Capacitive voltage transformer

Abstract

The utility model relates to a capacitive voltage transformer. The capacitive voltage transformer comprises an electromagnetic unit and a capacitive voltage divider. The same insulating fluid is adopted in the capacitive voltage transformer, certain pressure exists, compared with a traditional capacitive voltage transformer, a metal bottom cover, a medium-voltage sleeve, a low-voltage sleeve and corresponding sealing washers of the capacitive voltage divider are reduced, the risk of leakage of the medium-voltage sleeve and the low-voltage sleeve is eradicated, and the reliability of the capacitive voltage transformer is improved. The insulating channels of the capacitive voltage divider and the electromagnetic unit are communicated with each other, so that the capacitive voltage divider and the electromagnetic unit share the same insulating fluid, and certain internal pressure is applied to the capacitive voltage transformer through the expander for temperature compensation, so that medium-voltage and low-voltage bushings can be effectively prevented from leaking, loss is reduced, casualty accidents are reduced, and popularization and application of the capacitive voltage transformer are facilitated.

Description

Technical Field

[0001] The utility model relates to the technical field of protection of voltage transformers and electrical equipment, in particular to a capacitive voltage transformer using an insulating fluid. Background Art

[0002] Capacitor voltage transformers are widely used in high voltage, extra high voltage and ultra high voltage 35~1000kV power systems for electric energy metering, voltage measurement and carrier communication, providing analog voltage signals for microcomputer control and relay protection devices.

[0003] The capacitive voltage transformer consists of two parts: a capacitive voltage divider and an electromagnetic unit. The capacitive voltage divider consists of an upper cover, a lower cover, a core part, an expander with temperature and pressure regulation, and an outer insulating sleeve. The capacitive voltage divider consists of several capacitor units, and the inside of the capacitor unit is filled with insulating oil with a slight positive pressure. The insulating oil is mostly phenylxylene ethane (PXE), phenylethylphenylethane (PEPE), benzyltoluene, etc. The electromagnetic unit consists of an intermediate transformer, a compensating reactor and protection devices, a damping system for suppressing ferromagnetic resonance, and other components. The inside generally uses 25# and 45# transformer oil as the insulating medium.

[0004] At present, the connection part between the capacitor voltage divider and the electromagnetic unit is separated by a cover plate and a sealing gasket, and medium-voltage and low-voltage bushings are used for electrical isolation and insulation protection. This measure requires both isolation and insulation of the two phase-isolated components. The production operation is relatively complicated, and the requirements for the sealing parts and sealing gaskets are relatively strict. There is a risk of oil leakage, which can easily damage the insulation of the capacitor voltage transformer. If the oil leakage occurs during the operation of the product, it may even affect the connected power system, causing system damage or even system failure, threatening power safety. Utility Model Content

[0005] The utility model aims to provide a capacitive voltage transformer, comprising an electromagnetic unit and a capacitive voltage divider, wherein the insulating channels of the electromagnetic unit and the capacitive voltage divider are interconnected to solve the risk of leakage of medium-voltage and low-voltage bushings, which is beneficial for processing and manufacturing enterprises to reduce equipment investment, optimize production line layout, reduce process processing procedures, facilitate production and manufacturing manufacturers' process layout and reduce investment costs.

[0006] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0007] A capacitive voltage transformer comprises an electromagnetic unit and a capacitive voltage divider, wherein the voltage transformer contains an insulating fluid;

[0008] Further, the electromagnetic unit includes an insulating box, an intermediate transformer, a compensating reactor, a damping system and a protective device;

[0009] Furthermore, a secondary outlet box is provided on a side wall of one side of the insulation box, and a low-voltage terminal block is provided on the secondary outlet box;

[0010] Furthermore, the capacitive voltage divider is arranged on the insulating box, an insulating channel is arranged inside the capacitive voltage divider, and the channels of the electromagnetic unit and the capacitive voltage divider are interconnected;

