A CVT, system, method and use for accurately measuring dielectric capacitance
By installing a circuit breaker in a capacitive voltage transformer (CVT) and combining it with a clamp-on ammeter, the problems of inaccurate measurement of dielectric loss and capacitance in CVTs are solved, enabling accurate measurement under both power outage and power failure conditions, and reducing measurement risks.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- MAINTENANCE BRANCH OF STATE GRID HEBEI ELECTRIC POWER
- Filing Date
- 2022-10-31
- Publication Date
- 2026-07-31
AI Technical Summary
In the existing technology, the relative dielectric loss and capacitance measurements of capacitive voltage transformers (CVTs) are inaccurate, especially when measured under energized conditions, they are severely affected by interference from intermediate transformers and cannot truly reflect the insulation status of the capacitors.
A first circuit breaker and a second circuit breaker are installed between the high-voltage end of the intermediate transformer and ground, and between the intermediate transformer and the capacitor, respectively, to form a capacitive voltage transformer (CVT). The dielectric loss and capacitance are measured by clamp-on ammeters. Combined with the status control of the circuit breakers, measurements can be performed without power interruption and during power outage.
This method enables accurate measurement of dielectric loss and capacitance of capacitive voltage transformers without interference from intermediate transformers, improving measurement accuracy and efficiency while reducing measurement risks.
Smart Images
Figure CN115825573B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of capacitive voltage transformer technology, and in particular to a CVT, system, method and application for accurately measuring dielectric loss capacitance. Background Technology
[0002] The authorization announcement number is CN 103076560 B, and the name is "Non-contact Measurement Combination Device for Electrical Testing Equipment and Its Application." It includes a control host and multiple detection terminals; these terminals communicate remotely via radio frequency modules to form a star network, thus creating a point-to-multipoint combined measurement device. One end of the measurement combination device is connected to the power equipment through the detection terminals, and the other end is connected to the electrical testing equipment through the control host. By connecting the modules of the detection terminals to the power equipment, corresponding electrical testing measurements can be performed on the power equipment. This device is based on non-contact sensing technology and radio frequency technology, using non-contact sensor technology to replace traditional measurement methods. Through networking technology, it achieves digital data acquisition and transmission, effectively separating measurement and data acquisition processes, avoiding workers from working in high-risk areas, improving work efficiency, and reducing operational risks.
[0003] The authorization announcement number is CN 203117297 U, and the name is "500kV CVT Multiple Dielectric Loss Testing System". It includes an on-board dielectric loss tester and a capacitive voltage transformer. The on-board dielectric loss tester includes a transformer with two output windings. One end of output winding one is connected in series with a relay, and the other end is grounded. One end of output winding two is grounded, and the other end is connected to the capacitive voltage transformer through a high-voltage vacuum relay. This testing system automates the measurement process, requiring only one connection and one-button operation to complete all test items for a 500kV CVT, effectively reducing testing time. Through effective functional integration, it reduces size, wiring attempts, and work efficiency, lowers labor intensity, and shortens testing time by two-thirds. The instrument has two output channels and simultaneously completes two capacitance measurements.
[0004] Authorization notice number CN 204789832 U, titled "Cable Changing Device and CVT High Voltage Testing Device for CVT High Voltage Testing," includes a first test circuit, a second test circuit, and connecting wires that connect the first and second test circuits. The first test circuit includes a first test wire, a high-voltage line, a first control switch, and a second control switch. The second test circuit includes a second test wire, a measuring line, and a third control switch. By controlling the states of the first and second control switches, the conduction and disconnection of the test circuits are controlled, changing the circuit connection method and achieving automatic cable changing. The cable changing device handles the high-altitude cable changing, reducing the number of personnel and physical exertion required, and lowering the equipment and personal injury risks during testing. By switching the internal measuring channels on and off, high-voltage testing of different voltage-dividing capacitors in the CVT is completed, allowing the entire high-voltage test to be completed with a single wiring connection, thus improving work efficiency.
