110kV operating bay access bus differential DC control circuit and load test method

Abstract

110kV operating interval access bus differential DC control loop and load test method. Since the equipment connected to the 110kV bus of the second plant is all in operation, it is not convenient to rewire the secondary cables on a large scale. The present invention comprises: an air switch, a synchronization device and an extension relay. The 1 and 2 normally open contacts of the air switch are connected in series with the input end of the synchronization device, and the output end of the synchronization device is respectively connected to the two input nodes of the extension relay coil, and the two output nodes of the extension relay coil are connected in parallel and in series with the 3 and 4 normally open contacts of the air switch. The present invention is used for 110kV operating interval access bus differential load test.

Description

Technical Field

[0001] The invention relates to a 110kV operating interval access bus differential DC control loop and a load test method. Background Art

[0002] The 110kV bus differential protection was transformed from medium impedance bus differential protection to Shenzhen Nanrui BP-2B microcomputer protection device. Since it was put into operation, the 110kV bus differential protection needs to be replaced and transformed to improve the operating reliability of the 110kV power grid.

[0003] Since all the equipment connected to the 110kV busbar of the second plant is in operation, it is not convenient to rewire the secondary cables on a large scale. Summary of the invention

[0004] The purpose of the present invention is to provide a 110kV operating interval access bus differential DC control loop and a load test method.

[0005] The above purpose is achieved through the following technical solutions:

[0006] A 110kV operating interval access bus differential DC control circuit comprises an air switch, a synchronization device and an extension relay. The normally open contacts 1 and 2 of the air switch are connected in series with the input end of the synchronization device. The output end of the synchronization device is respectively connected to the two input nodes of the extension relay coil. The two output nodes of the extension relay coil are connected in parallel and connected in series with the normally open contacts 3 and 4 of the air switch.

[0007] The 110kV operating interval is connected to the bus differential DC control circuit, and the normally open contact of the extension relay is connected to the closing circuit.

[0008] A load test method for connecting a 110 kV operating interval to a busbar differential DC control loop, the method comprising the following steps:

[0009] (1) The bus differential protection access work of the second plant is completed, and the secondary circuit is checked to be complete and the operation test is correct;

[0010] (2) Prepare the instruments and meters required for load testing.

[0011] (3) Use a multimeter and phase sequence meter to check the voltage amplitude and phase sequence of A, B, C630 and A, B, C640 in the protection panel.

[0012] (4) Check the current polarity at each operating interval and keep records.

[0013] (5) Read the current of each operating interval on the DCS screen, check the correctness of the reading according to the system power flow distribution, and calculate the line load impedance angle based on the checked reactive power values:

[0014]

[0015] Where: Φ L is the angle by which the voltage leads the current;

[0016] (6) Use the current amplitude and phase of each operating interval on the clamp phase meter side to compare and confirm that they are correct, measure the Ua∧Ia angle, and check that it is consistent with the load impedance angle calculated above;

[0017] (7) Read the power flow distribution of each unit of the 110kV busbar, check whether the current angle difference of each unit of the bus differential protection of the second plant is consistent with the PQ angle difference in the 110kV bus differential protection, and record the measurement results;

[0018] (8) Read the large difference and small difference of bus A and B of 110kV bus differential protection to see if they are zero, and record the measurement results. After checking that the differential current loop entering the bus differential current loop is correct, open the output tripping and locking reclosing pressure plate in the bus differential protection screen, and restore the bus differential tripping and locking reclosing line ends in each interval protection screen.

[0019] Beneficial effects:

[0020] 1. The present invention connects a synchronization device in a DC control loop. When the circuit breaker is closed, the voltage phase, amplitude and frequency of the power supplies on both sides of the circuit breaker are detected to reach the conditions allowing closing, and then a closing command is issued to close the circuit breaker to ensure closing safety.

[0021] 2. The present invention increases the expansion node in the transformation by connecting the expansion relay.

