A strict phasor check of relay protection must be conducted before a substation is commissioned, as phasor errors will cause maloperation or refusal of relay protection during normal operation or fault conditions. The HTA-3300 Phasor Check Three-Phase Digital Current Source, combined with a wireless phase reference source and the YD-300 Wireless Telemetry Voltmeter-Ammeter Phase Meter, can simulate primary side load operation. It injects a large current from the primary side CT terminal when the substation is not commissioned, and the corresponding current and phase data are read from the secondary side by the YD-300 Wireless Telemetry Voltmeter-Ammeter Phase Meter to judge the correctness of the transformation ratio, phase identification and wiring, completing the phasor check of the primary and secondary circuit systems in one go.

△ HTA-3300 Phasor Check Three-Phase Digital Current Source

System Principle

The HTA-3300 Phasor Check Three-Phase Digital Current Source has a maximum three-phase AC output of 300A and an output frequency of 50Hz. It is synchronized with the wireless phase reference source in a wireless manner and can complete the relay protection phasor check for three phases simultaneously.

△ System Principle

The input of the wireless phase reference source is connected to an AC 220V power supply or the PT secondary side voltage, providing a voltage phase reference for the current source and the YD-300 Wireless Telemetry Voltmeter-Ammeter Phase Meter. The three-phase current source injects a large current into phase A, phase B and phase C from the primary side of the CT, and receives the voltage phase reference signal of the wireless phase reference source in a wireless manner. The YD-300 Wireless Telemetry Voltmeter-Ammeter Phase Meter measures the secondary current from the secondary side of the CT to obtain the amplitude and phase of the secondary current, with the measured phase referenced to the wireless phase reference source. According to the current and phase data displayed by the YD-300 Wireless Telemetry Voltmeter-Ammeter Phase Meter, the correctness of the transformation ratio, phase identification and wiring is judged, completing the phasor check of the entire primary and secondary circuit systems in one go.

Field Application

△ 330kV Substation Application Site

The HTA-3300 Phasor Check Three-Phase Digital Current Source is small in size and light in weight, enabling convenient and fast on-site tests. Taking a 330kV substation as an example, the relay protection phasor check before commissioning is carried out as follows:

1. Test Output: The current source outputs a fixed 100A current to test the correctness of the wiring of the entire circuit and record the relevant load parameters at the same time.
2. Timed Output: Set the target current, phase and output time, the current source outputs the target current and stops automatically when the output time is reached. The YD-300 Wireless Telemetry Voltmeter-Ammeter Phase Meter measures the current and phase on the secondary side and records the data of the current rising to the target value for judgment.

Before the substation is commissioned, a signal is applied on the primary side to simulate primary on-load operation, wireless synchronization is adopted, and monitoring is conducted on the secondary side, thus completing the phasor check of the primary and secondary systems in one go. This greatly improves work efficiency and has won unanimous praise from on-site users.