[0005] The authorization announcement number is CN 211505705 U, and the name is "A CVT Multi-Functional Dielectric Loss Testing System". It includes a multi-functional testing device with primary-side capacitor connection points, secondary-side winding connection points, and dielectric loss tester connection points. The primary-side capacitor connection points are electrically connected to the primary-side capacitor of the capacitive voltage transformer, the secondary-side winding connection points are electrically connected to the secondary-side coil of the capacitive voltage transformer, and the dielectric loss tester connection points are electrically connected to the test points on the dielectric loss tester. Various dielectric loss measurement connections for the capacitive voltage transformer are achieved through an internal relay combination. The modular plug-in wiring facilitates operation, improves efficiency, saves time, and eliminates the safety risks associated with multiple climbing required for switching between different wiring methods.
[0006] Based on the above four patent documents and existing technical solutions, the inventors have identified the following technical problems in the existing technical solutions.
[0007] When measuring the relative dielectric loss and capacitance of a capacitive voltage transformer (CVT) under energization, the test data are only highly accurate when the device under test is a pure capacitor.
[0008] Testing the dielectric loss and capacitance of a capacitive voltage transformer (CVT) requires taking a current signal from the N-side of the CVT. However, due to interference from the intermediate transformer, the test data has a large deviation and cannot accurately reflect the insulation status of each capacitor in the CVT.
[0009] Existing technical issues and considerations:
[0010] How to solve the technical problem of poor performance in measuring dielectric loss and capacitance of capacitive voltage transformers. Summary of the Invention
[0011] The technical problem to be solved by the present invention is to provide a CVT, system, method and application for accurately measuring dielectric loss and capacitance, thereby solving the technical problem of poor measurement of dielectric loss and capacitance of capacitive voltage transformers.
[0012] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A CVT for accurately measuring dielectric loss capacitance includes a first capacitor section and an intermediate transformer. The first capacitor section includes a first capacitor and a second capacitor connected from bottom to top. The high-voltage terminal of the high-voltage coil of the intermediate transformer is connected to the junction of the first capacitor and the second capacitor. The device also includes a first circuit breaker and a second circuit breaker. One end of the first circuit breaker is connected to the junction of the first capacitor and the second capacitor, and the other end of the first circuit breaker is grounded. The high-voltage terminal of the high-voltage coil of the intermediate transformer is connected to the junction of the first capacitor and the second capacitor via the second circuit breaker. The first capacitor section, the intermediate transformer, the first circuit breaker, and the second circuit breaker form a capacitive voltage transformer (CVT).
[0013] A further technical solution includes a second capacitor located above the first capacitor, which is connected to the second capacitor on the side of the first capacitor.
[0014] A further technical solution includes a third capacitor located above the second capacitor, which is connected to the second capacitor.
[0015] A system for accurately measuring dielectric loss and capacitance includes the aforementioned capacitive voltage transformer (CVT) and a tester for measuring dielectric loss and capacitance, the tester being connected to the CVT.
[0016] A further technical solution is as follows: The capacitive voltage transformer (CVT) includes a first capacitive voltage transformer CVT1 and a second capacitive voltage transformer CVT2 with identical structures. The first circuit breaker of the first capacitive voltage transformer CVT1 is the first group of circuit breakers CB1, the second circuit breaker of the first capacitive voltage transformer CVT1 is the second group of circuit breakers CB2, the first circuit breaker of the second capacitive voltage transformer CVT2 is the third group of circuit breakers CB3, and the second circuit breaker of the second capacitive voltage transformer CVT2 is the fourth group of circuit breakers CB4. The first clamp-on ammeter CT1 of the tester is connected to the grounding wire of the first group of circuit breakers CB1, and the second clamp-on ammeter CT2 of the tester is connected to the grounding wire of the third group of circuit breakers CB3.
[0017] A further technical solution is that the high-voltage end of the tester is connected to the bottom of the first capacitor on the first capacitor side.
