CN119921218A - A 17.5kV ring network box - Google Patents

Abstract

The present invention discloses a 17.5kV ring network box, including an outdoor box shell and a ring network cabinet shell with an integrated design. The upper end of the box body is hinged with an upper door panel, a gas box is arranged in the middle, a cable room and a cable withstand voltage test room are arranged at the lower end, and an instrument room is arranged at the top. The gas box is symmetrically arranged, with load switches on both sides, a circuit breaker switch embedded in the middle, and connected through a CV busbar. The load switch is provided with an arc extinguishing grid, an insulating umbrella skirt and a specially designed grounding contact, which can effectively extinguish arcs, improve insulation performance and optimize grounding effects. Its transmission component design accurately controls the movement of the moving contact. The circuit breaker switch contains components such as vacuum bubbles, which can extinguish arcs efficiently. In addition, the lower end of the load switch is provided with test and inlet and outlet terminals, the drive unit has a program lock, and the instrument room is equipped with a power supply and a voltage transformer. This ring network box optimizes space utilization through an integrated design, has significant advantages in electrical performance, ease of operation and maintenance, is suitable for a variety of power scenarios, and effectively guarantees the stable operation of the power system.

Description

17.5KV ring main unit

Technical Field

The invention relates to the field of ring main units, in particular to a 17.5kV ring main unit.

Background

In an electric power system, a ring main unit is a key device for guaranteeing electric power distribution and control. With the diversification of power requirements and the continuous development of power grids, ring main units with different voltage levels are applied to various scenes. For a ring main unit with a voltage level of 17.5kV, the voltage level of rated voltage sequence 1 in IEC62271-1 standard is corresponding, and the ring main unit is usually used for a power network with nominal voltage of 13.8kV and 15 kV. The 24kV ring main unit has higher manufacturing cost. The electrical components, insulation etc. inside the device need to be designed and selected according to the 24kV standard, and these high-performance components cause an increase in the overall cost. Due to the larger structure and size of the 24kV ring main unit, more space and more stringent transportation conditions are required during transportation, which also increases transportation costs. The 24kV ring main unit has large volume, and occupies more precious space in places such as a transformer substation or a distribution room. For some places with limited space, additional space modifications may be required to install, which not only increases construction costs, but may also affect the overall power system layout and operating efficiency.

The insulation parameters such as rated power frequency withstand voltage and lightning impulse withstand voltage of the 12kV ring main unit are greatly different from those of the 17.5kV ring main unit. According to IEC standard requirements, rated power frequency withstand voltage of the 17.5kV circuit breaker and the ring main unit is 38kV and lower than 42kV rated power frequency withstand voltage of the 12kV circuit breaker and the ring main unit in national standard, and on the parameter requirements of lightning impulse withstand voltage of interphase grounding and circuit breaker breaks, the 17.5kV circuit breaker and the ring main unit are 95kV and much higher than 75kV rated lightning impulse withstand voltage specified by the 12kV circuit breaker and the ring main unit in national standard.

In order to seek a more economical solution, the market considers adopting a miniaturized 12kV ring main unit to reform so as to meet the service performance requirement of a 17.5kV product, but a plurality of technical difficulties are encountered in the process, namely 1. The insulation performance problem is solved, and the 12kV ring main unit is a miniaturized product, so that the external space structure is very compact, and the insulation performance is improved. The situation that insulation is insufficient easily occurs at the distance between phase and between phase and ground in the ring main unit under the voltage of 17.5kV, so that the probability of insulation failure in the operation process is greatly increased. 2. The space utilization and installation problems are that the independent ring main unit and the outdoor box need to be manufactured, transported and installed respectively, so that the whole volume and weight are increased, and a large space is needed to accommodate two independent boxes and the connecting part between the two independent boxes in the installation process. This increases the difficulty and complexity of installation for some places where space is limited.

Disclosure of Invention

(One) solving the technical problems

Aiming at the defects of the prior art, the invention aims to provide the 17.5kV ring main unit, solve the problems in the prior art, abandon the form of adding an outdoor box to a conventional independent ring main unit, adopt the integral design of an outer box body and the ring main unit, directly use an upper door plate and a cable chamber door plate of the original ring main unit as the components of the outer box body, intuitively reduce the size of the outer box, save the installation position of products, and effectively reduce the unnecessary space occupation caused by the splicing of independent box bodies by adopting the innovative structural integration, so that the integral structure is more compact. Meanwhile, the reasonable layout of the functional chambers such as the gas tank, the cable chamber, the cable withstand voltage test chamber and the instrument chamber in the box body further optimizes the space utilization efficiency.

The inside symmetrical layout that adopts of gas tank, both sides set up load switch, and the middle embedding circuit breaker switch to connect through CV busbar, make charge distribution relatively balanced, reduced the distortion of electric field. The symmetrical structure ensures that equal positive and negative charges are regularly distributed in space, and the electric field components in all directions offset one another, so that the excessive accumulation of the electric field intensity in a single direction is avoided. Meanwhile, the compact layout shortens the electrical distance among the components, so that the electric field can be transited relatively smoothly, the electric field non-uniformity is reduced, the electric field inside the equipment is ensured to be in a stable and uniform state, and the foundation guarantee is provided for the reliable operation of the equipment.

