Integrated sleeve type electronic current and voltage combined transformer

Abstract

The utility model relates to the technical field of mutual inductors in power equipment, in particular to an integrated sleeve type electronic current and voltage combined mutual inductor. Comprising an insulation packaging structure, a conducting rod, a current measuring module, a voltage measuring module and a capacitance monitoring module, the insulation packaging structure is an epoxy resin shell, a wiring platform is arranged on the side portion of the insulation packaging structure, and the capacitance monitoring module comprises a capacitance induction net and a capacitance wiring terminal which are arranged on the conducting rod in a sleeving mode; the current measuring module comprises a coil device body and a current shielding twisted pair which are sleeved on the conducting rod; the voltage measuring module comprises a primary ceramic capacitor, a secondary capacitor and a voltage shielding twisted pair, the primary ceramic capacitor is fixed on the outer side of the conducting rod, the secondary capacitor is arranged in the wiring platform and is connected with the primary ceramic capacitor in series, and the voltage shielding twisted pair is connected with the secondary capacitor. The transformer is compact in structure, can directly replace a standard sleeve in equipment such as a ring main unit to be installed, and solves the problems that a traditional transformer is difficult to install and high in cost.

Description

Technical Field

[0001] This utility model relates to the field of instrument transformer technology in power equipment, specifically to an integrated bushing type electronic current and voltage combined instrument transformer. Background Technology

[0002] Ring main units are indispensable key power distribution equipment in modern urban power distribution networks, industrial parks, commercial centers, large buildings, infrastructure (such as airports, train stations, and hospitals), residential communities, and renewable energy power plants (such as wind farms and photovoltaic power stations) and their substations. They have advantages such as high reliability, compact structure, and high degree of modularity, and are widely used in power grids.

[0003] However, the internal space of ring main units is usually extremely limited, and they generally adopt a fully insulated and sealed structure. This characteristic makes it very difficult to directly install traditional electromagnetic voltage transformers (PTs), current transformers (CTs), or large electronic transformers (such as electronic current transformers ECTs plus electronic voltage transformers EVTs) inside the cabinet. With the deepening of the automation transformation of distribution networks, the number of secondary equipment that needs to be integrated into ring main units has increased significantly, and the demand for current and voltage signal acquisition, measurement, monitoring, and protection functions is becoming increasingly prominent.

[0004] The main problems with existing technologies are:

[0005] Limited installation space and structural conflicts: The small, fully insulated structure of the ring main unit cannot accommodate large traditional instrument transformers or combined electronic instrument transformers.

[0006] High retrofit costs: To meet automation requirements, dedicated PTs and CTs are typically needed, which not only incur high equipment costs but also occupy valuable cabinet space. Retrofitting existing ring main units is even more challenging, complex, and extremely costly. Utility Model Content

[0007] To address the aforementioned problems, the purpose of this utility model is to provide an integrated bushing-type electronic current and voltage combined transformer to solve the problems of traditional transformers occupying a large space and being unable to fit into compact cabinets.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] This utility model provides an integrated bushing type electronic current and voltage combined transformer, including an insulating encapsulation structure and a conductive rod, a current measurement module, a voltage measurement module and a capacitance monitoring module encapsulated in the insulating encapsulation structure. The insulating encapsulation structure is an epoxy resin shell cast into a sleeve shape by epoxy resin, and a terminal block is provided on the side. The conductive rod axially penetrates the insulating encapsulation structure and its two ends are exposed.

[0010] The capacitance monitoring module includes capacitance terminals and a cylindrical capacitance sensing mesh. The capacitance sensing mesh is fitted onto the outside of the conductive rod, and the capacitance terminals are located on the terminal block and connected to the capacitance sensing mesh.

[0011] The current measurement module includes a current-shielded twisted pair cable and a ring-shaped coil body. The coil body is fitted onto the outside of the conductive rod, and the current-shielded twisted pair cable is placed on the terminal block and connected to the coil body.

