Project Location: A 35kV GIS Substation

Test Equipment: HTA/HTV Wireless Remote-Control Digital Intelligent Current/Voltage Source, YD-300 Intelligent Wireless Telemetry Voltage-Current Phase Indicator

Before a substation is put into operation, a rigorous phasor check of relay protection is essential. Incorrect phasors can lead to maloperation or refusal of relay protection during normal operation or fault conditions. Using the HTA-3300 Three-phase Digital Intelligent High-Current Source and HTV-6000 Three-phase Digital Intelligent High-Voltage Source, we can simulate primary-side load operation by injecting high current and voltage from the primary-side CT and PT terminals when the substation is not yet in service. The corresponding voltage and current amplitudes and phase data are then read from the secondary side using the YD-300 Intelligent Wireless Telemetry Voltage-Current Phase Indicator or protection devices to verify the correctness of transformation ratios, phase identities, and wiring, thus completing a full-system phasor check of both primary and secondary circuits in one go.

I Wiring Modes

1. Voltage Source Wiring

Considering the risks of applying high voltage on the primary side, a low voltage of 57.7V is applied from the secondary side of the protection panel as a reference.

2. Current Source Wiring

Close the isolation switch Q9 1684, switch Q0 168, and earthing switch 16880.

Open the isolation switch Q1 1681, earthing switch 16800, and line earthing switch 16340.

Connect the HTA-3300 Three-phase Digital Intelligent High-Current Source to the 35kV leads to inject three-phase currents IA, IB, IC, forming a current loop through the isolation switch 1684, switch 168, and earthing switch 16880.

△ Three-phase Digital Current Source Wiring Diagram

 

3. Disconnect the isolation switches connecting other bays to the 35kV busbar.

 

△ GIS Internal Diagram

△ HTA-3300 Three-phase Digital Intelligent High-Current Source Wiring Layout

 

II Test Procedure

The HTA-3300 Three-phase Digital Intelligent High-Current Source is powered by AC 380V, and the HTV-6000 Three-phase Digital Intelligent High-Voltage Source by AC 220V. Wireless operation via the YD-300 Intelligent Wireless Telemetry Voltage-Current Phase Indicator ensures the synchronization of output voltage and current.

Power on the current and voltage sources and set them to remote-control mode. The remote control host automatically searches for and connects to the current and voltage sources.

Set the current and voltage of each phase to different amplitudes to verify the correctness of the phase sequence.

Inject the secondary voltage through the PT and the primary current through the CT, then check the amplitude and phase on the YD-300 to verify all secondary circuits and polarities.

The transformation ratio of the CT protection winding in this substation is 600A/1A.

1. Parameter Setting on the YD-300 Remote Control Host

Set the three-phase current output to 120A and the three-phase voltage output to 57.735V, with specific parameters as follows:

Item	Amplitude (V/A)	Phase (°)
UA	57.735V	0
UB	57.735V	240
UC	57.735V	120
IA	120A	180
IB	120A	60
IC	120A	300

2. Test Execution and Result Verification

The YD-300 remote control host performs measurement and control on the secondary side of the protection panel. Click Start Test to activate the output of the current and voltage sources, then read the corresponding values on the YD-300.

Convert the applied primary current to the secondary current: 120A/600 = 0.2A, which is basically consistent with the sampling amplitude on the YD-300.

The three-phase phase is in positive sequence. Since the current flows from P1 to P2 on the CT primary side, the set phase of current and voltage differs by 180°. Due to phase shift caused by the inductive reactance of the line and PT, there may be a slight phase deviation in the protection measurement.

Conclusion: The secondary circuit, phase sequence, phase, and polarity of this bay are all correct.

 

By directly applying primary current and secondary voltage to the newly built substation, the entire primary/secondary circuit and polarity phase can be verified, solving the problem of polarity check without load in traditional methods and improving the reliability of one-time power transmission.