[0011] Further, the capacitive voltage divider includes a bottom support member, the bottom support member is arranged at the upper end of the insulation box, and the insulation channel is arranged in the middle of the bottom support member;

[0012] Furthermore, a baffle is fixed on the bottom support member, a sleeve is arranged at the upper end of the bottom support member, a core is arranged inside the sleeve, and the core is fixed on the baffle;

[0013] Furthermore, a top cover is provided at the upper end of the core, an expander protection device is fixed at the upper end of the top cover, a primary terminal board is provided at the upper end of the expander protection device, and an expander is arranged inside the expander protection device;

[0014] Furthermore, the bottom support member is made of non-metallic material;

[0015] Furthermore, the baffle is made of non-metallic material;

[0016] Further, the bottom support member is provided with a threading hole;

[0017] Furthermore, the core contains a medium voltage connecting line and a low voltage connecting line;

[0018] Furthermore, the medium voltage connecting wire of the core is connected to the primary of the intermediate transformer of the electromagnetic unit through the threading hole of the bottom support member;

[0019] Furthermore, the low-voltage connecting wire of the core is connected to the low-voltage wiring board of the secondary outlet box of the electromagnetic unit through the threading hole of the bottom support member;

[0020] Furthermore, a scale mark is provided on the outside of the expander;

[0021] Furthermore, the expander protection device is provided with an inspection window;

[0022] Furthermore, an injection port for pressurization and pressure relief is provided at the upper end of the expander;

[0023] Furthermore, the pressure of the expander is released by loosening the injection port, and the insulating fluid in the expander is discharged.

[0024] Furthermore, the insulating fluid is insulating liquid or insulating gas.

[0025] Compared with the prior art, the utility model has the following beneficial technical effects:

[0026] Compared with the traditional capacitive voltage transformer, the capacitive voltage transformer of the utility model abandons the current design concept of isolating the capacitive voltage divider and the electromagnetic unit of the capacitive voltage transformer, and interconnects the insulating channels of the capacitive voltage divider and the electromagnetic unit so that the capacitive voltage divider and the electromagnetic unit use the same insulating fluid, which can reduce the types of insulating fluids of the capacitive voltage transformer, is beneficial for processing and manufacturing enterprises to reduce equipment investment, optimize production line layout, reduce process processing procedures, etc., and eliminate the risk of leakage of medium-voltage and low-voltage bushings.

[0027] Furthermore, compared with the traditional capacitive voltage transformer, the capacitive voltage transformer of the utility model reduces the metal bottom cover, medium-voltage bushing, low-voltage bushing and corresponding sealing gasket of the capacitor voltage divider. The bottom of the voltage-dividing capacitor adopts a non-metallic support, and the non-metallic support contains a non-metallic baffle, so that discharge breakdown will not occur. It is only necessary to properly separate the medium voltage and the low voltage to meet the potential difference, which not only reduces the weight of the equipment, but also reduces the manufacturing cost and improves the sealing and insulation performance of the equipment. In the prior art, the electromagnetic unit and the capacitive voltage divider use two different insulating oils. Because the potential of the metal cover plate and the oil tank is low (zero) after installation, it is necessary to use a metal cover plate and a sealing gasket for isolation, and use the umbrella skirts of the medium-voltage and low-voltage bushings for electrical conduction and insulation compensation, so that there is no discharge breakdown when the medium and low voltage connecting lines pass through.

[0028] Furthermore, compared with traditional capacitive voltage transformers, the capacitive voltage transformer of the utility model applies a certain internal pressure to the capacitive voltage transformer through an expander, which can automatically adjust the volume of the insulating fluid when the temperature changes, thereby achieving temperature compensation and ensuring that the capacitive voltage transformer can maintain high precision and stability under various temperature conditions, thereby extending the service life of the capacitive voltage transformer.

