A solid-sealed pole for a three-phase intelligent recloser

Abstract

The application relates to the technical field of high-voltage switch equipment, and particularly discloses a solid-sealed pole for a three-phase intelligent recloser, which comprises a vacuum arc-extinguishing chamber, a main conducting rod, a solid-sealed body and an external package; a voltage sensor is coaxially sleeved on the outer part of the main conducting rod; a current transformer is coaxially sleeved on the outer part of the main conducting rod of a lower outgoing line end; the concentricity error of the voltage sensor and the main conducting rod is within + / -0.5mm; the application sets the insulating sleeve, the supporting ring and the heat-conducting rod with an inclined surface; the automatic centering is realized by the cooperation of the conical surfaces during assembly; the concentricity error of the voltage sensor and the main conducting rod is controlled; the stress generated by the epoxy resin curing shrinkage is resisted by the rigid mechanical locking; the stability of the installation position is ensured; therefore, the accuracy of the final measurement result is ensured; the heat-conducting rod can also form an active heat dissipation path at the same time, the change of the dielectric properties of the sensor caused by high temperature is avoided, and the accuracy of the measurement result is further ensured.

Description

Technical Field

[0001] This invention relates to the field of high-voltage switchgear technology, and specifically proposes a solid-sealed pole for a three-phase intelligent recloser. Background Technology

[0002] With the deepening of smart grid construction and the continuous improvement of distribution network automation, the performance of intelligent reclosers, as core control and protection equipment, is directly related to the reliability and quality of power supply. Modern intelligent reclosers are not only required to have traditional current breaking capacity, but are also endowed with advanced functions such as automatic fault detection, location, isolation, and power restoration in non-faulty sections. The realization of these functions depends heavily on the real-time and accurate sensing of electrical parameters such as line voltage and current. Solid-sealed pole technology, by solidifying the vacuum interrupter and main conductive circuit with epoxy resin, effectively improves the insulation strength, mechanical strength, and environmental adaptability (such as dustproof and moisture-proof) of the equipment, and has become the mainstream technology for medium-voltage switchgear.

[0003] Chinese invention patent publication number CN113793773A discloses a Z-shaped solidified electrode and vacuum recloser with a built-in voltage sensor and Rogowski coil. The voltage sensor is installed by "thread fixing" or similar conventional methods. However, no effective technical means are proposed to address the core issue of how to ensure and maintain the extremely high concentricity between the voltage sensor and the main conductive rod. For capacitive or resistive voltage sensors, the measurement accuracy is closely related to the relative position of the primary conductor (main conductive rod) and the sensor sensing plate. Especially during the epoxy resin curing process, the tendency of epoxy resin to shrink can greatly affect the concentricity of the voltage sensor and the main conductive rod. Furthermore, the recloser needs to undergo thousands or even tens of thousands of opening and closing operations during its lifespan. The resulting mechanical vibration and impact will continuously act on the internal structure. Under long-term operation, the threaded connection may loosen, causing slight displacement or deflection of the sensor, resulting in signal drift, which will cause the initial calibration to fail and seriously threaten the reliability of intelligent judgment.

[0004] Furthermore, the technical solution of this patent essentially involves "wrapping" the heat-generating components (main conductive rod, vacuum interrupter contacts, voltage / current sensor) in epoxy resin with poor thermal conductivity, relying on the limited thermal conductivity of the epoxy resin itself for passive heat dissipation. This purely passive heat dissipation method cannot dissipate heat in time when the current load is large or the ambient temperature is high, resulting in heat accumulation within the solid enclosure. This leads to a continuous increase in the internal local temperature. High temperature will cause changes in the dielectric properties of the capacitive sensor, causing measurement drift, making the initial calibration fail, and severely reducing measurement accuracy.

[0005] Therefore, there is an urgent need for a solid-sealed pole for three-phase intelligent reclosers that can ensure the coaxiality of the voltage sensor and the main conductive rod, improve the heat dissipation of the internal electrical components of the epoxy resin, and improve the measurement accuracy. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a solid-sealed pole for a three-phase intelligent recloser, which solves the problems mentioned in the background section.

