same as the setting value. For the verification of distance and zero-sequence protection setting values, there is a dedicated verification module later, which will make the testing more convenient. Regarding this part of the software, it will be introduced later.
When testing the low-frequency protection, the frequency can be variable. The step size of the frequency change should be set according to the accuracy requirements. It is better to use the “automatic” mode to complete this, because there is a df/dt lock value for low frequency, and it is difficult to control manually. The frequency should decrease from 50 all the way down to the point where the protection action occurs. It should be noted that the interval time should be greater than the protection action time.
Post time: May-06-2026