Emergency station ac power security box

Abstract

The application discloses an AC power supply security box for an emergency station, which comprises a box body, wherein at least a power input port, a power output port, a signal output port, at least one row of micro-break switches, a closing button, an opening button, a closing indicator lamp, an opening indicator lamp, a phase sequence error indicator lamp and a voltage abnormality indicator lamp are arranged on the box body; and at least a main circuit, a phase sequence measuring device, a power conversion module, a voltage measuring and protecting module, a microcomputer protection device, a switch control circuit and a signal output circuit are arranged in the box body. The embodiment of the application has the advantages of strong function, safety and reliability, remote monitoring and wide application scenarios.

Description

Technical Field

[0001] This invention relates to the field of on-site maintenance technology for power supply equipment, and in particular to AC power supply security boxes for emergency stations. Background Technology

[0002] Currently, in the renovation of station AC power supply sites and the use of emergency station AC power supply, the station power supply incoming cable is directly connected to the incoming switch side of the temporary power supply equipment. This results in problems such as excessively large cable bends and excessive mechanical stress on the cable, which can cause certain damage to the cable's mechanical properties. In addition, insufficient cable transfer space poses a potential short-circuit fault, which has a significant impact on the stable operation of the temporary AC system.

[0003] Traditional temporary power supply equipment only has a certain overload and short circuit protection function for the main switch. However, the characteristics of the switch protection function are different from those of the substation auxiliary transformer protection function. One is switch protection and the other is microprocessor protection. The two protections are not well coordinated and some protections cannot be adapted, which can easily cause cascading tripping and lead to an expansion of the fault outage area.

[0004] Furthermore, the temporary communication system lacks telemetry and remote signaling functions.

[0005] Therefore, traditional temporary power supply equipment suffers from low stability, poor protection reliability, and low adaptability during the transformation process, and it cannot achieve functions such as remote monitoring. Furthermore, determining the phase sequence after the equipment is connected requires specialized instruments or comparison with an AC power supply whose phase sequence has already been confirmed to be correct, making the process rather cumbersome.

[0006] As companies and the industry place increasing emphasis on station AC systems, the assessment of AC voltage loss is becoming more stringent. In general, the temporary power supply boxes currently used for AC upgrades can no longer meet the requirements and need further improvement and optimization. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide an AC power security box for emergency stations, which has the advantages of strong function, safety and reliability, and remote monitoring, and has a wide range of applications.

[0008] In one aspect, the present invention provides an AC power supply security box for emergency stations, characterized in that it comprises:

[0009] The enclosure is equipped with at least a power input port, a power output port, a signal output port, at least one row of micro-break switches, a closing button, a closing button, a closing indicator light, a closing indicator light, a phase sequence error indicator light, and a voltage abnormality indicator light.

[0010] At least the following are provided inside the box:

[0011] The main circuit includes a three-phase incoming power supply that enters the enclosure through the power input port, passes through the frame switch (QF) inside the enclosure, and is then connected to the power output port through the three-phase outgoing power supply.

[0012] The phase sequence measuring device is connected to the three-phase incoming power supply via a first micro-break switch (QF1) and a fuse. It is used to measure the phase sequence of the three-phase incoming power supply and to indicate when an error occurs in the phase sequence.

[0013] The power conversion module is connected to the first micro-break switch (QF1) via the second micro-break switch (QF2) and is used to convert the three-phase incoming power supply into 110V DC power supply.

[0014] The voltage measurement and protection module includes at least a voltmeter, a voltage transmitter, and an intermediate relay. The voltmeter and voltage transmitter are connected to the three-phase outgoing power supply via a fuse. The voltmeter is used for measurement and display of the power output circuit inside the enclosure. The voltage transmitter communicates with the substation monitoring and control device. The normally closed contact of the intermediate relay closes when the output circuit voltage is abnormal and communicates with the substation monitoring and control device for voltage abnormality alarm.

[0015] The microprocessor-based protection device has an AC power input terminal, a current input terminal, a DC power input terminal, an overcurrent protection control terminal, a zero-sequence overcurrent protection control terminal, a switch action signal output terminal, and a fault signal output terminal; it is used to determine whether there is a fault in the main circuit, and when a fault exists, to control the tripping circuit of the main switch to isolate the fault.

[0016] The signal output circuit is used to report switch action signals and fault signals to the substation monitoring and control equipment.