[0012] The voltage measurement module includes a primary ceramic capacitor, a secondary capacitor, and a voltage-shielded twisted pair cable. The primary ceramic capacitor is fixedly connected to the outside of the conductive rod, the secondary capacitor is located inside the terminal block and connected in series with the primary ceramic capacitor, and the voltage-shielded twisted pair cable is located on the terminal block and connected to the secondary capacitor.

[0013] The coil body includes a toroidal iron core, a secondary winding, and a sampling resistor. The secondary winding is wound on the toroidal iron core, the sampling resistor is connected in parallel between the two ends of the secondary winding, and the two ends of the secondary winding are connected to a current-shielded twisted pair.

[0014] The toroidal core is made of silicon steel sheet or amorphous alloy high magnetic permeability material, and the secondary winding is an insulated enameled wire winding.

[0015] The space between the coil body and the conductive rod is filled with epoxy resin for insulation.

[0016] The capacitive sensing mesh is a metal mesh structure. An epoxy resin dielectric is filled between the capacitive sensing mesh and the conductive rod to form a monitoring capacitor. The capacitor terminal is used to output a capacitance signal that reflects the dielectric state of the epoxy resin.

[0017] The shielding layers of both the current-shielded twisted pair and the voltage-shielded twisted pair are connected to the grounding terminal, which is located on the terminal block.

[0018] The front and rear ends of the epoxy resin shell are conical and cylindrical, respectively. The cylindrical part can pass through the ring main unit mounting hole. The insulating encapsulation structure has a flange plate near the cylindrical part, and the flange plate extends radially to form the terminal block.

[0019] The flange plate has a sealing groove along its circumferential direction on its mounting surface for fitting a sealing ring.

[0020] The conductive rod has threaded holes at both ends.

[0021] The capacitive sensing network, coil body, and primary ceramic capacitor are arranged coaxially in sequence along the axial direction.

[0022] The advantages and beneficial effects of this utility model are as follows: This utility model provides an integrated bushing-type electronic current and voltage combined transformer, which integrates current measurement, voltage measurement and capacitance status monitoring into a single bushing structure. It adopts a standardized design to support direct installation in existing ring main units without modification. It achieves maintenance-free operation with full epoxy resin sealing. It uses a capacitance sensing network to sense changes in the state of the epoxy resin insulation medium in real time, ensuring the monitoring and early warning effect. At the same time, it saves the cost of purchasing independent PT / CT and expanding the cabinet. It not only solves the problems of large space occupation and poor adaptability of traditional transformers, but also achieves comprehensive optimization of function, installation, maintenance, performance and cost-effectiveness.

[0023] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0024] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0025] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:

[0026] Figure 1 This is a schematic diagram of the structure of an integrated bushing-type electronic current and voltage combined transformer according to this utility model;

[0027] Figure 2 for Figure 1 AA section view;

[0028] Figure 3 This is a front view of an integrated bushing-type electronic current and voltage combined transformer according to this utility model.

[0029] Figure 4 for Figure 3 The left view;

[0030] Figure 5 This is a circuit diagram of the current measurement module in this utility model;

[0031] Figure 6 This is a circuit diagram of the voltage measurement module in this utility model;

[0032] Figure 7 This is the wiring circuit diagram of the current-shielded twisted pair in this utility model;

[0033] Figure 8This is the wiring circuit diagram of the voltage shielded twisted pair cable in this utility model.

[0034] The components are: 1. Epoxy resin shell; 4. Sealing groove; 5. Conductive rod; 6. Capacitive sensing mesh; 7. Ring core; 8. Secondary winding; 9. Sampling resistor; 10. Primary ceramic capacitor; 11. Secondary capacitor; 12. Current-shielded twisted pair; 13. Voltage-shielded twisted pair; 14. Capacitor terminal; 15. Grounding terminal; 16. Current-shielded wire; 17. Voltage-shielded wire; 101. Cone; 102. Flange plate; 103. Cylindrical-like shape. Detailed Implementation