The left connecting part of the grounding contact is fixed with the insulating umbrella skirt, so that the grounding path is ensured to be stable, the insulating environment constructed by the insulating umbrella skirt is not damaged, and the left connecting part and the insulating umbrella skirt cooperate to maintain the whole insulating balance. On the one hand, the grounding resistance is reduced by increasing the contact area, the damage to insulation caused by abnormal potential rise due to poor grounding is reduced, and on the other hand, the electric field distribution is optimized, so that the electric field lines uniformly bypass the grounding contact, the local insulation breakdown caused by electric field concentration is avoided, and the insulation safety of the equipment under high-voltage operation is comprehensively ensured.

A cable withstand voltage test chamber is arranged above the cable chamber, a test terminal and an incoming and outgoing terminal are arranged at the lower end of the load switch, the test terminal is connected with the grounding contact through a copper bar, and the incoming and outgoing terminal is connected with the moving contact seat through the copper bar. Therefore, a tester does not need to enter the cable compartment, and can conveniently and safely test the insulation level of the cable by opening corresponding parts outside, so that the defect that the traditional ring main unit is complicated and dangerous in test is overcome.

(II) technical scheme

The 17.5kV ring main unit comprises a box body, wherein an air box is arranged in the middle of the box body, a cable chamber and a cable withstand voltage test chamber are arranged at the lower end of the air box, an instrument chamber is arranged at the top of the box body, symmetrical layout is adopted in the air box, two groups of load switches are arranged on two sides of the inside of the air box, a breaker switch is embedded between the load switches, and the breaker switch is connected with the load switches through CV busbar;

The load switch comprises a mounting frame and a load switch driving unit, wherein a load switch transmission assembly is arranged on the left side of the load switch driving unit, a moving contact is hinged to the lower end of the load switch transmission assembly, a moving contact seat is hinged to the bottom of the moving contact, an upper fixed contact is arranged on the upper portion of the mounting frame, arc extinguishing grid plates are fixed on the two sides of the upper fixed contact, and an insulating umbrella skirt and a grounding contact are arranged on the front portion of the mounting frame.

Preferably, the left side of the grounding contact is a connecting part which is fixed with the insulating umbrella skirt, the right part is of an inverted T-shaped design, and the bottom of the inverted T-shaped part is arc-shaped.

Preferably, the lower end of the load switch is provided with a test terminal and an incoming and outgoing line terminal, the test terminal is connected with the grounding contact through a copper bar, and the incoming and outgoing line terminal is connected with the moving contact seat through the copper bar.

Preferably, the load switch transmission assembly comprises a load switch main shaft in transmission connection with the load switch driving unit, a transmission connecting piece is fixed on the load switch main shaft, the end part of the transmission connecting piece is hinged with arc-shaped pull plates, and movable contact pull plates are hinged between the arc-shaped pull plates.

Preferably, the upper and lower sides of the mounting frame are respectively provided with a load switch upper beam and a load switch lower beam, and are made of plastic materials.

Preferably, the load switch driving unit is provided with a program lock.

Preferably, the circuit breaker switch comprises a circuit breaker switch driving unit and a fixing assembly, wherein the upper end of the circuit breaker switch driving unit is in transmission connection with a circuit breaker transmission main shaft, a cam connecting piece is arranged on the transmission main shaft in an array mode, a vacuum bubble pull rod is movably connected to the cam connecting piece, the vacuum bubble pull rod is longitudinally arranged in a movable mode, three groups of vacuum bubbles are arranged in the fixing assembly, a circuit breaker fixed contact is fixed at the lower end of the vacuum bubble pull rod, a lower isolation transmission assembly is arranged at the lower end of the circuit breaker switch driving unit, an isolation switch moving contact is hinged to the lower end of the lower isolation transmission assembly, an isolation switch moving contact seat is fixed at the bottom of the isolation switch moving contact seat, a three-phase copper rod is connected to the upper portion of the isolation switch moving contact seat, and an inlet and outlet wire terminal is connected to the end of the three-phase copper rod.

Preferably, the bottom of the fixed component is provided with a grounding connection row, and the upper end of the grounding connection row is provided with three groups of T-shaped grounding contacts.

Preferably, the load switch lower cross beam is fixedly connected with the fixing component.

Preferably, the upper end of the vacuum bubble is provided with a soft connection, and two sides of the soft connection are respectively connected with two groups of load switches.

Further, the power supply is arranged in the instrument room, the power supply is in a power supply voltage transformer VT integrated form, VT directly supplies power to the storage battery, and the storage battery supplies power to the secondary control loop and the breaker operation loop through the power supply module, so that external power supply is not needed.

Furthermore, the copper bar of the load switch fixed contact connected to the outlet sleeve is longer, and the copper bar is fixed by adopting the bracket, so that the synchronism of the switching-on of the load switch is influenced by the vibration of the copper bar due to the electromotive force generated in the operation.

Further, the box body comprises an outdoor box shell and a ring main unit shell, the outdoor box shell and the ring main unit shell are integrally designed, an upper door plate is hinged to the upper end of the box body, a special bending design is arranged on the structure of the box body, sealing and waterproof requirements are met by the upper door plate and the cable chamber door in a mode of adding sealing strips and the like, and meanwhile, the upper door plate is designed to be of a flip-type structure for conveniently checking a switch state and a secondary circuit state.

(III) beneficial effects

The invention has various obvious beneficial effects. The combination form of traditional independent looped netowrk cabinet and outdoor box has been abandoned, outer box and looped netowrk cabinet integrated design are adopted, will be originally the last door plant and the cable chamber door plant of looped netowrk cabinet as outer box, have reduced equipment whole volume by a wide margin. The design effectively saves the installation space, is particularly suitable for places with limited space, such as power distribution rooms of old and old communities in cities, power facility reconstruction projects in narrow streets and the like, and can obviously reduce the installation difficulty and complexity.