[0007] To achieve the above objectives, the present invention employs the following technical solution: a solidified pole for a three-phase intelligent recloser, comprising a vacuum interrupter, main conductive rods for upper and lower inlet and outlet lines respectively, an epoxy resin encapsulation body, and an external encapsulation. A voltage sensor is coaxially sleeved on the outside of the main conductive rod, and a current transformer is coaxially sleeved on the outside of the main conductive rod at the lower outlet line. The concentricity error between the voltage sensor and the main conductive rod is within ±0.5mm. The inlet and outlet lines of the vacuum interrupter are each covered with an equipotentially conductive shielding mesh of the upper and lower inlet and outlet main conductive rods. An elastic conductive element is cast at the lower outlet line of the vacuum interrupter; a positioning heat-conducting assembly, comprising a coaxial solidified pole... A tapered rigid insulating sleeve is fixedly fitted onto the surface of the main conductive rod. Multiple positioning grooves are formed along the tapered inclined surface of the insulating sleeve. A rigid insulating support ring is coaxially fixedly installed inside the voltage sensor. Multiple rigid heat-conducting rods are fixedly connected to the surface of the support ring. The side of the heat-conducting rod near the insulating sleeve is set as an inclined surface parallel to the surface of the insulating sleeve. The inclined end of the heat-conducting rod abuts against the inside of the positioning groove. Multiple heat dissipation rods for heat conduction are installed on the surface of the heat-conducting rod. The solid seal encapsulates the vacuum interrupter, main conductive rod, voltage sensor, current transformer, shielding mesh, and positioning heat-conducting components into a whole and encapsulates them externally. The ends of the heat dissipation rods extend to the outer surface of the solid seal.

[0008] Preferably, the insulating sleeve is made of a high thermal conductivity ceramic material.

[0009] Preferably, the heat-conducting rod is made of copper or aluminum alloy.

[0010] Preferably, the elastic conductive element includes a silver-plated spring finger and a finger ring.

[0011] Preferably, a Rogowski coil is also integrated, which is disposed outside the conductive shielding mesh at the lower end and encapsulated inside an epoxy resin encapsulation.

[0012] Preferably, the signal output terminals of the Rogowski coil and the voltage sensor at the upper input terminal are led to an integrated aviation connector via shielded signal lines.

[0013] Preferably, the shielding mesh is a semi-conductive epoxy resin layer or a metal film layer, and its material is usually silver-plated or tin-plated copper wire.

[0014] Preferably, the heat dissipation groove is provided at the position of the heat dissipation rod corresponding to the encapsulation, and the encapsulation is made of high-temperature vulcanized silicone rubber material and adopts the "additional molding" process.

[0015] The above technical solution has the following advantages or beneficial effects: 1. This invention provides a solid-sealed pole for a three-phase intelligent recloser. By setting an insulating sleeve, a support ring, and a heat-conducting rod with an inclined surface, automatic centering is achieved during assembly using the fit of the conical surface, controlling the concentricity error of the voltage sensor and the main conductive rod. At the same time, the rigid mechanical locking resists the stress generated by the curing shrinkage of epoxy resin. The addition of silicone rubber encapsulation can effectively buffer and resist the mechanical vibration and impact generated by the recloser during thousands of opening and closing operations, ensuring the stability of the installation position. Therefore, the accuracy of the final measurement result is guaranteed. The heat-conducting rod can also form an active heat dissipation path at the same time, avoiding changes in the dielectric properties of the sensor caused by high temperature, further ensuring the accuracy of the measurement result.

[0016] 2. This invention provides a solid-encapsulated terminal block for a three-phase intelligent recloser. By leading the signal terminals of the Rogowski coil and voltage sensor to an integrated, multi-core aviation connector through an internal double-shielded signal line, the combination of the shielding mesh and shielded signal line inside the solid enclosure constitutes a complete shielding system, effectively isolating the strong electromagnetic interference generated when the recloser is turned off, ensuring the transmission quality of weak sensor signals, and further improving measurement accuracy. Attached Figure Description

[0017] The invention, its features, shape, and advantages will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings. Like reference numerals denote like parts throughout the drawings, which are not intentionally drawn to scale; the focus is on illustrating the spirit of the invention.