[0035] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0036] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0037] See Figures 1 to 8 As shown, this utility model provides an integrated bushing-type electronic current and voltage combined transformer, including an insulating encapsulation structure and a conductive rod 5, a current measurement module, a voltage measurement module, and a capacitance monitoring module encapsulated within the insulating encapsulation structure. The insulating encapsulation structure is an epoxy resin shell 1 cast into a sleeve shape by epoxy resin, with a terminal block on the side. The conductive rod 5 axially penetrates the insulating encapsulation structure and has both ends exposed. The capacitance monitoring module includes capacitance terminals 14 and a cylindrical capacitance sensing mesh 6. The capacitance sensing mesh 6 is fitted onto the outside of the conductive rod 5, and the capacitance terminals 14 are disposed on the terminal block. The current measurement module includes a current-shielded twisted pair 12 and a ring-shaped coil body, which is fitted onto the outside of the conductive rod 5. The current-shielded twisted pair 12 is placed on the terminal block and connected to the coil body. The voltage measurement module includes a primary ceramic capacitor 10, a secondary capacitor 11, and a voltage-shielded twisted pair 13. The high-voltage end of the primary ceramic capacitor 10 is fixedly connected to the outside of the conductive rod 5. The secondary capacitor 11 is placed inside the terminal block and connected in series with the primary ceramic capacitor 10. The voltage-shielded twisted pair 13 is placed on the terminal block and connected to the secondary capacitor 11.

[0038] In this embodiment of the invention, the conductive rod 5 is a rod-shaped metal conductor that passes through the central axis of the current transformer. Both ends of the conductive rod 5 have threaded holes. The two ends of the conductive rod 5 serve as the inflow and outflow terminals of the current transformer, namely terminals P1 and P2, respectively. (See [reference]). Figure 5 As shown.

[0039] See Figure 1 As shown, in this embodiment of the present invention, the capacitive sensing network 6, the coil body, and the primary ceramic capacitor 10 are arranged coaxially along the axial direction. The space between the coil body and the conductive rod 5 is filled with epoxy resin for insulation. The coil body includes a toroidal iron core 7, a secondary winding 8, and a sampling resistor 9. The secondary winding 8 is uniformly wound on the toroidal iron core 7, and the sampling resistor 9 is connected in parallel between the two ends of the secondary winding 8. The two ends of the secondary winding 8 are connected to a current-shielded twisted pair 12.

[0040] Furthermore, the toroidal core 7 has a toroidal structure and is made of silicon steel sheets or amorphous alloy high-permeability materials. The secondary winding 8 is an insulated enameled wire winding with an insulating varnish layer on the surface of the enameled wire, forming insulation between each turn. The uniform winding of the enameled wire ensures a uniform magnetic field distribution in the secondary winding 8. The two ends of the enameled wire extend out of the secondary winding 8 as S1 and S2 terminals, respectively. A high-precision sampling resistor 9 is connected in parallel between the S1 and S2 terminals, and the current signal is output through a current-shielded twisted pair 12. (See [reference]). Figure 5 As shown.

[0041] Specifically, the current-shielded twisted pair 12 is a two-core shielded cable, with the two cores twisted together to form a twisted pair. The twisted pair is further protected by a metal braided mesh shielding layer. The two ends of the secondary winding 8 are connected to the two cores at one end of the current-shielded twisted pair 12. The shielding layer of the current-shielded twisted pair 12 is connected to the grounding terminal 15 via the current shielding wire 16. The grounding terminal 15 is located on a terminal block. Current signals are transmitted through the current-shielded twisted pair 12. (See [reference]). Figure 7 As shown.

[0042] In this embodiment of the invention, the high-voltage end of the primary ceramic capacitor 10 is fixedly connected to the outer wall of the conductive rod 5, forming the high-voltage arm of the capacitor voltage divider circuit. The secondary capacitor 11 is connected in series with the primary ceramic capacitor 10, forming the low-voltage arm of the capacitor voltage divider circuit, used to output a secondary voltage signal. The signal is output through the voltage-shielded twisted pair cable 13. (See [reference]). Figure 6 As shown.

[0043] Specifically, the voltage-shielded twisted pair cable 13 is a two-core shielded cable, with the two cores twisted together to form a twisted pair. The twisted pair is further protected by a metal braided mesh shielding layer. The two ends of the secondary capacitor 11 are connected to the two cores at one end of the voltage-shielded twisted pair cable 13. The shielding layer of the voltage-shielded twisted pair cable 13 is connected to the grounding terminal 15 via the voltage shielding wire 17. (See [reference]). Figure 8 As shown.