The inside symmetrical layout that adopts of gas tank, both sides are load switch, and the middle embedding circuit breaker switch just is connected through the female row of CV. The layout promotes the high balance of charge distribution, and according to the electric field superposition principle, the electric field components in all directions can offset one part of the electric field components, so that the excessive accumulation of the electric field intensity in a single direction is effectively avoided, and the distortion of the electric field is remarkably reduced. Compared with the traditional layout, the compact structural layout greatly shortens the electrical distance between the components, and enables the electric field to be smoothly transited. For example, the electric field connection between the adjacent load switch and the breaker switch is more coordinated, and the problems of unsmooth electric field connection and local abrupt change caused by too far distance can not occur. This allows the internal electric field of the device to be always in a stable, uniform ideal state. The stable electric field environment greatly reduces the discharge phenomenon caused by the overhigh intensity of the local electric field, effectively reduces the fault probability of equipment, ensures the long-term stable operation of the equipment, and powerfully supports the reliable power supply of a power system.

Drawings

FIG. 1 is a schematic diagram of the 17.5kV ring main unit with a front cover plate removed integrally;

FIG. 2 is a cross-sectional view of the whole 17.5kV ring main unit of the invention;

FIG. 3 is a cross-sectional view of an air box in a 17.5kV ring main unit of the invention;

FIG. 4 is a schematic diagram of a load switch and breaker switch connection in a 17.5kV ring main unit of the invention;

FIG. 5 is a schematic diagram of a load switch in a 17.5kV ring main unit of the invention;

FIG. 6 is an enlarged view of the load switch A in the 17.5kV ring main unit;

FIG. 7 is a cross-sectional view of a load switch in a 17.5kV ring main unit of the invention;

FIG. 8 is a schematic view of a ground contact in a 17.5kV ring main unit according to the present invention;

FIG. 9 is a schematic diagram of a 17.5kV ring main unit interrupt circuit breaker switch of the present invention;

FIG. 10 is a schematic diagram of a circuit breaker switch removal fixture assembly in a 17.5kV ring main unit in accordance with the present invention;

FIG. 11 is an enlarged view of portion B of FIG. 10 of a 17.5kV ring main unit in accordance with the present invention;

In the figure, the device comprises a 1-box body, a 2-gas box, a 3-cable chamber, a 4-cable withstand voltage test chamber, a 5-instrument chamber, a 6-power supply, a 11-outdoor box shell, a 12-ring main unit shell, a 13-upper door plate, a 21-load switch, a 22-breaker switch, a 23-CV busbar, a 24-program lock, a 211-mounting frame, a 212-load switch driving unit, a 213-load switch transmission assembly, a 214-moving contact, a 215-moving contact seat, a 216-upper fixed contact, a 217-arc extinguishing grid sheet, a 218-insulating umbrella skirt, a 219-grounding contact, a 2101-test terminal, a 2102-incoming and outgoing line terminal, a 2191-connecting part, a 2111-load switch upper beam, a 2112-load switch lower beam, a 2131-load switch main shaft, a 2132-transmission connecting piece, a 3-arc pulling plate, a 2134-moving contact pulling plate, a 221-breaker switch driving unit, a 2222-fixing assembly, a 224-cam connecting piece, a 225-vacuum bulb static contact, a 226-vacuum bulb contact, a 227-lower contact seat, a 2222-moving contact seat, a 2222-connecting piece, a 2221-insulating insulator, a 2222, a three-phase insulator, a 2222-insulator, a high-insulator, and a 2222.

Detailed Description

The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to fig. 1 to 11 in the examples of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments, and all other embodiments obtained by those skilled in the art without making any inventive effort based on the embodiments of the present invention are within the scope of the present invention.

The invention provides a technical scheme that a 17.5kV ring main unit comprises a box body 1, wherein an air box 2 is arranged in the middle of the box body 1, a cable chamber 3 and a cable withstand voltage test chamber 4 are arranged at the lower end of the air box 2, an instrument chamber 5 is arranged at the top of the box body 1, the inside of the air box 2 is symmetrically distributed, two groups of load switches 21 are arranged on two sides of the inside of the air box 2, a breaker switch 22 is embedded between the load switches 21, and the breaker switch 22 and the load switches 21 are connected through a CV busbar 23. The box 1 is used as the outer shell of the whole ring main unit, plays a role in protecting and supporting internal parts, resists external physical impact, dust, moisture and other adverse factors for internal equipment, ensures stable operation of the equipment, and provides a foundation for optimizing internal layout by reasonable structural design.

The air box 2 is positioned in the middle of the box body, is a centralized placement area of core electric components, creates a relatively stable operation environment for key equipment such as a load switch, a breaker switch and the like, prevents the external environment from interfering with the electric performance, and ensures the reliability and the safety of power transmission. The cable chamber 3 is used for leading in and leading out cables, realizes the connection of the ring main unit and the electric energy transmission of an external power grid or electric equipment, is a key channel for inputting and outputting electric power, and the cable fixing device inside ensures stable cable connection and avoids loosening to cause faults. The cable withstand voltage test chamber 4 is specially designed for testing the insulation performance of the cable, and is matched with a test terminal and an incoming and outgoing line terminal at the lower end of the load switch, so that a tester can conveniently and safely operate outside, detect whether the cable has insulation hidden danger or not, and ensure the power supply safety of a power grid. The instrument room 5 bears various monitoring and control instruments and innovative power supply systems, and feeds back the operation parameters of the ring main unit in real time to provide key data basis for operation and maintenance personnel, wherein a power supply and a voltage transformer VT continuously supply energy for a secondary control loop and a breaker operation loop, so that the normal operation of the automation function of the ring main unit is ensured.

