Test Equipment: HTA-3300 Three-phase Digital Intelligent High-current Source, YD-300E Intelligent Wireless Remote Control Host for Current and Voltage Sources/Wireless Telemetry Voltmeter-Ammeter Phase Indicator

Test Site: A 220kV GIS Substation

Test Item: Apply high current to the primary side of the current transformer (CT), check the amplitude and phase of the secondary current in the secondary circuit, and judge the correctness of polarity, phase and ratio accordingly.

Wiring Method

Connect the HTA-3300 Three-phase Digital Intelligent High-current Source to Phase A of Bus 2. Close the TDS1 switch, CB1 switch and the 1102C0 grounding switch on the CT side of the medium-voltage side of No. 2 Main Transformer, and open the TES3 switch handle. The high current flows into the transformer through Phase A of the bus, and forms a closed loop by grounding through the 1102C0 grounding switch after passing through the transformer.

Test Method

The HTA-3300 Three-phase Digital Intelligent High-current Source features large output power, and can operate with multiple bays to simulate actual power transmission. It can be operated locally or connected to the YD-300E Intelligent Wireless Remote Control Host for Current and Voltage Sources to realize wireless remote control and telemetry functions.

During the test, connect the HTA-3300 to a 380V power supply, set the host to online mode, and realize wireless communication with the YD-300E via a wireless antenna. According to user requirements, only Phase A current is applied in this test; set the current to 120A and phase to 0° on the host.

Remotely control the output of the HTA-3300 through the YD-300E. The YD-300E can clamp the current and phase of the secondary side on the secondary circuit at any position within a 2km range, collect the primary-side values in real time wirelessly, and plot the output current phase and the measured values of the secondary side in the same hexagon diagram.

Test Analysis

Analysis of the test results shows that when a current of 120A is applied to the primary side, the current measured in the secondary circuit is 0.05A, and the calculated ratio is 2400:1, which is consistent with the actual ratio. The polarity of Phase A is reversed. After on-site personnel inspected the wiring, it was found that the polarity of Phase A CT was reversed. The polarity was consistent after the wiring was corrected.

The ratio and polarity test conducted before the substation commissioning eliminated potential risks that might exist during commissioning, and greatly improved the one-time power transmission success rate.