[0044] In this embodiment of the invention, the capacitive sensing mesh 6 is a metal mesh structure, and a wire is led out from the capacitive sensing mesh 6 and connected to the capacitor terminal 14. An epoxy resin dielectric is filled between the capacitive sensing mesh 6 and the conductive rod 5 to form a monitoring capacitor. The capacitor terminal 14 is used to output a capacitance signal reflecting the dielectric state of the epoxy resin. Specifically, the outer wall of the conductive rod 5 and the inner wall of the capacitive sensing mesh 6 form two parallel capacitor plates, with an epoxy resin dielectric between the two plates, constituting a capacitor that monitors the state of the epoxy resin insulating dielectric. The signal of this capacitor can be measured at the capacitor terminal 14.

[0045] See Figure 3 As shown in the embodiment of this utility model, the epoxy resin shell 1 is integrally cured and molded from epoxy resin insulating material, encapsulating and fixing the conductive rod 5, current measurement module, voltage measurement module, and capacitance monitoring module to form a fully sealed, maintenance-free integrated structure. During the curing process, reliable insulation between electrical components and between components and the shell is ensured. Specifically, the front and rear ends of the epoxy resin shell 1 are a cone 101 and a quasi-cylinder 103, respectively. The quasi-cylinder 103 can pass through the ring main unit mounting hole. A flange plate 102 is provided on the insulating encapsulation structure near the quasi-cylinder 103. The flange plate 102 extends radially to form a terminal block. The cone 101 is an outer cone conforming to standard dimensions and can be connected to a standard equipment cone sleeve.

[0046] Furthermore, the mounting surface of the flange plate 102 is provided with a sealing groove 4 along the circumference for embedding a sealing ring. The mounting surface of the flange plate 102 is fixed and sealed to the equipment panel. The near-cylinder 103 is a regular, approximately cylindrical shape, which facilitates installation through the mounting holes on the switchgear.

[0047] The working principle of the integrated bushing-type electronic current and voltage combined transformer provided by this utility model is as follows:

[0048] Current Measurement: Based on the principle of Low Power Current Coil (LPCT), a primary current is induced in the toroidal core 7, which in turn induces a secondary small current in the secondary winding 8. This secondary current is then converted into a low-voltage small signal through a sampling resistor 9 (R in the diagram) connected in parallel across the secondary winding 8, resulting in a voltage signal as the secondary output. The phase of this voltage signal is consistent with that of the primary current, and its amplitude is proportional to the amplitude of the primary current. The secondary signal is output through a current-shielded twisted pair cable 12, providing strong anti-interference capabilities and high product accuracy. (See also...) Figure 5 and Figure 7 As shown.

[0049] Voltage Measurement: Based on the principle of capacitive voltage division, a primary ceramic capacitor 10 is fixed on the conductive rod 5 to form a high-voltage arm. The primary voltage is divided into a lower intermediate voltage by the primary ceramic capacitor 10. A secondary capacitor is connected in series with the secondary terminals of the primary ceramic capacitor 10 to form a low-voltage arm. Voltage is divided across the secondary capacitor, and the voltage is converted into a standard secondary voltage output by the secondary capacitor 11. Specifically, the output is via a voltage-shielded twisted-pair cable 13, providing strong anti-interference capabilities and high product accuracy. (See [reference]). Figure 6 and Figure 8 As shown.

[0050] Capacitance monitoring: A cylindrical capacitance sensing network 6 is arranged coaxially around the conductive rod 5. The capacitance sensing network 6 and the conductive rod 5 together form a monitoring capacitor, which is used to sense and output the capacitance value that reflects the state of the insulating medium.

[0051] All modules are encapsulated in an epoxy resin shell 1 through epoxy resin, forming a fully sealed, maintenance-free integrated structure. This integrates the current and voltage transformers, making installation easier and taking up less space. The internal components are arranged in an orderly manner to avoid electromagnetic interference, and the output voltage signal is small and does not interfere with each other, resulting in superior performance.

