How do you calibrate a power protective relay?

Calibrating a power protective relay involves adjusting the relay settings according to the specific protection requirements of the system it serves. This typically includes setting the pickup values for overcurrent, undervoltage, and other protective functions based on system parameters and coordination studies. Calibration may also involve testing the relay under simulated fault conditions using a secondary injection test set to verify its response and ensure it operates within the desired specifications. Finally, document all settings and test results for future reference and compliance.