A CVT structure and test method convenient for field testing

Abstract

The present invention discloses a CVT structure and test method that is convenient for field testing, including a CVT device, an operating handle, a rotating shaft, and a multi-point contactor. The operating handle is installed on the outside of the CVT device, and the rotating shaft is installed on the CVT device housing through the operating handle. One end of the rotating shaft is fixed to the operating handle outside the CVT device and can be rotated by rotating the operating handle. The other end of the rotating shaft is located inside the CVT device and is equipped with a multi-point contactor. The multi-point contactor can change its contact position by rotating the rotating shaft, thereby contacting different circuit contacts of the internal circuit of the CVT device, thereby changing the internal circuit state of the CVT device. The present invention enables the CVT product to undergo power frequency withstand voltage testing and no-load testing in a field environment without disassembly by changing the connection method of the capacitive voltage divider and the electromagnetic unit.

Description

Technical Field

[0001] The present invention relates to the field of capacitor voltage transformers, and in particular to a CVT structure and a test method that are convenient for on-site testing. Background Art

[0002] The CVT product is a single-column upright mounted electrical device. The capacitive voltage divider and the lower electromagnetic unit are connected inside the device, and the wiring part is located in the oil tank between the two and is sealed.

[0003] In most cases, the on-site acceptance of CVT products requires a power frequency withstand voltage test according to the acceptance procedures. Due to the high power frequency withstand voltage test voltage and the internal connection of the capacitor voltage divider and the electromagnetic unit, conducting the test directly will cause the intermediate transformer core to saturate and damage the product. At the same time, the on-site environment is much harsher than that of the test laboratory. Disassembling the product and removing the wiring will damage the original seal of the product. There are also risks such as moisture and contamination. Therefore, it is impossible to conduct the power frequency withstand voltage test in full accordance with the specified test voltage during the on-site test. Similarly, when conducting a no-load test on the medium-voltage transformer of the electromagnetic unit of the product on site, the test voltage sensed by the secondary boost voltage is higher than the insulation capacity of the N terminal of the capacitor voltage divider to the ground. Without removing the wiring between the capacitor voltage divider and the medium-voltage transformer of the electromagnetic unit, the test cannot be performed.

[0004] Existing technology requires removing the connection between the product's capacitor voltage divider and electromagnetic unit before conducting CVT power frequency withstand voltage or no-load tests. This technology is suitable for laboratory environments. However, when testing in a field environment after disassembly and removal of wiring, it can easily contaminate the product's interior. Furthermore, consideration must be given to product disassembly and placement, coordination of lifting equipment, and consideration of live electrical safety distances during disassembly. This is unsafe and time-consuming, requiring a full day of preparation for a test that takes less than half an hour.

[0005] The following is an explanation of the above technical terms:

[0006] CVT: Capacitor voltage transformer is an electrical device used for power metering, relay protection, and carrier communication in power transmission and transformation projects. It consists of two parts: a capacitive voltage divider and an electromagnetic unit.

[0007] Capacitive voltage divider: divides the rated primary voltage of the CVT and generates a relatively low intermediate voltage to supply the electromagnetic unit.

[0008] Electromagnetic unit: Contains components such as a medium-voltage transformer and a fuel tank, and transforms the medium-voltage voltage derived from the capacitive voltage divider into a lower secondary voltage for collection by secondary instruments such as protection and metering.

[0009] Power frequency withstand voltage test: A test voltage several times the rated operating voltage is applied to the capacitor voltage divider of the CVT product to verify the insulation capacity of the CVT capacitor voltage divider.

[0010] No-load test: Boosting the voltage from the secondary side of the electromagnetic unit and inducing high voltage to the primary side of the intermediate transformer is one of the important tests for testing the performance of the medium-voltage transformer in the CVT electromagnetic unit. Summary of the Invention

[0011] The purpose of the present invention is to provide a CVT structure and test method that is convenient for on-site testing to overcome the defects of the prior art. The present invention changes the internal wiring circuit structure of the CVT equipment so that the CVT product can undergo power frequency withstand voltage test and no-load test in the on-site environment without disassembly.

[0012] In order to achieve the above object, the present invention adopts the following technical solutions:

[0013] A CVT structure that is convenient for on-site testing includes a CVT device, an operating handle, a rotating shaft and a multi-point contactor. The operating handle is installed on the outside of the CVT device, and the rotating shaft is installed through the CVT device housing. One end of the rotating shaft is fixed to the operating handle outside the CVT device and can be rotated by rotating the operating handle. The other end of the rotating shaft is located inside the CVT device and is equipped with a multi-point contactor. The multi-point contactor can change its contact position by rotating the rotating shaft, and then contact different circuit contacts of the internal circuit of the CVT device, thereby changing the internal circuit state of the CVT device.