[0022] 3. The present invention reads the large difference of the 110kV bus differential protection and the small difference of the A and B bus to see if they are zero, and records the measurement results. After checking that the differential current loop is correct, the bus differential protection screen opens the exit tripping and locks the reclosing pressure plate. In each interval protection screen, the bus differential tripping and locks the reclosing line head to ensure the safety of the test and the accuracy of the data. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Attached Figure 1 It is a circuit diagram of the present invention. DETAILED DESCRIPTION

[0024] Embodiment 1:

[0025] A 110kV operating interval access bus differential DC control circuit comprises an air switch, a synchronization device and an extension relay. The normally open contacts 1 and 2 of the air switch are connected in series with the input end of the synchronization device. The output end of the synchronization device is respectively connected to the two input nodes of the extension relay coil. The two output nodes of the extension relay coil are connected in parallel and connected in series with the normally open contacts 3 and 4 of the air switch.

[0026] Embodiment 2:

[0027] According to the 110kV operating interval access bus differential DC control circuit described in Example 1, the normally open contact of the extension relay is connected to the closing circuit.

[0028] Embodiment 3:

[0029] A load test method for connecting a 110 kV operating interval to a busbar differential DC control loop, the method comprising the following steps:

[0030] (1) The bus differential protection access work of the second plant is completed, and the secondary circuit is checked to be complete and the operation test is correct;

[0031] (2) Prepare the instruments and meters required for load testing.

[0032] (3) Use a multimeter and phase sequence meter to check the voltage amplitude and phase sequence of A, B, C630 and A, B, C640 in the protection panel.

[0033] (4) Check the current polarity at each operating interval and keep records.

[0034] (5) Read the current of each operating interval on the DCS screen, check the correctness of the reading according to the system power flow distribution, and calculate the line load impedance angle based on the checked reactive power values:

[0035]

[0036] Where: Φ L is the angle by which the voltage leads the current;

[0037] (6) Use the current amplitude and phase of each operating interval on the clamp phase meter side to compare and confirm that they are correct, measure the Ua∧Ia angle, and check that it is consistent with the load impedance angle calculated above;

[0038] (7) Read the power flow distribution of each unit of the 110kV busbar, check whether the current angle difference of each unit of the bus differential protection of the second plant is consistent with the PQ angle difference in the 110kV bus differential protection, and record the measurement results;

[0039] (8) Read the large difference and small difference of bus A and B of 110kV bus differential protection to see if they are zero, and record the measurement results. After checking that the differential current loop entering the bus differential current loop is correct, open the output tripping and locking reclosing pressure plate in the bus differential protection screen, and restore the bus differential tripping and locking reclosing line ends in each interval protection screen.

Claims

1. A 110kV operating interval access bus differential DC control loop, characterized by: It consists of an air switch, a synchronization device and an extension relay. The normally open contacts 1 and 2 of the air switch are connected in series with the input end of the synchronization device. The output end of the synchronization device is respectively connected to the two input nodes of the extension relay coil. The two output nodes of the extension relay coil are connected in parallel and connected in series with the normally open contacts 3 and 4 of the air switch.

2. The 110kV operating interval access bus differential DC control loop according to claim 1 is characterized in that: The normally open contact of the extension relay is connected to the closing circuit.

3. A load test method for a 110 kV operating interval connected bus differential DC control loop according to any one of claims 1-2, characterized in that: The method comprises the following steps: (1) The bus differential protection access work of the second plant is completed, and the secondary circuit is checked to be complete and the operation test is correct; (2) Prepare the instruments and meters required for the load test; (3) Use a multimeter and phase sequence meter to check the voltage amplitude and phase sequence of A, B, C630 and A, B, C640 in the protection panel. (4) Check the current polarity during the operation interval and keep records; (5) Read the current of each operating interval on the DCS screen, check the correctness of the reading according to the system power flow distribution, and calculate the line load impedance angle based on the checked reactive power values: Where: Φ L is the angle by which the voltage leads the current; (6) Use the current amplitude and phase of each operating interval on the clamp phase meter side to compare and confirm that they are correct, measure the Ua∧Ia angle, and check that it is consistent with the load impedance angle calculated above; (7) Read the power flow distribution of each unit of the 110kV busbar, check whether the current angle difference of each unit of the bus differential protection of the second plant is consistent with the PQ angle difference in the 110kV bus differential protection, and record the measurement results; (8) Read the large difference and small difference of bus A and B of 110kV bus differential protection to see if they are zero, and record the measurement results. After checking that the differential current loop entering the bus differential current loop is correct, open the output tripping and locking reclosing pressure plate in the bus differential protection screen, and restore the bus differential tripping and locking reclosing line ends in each interval protection screen.

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