Project Location: A Newly-Built 220kV Smart Substation

Test Equipment: HTA/HTV Wireless Remote-Control Intelligent Current/Voltage Source

Polarity check of primary and secondary circuits cannot be conducted due to the absence of load before a substation is commissioned. Traditional methods only allow applying secondary current and voltage from the secondary side of CT and PT with a relay protection tester to check the circuits, which fails to verify the correctness of wiring and polarity for the entire complete circuit. In response to this problem, Wuhan Haomai has developed and produced the HTA/HTV Wireless Remote-Control Intelligent Current/Voltage Source, which can apply high current and high voltage from the primary circuit of the substation to conduct phasor calibration of primary and secondary circuits. This article introduces how to perform the injection-type phasor check test before substation commissioning using the HTA/HTV Wireless Remote-Control Intelligent Current/Voltage Source.

1 Test Wiring

 

1. The primary equipment of the substation adopts a fully enclosed GIS structure. The figure below shows the two selected test bays and a schematic diagram of the bus equipment.

△ Primary Schematic Diagram (Partial Bays)

 

 

2. Since wiring cannot be performed inside the GIS for each primary equipment, the current and voltage are designed to be connected from the incoming and outgoing line lead sides of the two bays:

Current connection: Select the 226 switch bay. Inject current from the 226 lead, flow it through the CT via the isolation switch 2266, then through the switch 226, and finally into the ground via the earthing switch 2265 to form a current loop.

Voltage connection: Select the 221 switch bay. Inject voltage from the 221 lead, flow it through the isolation switch 2216, switch 221, isolation switch 2211, isolation switch HU 01A to the IMA voltage transformer.

All other isolation switches and earthing switches are open. Three-phase current and three-phase voltage can be connected simultaneously.

△ Wiring Schematic Diagram

Notes:① During wiring, the N phase of the three-phase current source is directly earthed, and the N phase of the three-phase voltage source is short-circuited and earthed.② Do not apply the primary quantities of the voltage source and current source to the same branch at the same time.③ The voltage of each bay is cascaded bus voltage. To view the voltage value on the protection device in the 226 bay, short-circuit the outside of the intelligent terminal to keep the isolation switch 2261 closed, so that the 226 bay samples the Bus I voltage.

2 Test Settings and Operation Method

After connecting the primary lines of the three-phase current source and three-phase voltage source, the operation can be performed via a handheld remote control host.

Power on the current source and voltage source, and set them to the remote control operation mode; the remote control host will automatically search for and connect to the current source and voltage source.

Set the current and voltage of each phase to different amplitude states to check the correctness of the current and voltage phase sequence.

Inject the primary current and voltage values through CT and PT, and check the amplitude and phase on the protection device to verify all secondary circuits and polarities.

The transformation ratios of the substation are as follows:

PT transformation ratio: 220kV/100V

CT protection winding transformation ratio: 1200A/1A

1) Parameter Setting on the Remote Control Host

Phase	Set Amplitude	Set Phase
UA	2200V	∠0°
UB	2200V	∠240°
UC	2200V	∠120°
IA	240A	∠0°
IB	240A	∠240°
IC	240A	∠120°

2) Test Execution

Click Start Test; the current source and voltage source start outputting, and the recovered values can be viewed on the host.

3 Test Results

Keep the primary quantities outputting, and check the data on the protection device.

Test Conclusion

Convert the applied primary values to secondary values with the following calculations:

Voltage: 2200V / 2200 = 1V

Current: 240A / 1200 = 0.2A

The sampling amplitude displayed on the protection device is basically consistent with the calculated secondary values, and the three-phase phase is in positive sequence. Since the current flows from P2 to P1 on the CT primary side, the phase difference is exactly 180°. It can be concluded that the secondary circuit, phase sequence, phase and polarity of this bay are all correct.