Test Equipment: Three HTA-1300 Single-phase Digital Intelligent High-current Sources, YD-300E Wireless Telemetry Voltmeter-Ammeter Phase Indicator

1. Test Preparation

Disconnect the disconnecting switch 50111 that connects the line to the busbar, open the 501127 grounding switch, close the circuit breaker 5011. Ensure the PT secondary side is not short-circuited and the CT secondary side is not open-circuited. Disconnect the power air switch of the HTA-1300 Single-phase Digital Intelligent High-current Source, and confirm no personnel are working in this bay before starting the device.

2. Test Wiring

For Phase A test wiring: Connect the red current wire of the intelligent high-current source to the incoming side P1 (i.e., 501127A) of the CT primary side, and the black wire to the outgoing side P2 (i.e., 501117A) to form a loop for the current source.

△ Three Intelligent High-current Sources Connected to Phase A/B/C Respectively

△ Disconnecting Switch at P2 Connected to N Phase of the Current Source

Inject current through the intelligent high-current source on the primary side to form a loop via the CT, and obtain secondary current sampling at the protection device. At this point, the amplitude will display correctly but the angle will change (no voltage reference). Disconnect the voltage terminal block, apply secondary voltage directly to the voltage sampling terminals of the protection panel (apply three-phase rated voltage), and connect the UA voltage in parallel to the voltage sampling terminal of the wireless telemetry voltmeter-ammeter phase indicator. Then use the wireless telemetry device to control the current source output: the current source output current and the voltage/current angle of the protection device share the same reference (UA angle = 0°), and calculate whether the angle is leading or lagging.

△ Voltage Application Point at 5011 Circuit Breaker Protection Voltage Terminal

3. Parameter Settings

Set the current source operation mode to remote control. Use the wireless telemetry voltmeter-ammeter phase indicator to search for the corresponding device; after connection, set the output amplitude and angle, return to the remote control main interface, and click Start to control the connected device for output. The three output configurations are shown in the table below:

First, test whether the three-phase wiring is correct: Apply unbalanced three-phase voltage and current, check if the secondary sampling values of Phase A/B/C correspond correctly. Then calculate the CT/PT ratio, compare it with the value read from the protection device to judge if the ratio is normal. Use the phase angle to judge polarity correctness (a 180° deviation between the phase angle and the applied value indicates reversed polarity). Finally, apply 0° to all three phases to check if the zero-sequence current is correct.

First injection: Apply 40A, 60A, 80A to Phase A/B/C respectively.

The secondary current displays 0.02A/0.03A/0.04A for Phase A/B/C, with positive-sequence angles.

Second injection: Apply 60A (positive-sequence) to all three phases.

The secondary current amplitude displays 0.03A, with an angle around 360°.

Third injection: Apply 40A, 60A, 80A to Phase A/B/C respectively (angle = 0° for all).

4. Test Results

After the three HTA-1300 Single-phase Digital Intelligent High-current Sources operate normally, inject 40A/60A/80A to Phase A/B/C respectively. From the secondary values (0.02A/0.04A/0.06A) and phases collected at the CT secondary side on the protection device main interface, the three phases correspond correctly. The CT ratio is 2000:1, and the calculated CT/PT ratio is basically consistent with the actual value.

When 60A is applied to all three phases: If the PT/CT polarity is normal, the IA/IB/IC current flows from the line to the busbar bay, so the secondary output phase should deviate 180° from the primary input phase. When the primary current angles of Phase A/B/C are set to 180°/60°/300° respectively, the secondary voltage and current angles display the same (corresponding to reversed polarity), so the line polarity is correct.

When Phase A/B/C currents are 40A/60A/80A (angle = 0°), the zero-sequence current is the sum of the three-phase currents, and the secondary zero-sequence current is 0.09A. Thus, the zero-sequence current display is correct, and this line bay is normal.