[0018] A method for accurately measuring dielectric loss capacitance, based on the above system, includes the following steps: disconnecting the protection device connected to the secondary windings of the first capacitive voltage transformer CVT1 and the second capacitive voltage transformer CVT2; closing the first circuit breaker CB1; opening the second circuit breaker CB2; closing the third circuit breaker CB3; opening the fourth circuit breaker CB4; and measuring the relative dielectric loss or relative capacitance between the two capacitive voltage transformers.
[0019] A method for accurately measuring dielectric loss and capacitance, based on the above system, includes the following steps: closing the first circuit breaker, opening the second circuit breaker, disconnecting the bottom of the first capacitor on the first capacitor side from ground, and measuring the dielectric loss or capacitance of the first capacitor on the first capacitor side using a power outage test method and a reverse wiring method.
[0020] One application, based on the above-mentioned capacitive voltage transformer (CVT), is for accurately measuring dielectric loss or capacitance.
[0021] A further technical solution is to accurately measure the relative dielectric loss or relative capacitance between two capacitive voltage transformers without power interruption.
[0022] A further technical solution is to accurately measure the dielectric loss or capacitance of the first capacitor on the first capacitor side during a power outage.
[0023] The beneficial effects of adopting the above technical solution are as follows:
[0024] A CVT for accurately measuring dielectric loss and capacitance includes a first capacitor section and an intermediate transformer. The first capacitor section comprises a first capacitor and a second capacitor connected from bottom to top. The high-voltage terminal of the high-voltage coil of the intermediate transformer is connected to the junction of the first and second capacitors. The system also includes a first circuit breaker and a second circuit breaker. One end of the first circuit breaker is connected to the junction of the first and second capacitors, and the other end is grounded. The high-voltage terminal of the high-voltage coil of the intermediate transformer is connected to the junction of the first and second capacitors via the second circuit breaker. The first capacitor section, the intermediate transformer, the first circuit breaker, and the second circuit breaker form a capacitive voltage transformer (CVT). This technical solution, through the first and second circuit breakers, provides a foundation for achieving better and more accurate measurement of the dielectric loss and capacitance of the capacitive voltage transformer.
[0025] A system for accurately measuring dielectric loss and capacitance includes the aforementioned capacitive voltage transformer (CVT) and a tester for measuring dielectric loss and capacitance, the tester being connected to the CVT. This technical solution, through a first circuit breaker, a second circuit breaker, and the tester, achieves better and more accurate measurement of the dielectric loss and capacitance of the capacitive voltage transformer.
[0026] The capacitive voltage transformer (CVT) includes a first capacitive voltage transformer CVT1 and a second capacitive voltage transformer CVT2 with identical structures. The first circuit breaker of the first capacitive voltage transformer CVT1 is the first group of circuit breakers CB1, the second circuit breaker of the first capacitive voltage transformer CVT1 is the second group of circuit breakers CB2, the first circuit breaker of the second capacitive voltage transformer CVT2 is the third group of circuit breakers CB3, and the second circuit breaker of the second capacitive voltage transformer CVT2 is the fourth group of circuit breakers CB4. The first clamp-on ammeter CT1 of the tester is connected to the grounding wire of the first group of circuit breakers CB1, and the second clamp-on ammeter CT2 of the tester is connected to the grounding wire of the third group of circuit breakers CB3. This technical solution allows for accurate measurement of the relative dielectric loss and relative capacitance between the two capacitive voltage transformers without power interruption.
[0027] A method for accurately measuring dielectric loss and capacitance, based on the aforementioned system, includes the following measurement steps: disconnecting the protection device connected to the secondary windings of the first capacitive voltage transformer CVT1 and the second capacitive voltage transformer CVT2; closing the first circuit breaker CB1; opening the second circuit breaker CB2; closing the third circuit breaker CB3; opening the fourth circuit breaker CB4; and measuring the relative dielectric loss or relative capacitance between the two capacitive voltage transformers. This technical solution, through the aforementioned measurement steps, achieves better and more accurate measurement of the dielectric loss and capacitance of capacitive voltage transformers.