[0017] Preferably, the AC power input terminal of the microcomputer protection module is used to connect to the output terminal of the first micro-break switch QF1 through multiple fuses to collect the voltage of the main circuit;

[0018] The current input terminal of the microcomputer protection module is used to collect the current of the main circuit through multiple current transformers;

[0019] The microcomputer protection module is further used to determine whether there is a fault in the main circuit based on the collected main circuit voltage and current.

[0020] Preferably, the microcomputer protection module is further connected to a switch control circuit, which includes at least: a manual closing circuit, a manual opening circuit, an overcurrent protection tripping circuit, a zero-sequence overcurrent protection tripping circuit, a switch closing indication circuit, a switch opening indication circuit, and a switch opening / closing energy storage circuit.

[0021] Preferably, the manual tripping circuit includes: a tripping button (ST2) connected to the positive terminal of the DC power supply, a tripping coil (YO) and a first normally open contact (Q1) connected in sequence to the tripping button, and the other end of the first normally open contact connected to the negative terminal of the DC power supply;

[0022] The manual closing circuit includes: a closing button (ST1) connected to the positive terminal of the DC power supply, a closing coil (YC) and a first normally closed contact (Q2) connected in sequence to the closing button, and the other end of the first normally closed contact connected to the negative terminal of the DC power supply;

[0023] The overcurrent protection trip circuit includes: a normally open auxiliary contact (K1) of the overcurrent protection relay connected to the positive terminal of the DC power supply, a trip coil (YO) and a first normally open contact (Q1) connected in sequence to the overcurrent protection relay, the other end of the first normally open contact being connected to the negative terminal of the DC power supply, and the normally open auxiliary contact (K1) of the overcurrent protection relay being energized by a relay (K7) connected to the overcurrent protection control terminal;

[0024] The zero-sequence overcurrent protection trip circuit includes: a normally open auxiliary contact (K2) of the zero-sequence overcurrent protection relay connected to the positive terminal of the DC power supply, a trip coil (YO) and a first normally open contact (Q1) connected in sequence to the zero-sequence overcurrent protection relay, the other end of the first normally open contact being connected to the negative terminal of the DC power supply, and the normally open auxiliary contact (K2) of the zero-sequence overcurrent protection relay being energized by a relay (K8) connected to the zero-sequence overcurrent protection control terminal;

[0025] The switch closing indication circuit includes: a closing indicator light connected to the positive terminal of the DC power supply, the closing indicator light connected to the second normally open contact (Q3), and the other end of the second normally open contact connected to the negative terminal of the DC power supply;

[0026] The circuit breaker tripping indicator circuit includes: a tripping indicator light connected to the positive terminal of the DC power supply, the tripping indicator light connected to the second normally closed contact (Q4), and the other end of the second normally closed contact connected to the negative terminal of the DC power supply;

[0027] The switch opening and closing energy storage circuit includes: an energy storage motor connected to the positive terminal of a DC power supply, the energy storage motor being connected to an auxiliary contact (S33M / 1) of the energy storage circuit via a fuse, and the other end of the auxiliary contact of the energy storage circuit being connected to the negative terminal of the DC power supply.

[0028] Preferably, the signal output port communicates with the substation monitoring and control device via cable transmission or fiber optic network communication, and displays the signal on the monitoring and control screen of the substation monitoring and control device.

[0029] Preferably, its main busbar adopts flame-retardant insulated copper busbar, and its grounding adopts grounding copper busbar.

[0030] Implementing the embodiments of the present invention has the following beneficial effects:

[0031] This invention provides an emergency station AC power supply security box. It solves the problem of unreliable wiring of the station power supply incoming cable by using copper busbars for connection. The box is equipped with a four-stage micro-break switch to ensure reliable cooperation with the upper-level protection and has microcomputer protection function. The box has remote measurement and remote signaling functions to realize remote monitoring, avoid the inability to monitor the dispatching during the AC upgrade process, realize full monitoring of the temporary station AC system, and avoid the problems of unreliable operation and inability to monitor the temporary AC system during the station AC upgrade.

[0032] This invention can be used as a temporary AC power system during the renovation of substation AC power systems, and also as an emergency incoming power supply box. It enables rapid phase sequence determination and quick connection, while the protective DC power supply is provided through the security box to prevent DC cable pulling. Simultaneously, it standardizes renovation work, improves on-site construction management, and ensures the safe and stable operation of the temporary substation AC system.