[0018] Figure 1 This is a three-dimensional structural diagram of a solid-sealed pole for a three-phase intelligent recloser provided by the present invention.

[0019] Figure 2 yes Figure 1 A cross section.

[0020] Figure 3 This is a three-dimensional structural diagram of the positioning heat-conducting component.

[0021] Figure 4 This is a schematic diagram of the disassembled structure between the heat dissipation rod and the insulating sleeve in the positioning heat conduction component.

[0022] Figure 5 It is a schematic diagram of the encapsulated planar cross-sectional structure.

[0023] In the diagram: 1. Vacuum interrupter; 2. Main conductive rod; 3. Solid seal; 4. Encapsulation; 5. Voltage sensor; 6. Current transformer; 7. Shielding mesh; 8. Elastic conductive component; 9. Positioning and heat-conducting assembly; 91. Insulating sleeve; 92. Positioning groove; 93. Support ring; 94. Heat-conducting rod; 95. Heat dissipation rod; 10. Rogowski coil; 11. Heat dissipation groove. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] like Figures 1-2 As shown, the present invention provides a solid-sealed pole for a three-phase intelligent recloser. Its main body is an integral solid-sealed body 3 structure formed by epoxy resin casting. The solid-sealed body 3 is covered with an encapsulation 4 made of high-temperature vulcanized silicone rubber through an "additional molding" process. The encapsulation 4 provides excellent outdoor weather resistance and mechanical buffering capability. The solid-sealed pole includes a core breaking element, a vacuum interrupter 1. The upper and lower contacts of the vacuum interrupter 1 are fixedly mounted with main conductive rods 2. The main conductive rod 2 at the lower output end is connected to the drive shaft crank arm of the recloser operating mechanism through an insulating pull rod (not shown in the figure) to realize the closing and opening operation.

[0027] To achieve intelligent detection, an inductive voltage sensor 5 is fitted on the outer bearing of the main conductive rod 2 for accurately acquiring voltage signals. A current transformer 6 is also coaxially fitted on the outer side of the main conductive rod 2 at the lower end for acquiring line current signals. It should be noted that the concentricity error between the voltage sensor 5 and the main conductive rod 2 is within ±0.5mm.

[0028] To optimize the electric field distribution inside the pole and suppress potential electric field distortion and partial discharge caused by the introduction of sensors, both the inlet and outlet ends of the vacuum interrupter 1 are covered with conductive shielding mesh 7. The upper conductive shielding mesh 7 is equipotentially connected to the main conductive rod 2 at the upper inlet end, and the lower conductive shielding mesh 7 is equipotentially connected to the main conductive rod 2 at the lower outlet end through an elastic conductive element 8. This ensures the insulation strength of the pole and controls the partial discharge to below 5pC. The elastic conductive element 8 is an elastic contact finger assembly composed of silver-plated spring contact fingers and contact finger rings, which is cast into the lower outlet end of the vacuum interrupter 1, ensuring both a conductive path and providing necessary elastic compensation.

[0029] A Rogowski coil 10 is installed on the outside of the conductive shielding mesh 7 at the lower end. Since the Rogowski coil 10 does not contain an iron core, it has good linearity and almost no saturation phenomenon. Therefore, it can accurately measure the fault current waveform from the power frequency to several kilohertz, thereby improving the accuracy of the detection data. In order to simplify the external wiring structure and improve electromagnetic compatibility performance, the signal output terminals of the Rogowski coil 10 and the signal output terminals of the voltage sensor 5 at the upper input end are led to an integrated, multi-core aviation connector through an internal double-shielded signal cable. This aviation connector can be fixed to the base or side wall of the pole. The integrated signal lead-out method reduces external wiring and installation complexity. At the same time, the shielded cable and aviation connector can effectively resist on-site electromagnetic interference and ensure the accuracy of the detection data results.