The box 1 includes outdoor case casing 11 and looped netowrk cabinet casing 12, and outdoor case casing and looped netowrk cabinet casing are integrated into one piece's design, and the upper end of box articulates has door plant 13, through abandoning the form that conventional independent looped netowrk cabinet added outdoor case, adopts outer box and looped netowrk cabinet integrated into one piece's design, will originally the upper door plant and the cable chamber door plant of looped netowrk cabinet directly as the component part of outer box. Through special bending design, the whole structure is more compact and stable, and the strength of the shell is enhanced. After the sealing strip is further added, the sealing and waterproof requirements are effectively met, and a good operation environment is created for the internal electric elements. The integrated shell provides reasonable space layout for each functional area inside the ring main unit. From the gas tank to the cable chamber, the cable withstand voltage testing chamber and the instrument chamber, all the parts are closely arranged and mutually independent and organically connected. The special bending design optimizes the space utilization and simultaneously enhances the stability of the structure, so that the whole ring main unit can adapt to different installation environments and working conditions.

The load switches 21 are distributed on two sides of the inside of the gas tank, and are mainly used for controlling the opening and closing of load current in normal operation, such as the connection and disconnection of daily power utilization lines, accurately control the power distribution, ensure the power supply of different loads as required, and play a certain isolating role in the initial stage of failure. The breaker switch 22 is embedded between the two groups of load switches, and can cut off the circuit rapidly when the circuit has a short circuit condition of instantaneous ultra-large current, protect equipment from overload impact, prevent fault spreading and maintain the stability of the whole ring main unit and the power grid system. The CV busbar 22 is used as a conductive component for connecting a breaker switch and a load switch, bears the heavy duty of efficient transmission of electric energy, ensures smooth current circulation with low resistance characteristics, ensures cooperative work of all switching devices, and realizes ordered distribution and control of electric power.

The overall arrangement is symmetrical and compact, with the two groups of load switches 21 being symmetrical about a central axis and the breaker switch 22 being centrally located, which results in a relatively balanced charge distribution. On the one hand, the symmetrical structure enables equal positive and negative charges to be regularly distributed in space, and according to the electric field superposition principle, electric field components in all directions can offset one another, so that the situation that the electric field intensity in a single direction is excessively accumulated is avoided, and the distortion of an electric field is effectively reduced. On the other hand, the compact arrangement shortens the electrical distance between the components, enabling the electric field to transition relatively smoothly, as if the dispersed electric field were "bunched" reducing the electric field inhomogeneity. Taking the adjacent load switch and breaker switch as an example, the electric fields between the load switch and the breaker switch are closely arranged so that the mutual influence of the electric fields is more coordinated, the problems of unsmooth electric field connection and local abrupt change caused by too far distance can be avoided, the situation that the local electric field intensity is too high is avoided, the electric field inside the equipment is ensured to be in a stable and uniform state, and a firm foundation is built for the reliable operation of the equipment.

The load switch 21 comprises a mounting frame 211 and a load switch driving unit 212, a load switch transmission assembly 213 is arranged on the left side of the load switch driving unit 212, a moving contact 214 is hinged to the lower end of the load switch transmission assembly 213, a moving contact seat 215 is hinged to the bottom of the moving contact 214, an upper fixed contact 216 is arranged on the upper portion of the mounting frame 211, arc extinguishing grid plates 217 are fixed on the two sides of the upper fixed contact 216, and an insulating umbrella skirt 218 and a grounding contact 219 are arranged on the front portion of the mounting frame 211.

The mounting bracket 211 provides a mounting base and positioning reference for other components of the load switch. The upper and lower sides of the switch are respectively provided with a load switch upper beam 2111 and a load switch lower beam 2112, which can bear the weight of each component and the mechanical force generated in the operation process, and maintain the stability of the whole switch structure. The load switch driving unit 212 is a power source for the load switch operation. The power circuit can receive an external control signal, convert the external control signal into mechanical power and drive the load switch transmission assembly 213, so that the switching-on and switching-off actions of the movable contact 214 are realized, and the switching-on and switching-off operations of a power circuit are completed.

The load switch driving unit 212 is composed of a load switch main shaft 2131 in transmission connection, a transmission connecting piece 2132 fixed on the main shaft 2131, arc-shaped pull plates 2133 hinged at the end parts and movable contact pull plates 2134 hinged between the arc-shaped pull plates 2133. The main function of the assembly is to effectively transmit the power generated by the load switch driving unit 212 to the moving contact 214, and precisely control the movement track and speed of the moving contact 214 through the hinging relation among the components, so as to ensure that the moving contact 214 can be accurately contacted with or separated from the fixed contact 216 in the opening and closing process, and realize stable electrical connection and disconnection.

The movable contact 214 is a component of the load switch that directly participates in the circuit on and off operation. In the switching-on process, the movable contact 214 moves upwards under the drive of the load switch transmission assembly 213 to contact with the upper fixed contact 216 to form an electric path, so that current can smoothly pass through, and in the switching-off process, the movable contact 214 moves downwards to be separated from the upper fixed contact 216 to cut off the circuit. The movable contact seat 215 provides a stable support and connection foundation for the movable contact 214, ensures the stability and accuracy of the movable contact 214 in the moving process, and can conduct the current on the movable contact 214 to other electrical components or a grounding system.