[0033] This invention is applicable to any industry that uses AC power systems, such as buildings, industrial parks, and any other industry that uses AC power, especially the power industry. It greatly improves the reliability of AC power supply during construction and renovation. It can be promoted to district bureaus and extended to other enterprises outside the power grid, and has broad promotional value and economic benefits. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of the external structure of an AC power supply security box for emergency stations provided by the present invention;

[0036] Figure 2 This is a schematic diagram of the internal functional modules of an embodiment of an AC power supply security box for emergency stations provided by the present invention;

[0037] Figure 3 yes Figure 2 The corresponding circuit structure schematic diagram. Detailed Implementation

[0038] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0039] It should also be noted that, in order to avoid obscuring the invention with unnecessary details, only the structures and / or processing steps closely related to the solution according to the invention are shown in the accompanying drawings, while other details that are not closely related to the invention are omitted.

[0040] like Figure 1 The diagram shows a schematic representation of the external structure of an AC power supply security box for an emergency station, as provided by the present invention. It can be understood that, in the present invention, the box (cabinet) can be made into a regular cube, with a power inlet, indicator lights, and control buttons on its frame; the interior is equipped with circuit structures and functional modules.

[0041] In a more specific example, the enclosure can be based on a C-shaped profile frame with a side panel (e.g., 20mm thick) on the rear side to conceal the modular holes on the frame. Its panel is made of sheet metal bent in 20mm height modules, assembled in a modular, top-to-bottom configuration. Depending on functional requirements, it can be designed as a rotating door or a detachable fixed panel for front-side maintenance. Fireproof panels or side panels can be installed on both sides of the enclosure as needed. The fireproof panels have cable entry holes at the top and bottom for easy passage of signal cables between panels. The side panels do not have cable entry holes and are suitable for placement on the outer side of end cabinets, flush with the side frame after installation. The upper cover is equipped with louvers and a dust cover, and lifting rings at the four corners. The lower base plate has cable entry holes for easy disassembly. The main busbar uses flame-retardant insulated copper busbars, strictly selected according to the system's short-circuit capacity. Grounding: A grounding copper busbar of not less than 30×4 is installed, ensuring reliable contact with the equipment and structural components inside the enclosure, and is clearly marked with grounding information. The enclosure has an IP30 / 31 protection rating. In one embodiment, the enclosure is designed to be 1500 (height) × 600 (width) × 450 (depth).

[0042] More specifically, in one example, the enclosure is provided with at least a power input port, a power output port, a signal output port, at least one row of micro-break switches, a closing button, a closing button, a closing indicator light, a closing indicator light, a phase sequence error indicator light, and a voltage abnormality indicator light.

[0043] like Figure 2 The diagram shows a schematic representation of the internal functional modules of an embodiment of an AC power supply security box for emergency stations provided by the present invention; in conjunction with... Figure 3As shown, in this embodiment, at least the following functional modules (or circuit devices) are provided inside the housing:

[0044] The main circuit includes a three-phase incoming power supply (phases A, B, and C) that enters the enclosure through the power input port, passes through the frame switch (QF) inside the enclosure, and is then connected to the power output port through the three-phase outgoing power supply.

[0045] The phase sequence measuring device is connected to the three-phase incoming power supply via a first micro-break switch (QF1) and a fuse. It is used to measure the phase sequence of the three-phase incoming power supply and to indicate when an error occurs in the phase sequence.

[0046] The power conversion module is connected to the first micro-break switch (QF1) via the second micro-break switch (QF2) and is used to convert the three-phase incoming power (380V AC) into 110V DC power.

[0047] The voltage measurement and protection module includes at least a voltmeter, a voltage transmitter, and an intermediate relay. The voltmeter and voltage transmitter are connected to the three-phase outgoing power supply via a fuse. The voltmeter is used for measuring and displaying the power output circuit inside the enclosure. The voltage transmitter communicates with the substation monitoring and control device. The normally closed contact of the intermediate relay closes when the output circuit voltage is abnormal and communicates with the substation monitoring and control device for voltage abnormality alarm. In this embodiment, the voltmeter measures and displays the current voltage in real time on the enclosure and uses an indicator light to display when the current voltage is abnormal.

[0048] The microprocessor-based protection device has an AC power input terminal, a current input terminal, a DC power input terminal, an overcurrent protection control terminal, a zero-sequence overcurrent protection control terminal, a switch action signal output terminal, and a fault signal output terminal; it is used to determine whether there is a fault in the main circuit, and when a fault exists, to control the tripping circuit of the main switch and isolate the fault number.