[0028] A method for accurately measuring dielectric loss and capacitance, based on the aforementioned system, includes the following measurement steps: closing the first circuit breaker, opening the second circuit breaker, disconnecting and grounding the bottom of the first capacitor on the first capacitor side, and using a power-off test method and a reverse connection method to measure the dielectric loss or capacitance of the first capacitor on the first capacitor side. This technical solution, through the aforementioned measurement steps, achieves better and more accurate measurement of the dielectric loss and capacitance of capacitive voltage transformers.
[0029] One application, based on the aforementioned capacitive voltage transformer (CVT), is for accurately measuring dielectric loss or capacitance. This technical solution provides better and more accurate measurement of dielectric loss and capacitance using the capacitive voltage transformer.
[0030] See the detailed implementation section for further description. Attached Figure Description
[0031] Figure 1 This is a wiring diagram of Embodiment 1 of the present invention;
[0032] Figure 2 This is a wiring diagram of Embodiment 2 of the present invention;
[0033] Figure 3 This is a wiring diagram of Embodiment 3 of the present invention;
[0034] Figure 4 This is the wiring diagram for a CVT with a selector switch;
[0035] Figure 5 This is the wiring diagram for measuring C42;
[0036] Figure 6 This is the wiring diagram for measuring C41. Detailed Implementation
[0037] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.
[0038] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.
[0039] Example 1:
[0040] like Figure 1 As shown, the present invention discloses a CVT for accurately measuring dielectric loss capacitance, comprising a first capacitor, a second capacitor C1-2 located above the first capacitor, a third capacitor C1-3 located above the second capacitor C1-2, an intermediate transformer, a first circuit breaker, and a second circuit breaker. The first capacitor includes a first capacitor C1-11 and a second capacitor C1-12 connected from bottom to top on the first capacitor side.
[0041] The first circuit breaker is the first group of circuit breakers, CB1.
[0042] The second circuit breaker is the second group of circuit breakers, CB2.
[0043] The second capacitor C1-2 is connected to the second capacitor C1-12 on the side of the first capacitor.
[0044] The third capacitor C1-3 is connected to the second capacitor C1-2.
[0045] like Figure 1 As shown, one end of the first circuit breaker CB1 is connected to the junction A1 of the first capacitor C1-11 and the second capacitor C1-12.
[0046] The other end of the first circuit breaker CB1 is grounded.
[0047] The high-voltage end of the high-voltage coil of the intermediate transformer is connected to the junction A1 of the first capacitor C1-11 and the second capacitor C1-12 via the second circuit breaker CB2.
[0048] The first capacitor, the second capacitor C1-2, the third capacitor C1-3, the intermediate transformer, the first circuit breaker, and the second circuit breaker form a capacitive voltage transformer (CVT).
[0049] Example 2:
[0050] like Figure 2 As shown, the present invention discloses a system for accurately measuring dielectric loss and capacitance, based on the capacitive voltage transformer (CVT) of Embodiment 1, and also includes a tester for measuring dielectric loss and capacitance.
[0051] like Figure 2 As shown, the capacitive voltage transformer (CVT) includes a first capacitive voltage transformer (CVT1) and a second capacitive voltage transformer (CVT2) with identical structures.
[0052] The first circuit breaker of the first capacitive voltage transformer CVT1 is the first group of circuit breakers CB1.
[0053] The second circuit breaker of the first capacitive voltage transformer CVT1 is the second set of circuit breakers CB2.
[0054] The first circuit breaker of the second capacitor voltage transformer CVT2 is the third circuit breaker CB3.
[0055] The second circuit breaker of the second capacitor voltage transformer CVT2 is the fourth circuit breaker CB4.
[0056] The first clamp meter CT1 of the tester is connected to the grounding wire of the first circuit breaker CB1.
[0057] The second clamp meter CT2 of the tester is connected to the grounding wire of the third circuit breaker CB3.