The upper stationary contact 216 is a fixed member that cooperates with the movable contact 214 to achieve electrical connection. When the movable contact 214 contacts it, a complete current path is formed, enabling the normal transmission of power in the circuit. During operation of the device, the upper stationary contact 216 needs to bear thermal effects and mechanical forces generated when current passes through, and the material and structural design of the upper stationary contact have good conductivity and mechanical strength. The arc extinguishing bars 217 are fixed on both sides of the upper static contact 216, and mainly serve to extinguish the arc by utilizing the special structure and material characteristics of the arc extinguishing bars 217 when the moving contact 214 is separated from the upper static contact 216 to generate the arc in the process of opening the load switch. The arc extinguishing grid sheet 217 can introduce the arc into the grid sheet, and the arc is rapidly extinguished in the modes of cutting, cooling, stretching the arc and the like, so that the contact and other electrical components are protected, the service life of the equipment is prolonged, and the safety and reliability of the equipment are improved.

An insulating umbrella skirt 218 is installed at the front of the mounting frame 211, and has a main function of increasing a creepage distance to prevent insulation breakdown due to excessively high electric field strength in a high voltage environment. The shape and material of the insulating umbrella skirt 218 can effectively prevent the leakage path of current on the insulating surface, and improve the insulating performance of the device. The grounding contact 219 is fixed with the insulating umbrella skirt 218 to play a certain role in fixing and supporting, and on the other hand, the grounding contact 219 can safely introduce current into the ground under the condition of normal operation or failure of equipment, so that the safety of the equipment and personnel is ensured. The special shape of the ground contact 219 can optimize the electric field distribution and enhance the grounding effect. The ground contact 219 has a connecting portion 2191 on the left side and is fixed to the insulating umbrella skirt 218, and has an inverted T-shaped right side, with the bottom of the inverted T-shaped body being arcuate. The connection 2191 securely secures the ground contact 219 to the insulating umbrella skirt 218, providing stable mechanical support for the ground contact. The inverted T-shaped structure provides a better mechanical fit for connection with other components. Secondly, under the high voltage environment, the electric field concentration is easy to be caused by sharp corners, and the arc-shaped design can enable the electric field lines to be distributed more uniformly around the grounding contact. This reduces the local electric field strength and reduces the risk of corona discharge and dielectric breakdown.

The load switch 21 has a test terminal 2101 and a wire inlet and outlet terminal 2102 at the lower end, the test terminal 2101 is connected to the ground contact 219 via a copper rod, and the wire inlet and outlet terminal 2102 is connected to the movable contact base 215 via a copper rod. The test terminal 2101 and the in-out terminal 2102 are externally provided with insulating sleeves, and the test terminal 2101 is connected with the ground contact 219 through a copper bar, so that a direct connection channel is created for cable withstand voltage test. In the operation and maintenance flow of the power system, the periodic detection of the insulation level of the cable is of great importance, the traditional test scheme often needs complex wiring, and the design enables an operator to rapidly perform the test only by connecting the test equipment to the test terminal 2101, so that the operation flow is greatly simplified, the test preparation time is saved, and the operation and maintenance efficiency is improved. Meanwhile, once faults such as leakage, short circuit and the like occur, the current can be rapidly led to the ground. The copper bar has good conductivity, ensures that the grounding path resistance is low enough, can lead fault current to be discharged rapidly, prevents the equipment shell from being electrified, guards the safety of operators and avoids the electrical equipment from being further damaged. The wire inlet and outlet terminals 2102 are communicated with the movable contact base 215 through copper bars, and when a circuit is conducted, the structure can reliably transmit electric energy from the wire inlet and outlet terminals to corresponding contacts of the switch, so that electric energy transmission is achieved.

The program lock 24 is provided in the load switch driving unit 212, so that malfunction of the load switch due to erroneous touch or unauthorized operation can be effectively prevented. When the cable test is required, the program lock is rotated to be pointed to the corresponding position, and the load switch 21 is at the grounding position, and the mechanism is in a locking state, so that misoperation is prevented. In testing, the test terminal 2101 is connected to a high voltage test device to directly test the insulation level of the cable by a high voltage. After the test is finished, the test equipment is removed, the grounded short circuit bars are connected, the switch is in a grounded state again, the compartment door is closed, the ground switch can be operated to be separated, the load switch is operated to be separated and closed, and the normal function of the three-station switch is realized.

The circuit breaker switch 22 comprises a circuit breaker switch driving unit 221 and a fixing component 222, wherein the upper end of the circuit breaker switch driving unit 221 is in transmission connection with a circuit breaker transmission main shaft 223, a cam connecting piece 224 is arranged on the transmission main shaft 223 in an array mode, a vacuum bubble pull rod 225 is movably connected to the cam connecting piece 224, the vacuum bubble pull rod 225 is longitudinally arranged in a movable mode, three groups of vacuum bubbles 226 are arranged in the fixing component 222, a circuit breaker fixed contact 227 is fixed at the lower end of the vacuum bubble pull rod 225, a lower isolation transmission component 228 is arranged at the lower end of the circuit breaker switch driving unit 221, an isolation switch movable contact 229 is hinged to the lower end of the lower isolation transmission component 228, an isolation switch movable contact seat 230 is fixed at the bottom of the isolation switch movable contact 229, a three-phase copper rod 231 is connected to the upper portion of the isolation switch movable contact seat 230, and an inlet and outlet wire terminal 2102 is connected to the end of the three-phase copper rod 231.