[0049] The signal output circuit is used to report switch action signals and fault signals to the substation monitoring and control device; among them, contacts K4-K6 are the normally open contacts in the signal output circuit that enable the protection device to send signals to the station monitoring and control panel.

[0050] The AC power input terminal of the microcomputer protection module is used to connect to the output terminal of the first micro-break switch QF1 through multiple fuses to collect the voltage of the main circuit.

[0051] The current input terminal of the microcomputer protection module is used to collect the current of the main circuit through multiple current transformers.

[0052] The microcomputer protection module is further used to determine whether there is a fault in the main circuit based on the collected main circuit voltage and current.

[0053] More specifically, the microcomputer protection module is further connected to a switch control circuit, which includes at least: a manual closing circuit, a manual opening circuit, an overcurrent protection tripping circuit, a zero-sequence overcurrent protection tripping circuit, a switch closing indication circuit, a switch opening indication circuit, and a switch opening / closing energy storage circuit.

[0054] The manual tripping circuit includes: a tripping button (ST2) connected to the positive terminal of the DC power supply, a tripping coil (YO) and a first normally open contact (Q1) connected in sequence to the tripping button, and the other end of the first normally open contact connected to the negative terminal of the DC power supply; that is, the connection sequence of the circuit is: positive power -- ST2 (tripping button) -- YO (tripping coil) -- Q1 (normally open contact) -- negative power;

[0055] The manual closing circuit includes: a closing button (ST1) connected to the positive terminal of the DC power supply, a closing coil (YC) and a first normally closed contact (Q2) connected in sequence to the closing button, and the other end of the first normally closed contact connected to the negative terminal of the DC power supply; that is, the connection sequence of the circuit is: positive power - ST1 (closing button) - YC (closing coil) - Q2 (normally closed contact) - negative power;

[0056] The overcurrent protection trip circuit includes: a normally open auxiliary contact (K1) of the overcurrent protection relay connected to the positive terminal of the DC power supply, a trip coil (YO) and a first normally open contact (Q1) connected in sequence to the overcurrent protection relay, and the other end of the first normally open contact connected to the negative terminal of the DC power supply. That is, the connection sequence of the circuit is: positive power - K1 (normally open auxiliary contact of overcurrent protection relay) - YO (trip coil) - Q1 (normally closed contact) - negative power. The normally open auxiliary contact (K1) of the overcurrent protection relay is energized by a relay (K7) connected to the overcurrent protection control terminal. For example, when the microprocessor protection device detects an overcurrent protection action caused by a fault (such as a phase-to-phase short circuit), the K7 relay is energized, and the trip circuit of the main switch is opened through its auxiliary contact (K1) to isolate the fault. At the same time, when the busbar loses voltage, the microprocessor protection device can output a signal to the substation monitoring and control device to realize remote monitoring.

[0057] The zero-sequence overcurrent protection trip circuit includes: a normally open auxiliary contact (K2) of the zero-sequence overcurrent protection relay connected to the positive terminal of the DC power supply; a tripping coil (YO) and a first normally open contact (Q1) connected in sequence to the zero-sequence overcurrent protection relay; the other end of the first normally open contact is connected to the negative terminal of the DC power supply. The circuit sequence is: positive power - K2 (normally open auxiliary contact of the zero-sequence overcurrent protection relay) - YO (tripping coil) - Q1 (normally open contact) - negative power. The normally open auxiliary contact (K2) of the zero-sequence overcurrent protection relay is energized by a relay (K8) connected to the zero-sequence overcurrent protection control terminal.

[0058] The switch closing indicator circuit includes: a closing indicator light connected to the positive terminal of the DC power supply, the closing indicator light connected to the second normally open contact (Q3), and the other end of the second normally open contact connected to the negative terminal of the DC power supply; that is, its circuit sequence is: positive power - closing indicator light - Q3 (normally open contact) - negative power;

[0059] The circuit breaker tripping indicator circuit includes: a tripping indicator light connected to the positive terminal of the DC power supply, the tripping indicator light connected to the second normally closed contact (Q4), and the other end of the second normally closed contact connected to the negative terminal of the DC power supply; that is, its circuit sequence is: positive power - tripping indicator light - Q4 (normally closed contact) - negative power;

[0060] The switch opening and closing energy storage circuit includes: an energy storage motor connected to the positive terminal of a DC power supply; the energy storage motor is connected to an auxiliary contact (S33M / 1) of the energy storage circuit via a fuse; and the other end of the auxiliary contact is connected to the negative terminal of the DC power supply. That is, the circuit sequence is: positive power - energy storage motor - S33M / 1 (auxiliary contact of the energy storage circuit) - negative power.