[0058] Example 3:
[0059] like Figure 3 As shown, the present invention discloses a system for accurately measuring dielectric loss and capacitance, based on the capacitive voltage transformer (CVT) of Embodiment 1, and also includes a tester for measuring dielectric loss and capacitance.
[0060] like Figure 3 As shown, the high voltage terminal of the tester is connected to the bottom of the first capacitor C1-11 on the first capacitor side.
[0061] Example 4:
[0062] This invention discloses a method for accurately measuring dielectric loss and capacitance. Based on the system of Embodiment 2, the method includes the following steps: disconnecting the protection device connected to the secondary windings of the first capacitive voltage transformer CVT1 and the second capacitive voltage transformer CVT2; closing the first circuit breaker CB1; opening the second circuit breaker CB2; closing the third circuit breaker CB3; opening the fourth circuit breaker CB4; and measuring the relative dielectric loss and relative capacitance between the two capacitive voltage transformers.
[0063] Example 5:
[0064] This invention discloses a method for accurately measuring dielectric loss and capacitance. Based on the system of Embodiment 3, the method includes the following steps: closing the first circuit breaker, opening the second circuit breaker, disconnecting the bottom of the first capacitor C1-11 on the first capacitor side from ground, and using a power outage test method and reverse wiring method to measure the dielectric loss and capacitance of the first capacitor C1-11 on the first capacitor side.
[0065] Example 6:
[0066] This invention discloses an application, based on the system of Embodiment 2, for accurately measuring the relative dielectric loss and relative capacitance between two capacitive voltage transformers without power interruption.
[0067] Example 7:
[0068] This invention discloses a use of a system based on Embodiment 3 for accurately measuring the dielectric loss and capacitance of the first capacitor C1-11 on the first capacitor side during a power outage.
[0069] The testers used to measure dielectric loss and capacitance are existing technologies and will not be described in detail here.
[0070] The concept of this application:
[0071] A first set of circuit breakers CB1 is installed between the high-voltage end A1 of the intermediate transformer of the first capacitive voltage transformer CVT1 and ground; a second set of circuit breakers CB2 is installed between the high-voltage end A1 of the intermediate transformer and the intermediate transformer.
[0072] A third set of circuit breakers CB3 is installed between the high-voltage end A2 of the intermediate transformer of the second capacitive voltage transformer CVT2 and ground; a fourth set of circuit breakers CB4 is installed between the high-voltage end A2 of the intermediate transformer and the intermediate transformer.
[0073] By controlling the states of CB1 to CB4, the relative dielectric loss and capacitance of (C1-12, C1-2, and C1-3) in series were measured using a live-line test method with (C2-12, C2-2, and C2-3) in series as a reference. The problem of inaccurate relative dielectric loss and capacitance was solved by using reverse connection to measure the dielectric loss and capacitance of C1-11.
[0074] 1. Technical problems to be solved
[0075] When measuring the relative dielectric loss and capacitance of a capacitive voltage transformer (CVT) under energization, the test data are only highly accurate when the device under test is a pure capacitor.
[0076] Testing the dielectric loss and capacitance of a capacitive voltage transformer (CVT) requires taking a current signal from the N-side of the CVT. However, due to interference from the intermediate transformer, the test data has a large deviation and cannot accurately reflect the insulation status of each capacitor in the CVT.
[0077] 2 Technical Solution
[0078] A first set of circuit breakers CB1 is installed between the high-voltage end A1 of the intermediate transformer of the first capacitive voltage transformer CVT1 and ground; a second set of circuit breakers CB2 is installed between the high-voltage end A1 of the intermediate transformer and the intermediate transformer.
[0079] A third set of circuit breakers CB3 is installed between the high-voltage end A2 of the intermediate transformer of the second capacitive voltage transformer CVT2 and ground; a fourth set of circuit breakers CB4 is installed between the high-voltage end A2 of the intermediate transformer and the intermediate transformer.