[0029] Furthermore, compared with traditional capacitive voltage transformers, the capacitive voltage transformer of the utility model can clearly display the insulating fluid scale by providing an inspection window, so that operation and maintenance personnel can directly observe the scale changes of the expander without disassembling the equipment or adopting other complex detection methods, which effectively improves the accuracy of insulating fluid scale observation, helps to prevent equipment failures caused by abnormal insulating fluid scale, and enhances the safe operation capability of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a front view of a capacitive voltage transformer of the utility model;

[0031] Figure 2 This is a left view of a capacitive voltage transformer of the utility model;

[0032] Among them, 1-electromagnetic unit, 2-capacitor voltage divider, 3-secondary outlet box, 4-low-voltage terminal board, 5-bottom support, 6-top cover, 7-expander protection device, 8-primary terminal board, 9-insulating box, 10-insulating fluid, 11-porcelain sleeve, 12-core, 13-expander, 14-injection port, 15-baffle. DETAILED DESCRIPTION

[0033] In order to make the purpose, features and advantages of the utility model more obvious and easy to understand, the technical scheme in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the embodiment described below is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0034] In the description of the present utility model, it is to be understood that when a component is considered to be "connected" to another component, it may be directly connected to the other component or there may be a centrally arranged component at the same time. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a centrally arranged component at the same time.

[0035] In addition, terms such as "long", "short", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings and are only used to facilitate the description of the present invention. They do not indicate or imply that the device or component referred to must have this specific direction or operate with a specific direction structure, and should not be understood as a limitation of the present invention.

[0036] The technical solution of the utility model is further explained below with reference to the accompanying drawings and through specific implementation methods.

[0037] Embodiment 1:

[0038] See also Figure 1 and Figure 2 , this embodiment provides a capacitive voltage transformer in which the electromagnetic unit 1 and the capacitive voltage divider 2 are interconnected, so that the same insulating liquid is used inside the voltage transformer and has a certain pressure;

[0039] Preferably, the insulating liquid is phenylxyleneethane (PXE), phenylethylphenylethane (PEPE), benzyltoluene, environmentally friendly insulating oil, etc.;

[0040] Preferably, the electromagnetic unit 1 includes an insulating box 9, an intermediate transformer, a compensating reactor, a damping system, and a protective device;

[0041] Preferably, the insulating box 9 is a carrier for containing the intermediate transformer, the compensating reactor, the damping system, and the protective device;

[0042] Preferably, a secondary outlet box 3 is provided on one side of the insulation box 9, and a low-voltage terminal block 4 is provided on the secondary outlet box 3;

[0043] Preferably, the capacitive voltage divider 2 comprises a bottom support member 5, the bottom support member 5 is arranged at the upper end of the insulating box 9, and the insulating channel is arranged in the middle of the bottom support member;

[0044] Preferably, a baffle 15 is fixed on the bottom support member 5, a sleeve 11 is provided at the upper end of the bottom support member 5, a core 12 is provided inside the sleeve 11, the core 12 is fixed on the baffle 15, a top cover 6 is provided at the upper end of the core 12, an expander protection device 7 is fixed at the upper end of the top cover 6, a primary terminal board 8 is provided at the upper end of the expander protection device 7, and an expander 13 is provided inside the expander protection device 7;

[0045] Preferably, the bottom support member 5 is made of non-metallic material, and the baffle 15 is also made of non-metallic material;

[0046] Preferably, the sleeve 11 is made of two materials: porcelain and composite;

[0047] Preferably, the core 12 contains a medium voltage connection line and a low voltage connection line, and the medium voltage connection line is connected to the primary of the intermediate transformer of the electromagnetic unit 1 through the bottom support 5;

[0048] Preferably, the low-voltage connecting wire of the core 12 is connected to the low-voltage terminal board 4 of the secondary outlet box 3 of the electromagnetic unit 1 through the bottom support 5;

[0049] Preferably, the expander 13 is provided with a marking scale on the outside;

[0050] Preferably, the expander 13 has an injection port 14;

[0051] Preferably, a certain pressure is applied to the capacitive voltage divider 2 through the injection port 14 of the expander 13 for temperature compensation of the capacitive voltage transformer, and the pressure value is 0 to 0.018 MPa;

[0052] Preferably, the pressure of the expander 13 can be released by loosening the injection port 14 of the expander 13, and the insulating liquid in the expander 13 can be discharged;

[0053] Preferably, the expander protection device 7 has an inspection window, through which the scale of the expander 13 can be observed;

[0054] Preferably, the inspection window is made of resin or glass.