[0014] Furthermore, the rotating shaft is made of insulating material, and a sealing device is installed between the rotating shaft and the CVT equipment housing.

[0015] Furthermore, the CVT device is internally provided with a capacitive voltage divider, a grounding device and a medium-voltage transformer; the medium-voltage end of the capacitive voltage divider is provided with a first contact with a fixed position, which is located on the rotation track of the multi-point contactor; the medium-voltage transformer head end of the medium-voltage transformer is provided with a second contact with a fixed position, which is located on the rotation track of the multi-point contactor; one end of the grounding device is grounded, and the other end is provided with a third contact with a fixed position, which is located on the rotation track of the multi-point contactor.

[0016] Furthermore, the capacitive voltage divider includes a high-voltage arm capacitor and a low-voltage arm capacitor, the medium-voltage end of the capacitive voltage divider is located between the high-voltage arm capacitor and the low-voltage arm capacitor, and the medium-voltage end of the capacitive voltage divider is provided with a fixed first contact through an insulating support.

[0017] Furthermore, the medium voltage transformer includes a medium voltage transformer head end and a medium voltage transformer tail end, and the medium voltage transformer head end is provided with a second contact with a fixed position through an insulating support.

[0018] Furthermore, the multi-point contactor includes a first terminal and a second terminal for connecting the medium-voltage end of the capacitor voltage divider and the medium-voltage transformer head end of the medium-voltage transformer, or the medium-voltage end of the capacitor voltage divider and the grounding device, or the grounding device and the medium-voltage transformer head end of the medium-voltage transformer, and a third terminal is provided between the first terminal and the second terminal.

[0019] A test method for a CVT structure that is convenient for on-site testing, wherein a multi-point contactor is rotated to connect the medium voltage end of the capacitor voltage divider with the first end of the medium voltage transformer, so that the CVT structure is in normal working condition;

[0020] Rotate the multi-point contactor to connect the medium voltage end of the capacitor divider to the grounding device, putting the CVT structure in a low-voltage test state, which allows the dielectric loss test of C1 and C2 capacitors of the capacitor divider to be carried out; at the same time, the first end of the medium voltage transformer is suspended, which allows the no-load test of the electromagnetic unit to be carried out;

[0021] Turn the multi-point contactor to connect the first end of the medium-voltage transformer to the grounding device, so that the CVT structure is in a high-voltage test state, and the medium-voltage end of the capacitor divider is suspended. At this time, the Cn capacitance dielectric loss test and the power frequency withstand voltage test of the capacitor divider can be carried out.

[0022] Compared with the prior art, the present invention has the following beneficial technical effects:

[0023] The present invention controls the circuit of the device by adjusting the connection between the capacitor voltage divider, the electromagnetic unit, and the grounding device from the outside of the device. This allows CVT products to quickly and conveniently undergo acceptance tests, maintenance tests, emergency troubleshooting, and other tasks at the construction site. The above work can be completed within 1 to 2 hours by simply carrying simple portable test tools. Compared with the traditional working method, the intermediate links such as disassembly, transportation, and contacting the test site of the CVT product are avoided, and the traditional working method takes 1 to 2 days. The present invention can shorten the working time to several hours, greatly improving convenience and timeliness, and gaining valuable time for power maintenance and emergency repairs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the multi-point contactor connection structure of the present invention, wherein (a) is a first viewing angle and (b) is a second viewing angle;

[0025] Figure 2 A schematic diagram of the coordination between the multi-point contactor of the present invention and different circuit contacts of the internal circuit of the CVT device;

[0026] Figure 3 This is a schematic diagram of the CVT structure of the present invention in normal working state;

[0027] Figure 4 This is a schematic diagram of the low-pressure test state of the CVT structure of the present invention;

[0028] Figure 5 This is a schematic diagram of the high-voltage test state of the CVT structure of the present invention.

[0029] Among them, 1. CVT equipment housing; 2. Rotating shaft; 3. Operating handle; 4. Sealing device; 5. First contact; 6. Second contact; 7. Third contact; AN: Capacitive voltage divider; M: Medium voltage end of the capacitor voltage divider; AT-XT: Medium voltage transformer; AT: Medium voltage transformer head end; XT: Medium voltage transformer end end; E: Grounding device; K: Multi-point contactor. DETAILED DESCRIPTION

[0030] The present invention is described in further detail below:

[0031] See also Figures 1 to 2 A CVT structure that is convenient for on-site testing can change the internal circuit of the CVT by operating outside the CVT device to achieve the transition between the normal operating state and various test states of the CVT, including an operating handle 3, a rotating shaft 2, a multi-point contactor K, a sealing device and other parts, wherein the operating handle 3 is installed outside the CVT device, and the rotating shaft 2 is installed on the CVT device housing 1, passing through the CVT device housing 1, one end of the rotating shaft 2 is fixed to the operating handle 3 outside the CVT device, and the rotating shaft 2 can be rotated by rotating the operating handle 3, the other end of the rotating shaft 2 is inside the CVT device, and a multi-point contactor K is installed, and the position of the multi-point contactor K contacts can be changed by rotating the rotating shaft 2, contacting different circuit contacts to change the circuit state; a sealing device is installed between the rotating shaft 2 itself and the CVT device housing 1 to isolate and seal the inside of the CVT device from the outside.

[0032] See also Figures 3 to 5 The medium-voltage end of the capacitor voltage divider and the head end of the intermediate transformer of the CVT equipment are separately led out and contacts are set. The two contacts are not connected and there is sufficient distance for insulation. The two contacts are fixed in position by insulating supports such as small bushings. The positions are on the track that can be touched after the multi-point contactor K rotates. A grounding device is set inside the CVT equipment. The grounding device is a conductor. One end of the grounding device is firmly grounded, and a contact is set at the other end. The contact position is also on the track that can be touched after the contactor rotates.

[0033] Specifically, the CVT device is internally provided with a capacitive voltage divider AN, a grounding device E and a medium-voltage transformer AT-XT. The medium-voltage end M of the capacitive voltage divider AN is provided with a fixed first contact 5, which is located on the rotation track of the multi-point contactor K; the medium-voltage transformer head end AT of the medium-voltage transformer AT-XT is provided with a fixed second contact 6, which is located on the rotation track of the multi-point contactor K; one end of the grounding device E is grounded, and the other end is provided with a fixed third contact 7, which is located on the rotation track of the multi-point contactor K.

[0034] The capacitive voltage divider AN includes a high-voltage arm capacitor and a low-voltage arm capacitor, the medium-voltage end M of the capacitive voltage divider is located between the high-voltage arm capacitor and the low-voltage arm capacitor, the medium-voltage end M of the capacitive voltage divider is provided with a fixed first contact 5 through an insulating support, the medium-voltage transformer AT-XT includes a medium-voltage transformer head end AT and a medium-voltage transformer terminal XT, the medium-voltage transformer head end AT is provided with a fixed second contact 6 through an insulating support, and the multi-point contactor K includes a first terminal and a second terminal for connecting the medium-voltage end M of the capacitive voltage divider and the medium-voltage transformer head end AT of the medium-voltage transformer AT-XT, or the medium-voltage end M of the capacitive voltage divider and the grounding device E, or the grounding device E and the medium-voltage transformer head end AT of the medium-voltage transformer AT-XT, and a third terminal is provided between the first terminal and the second terminal.

[0035] A test method for a CVT structure that is convenient for on-site testing: rotating the multi-point contactor K to connect the medium voltage terminal M of the capacitor voltage divider and the first terminal AT of the medium voltage transformer, so that the CVT structure is in normal working condition;

[0036] Turn the multi-point contactor K to connect the medium voltage terminal M of the capacitor divider to the grounding device E, putting the CVT structure in a low-voltage test state, which means that the dielectric loss test of the capacitors C1 and C2 of the capacitor divider AN can be carried out; at the same time, the first terminal AT of the medium voltage transformer is suspended, which means that the no-load test of the electromagnetic unit can be carried out;

[0037] Turn the multi-point contactor K to connect the medium voltage transformer head end AT and the grounding device E, so that the CVT structure is in a high voltage test state. The medium voltage end M of the capacitor divider is suspended. At this time, the Cn capacitance dielectric loss test of the capacitor divider AN and the power frequency withstand voltage test can be carried out.

[0038] The embodiments of the present invention are described in detail below with reference to the accompanying drawings:

[0039] The present invention enables the CVT product to undergo a power frequency withstand voltage test and a no-load test in a field environment without disassembling by changing the connection mode of the capacitive voltage divider and the electromagnetic unit.

[0040] During the test, the test circuit is controlled by changing the tapping status among the medium voltage terminal M of the capacitor voltage divider, the first terminal AT of the medium voltage transformer, and the grounding device E through the connector.

[0041] See also Figure 3 , connect the medium-voltage end M of the capacitor voltage divider to the medium-voltage transformer AT-XT. Specifically, rotate the multi-point contactor K to connect the medium-voltage end M of the capacitor voltage divider to the first end AT of the medium-voltage transformer. This is also the normal working state of the CVT product.