[0080] ①Measure the relative dielectric loss and capacitance with (C2-12, C2-2 and C2-3) connected in series as the reference, and (C1-12, C1-2 and C1-3) connected in series.
[0081] like Figure 2 The diagram shown is a wiring diagram for measuring the relative dielectric loss and relative capacitance of (C1-12, C1-2, and C1-3) with (C2-12, C2-2, and C2-3) connected in series as a reference.
[0082] The first step is to disconnect the protection device connected to the secondary windings of the first capacitive voltage transformer CVT1 and the second capacitive voltage transformer CVT2 (the secondary voltage of the capacitive voltage transformer CVT will change during the measurement process, which may cause the protection to malfunction).
[0083] The second step is to close the first circuit breaker CB1, open the second circuit breaker CB2, close the third circuit breaker CB3, and open the fourth circuit breaker CB4.
[0084] The third step involves clamping the first clamp meter CT1 of the relative dielectric loss and capacitance tester onto the grounding wire to the left of the first circuit breaker CB1 to measure the grounding current.
[0085] The third step involves attaching the second clamp meter CT2 of the relative dielectric loss and capacitance tester to the grounding wire on the left side of the third circuit breaker CB3 to measure the grounding current.
[0086] The fourth part involves using a relative dielectric loss and capacitance tester to measure the relative dielectric loss and capacitance based on (C2-12, C2-2, and C2-3) connected in series, and (C1-12, C1-2, and C1-3) connected in series.
[0087] At this time, C1-12, C1-2 and C1-3 are connected in series and grounded through CB1 to form a pure capacitor circuit; C2-12, C2-2 and C2-3 are connected in series and grounded through CB3 to form a pure capacitor circuit, which is not affected by the intermediate transformer.
[0088] At this time, by taking the current signal through the grounding wires behind CB1 and CB3, the relative dielectric loss and capacitance of (C1-12, C1-2 and C1-3) in series can be accurately measured with (C2-12, C2-2 and C2-3) in series as the reference.
[0089] ② Measure the dielectric loss capacitance of C1-11
[0090] like Figure 3 As shown, close CB1 and open CB2. C1-11 is grounded at both ends and not energized. Use the power-off test method and reverse connection method to measure the dielectric loss and capacitance of C1-11.
[0091] First, close CB1 and open CB2.
[0092] The second step is to turn on the ground of N1.
[0093] The third step is to connect the dedicated high-voltage output line of the dielectric loss and capacitance tester to N1.
[0094] The fourth step involves operating the dielectric loss and capacitance tester and measuring the dielectric loss and capacitance of C1-11 using the reverse connection method.
[0095] To clearly illustrate the differences between the technical solution of this application and the technical solution of another application filed concurrently, the following explanation is provided.
[0096] The technical solution of this application focuses on uninterrupted measurement, but can also be used for measurement during power outages.
[0097] The technical solution in another application focuses on power outage measurement.
[0098] The technical solution of another application is as follows:
[0099] CVT with Selector Switch Schematic Diagram and Precautions
[0100] like Figure 4 As shown, the CVT selector switch wiring principle is as follows: one end is grounded, and the other end is connected to the high-voltage end of the intermediate transformer.
[0101] The following points should be noted:
[0102] 1. Select switch position management
[0103] Once the selector switch is confirmed to be in the "Run" position, it should be locked, managed by designated personnel, and should not be moved arbitrarily to prevent damage or accidental operation.
[0104] 2. The operating position can be measured using the "self-excitation method".
[0105] like Figure 4 As shown, when the selector switch is in the "Run" position, the wiring method is the same as that of a conventional CVT, and the self-excitation method can normally measure the test data in the next section.
[0106] 3. The "self-excitation method" cannot be used for measurement at the "test" location.
[0107] The self-excited method involves applying voltage to the secondary coil to excite a high voltage at the "high voltage terminal (A)" of the intermediate transformer, i.e., generating a high voltage across C41 and C42, and then measuring the dielectric loss capacitance of C41 and C42.
