Test Location: 20kV Switching Station

Test Equipment: HTA-3300 Three-phase Digital Intelligent High-current Source, HTV-6000 Three-phase Digital Intelligent High-voltage Source, YD-300 Intelligent Current & Voltage Source Wireless Remote Control Host

Strict phasor verification must be performed on relay protection prior to commissioning. Incorrect phasors will cause malfunction or refusal to operate of relay protection during normal operation or fault conditions.

Traditional phasor verification work is carried out by organizing loads to apply "operating voltage and load current" after commissioning, and using relay protection testers to inject secondary current and voltage from the secondary sides of CTs and PTs for circuit inspection. However, this method cannot verify the correctness of the wiring and polarity of the entire complete circuit. In the initial stage of substation commissioning, load organization is often difficult, such as light load, reverse power supply from power plants, power transmission for high-speed railway traction stations, etc. As a result, incomplete detection often occurs, affecting the normal operation of the substation.

To address this issue, Wuhan Haomai has independently developed the HTA/HTV Wireless Remote Control Intelligent Current/Voltage Source, which can inject high current and high voltage into the primary circuit of the substation to achieve complete phasor verification of both primary and secondary circuits. The following briefly introduces the injection-based phasor verification test method for substations prior to commissioning.

Test Wiring

Voltage WiringConnect the HTV-6000 Three-phase Digital Intelligent High-voltage Source to the primary side of the bus PT, and check the secondary voltage at the secondary equipment measurement and control unit.

△ Wiring Layout Diagram

Current Wiring: Connect the HTA-3300 Three-phase Digital Intelligent High-current Source to the primary side of the CT, and check the amplitude, phase and phase sequence of the secondary current at the measurement and control device. When conducting angle and polarity tests of current and voltage, inject the current from the primary side of the CT. Take the HTV-6000 Three-phase Digital Intelligent High-voltage Source as the reference source, and simultaneously collect current and voltage data to the YD-300 Intelligent Current & Voltage Source Wireless Remote Control Host via wireless remote control.

Test Settings

First, power on the HTA-3300 and HTV-6000 and set them to the remote control operation state. The YD-300 will automatically search for the current source and voltage source. Set each phase of current and voltage to different amplitude states to check if the current and voltage phase sequences are correct. Inject primary current and voltage values through CTs and PTs, and check the amplitude and phase at the protection device to verify all secondary circuits and polarities. The PT ratio of this substation is 20kV/100V, and the CT protection winding ratio is 3150A/1A.

Test Results

△ YD-300 Display Values

△ Measurement and Control Device Display Values

By continuously injecting quantities into the primary side, check the amplitude and phase of current and voltage at the secondary equipment. The polarity can be judged as correct based on the vector diagram on the phase meter. Injecting 126A from the primary side of the CT results in a measured current of 0.04A on the secondary side, which is consistent with the 3150A/1A ratio. Injecting 2500V on the primary side of the PT results in a secondary voltage of 12.46V, with the ratio within the basic error range and meeting the requirements.

On-site application of the HTA/HTV Wireless Remote Control Intelligent Current/Voltage Source to inject high current and high voltage into the primary circuit of the substation for phasor verification of primary and secondary circuits solves the problems of unreliable step-by-step phasor verification prior to substation commissioning and difficult load organization after commissioning, greatly reducing the workload. During the test, the measured voltage and current phase polarities can be viewed on the equipment terminals and protection devices, and various quantity injection combinations can be implemented as required. The operation is simple and the communication is smooth, winning unanimous recognition and praise from users.