The breaker switch driving unit 221 is used as a core power source of breaker switch action and is used for receiving the opening and closing signals from the control system and driving the breaker transmission main shaft 223 connected with the opening and closing signals to rotate, so that a subsequent series of actions are started, accurate control of the circuit by the breaker is realized, and reliable operation of the power line under normal and fault states is ensured. The cam connection 224 is movably connected with the vacuum bubble pull rod 225, and converts the rotation motion of the circuit breaker transmission main shaft 223 into the longitudinal linear motion of the vacuum bubble pull rod 225 by utilizing the unique profile curve of the cam. The motion conversion mode is efficient and accurate, so that the vacuum bubble pull rod 225 can quickly drive the fixed contact 227 of the circuit breaker to realize opening and closing actions according to a preset track, and a circuit is effectively cut off or switched on to cope with various working conditions in a power system.

When the switch is opened, the vacuum bubble pull rod 225 moves upwards rapidly to drive the fixed contact and the movable contact in the arc extinguishing chamber to separate, the arc is extinguished rapidly by utilizing a vacuum environment, the contact ablation is reduced, and when the switch is closed, the reverse movement is realized, the close contact between the fixed contact and the movable contact is ensured, the reliable electrical connection is realized, and the smooth passing of current is ensured. The fixing assembly 222 provides stable installation space for the three groups of vacuum bubbles 226, protects the vacuum bubbles 226 from being interfered by external mechanical impact, dust and water vapor and the like, ensures stable internal high-vacuum environment and maintains good insulation and arc extinguishing performance, and on the other hand, enhances the integrity and stability of the whole switchgear structure by being fixedly connected with other parts, such as the lower beam of the load switch. The vacuum bulb 226 is a key element of the circuit breaker for realizing an arc extinguishing function, and the internal high vacuum environment can effectively inhibit the generation and maintenance of an arc. When the breaker breaks off and instantaneously generates an electric arc, the vacuum bubbles 226 utilize the rapid cooling and diffusion effects of vacuum on the electric arc to rapidly extinguish the electric arc, prevent the electric arc from continuously burning to damage contacts and other electrical components, and ensure the service life of the breaker and safe and stable operation of a power system. The fixed contact 227 of the circuit breaker is used as one of fixed endpoints of circuit connection, and is closely contacted with the moving contact 229 of the isolating switch in a closing state, so that a low-resistance electric path is formed and load current in normal operation is carried. The material and the structural design of the high-voltage power supply have good conductivity and wear resistance so as to cope with the examination brought by long-term current passing and frequent switching-on and switching-off operation and ensure the high efficiency and stability of power transmission. The lower isolating transmission assembly 38 is responsible for transmitting power to the isolating switch moving contact 229 to drive the isolating switch moving contact to perform opening and closing actions. The disconnecting switch moving contact 229 and the circuit breaker fixed contact 227 work cooperatively, and in the switching-on process, the disconnecting switch moving contact 229 is quickly close to and closely attached to the circuit breaker fixed contact 227 under the drive of power to complete electrical connection, and the disconnecting switch is quickly separated to cut off current. The movable contact seat 230 of the isolating switch provides a firm supporting base for the movable contact 229 of the isolating switch, and ensures that the movable contact 229 is stable in position and smooth in movement in frequent opening and closing operations. Meanwhile, the three-phase copper bar 231 is used as an intermediate link of current conduction, and current on the movable contact 229 of the isolating switch is transmitted to the in-out terminal 2102 through the three-phase copper bar 231, so that the ordered output of power is ensured. The three-phase copper bar 231 has excellent conductivity, and efficiently and stably transmits the three-phase current collected by the movable contact seat 230 of the isolating switch to the wire inlet and outlet terminal 2102, so that the loss of electric energy in the transmission process is reduced, and the balanced distribution and stable transmission of the three-phase current of the electric power system are ensured. The inlet and outlet terminals 2102 are used as interfaces for externally connecting the power system, are convenient to connect with power transmission lines such as external cables and buses, realize power input and output, ensure interconnection and intercommunication of the whole power system, and meet power distribution and use requirements in different application scenes.

The bottom of the fixed assembly 222 is provided with a ground connection row 2221, and the upper end of the ground connection row 2221 is provided with three sets of T-shaped ground contacts 2222. The grounding connection row 2221 provides a centralized and smooth discharging channel for grounding current, introduces electric leakage, fault current and the like possibly generated in the running process of the equipment into the ground, ensures the equipment shell and the surrounding environment to be at safe potential, and prevents personnel from electric shock and equipment damage. The three groups of T-shaped grounding contacts 2222 are matched with the grounding connection row 2221, so that on one hand, the reliability of grounding connection is enhanced, the contact area with a grounding part is increased, the contact resistance is reduced, and the grounding effect is improved through the special T-shaped structure of the three groups of T-shaped grounding contacts, and on the other hand, the three groups of T-shaped grounding contacts are convenient to accurately butt against other grounding circuits or parts in the equipment assembling and maintaining processes, and the integrity and the effectiveness of a grounding system are ensured.