[0108] When the selector switch is in the "Test" position, the transformer's "high voltage terminal (A)" is grounded. At this time, the voltage across C41 and C42 is 0, and the "self-excitation method" cannot measure the correct test data.
[0109] 4. Measurement method for the "reverse connection" of C41 and C42 at the "test" location.
[0110] like Figure 5 and Figure 6 As shown, the dielectric loss and capacitance of C41 and C42 were measured using a 10kV reverse connection with M shield and a 2kV reverse connection, respectively.
[0111] After this application was kept confidential for a period of time, the beneficial aspects reported by the on-site technical personnel were:
[0112] like Figure 1 As shown, the technical solution of this application is a capacitive voltage transformer (CVT) and its testing method for accurately measuring dielectric loss and capacitance without power interruption. The method uses a live testing approach to measure the relative dielectric loss and capacitance with (C2-12, C2-2, and C2-3) connected in series as a reference and (C1-12, C1-2, and C1-3) connected in series. The method of measuring the dielectric loss and capacitance of C1-11 by reverse connection solves the problem of inaccurate relative dielectric loss and capacitance.
[0113] A CVT for accurately measuring dielectric loss and capacitance includes a first capacitor section and an intermediate transformer. The first capacitor section includes a first capacitor and a second capacitor connected from bottom to top. The high-voltage terminal of the high-voltage coil of the intermediate transformer is connected to the junction of the first and second capacitors. The system also includes a first circuit breaker and a second circuit breaker. One end of the first circuit breaker is connected to the junction of the first and second capacitors, and the other end is grounded. The high-voltage terminal of the high-voltage coil of the intermediate transformer is connected to the junction of the first and second capacitors via the second circuit breaker. The first capacitor section, the intermediate transformer, the first circuit breaker, and the second circuit breaker form a capacitive voltage transformer (CVT). Through the first and second circuit breakers, the CVT provides a foundation for more effective and accurate measurement of the dielectric loss and capacitance of the capacitive voltage transformer.
[0114] A system for accurately measuring dielectric loss and capacitance includes the aforementioned capacitive voltage transformer (CVT) and a tester for measuring dielectric loss and capacitance. The tester is connected to the CVT and, through a first circuit breaker, a second circuit breaker, and the tester, achieves better and more accurate measurement of the dielectric loss and capacitance of the CVT.
[0115] The capacitive voltage transformer (CVT) includes a first capacitive voltage transformer CVT1 and a second capacitive voltage transformer CVT2 with identical structures. The first circuit breaker of the first capacitive voltage transformer CVT1 is the first group of circuit breakers CB1, the second circuit breaker of the first capacitive voltage transformer CVT1 is the second group of circuit breakers CB2, the first circuit breaker of the second capacitive voltage transformer CVT2 is the third group of circuit breakers CB3, and the second circuit breaker of the second capacitive voltage transformer CVT2 is the fourth group of circuit breakers CB4. The first clamp-on ammeter CT1 of the tester is connected to the grounding wire of the first group of circuit breakers CB1, and the second clamp-on ammeter CT2 of the tester is connected to the grounding wire of the third group of circuit breakers CB3. This technical solution allows for accurate measurement of the relative dielectric loss and relative capacitance between the two capacitive voltage transformers without power interruption.
[0116] A method for accurately measuring dielectric loss and capacitance, based on the aforementioned system, includes the following measurement steps: disconnecting the protection device connected to the secondary windings of the first capacitive voltage transformer CVT1 and the second capacitive voltage transformer CVT2; closing the first circuit breaker CB1; opening the second circuit breaker CB2; closing the third circuit breaker CB3; opening the fourth circuit breaker CB4; and measuring the relative dielectric loss or relative capacitance between the two capacitive voltage transformers. Through these measurement steps, the method achieves better and more accurate measurement of the dielectric loss and capacitance of the capacitive voltage transformers.