[0061] The signal output port communicates with the substation monitoring and control device via cable transmission or fiber optic network communication, and is displayed on the monitoring and control screen of the substation monitoring and control device.

[0062] It is understood that, in the embodiments of the present invention, the emergency station AC power supply security box is very flexible, lightweight, and easy to carry and connect, miniaturizing and lightening it as much as possible, making it suitable for most emergency uses. It meets the requirements for unmanned substation operation and adopts networked intelligent monitoring and control technology. It can achieve AC / DC conversion, rapid cable connection, phase sequence determination, measurement of parameters such as voltage, current, and power, multiple protections, automatic fault identification and isolation, communication and remote monitoring, automatic anomaly identification and transmission, lightning protection, and full enclosure protection.

[0063] The microprocessor-based protection device integrates control, protection, measurement, and communication to meet the requirements of automation and intelligence. It can include overcurrent protection (stages I and II) and zero-sequence protection, with selectable activation / deactivation and alarm / trip functionality. The zero-sequence current in the zero-sequence circuit is derived from the busbar and equal to the vector sum of the A, B, and C phase currents. It also has the capability to sample and measure data such as three-phase current, three-phase current phase angle, zero-sequence current, residual current, current imbalance, three-phase phase voltage, three-phase phase voltage phase angle, three-phase line voltage, total active power, total reactive power, total power factor, frequency, active energy, and reactive energy. The protection device must be able to display fault parameters, alarm information, status indication, and fault information recording for easy fault analysis. Communication should support a standard RS-485 communication interface, using the standard MODBUS-RTU protocol, a standard PROFIBUS communication interface, and standard DPV0 and DPV1 communication protocols.

[0064] When the microcomputer protection device detects a fault, it energizes its relay relay, which connects the auxiliary contact to the incoming line switch tripping circuit. After the tripping relay is energized, it connects the control circuit of the switch. When the tripping coil of the switch is energized, the switch trips, thereby isolating the fault.

[0065] The enclosure is equipped with a power exchange module, which can obtain a closed DC power circuit inside the enclosure. After the enclosure is powered on, the AC power taken from the incoming line can be converted into AC power through the AC-DC conversion circuit to meet the power requirements of the protection equipment, control circuit and other equipment inside the enclosure.

[0066] This enclosure features three hard-contact signal outputs: bus voltage abnormality, overcurrent protection activation, and zero-sequence protection activation. The protection activation signal is issued via a relay in conjunction with the protection device, while the bus voltage abnormality signal is issued via a voltmeter circuit in conjunction with a relay. For ease of connection, the signal terminal blocks are arranged logically.

[0067] To meet the need for quickly determining the phase sequence after a security box is connected, this invention provides a phase sequence measuring device. After the incoming line is connected and powered on, it can immediately determine whether the phase sequence is correct. If the phase sequence is incorrect, the circuit can immediately issue an alarm. If the phase sequence is correct, it can quickly proceed to the next step, saving working time.

[0068] The switch control circuit of the present invention includes a manual opening and closing circuit for the switch, an opening and closing indication circuit for the switch, an energy storage circuit for the switch, and a protection tripping circuit for the switch.

[0069] This invention improves and standardizes the operation and use of incoming line cabinets for AC power supply retrofitting at stations, preventing unqualified equipment such as self-assembled equipment, equipment modified from outdated equipment, and equipment with significant safety hazards from entering the construction site, thus avoiding personal injury and equipment accidents during construction and retrofitting. In emergency use or retrofitting construction, it adds microcomputer protection and remote monitoring functions, improving compatibility with higher-level protection systems to avoid protection mismatches, and enabling comprehensive monitoring of equipment throughout the process to prevent monitoring gaps. It allows for quick determination of the correct phase sequence circuit when connected to the security box, avoiding the risks of manual phase verification and saving verification time. The closed DC circuit design is not limited by the location of the DC power supply, allowing the security box to be used in any location.