Working principle:

1. Working principle of load switch

And a closing operation, namely when a closing instruction is received, the load switch driving unit 212 is activated, generates mechanical power and drives the load switch transmission assembly 213 to operate. The load switch main shaft 2131 immediately starts to rotate at a constant speed, drives the transmission connecting piece 2132 rigidly connected with the load switch main shaft to synchronously perform circular motion, the end part of the transmission connecting piece 2132 is driven to swing through the arc-shaped pull plate 2133 hinged with the pin shaft, and power is stably transmitted to the moving contact 214 by means of the linkage transmission mechanism of the moving contact pull plate 2134. The moving contact 214 slides upwards along a pre-designed guide rail under the action of the driving force, and finally is precisely attached to the upper fixed contact 216 at the upper part of the mounting frame 211, so that a low-impedance electric path is formed, current can smoothly pass through the load switch without resistance, a closing function is successfully realized, and a corresponding power line is connected. At this time, the arc extinguishing bar 217 is in a standby state, and an arc which may occur when the switch is to be opened is prepared at any time.

Switching-off operation-upon receipt of a switching-off signal, the load switch driving unit 212 rapidly reverses or activates the braking means to drive the load switch transmission assembly 213 to operate cooperatively in reverse order of switching-on. Each transmission component is linked in sequence to drive the movable contact 214 to move downwards and stably along the guide rail, so that the movable contact is quickly separated from the upper fixed contact 216, and the current path is instantaneously cut off. When the moving contact 214 is separated from the upper fixed contact 216, if an arc is generated due to electromagnetic induction or other factors, the arc extinguishing grid plates 217 positioned on both sides immediately exert efficiency. The arc extinguishing grating sheet 217 is characterized in that the arc extinguishing grating sheet 217 is strongly led into the grating sheet by means of a special metal sheet arrangement structure and material characteristics with high heat conductivity and insulativity, and the arc is extinguished in a very short time by means of multistage segmentation, efficient cooling, elongation treatment and the like of the arc, so that the contact and other electrical components are practically protected from being burnt by the arc at high temperature, the switching-off process is ensured to be safe and reliable, and the impact on a system is very small.

2. Working principle of breaker switch

And in the closing operation, the lower isolation transmission assembly 228 drives the isolation switch moving contact 229 to move upwards stably until the isolation switch moving contact 229 is separated from the grounding contact 2222, so that the grounding operation is realized, and then the lower isolation transmission assembly 228 drives the isolation switch moving contact 229 to move upwards, so that the isolation switch moving contact 229 is tightly attached to the circuit breaker fixed contact 227, and the closing of the isolation switch is realized. Subsequently, the circuit breaker switch driving unit 221 drives the circuit breaker transmission main shaft 223 to start rotation after receiving the closing instruction. The cam connecting pieces 224 which are uniformly distributed on the main shaft 223 in an array form accurately and synchronously move along with the rotation of the main shaft, the unique profile curve characteristic of the cam is skillfully utilized, the rotation motion of the main shaft is efficiently converted into the longitudinal linear motion of the vacuum bubble pull rod 225, the vacuum bubble pull rod 225 is driven to rapidly and linearly displace downwards, and the moving contact in the arc extinguishing chamber is driven to move towards the fixed contact until the moving contact is reliably contacted. Therefore, a low-resistance electric path is constructed, the closing action is completed satisfactorily, and smooth connection of the power line is ensured. After closing, the three groups of vacuum bubbles 226 in the fixed assembly 222 cooperate to ensure that the surrounding environment is maintained in a high vacuum state, and ideal conditions are created in advance for the subsequent possible arc extinguishing operation.

Breaking operation when the system detects a fault or receives a breaking instruction, the breaker switch driving unit 221 drives the breaker transmission spindle 223 to rapidly rotate reversely. The cam connecting piece 224 drives the vacuum bubble pull rod 225 to move upwards at a high speed, so that the moving contact in the arc extinguishing chamber is separated from the fixed contact quickly, and the current is cut off immediately. Because the factors such as line inductance and the like are extremely easy to induce the generation of electric arcs at the moment of current cutting-off, the three groups of vacuum bubbles 226 now play a critical arc extinguishing core role. The vacuum bubbles 226 cool and diffuse the electric arc in an ultra-fast manner by virtue of the high vacuum environment inside, so that the electric arc is extinguished in an extremely short time (within a few milliseconds), the irreversible damage to the contacts and other electrical components caused by continuous combustion of the electric arc is fundamentally prevented, and the safe operation of the power system is powerfully ensured. Then, the lower isolation transmission assembly 228 drives the isolation switch moving contact 229 to move downwards stably, so that the circuit isolation switch moving contact 229 is separated from the circuit breaker fixed contact 227 rapidly, the isolation switch operation is realized, and then the lower isolation transmission assembly 228 is operated to drive the isolation switch moving contact 229 to move downwards until the isolation switch moving contact 229 is reliably contacted with the grounding contact 2222, and the circuit grounding operation is realized.

3. The cable test is that firstly, an operator operates a mechanism to enable a load switch to be in a grounding state, then carefully rotates a program lock 24 to enable the program lock 24 to accurately point to a corresponding test position, at the moment, the program lock 24 plays a forced locking function to firmly limit the load switch 21 to be in the grounding state, and the whole mechanism synchronously enters a locking mode, so that any misoperation is effectively prevented from occurring from the source. Next, the operator uses the dedicated cable to connect the test terminal 2101 with the professional high voltage test equipment reliably, rigorously preparing to test the cable insulation level. Thanks to the stable connection of the test terminal 2101 with the ground contact 219 via the copper bar, it is ensured that the test current can be smoothly transmitted along a preset accurate path, and a solid guarantee is provided for obtaining accurate test data.