[0117] A method for accurately measuring dielectric loss and capacitance, based on the above system, includes the following measurement steps: closing the first circuit breaker, opening the second circuit breaker, disconnecting the bottom of the first capacitor on the first capacitor side from ground, and using a power-off test method and reverse wiring method to measure the dielectric loss or capacitance of the first capacitor on the first capacitor side. Through the above measurement steps, the method achieves better and more accurate measurement of dielectric loss and capacitance of capacitive voltage transformers.
[0118] One application is based on the above-mentioned capacitive voltage transformer (CVT) for accurate measurement of dielectric loss or capacitance. The capacitive voltage transformer has better dielectric loss and capacitance performance and is more accurate.
[0119] Currently, the technical solution of this invention has undergone pilot testing, which is a small-scale trial of the product before large-scale mass production. After the pilot testing was completed, a user survey was conducted on a small scale, and the survey results showed that user satisfaction was high. Now, preparations have begun for the formal production and industrialization of the product (including intellectual property risk warning surveys).
Claims
1. A method of accurately measuring dielectric capacitance, characterized by: A system for accurately measuring dielectric loss and capacitance includes the following steps: disconnecting the protection device connected to the secondary windings of the first capacitive voltage transformer CVT1 and the second capacitive voltage transformer CVT2; closing the first circuit breaker CB1; opening the second circuit breaker CB2; closing the third circuit breaker CB3; opening the fourth circuit breaker CB4; and measuring the relative dielectric loss or relative capacitance between the two capacitive voltage transformers. The system includes a CVT for accurately measuring dielectric loss and capacitance, and a tester for measuring dielectric loss and capacitance. The CVT for accurately measuring dielectric loss and capacitance includes a first capacitor section, an intermediate transformer, a first circuit breaker, and a second circuit breaker. The first capacitor section includes a first capacitor and a second capacitor connected from bottom to top. The high-voltage end of the high-voltage coil of the intermediate transformer is connected to the junction of the first and second capacitors. One end of the first circuit breaker is connected to the junction of the first and second capacitors, and the other end of the first circuit breaker is grounded. The high-voltage end of the high-voltage coil of the intermediate transformer is connected to the junction of the first and second capacitors via the second circuit breaker. The first capacitor, the intermediate transformer, the first circuit breaker, and the second circuit breaker form a capacitive voltage transformer (CVT). The tester is connected to the CVT. The CVT includes a first CVT1 and a second CVT2 with identical structures. The first circuit breaker of the first CVT1 is the first group of circuit breakers CB1, the second circuit breaker of the first CVT1 is the second group of circuit breakers CB2, the first circuit breaker of the second CVT2 is the third group of circuit breakers CB3, and the second circuit breaker of the second CVT2 is the fourth group of circuit breakers CB4. The first clamp-on ammeter CT1 of the tester is connected to the grounding wire of the first group of circuit breakers CB1, and the second clamp-on ammeter CT2 of the tester is connected to the grounding wire of the third group of circuit breakers CB3.
2. The method of claim 1, wherein: It also includes a second capacitor located above the first capacitor, which is connected to the second capacitor on the side of the first capacitor; and a third capacitor located above the second capacitor, which is connected to the second capacitor.
3. The method for accurately measuring dielectric loss capacitance according to claim 1, characterized in that: The high-voltage terminal of the tester is connected to the bottom of the first capacitor on the first capacitor side.
4. The method of claim 3, wherein: It also includes the following steps: closing the first circuit breaker, opening the second circuit breaker, disconnecting the bottom of the first capacitor on the first capacitor side from ground, and measuring the dielectric loss or capacitance of the first capacitor on the first capacitor side using the power outage test method and the reverse wiring method.
5. The method of claim 1, wherein: It is also used to accurately measure the relative dielectric loss or relative capacitance between two capacitive voltage transformers without power interruption. 6. The method of accurately measuring dielectric loss capacitance according to claim 1, wherein: It is also used to accurately measure the dielectric loss or capacitance of the first capacitor on the first capacitor side during power outages.