[0042] See also Figure 4 , connect the medium-voltage terminal M of the capacitor divider to the grounding device E, and leave the first terminal AT of the medium-voltage transformer suspended. Specifically, turn the multi-point contactor K to connect the medium-voltage terminal M of the capacitor divider to the grounding device E. Now the medium-voltage transformer AT-XT is disconnected from the capacitor divider AN, and the capacitor dielectric loss test of the capacitor divider and the no-load test of the electromagnetic unit can be performed separately.

[0043] See also Figure 5 , separate the medium-voltage terminal M of the capacitor voltage divider from the medium-voltage transformer AT-XT and suspend it in the air. Specifically, turn the multi-point contactor K to connect the medium-voltage transformer head end AT to the grounding device E. With the medium-voltage terminal M of the capacitor voltage divider suspended, the power frequency withstand voltage test of the capacitor voltage divider can be performed.

Claims

1. A CVT structure that is convenient for field testing, characterized in that: The invention comprises a CVT device, an operating handle (3), a rotating shaft (2) and a multi-point contactor (K), wherein the operating handle (3) is installed outside the CVT device, the rotating shaft (2) is installed through the CVT device housing (1), and one end of the rotating shaft (2) is fixed to the operating handle (3) outside the CVT device, and the rotating shaft (2) can be rotated by rotating the operating handle (3); the other end of the rotating shaft (2) is located inside the CVT device and is installed with a multi-point contactor (K), and the multi-point contactor (K) can change its contact position by rotating the rotating shaft (2), thereby contacting different circuit contacts of the internal circuit of the CVT device, thereby changing the internal circuit state of the CVT device; The CVT device is internally provided with a capacitor voltage divider (AN), a grounding device (E) and a medium-voltage transformer (AT-XT); a capacitor voltage divider medium-voltage end (M) of the capacitor voltage divider (AN) is provided with a first contact (5) with a fixed position, which is located on a rotation track of a multi-point contactor (K); a medium-voltage transformer head end (AT) of the medium-voltage transformer (AT-XT) is provided with a second contact (6) with a fixed position, which is located on a rotation track of the multi-point contactor (K); one end of the grounding device (E) is grounded, and the other end is provided with a third contact (7) with a fixed position, which is located on a rotation track of the multi-point contactor (K).

2. A CVT structure convenient for field testing according to claim 1, characterized in that: The rotating shaft (2) is made of insulating material, and a sealing device is installed between the rotating shaft (2) and the CVT equipment housing (1).

3. A CVT structure convenient for field testing according to claim 1, characterized in that: The capacitive voltage divider (AN) comprises a high-voltage arm capacitor and a low-voltage arm capacitor, a medium-voltage end (M) of the capacitive voltage divider is located between the high-voltage arm capacitor and the low-voltage arm capacitor, and a first contact (5) with a fixed position is provided at the medium-voltage end (M) of the capacitive voltage divider via an insulating support.

4. A CVT structure convenient for field testing according to claim 1, characterized in that: The medium voltage transformer (AT-XT) comprises a medium voltage transformer head end (AT) and a medium voltage transformer tail end (XT). The medium voltage transformer head end (AT) is provided with a second contact (6) with a fixed position via an insulating support.

5. The CVT structure convenient for field testing according to claim 1, characterized in that: The multipoint contactor (K) includes a first connection terminal and a second connection terminal for connecting the medium-voltage end (M) of the capacitor voltage divider and the medium-voltage transformer head end (AT) of the medium-voltage transformer (AT-XT), or the medium-voltage end (M) of the capacitor voltage divider and the grounding device (E), or the grounding device (E) and the medium-voltage transformer head end (AT) of the medium-voltage transformer (AT-XT), wherein a third connection terminal is provided between the first connection terminal and the second connection terminal.

6. A CVT structure testing method that is convenient for on-site testing as claimed in claim 1, characterized in that: Turn the multi-point contactor (K) to connect the medium voltage end (M) of the capacitor divider and the head end (AT) of the medium voltage transformer, so that the CVT structure is in normal working condition; Rotate the multi-point contactor (K) to connect the medium voltage terminal (M) of the capacitor divider to the grounding device (E), placing the CVT structure in a low-voltage test state. This allows for dielectric loss testing of the capacitors C1 and C2 of the capacitor divider (AN). Simultaneously, the medium voltage transformer head (AT) is suspended, allowing for a no-load test of the electromagnetic unit. Turn the multi-point contactor (K) to connect the medium voltage transformer head end (AT) and the grounding device (E), putting the CVT structure in a high voltage test state. The medium voltage end (M) of the capacitor divider is suspended. At this time, the Cn capacitance dielectric loss test and the power frequency withstand voltage test of the capacitor divider (AN) can be carried out.

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