Illustration of the operation method of differential protection test of relay protection tester

The relay protection tester is a new type of intelligent testing instrument that replaces the previous testing tool that was composed of a voltage regulator and a phase shifter. It has the characteristics of small size, light weight, high precision, and simple operation. Relay protection testers are now widely used in various fields such as line protection, main transformer differential protection, and excitation control. Comprehensive automation has become mainstream.

At present, the relay protection testers produced by domestic manufacturers are very simple to operate and very cost-effective. Below we will take the most popular Huatian ht-702 microcomputer relay protection tester on the market as an example to introduce its differential protection test operation method in detail:

Relay protection tester interface description:

In the differential test, the device outputs two currents from the ia and ib terminals, which are mainly used to test differential.

The ia phase action current idz is fixed as the fundamental wave and has variable amplitude.

The ib phase braking current izd can be set to DC, fundamental wave, secondary current, and the amplitude of each time can be set.

When doing the ratio braking characteristics of the differential relay, set the braking current value at the fundamental wave value of izd. When doing the DC magnetizing characteristics, set the current value at the DC value. When doing the second harmonic braking characteristics Set the current value at the secondary current.

When izd and idz output AC, the maximum current is 30a; when izd outputs DC, the maximum current is 10a.

Various setting values ​​that the relay protection tester needs to input:

idz initial value, change step size, phase;

The amplitude and phase of each izd quantity;

Manual change/automatic change

Variables that can be changed in the test are idz amplitude and idz phase.

Binary input: During testing, the contacts of the component under test can be connected to any switching input terminal.

Output: Two output nodes, one tracks the test process, closes when the test "start" is pressed, and opens when the test "stops"; the other tracks the changes in the test data, that is, when the first press is pressed after the test starts It is closed when the "▲" or "▼" button is pressed and opened when the test is "stop".

Data recording area: In addition to recording the action time and return time during protection action and return, the two rows on the side display the current values ​​of idz and izd during action and return.

After the data is set, select "Confirm" and the screen will display the relay contact status diagram. Select "Start" to start output for testing. The change amount during the test can be changed automatically or manually. The test method is similar to the AC test. When the relay contact acts and returns, the test record area on the screen will display the action time and return time of the relay under test, and the current values ​​of idz and izd.