[0052] This utility model integrates current measurement, voltage measurement, and capacitor status monitoring functions into one compact structure. It can directly replace the standard bushings in equipment such as ring main units for installation. It is particularly suitable for the automation transformation of compact ring main units with limited space, and solves the problems of difficult installation and high cost of traditional current transformers.

[0053] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this utility model and their equivalents, this utility model also intends to include these modifications and variations.

Claims

1. An integrated bushing-type electronic current-voltage combined transformer, characterized by, The application relates to an insulation packaging structure and a conductive rod, a current measuring module, a voltage measuring module and a capacitor monitoring module packaged in the insulation packaging structure, wherein the insulation packaging structure is an epoxy resin shell in the form of a sleeve cast by epoxy resin, and a wiring platform is arranged on the side of the epoxy resin shell; the conductive rod axially penetrates the insulation packaging structure and is exposed at both ends; The capacitor monitoring module comprises a capacitor terminal and a cylindrical capacitor sensing net, the capacitor sensing net is sleeved on the outside of the conductive rod, and the capacitor terminal is arranged on the wiring platform and connected with the capacitor sensing net; The current measuring module comprises a current shielding double-twisted wire and a ring-shaped coil body, the coil body is sleeved on the outside of the conductive rod, and the current shielding double-twisted wire is arranged on the wiring platform and connected with the coil body; The voltage measuring module comprises a primary ceramic capacitor, a secondary capacitor and a voltage shielding double-twisted wire, wherein the primary ceramic capacitor is fixedly connected to the outside of the conductive rod, the secondary capacitor is arranged in the interior of the wiring platform and connected in series with the primary ceramic capacitor, and the voltage shielding double-twisted wire is arranged on the wiring platform and connected with the secondary capacitor.

2. The integrated bushing-type electronic current-voltage combination transformer according to claim 1, characterized in that, The coil body comprises a ring-shaped iron core, a secondary winding and a sampling resistor, the secondary winding is wound on the ring-shaped iron core, and the sampling resistor is connected in parallel between both ends of the secondary winding, and both ends of the secondary winding are connected with the current shielding double-twisted wire.

3. The integrated bushing-type electronic current-voltage combination transformer according to claim 2, characterized in that, The ring-shaped iron core is made of silicon steel sheet or amorphous alloy high-permeability magnetic material, and the secondary winding is an insulated enameled wire winding.

4. The integrated bushing-type electronic current-voltage combination transformer according to claim 1, characterized in that, Epoxy resin medium is filled between the coil body and the conductive rod for insulation.

5. The integrated bushing-type electronic current-voltage combination transformer according to claim 1, characterized in that, The capacitor sensing net is a metal net structure, epoxy resin medium is filled between the capacitor sensing net and the conductive rod to form a monitoring capacitor, and the capacitor terminal is used for outputting a capacitor signal reflecting the dielectric state of the epoxy resin.

6. The integrated bushing-type electronic current-voltage combination transformer of claim 1, wherein, The shielding layers of the current shielding double-twisted wire and the voltage shielding double-twisted wire are connected to a grounding terminal, and the grounding terminal is arranged on the wiring platform.

7. The integrated bushing-type electronic current-voltage combination transformer according to claim 1, characterized in that, The front end and the rear end of the epoxy resin shell are respectively a circular cone and a quasi-cylindrical body, the quasi-cylindrical body can pass through a looped net cabinet installation hole, a flange plate is arranged on the insulation packaging structure close to the quasi-cylindrical body, and the flange plate extends in the radial direction to form the wiring platform.

8. The integrated bushing-type electronic current-voltage combination transformer according to claim 7, characterized in that, A sealing groove for embedding a sealing ring is arranged on the mounting surface of the flange plate in the circumferential direction.

9. The integrated bushing-type electronic current-voltage combination transformer of claim 1, wherein, Threaded holes are arranged at both ends of the conductive rod.

10. The integrated bushing-type electronic current-voltage combination transformer of claim 1, wherein, The capacitor sensing net, the coil body and the primary ceramic capacitor are coaxially arranged in sequence in the axial direction.

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