[0030] like Figures 2-5 As shown, the solid-sealed pole has a positioning and heat-conducting component 9 inside to ensure the concentricity of the voltage sensor 5 and the main conductive rod 2. The positioning and heat-conducting component 9 includes a tapered rigid insulating sleeve 91. The insulating sleeve 91 is made of aluminum nitride ceramic with high thermal conductivity and is machined by a precision CNC diamond grinding machine. Its inner hole is designed with an international standard taper of 7:24 to ensure good self-centering and torque transmission. The insulating sleeve 91 and the main conductive rod 2 are fitted with an interference fit, and the interference is controlled within the range of 0.02-0.05mm. Before assembly, the mating surface of the main conductive rod 2 needs to be silver-plated (thickness ≥5μm) to reduce contact resistance and contact thermal resistance. On the outer tapered surface of the insulating sleeve 91, six "dovetail" shaped positioning grooves 92 are milled circumferentially. This groove shape can provide better circumferential shear resistance.

[0031] The voltage sensor 5 has a rigid insulating support ring 93 inside. The support ring 93 and the insulating sleeve 91 are made of the same material to ensure rigidity and high thermal conductivity. Six rigid heat-conducting rods 94 are fixedly installed on the surface array of the support ring 93. The support ring 93 and the heat-conducting rods 94 are welded by active metal brazing. This installation method is existing technology and will not be described in detail here. The side of each heat-conducting rod 94 near the insulating sleeve 91 is precision machined into a bevel. The angle of this bevel is completely parallel to the conical bevel of the insulating sleeve 91. The bevel of the heat-conducting rod 94 abuts against the inside of the positioning groove 92. In order to increase the heat dissipation area, two outwardly radiating heat dissipation rods 95 are welded to the surface of each heat-conducting rod 94. It should be noted that the heat dissipation rods 95 are located in the middle of the heat-conducting rod 94, away from the main conductive rod 2 and the voltage sensor 5. Sufficient thickness is provided when casting epoxy resin to prevent the high voltage discharge from affecting the heat-conducting rods 94.

[0032] The assembly process of the solidified electrode is as follows: the voltage sensor 5, which has been fitted with the support ring 93, is placed on the surface of the main conductive rod 2, which has been fitted with the insulating sleeve 91, and pressed in along the axial direction of the main conductive rod 2. The inclined end of the heat-conducting rod 94 abuts against the conical surface, slides in along the inside of the positioning groove 92, and fits tightly against the inner wall of the positioning groove 92. The cooperation between the conical surface and the inclined surface realizes automatic centering, ensuring the high concentricity of the voltage sensor 5 and the main conductive rod 2, while providing strong radial support force to prevent positional displacement caused by epoxy resin curing shrinkage.

[0033] The vacuum interrupter 1, main conductive rod 2, voltage sensor 5, current transformer 6, shielding mesh 7, elastic conductive component 8, and positioning heat-conducting component 9 are all cast into a whole using a vacuum epoxy resin automatic pressure gelation process. During this process, the end of the heat dissipation rod 95 extends to the surface of the solidified body 3. The outer enclosure 4 is provided with heat dissipation grooves 11 corresponding to the position of the heat dissipation rod 95. The mold core can be placed in advance during the high-temperature vulcanization of the enclosure 4, so that the heat dissipation grooves 11 are naturally formed after molding. The heat dissipation grooves 11 allow the end of the heat dissipation rod 95 to be directly exposed to the air, or only covered by a very thin layer of vacuum epoxy resin, thereby forming an efficient heat dissipation path between the main conductive rod 2, insulating sleeve 91, heat-conducting rod 94, heat dissipation rod 95, and the external air, avoiding changes in the dielectric properties of the sensor caused by high temperature, thereby ensuring the accuracy of the detection data.