In the testing process, by virtue of the locking state maintained by the program lock 24, not only the accuracy and reliability of the test data are strictly ensured, but also the external factors are practically prevented from interfering with the testing process, and the serious dangerous situations such as test interruption, equipment damage and even personnel electric shock caused by accidental touch of the switch are effectively avoided. After the test is finished, operators need to carefully remove the test equipment according to the standard flow, accurately connect the grounded shorting bar, make the switch in a grounded state again, and then carefully close the compartment door. And then the program lock 24 is rotated again, at this time, the state of the whole equipment is recovered to be normal, and the ground switch can be operated to be separated, so that the normal function of the three-station switch is smoothly realized.

If the equipment breaks down, the grounding system can be started instantly, fault current is rapidly led into the ground, the fault is effectively avoided from being further expanded by virtue of a low-impedance grounding path, the safety of the equipment and the whole power system is practically protected, and the loss is reduced to the greatest extent.

Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims (10)

1. The utility model provides a 17.5kV looped netowrk case, includes box (1), box (1) is including outdoor case casing (11) and looped netowrk cabinet casing (12), outdoor case casing (11) and looped netowrk cabinet casing (12) are integrated into one piece design, and upper end of box (1) articulates has upper door plant (13), the middle part of box (1) is equipped with gas tank (2), the lower extreme of gas tank (2) is equipped with cable chamber (3) and cable withstand voltage test room (4), the top of box (1) is equipped with instrument room (5), a serial communication port, be symmetrical overall arrangement inside gas tank (2), gas tank (2) inside both sides are provided with two sets of load switch (21), the embedding has circuit breaker switch (22) between load switch (21), be connected through CV busbar (23) between circuit breaker switch (22) and the load switch (21).

The load switch (21) comprises a mounting frame (211) and a load switch driving unit (212), a load switch driving assembly (213) is arranged on the left side of the load switch driving unit (212), a moving contact (214) is hinged to the lower end of the load switch driving assembly (213), a moving contact seat (215) is hinged to the bottom of the moving contact (214), an upper fixed contact (216) is arranged on the upper portion of the mounting frame (211), arc extinguishing grid plates (217) are fixed on the two sides of the upper fixed contact (216), and an insulating umbrella skirt (218) and a grounding contact (219) are arranged on the front portion of the mounting frame (211).

2. The 17.5kV ring main unit according to claim 1, wherein the left side of the grounding contact (219) is a connecting part (2191) which is fixed with an insulating umbrella skirt (218), the right part is of an inverted T-shaped design, and the bottom of the inverted T-shaped part is arc-shaped.

3. A 17.5kV ring main unit according to claim 1, wherein the lower end of the load switch (21) is provided with a test terminal (2101) and an in-out terminal (2102), the test terminal (2101) is connected with the ground contact (219) through a copper bar, and the in-out terminal (2102) is connected with the movable contact base (215) through a copper bar.

4. The 17.5kV ring main unit according to claim 1, wherein the load switch transmission assembly (213) comprises a load switch main shaft (2131) in transmission connection with a load switch driving unit (212), a transmission connecting piece (2132) is fixed on the load switch main shaft (2131), an arc-shaped pulling plate (2133) is hinged at the end part of the transmission connecting piece (2132), and a moving contact pulling plate (2134) is hinged between the arc-shaped pulling plates (2133).

5. The 17.5kV ring main unit according to claim 1, wherein a load switch upper beam (2111) and a load switch lower beam (2112) are respectively arranged on the upper side and the lower side of the mounting frame (211).

6. A 17.5kV ring main unit according to claim 1, characterized in that the load switch driving unit (212) is provided with a program lock (24).

7. The 17.5kV ring main unit according to claim 1, wherein the breaker switch (22) comprises a breaker switch driving unit (221) and a fixing component (222), a breaker transmission main shaft (223) is connected to the upper end transmission of the breaker switch driving unit (221), a cam connecting piece (224) is arranged on the transmission main shaft (223) in an array mode, a vacuum bubble pull rod (225) is movably connected to the cam connecting piece (224), the vacuum bubble pull rod (225) is movably arranged in the longitudinal direction, three groups of vacuum bubbles (226) are arranged in the fixing component (222), a breaker fixed contact (227) is fixed at the lower end of the vacuum bubble pull rod (225), a lower isolation transmission component (228) is arranged at the lower end of the breaker switch driving unit (221), an isolation switch movable contact (229) is hinged to the lower end of the lower isolation transmission component (228), an isolation switch movable contact (230) is fixed at the bottom of the isolation switch movable contact (229), three-phase copper contact seat (230) is connected to the upper portion of the isolation switch movable contact seat, and a three-phase copper rod (2102) is connected to the three-phase end portion of the copper rod (231).

8. The 17.5kV ring main unit according to claim 7, wherein a ground connection row (2221) is provided at the bottom of the fixing assembly (222), and three sets of T-shaped ground contacts (2222) are provided at the upper end of the ground connection row (2221).

9. The 17.5kV ring main unit according to claim 7, wherein a soft connection (233) is arranged at the upper end of the vacuum bulb (226), and two sides of the soft connection (233) are respectively connected with two groups of load switches (21).

10. A 17.5kV ring main unit according to claim 1, characterized in that a power supply (6) is arranged in the instrument room (5), the power supply (6) is used together with a power supply voltage transformer VT, and VT supplies power to a storage battery through the power supply (6).