[0055] Embodiment 2:

[0056] See also Figure 1 and Figure 2 , this embodiment provides a capacitive voltage transformer in which the electromagnetic unit 1 and the capacitive voltage divider 2 are interconnected, so that the same insulating gas is used inside the voltage transformer and has a certain pressure;

[0057] Preferably, the insulating gas is sulfur hexafluoride (SF6), nitrogen (N2), carbon dioxide (CO2), clean air, etc.;

[0058] Preferably, the electromagnetic unit 1 includes an insulating box 9, an intermediate transformer, a compensating reactor, a damping system, and a protective device;

[0059] Preferably, the insulating box 9 is a carrier for containing the intermediate transformer, the compensating reactor, the damping system, and the protective device;

[0060] Preferably, a secondary outlet box 3 is provided on one side of the insulation box 9, and a low-voltage terminal block 4 is provided on the secondary outlet box 3;

[0061] Preferably, the capacitive voltage divider 2 comprises a bottom support member 5, the bottom support member 5 is arranged at the upper end of the insulating box 9, and the insulating channel is arranged in the middle of the bottom support member;

[0062] Preferably, a baffle 15 is fixed on the bottom support member 5, a sleeve 11 is provided at the upper end of the bottom support member 5, a core 12 is provided inside the sleeve 11, the core 12 is fixed on the baffle 15, a top cover 6 is provided at the upper end of the core 12, an expander protection device 7 is fixed at the upper end of the top cover 6, a primary terminal board 8 is provided at the upper end of the expander protection device 7, and an expander 13 is provided inside the expander protection device 7;

[0063] Preferably, the bottom support member 5 is made of non-metallic material, and the baffle 15 is also made of non-metallic material;

[0064] Preferably, the sleeve 11 is made of two materials: porcelain and composite;

[0065] Preferably, the core 12 contains a medium voltage connection line and a low voltage connection line, and the medium voltage connection line is connected to the primary of the intermediate transformer of the electromagnetic unit 1 through the bottom support 5;

[0066] Preferably, the low-voltage connecting wire of the core 12 is connected to the low-voltage terminal board 4 of the secondary outlet box 3 of the electromagnetic unit 1 through the bottom support 5;

[0067] Preferably, the expander 13 is provided with a marking scale on the outside;

[0068] Preferably, the expander 13 has an injection port 14;

[0069] Preferably, a certain pressure is applied to the capacitive voltage divider 2 through the injection port 14 of the expander 13 for temperature compensation of the capacitive voltage transformer, and the pressure value is 0 to 0.018 MPa;

[0070] Preferably, the pressure of the expander 13 can be released by loosening the injection port 14 of the expander 13, and the insulating gas in the expander 13 can be discharged;

[0071] Preferably, the expander protection device 7 has an inspection window, through which the scale of the expander 13 can be observed;

[0072] Preferably, the inspection window is made of resin or glass.

[0073] The utility model provides a capacitive voltage transformer using insulating fluid, which solves the problem of leakage of medium-voltage and low-voltage bushings. It can not only reduce the types of insulating fluids of the capacitive voltage transformer, but also help processing and manufacturing companies to reduce equipment investment, optimize production line layout, and reduce process processing procedures. Correspondingly, it will also reduce considerable pressure on on-site inspection and maintenance of substations and switch converter stations.

[0074] As described above, the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the utility model.

[0075] The following is an explanation of the above technical terms:

[0076] Instrument Transformer: A special transformer designed to transmit information signals to measuring instruments, meters and protection or control devices or similar electrical equipment.

