Three-phase microcomputer relay protection tester test steps:

(1) Measurement of the action area and sensitive angle of the power directional relay

In the "gradient test" software module, set Uab and Ia as rated values, set the Uab phase angle step, add and subtract the voltage phase angle, and measure the boundary angles φ1 and φ2 on both sides of the action area, then the sensitive angle φLM=1/ 2(φ1+φ2).

(2) Measurement of minimum operating power

In the "gradient test" software module, set the angle at the sensitive angle φLM, set Ia (or Uab) as the rated value, Uab (or Ia) as zero, set the step size of Uab (or Ia), increase the voltage ( or current). Measure the minimum operating power.

(3) Submarine test

In the "gradient test" software module, open the current loop, set the initial value of Uab to zero, the step size is the rated voltage, and suddenly add or remove the voltage, the relay contacts should not be connected instantaneously.

The voltage loop is short-circuited by the resistor, the initial value of Ia is set to zero, the step size is several times the rated current, and the current is suddenly added or removed, and the relay contacts should not be connected instantaneously.

(4) Memory function test

In the "gradient test" software module, the angle is set as the sensitive angle, and when Ia is set to 0.5 times and several times the rated current, Uab suddenly drops from 100V to zero, the relay should operate reliably, indicating that the memory function is good.