[0034] The working principle of this solid-sealed pole is as follows: During operation, the load current passes through the main conductive rod 2 and the vacuum interrupter 1. The current transformer 6 measures the steady-state power frequency current, the Rogowski coil 10 captures the transient large current during a fault, and the voltage sensor 5 measures the voltage to ground of the main conductive rod 2 by capacitive voltage division. All signals are transmitted to the intelligent control unit via an aviation connector to ensure the accuracy of the measurement data. At the same time, the main conductive rod 2 and the vacuum interrupter 1 generate Joule heat through current flow. The heat is first conducted to the highly thermally conductive insulating sleeve 91, and then quickly transferred to the heat dissipation rod 95 that penetrates the solid body 3 through the closely contacting heat-conducting rod 94. Finally, the heat is dissipated into the surrounding air through the end exposed at the heat dissipation groove 11. This heat dissipation process is active heat dissipation, and its heat dissipation effect is better than the traditional passive heat dissipation method.

[0035] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0036] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "connected," "installed," and "linked" 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 will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] The preferred embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and the devices and structures not described in detail should be understood as being implemented in a manner common to the art; any possible variations and modifications made by those skilled in the art without departing from the technical solution of the present invention, or equivalent embodiments with equivalent changes, do not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A sealed terminal block for a three-phase intelligent recloser, comprising a vacuum interrupter chamber, main conductive rods for the upper and lower input / output terminals respectively, an epoxy resin sealing body, and an external encapsulation, characterized in that: A voltage sensor is coaxially sleeved on the outside of the main conductive rod, and a current transformer is also coaxially sleeved on the outside of the main conductive rod at the lower outlet end. The concentricity error between the voltage sensor and the main conductive rod is within ±0.5mm. The inlet and outlet ends of the vacuum interrupter are each covered with a shielding mesh that is equipotential to the main conductive rod at the upper and lower inlet and outlet ends. An elastic conductive element is cast at the lower outlet end of the vacuum interrupter. The positioning heat-conducting assembly includes a conical rigid insulating sleeve coaxially fixedly sleeved on the surface of the main conductive rod. The surface of the insulating sleeve is provided with multiple positioning grooves along the conical inclined surface. A rigid insulating support ring is coaxially fixedly installed inside the voltage sensor. Multiple rigid heat-conducting rods are fixedly connected to the surface of the support ring. The side of the heat-conducting rod near the insulating sleeve is provided with an inclined surface parallel to the surface of the insulating sleeve. The inclined end of the heat-conducting rod abuts against the inside of the positioning groove. The surface of the heat-conducting rod is equipped with multiple heat-dissipating rods for heat conduction. The solid seal encapsulates the vacuum interrupter, main conductive rod, voltage sensor, current transformer, shielding mesh, and positioning heat-conducting components into a whole and encapsulates them externally. The ends of the heat-dissipating rods extend to the outer surface of the solid seal.

2. A solid-sealed pole for a three-phase intelligent recloser according to claim 1, characterized in that: The insulating sleeve is made of a high thermal conductivity ceramic material.

3. A solid-sealed pole for a three-phase intelligent recloser according to claim 1, characterized in that: The heat-conducting rod is made of copper or aluminum alloy.

4. A solid-sealed pole for a three-phase intelligent recloser according to claim 1, characterized in that: The elastic conductive element includes a silver-plated spring finger and a finger ring.

5. A solid-sealed terminal block for a three-phase intelligent recloser according to claim 1, characterized in that: It also integrates a Rogowski coil, which is disposed outside the conductive shielding mesh at the lower end and encapsulated inside an epoxy resin encapsulation.

6. A solid-sealed pole for a three-phase intelligent recloser according to claim 5, characterized in that: The signal output terminals of the Rogowski coil and the voltage sensor at the upper input terminal are led to an integrated aviation connector via shielded signal lines.

7. A solid-sealed pole for a three-phase intelligent recloser according to claim 1, characterized in that: The shielding mesh is a semi-conductive epoxy resin layer or a metal film layer, and its material is silver-plated or tin-plated copper wire.

8. A solid-sealed pole for a three-phase intelligent recloser according to claim 1, characterized in that: The heat dissipation groove is provided at the position of the heat dissipation rod corresponding to the encapsulation. The encapsulation is made of high-temperature vulcanized silicone rubber and adopts the "additional molding" process.

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