The basic tasks of power system relay protection are:

1. Automatically, quickly and selectively remove the faulty components from the power system, so as to prevent the faulty components from being further damaged, and ensure that other fault-free parts quickly resume normal operation.

2. Respond to the abnormal operating status of electrical components, and act on the signal according to the conditions of operation and maintenance (if there is no regular staff on duty), so that the staff on duty can deal with it in time, or the device can automatically adjust, or continue to operate Electrical equipment that caused damage or developed into an accident is removed. At this time, it is generally not required to protect the rapid action, but a certain delay is prescribed according to the degree of damage to the power system and its components, so as to avoid unnecessary operation and interference caused by temporary operation fluctuations caused by misoperation.

3. The relay protection device can also cooperate with other automation devices in the power system. When conditions permit, take predetermined measures to shorten the power outage time of the accident and restore the power supply as soon as possible, thereby improving the reliability of the power system operation.