[0077] Capacitor voltage transformer: CVT for short, is an electrical device used in substations for electric energy metering, data measurement, relay microcomputer protection and carrier communication. It consists of two parts: a capacitive voltage divider and an electromagnetic unit.

[0078] Capacitor voltage divider: The rated primary voltage of the CVT is divided by the capacitor element and a relatively low intermediate voltage is drawn out and provided to the inside of the electromagnetic unit.

[0079] Electromagnetic unit: It includes the insulating box, medium-voltage transformer, compensating reactor and protection devices, damping system for suppressing ferromagnetic resonance and other components. It transforms the medium voltage led out by the capacitor divider into a lower secondary voltage for collection and use by secondary instruments such as relay protection and metering.

[0080] Insulation box: located at the bottom of the capacitive voltage transformer, it contains the components of the electromagnetic unit.

[0081] Bushing: The outer insulating part of the capacitive voltage transformer, which is divided into two types: porcelain and composite materials.

[0082] Expander: An internal hydraulic or pneumatic pressure regulating device of a capacitor voltage transformer, used to compensate for the volume change of the internal insulating fluid caused by temperature changes and ensure the safety of product operation.

Claims

1. A capacitive voltage transformer, characterized in that: It comprises an electromagnetic unit (1) and a capacitive voltage divider (2); The electromagnetic unit (1) comprises an insulating box (9); a secondary outlet box (3) is arranged on a side wall of one side of the insulating box (9); a low-voltage terminal block (4) is arranged on the secondary outlet box (3); and an insulating channel is arranged inside the electromagnetic unit (1); The capacitive voltage divider (2) is arranged on an insulating box (9), an insulating channel is arranged inside the capacitive voltage divider (2), and the insulating channels of the electromagnetic unit (1) and the capacitive voltage divider (2) are interconnected, so that the same insulating fluid (10) is used inside the voltage transformer.

2. A capacitive voltage transformer according to claim 1, characterized in that: The capacitive voltage divider (2) comprises a bottom support member (5), the bottom support member (5) is arranged at the upper end of the insulating box (9), and the insulating channel is arranged in the middle of the bottom support member (5).

3. A capacitive voltage transformer according to claim 2, characterized in that: A baffle (15) is fixed on the bottom support member (5), a sleeve (11) is arranged at the upper end of the bottom support member (5), a core (12) is arranged inside the sleeve (11), the core (12) is fixed on the baffle (15), a top cover (6) is arranged at the upper end of the core (12), an expander protection device (7) is fixed at the upper end of the top cover (6), a primary terminal board (8) is arranged at the upper end of the expander protection device (7), and an expander (13) is arranged inside the expander protection device (7).

4. A capacitive voltage transformer according to claim 3, characterized in that: The bottom support member (5) is made of a non-metallic material, and the baffle (15) is made of a non-metallic material.

5. A capacitive voltage transformer according to claim 3, characterized in that: The outside of the expander (13) is provided with scale markings.

6. A capacitive voltage transformer according to claim 3, characterized in that: The expander protection device (7) is provided with an inspection window.

7. A capacitive voltage transformer according to claim 3, characterized in that: The bottom support member (5) is provided with a threading hole, and the core (12) contains a medium-voltage connecting wire and a low-voltage connecting wire.

8. A capacitive voltage transformer according to claim 7, characterized in that: The medium-voltage connection line of the core (12) is connected to the primary of the intermediate transformer of the electromagnetic unit (1) through the wire threading hole of the bottom support member (5), and the low-voltage connection line of the core (12) is connected to the low-voltage terminal board (4) of the secondary outlet box (3) of the electromagnetic unit (1) through the wire threading hole of the bottom support member (5).

9. A capacitive voltage transformer according to claim 3, characterized in that: The upper end of the expander (13) is provided with an injection port (14) for pressurizing and releasing pressure.

10. A capacitive voltage transformer according to claim 1, characterized in that: The insulating fluid (10) is insulating liquid or insulating gas.

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