[0070] Implementing the embodiments of the present invention has the following beneficial effects:

[0071] This invention provides an emergency station AC power supply security box. It solves the problem of unreliable wiring of the station power supply incoming cable by using copper busbars for connection. The box is equipped with a four-stage micro-break switch to ensure reliable cooperation with the upper-level protection and has microcomputer protection function. The box has remote measurement and remote signaling functions to realize remote monitoring, avoid the inability to monitor the dispatching during the AC upgrade process, realize full monitoring of the temporary station AC system, and avoid the problems of unreliable operation and inability to monitor the temporary AC system during the station AC upgrade.

[0072] This invention can be used as a temporary AC power system during the renovation of substation AC power systems, and also as an emergency incoming power supply box. It enables rapid phase sequence determination and quick connection, while the protective DC power supply is provided through the security box to prevent DC cable pulling. Simultaneously, it standardizes renovation work, improves on-site construction management, and ensures the safe and stable operation of the temporary substation AC system.

[0073] This invention is applicable to any industry that uses AC power systems, such as buildings, industrial parks, and any other industry that uses AC power, especially the power industry. It greatly improves the reliability of AC power supply during construction and renovation. It can be promoted to district bureaus and extended to other enterprises outside the power grid, and has broad promotional value and economic benefits.

[0074] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the claims of the present invention. Therefore, any equivalent changes or modifications made without departing from the spirit disclosed in the present invention should be included within the scope of the claims of the present invention.

Claims

1. An AC power supply security box for emergency stations, characterized in that, include: The enclosure is equipped with at least a power input port, a power output port, a signal output port, at least one row of micro-break switches, a closing button, a closing button, a closing indicator light, a closing indicator light, a phase sequence error indicator light, and a voltage abnormality indicator light. At least the following are provided inside the box: The main circuit includes a three-phase incoming power supply that enters the enclosure through the power input port, passes through the frame switch (QF) inside the enclosure, and is then connected to the power output port through the three-phase outgoing power supply. The phase sequence measuring device is connected to the three-phase incoming power supply via a first micro-break switch (QF1) and a fuse. It is used to measure the phase sequence of the three-phase incoming power supply and to indicate when an error occurs in the phase sequence. The power conversion module is connected to the first micro-break switch (QF1) via the second micro-break switch (QF2) and is used to convert the three-phase incoming power supply into 110V DC power supply. The voltage measurement and protection module includes at least a voltmeter, a voltage transmitter, and an intermediate relay. The voltmeter and voltage transmitter are connected to the three-phase outgoing power supply via a fuse. The voltmeter is used for measurement and display of the power output circuit inside the enclosure. The voltage transmitter communicates with the substation monitoring and control device. The normally closed contact of the intermediate relay closes when the output circuit voltage is abnormal and communicates with the substation monitoring and control device for voltage abnormality alarm. The microprocessor-based protection module has an AC power input terminal, a current input terminal, a DC power input terminal, an overcurrent protection control terminal, a zero-sequence overcurrent protection control terminal, a switch action signal output terminal, and a fault signal output terminal; it is used to determine whether there is a fault in the main circuit, and when a fault is found, to control the tripping circuit of the main switch to isolate the fault. The signal output circuit is used to report switch action signals and fault signals to the substation monitoring and control equipment; The microcomputer protection module is further connected to a switch control circuit, which includes at least: a manual closing circuit, a manual opening circuit, an overcurrent protection trip circuit, a zero-sequence overcurrent protection trip circuit, a switch closing indication circuit, a switch opening indication circuit, and a switch opening and closing energy storage circuit. The manual tripping circuit includes: a tripping button (ST2) connected to the positive terminal of the DC power supply, a tripping coil (YO) and a first normally open contact (Q1) connected in sequence to the tripping button, and the other end of the first normally open contact connected to the negative terminal of the DC power supply. The manual closing circuit includes: a closing button (ST1) connected to the positive terminal of the DC power supply, a closing coil (YC) and a first normally closed contact (Q2) connected in sequence to the closing button, and the other end of the first normally closed contact connected to the negative terminal of the DC power supply; The overcurrent protection trip circuit includes: a normally open auxiliary contact (K1) of the overcurrent protection relay connected to the positive terminal of the DC power supply, a trip coil (YO) and a first normally open contact (Q1) connected in sequence to the overcurrent protection relay, the other end of the first normally open contact being connected to the negative terminal of the DC power supply, and the normally open auxiliary contact (K1) of the overcurrent protection relay being energized by a relay (K7) connected to the overcurrent protection control terminal; The zero-sequence overcurrent protection trip circuit includes: a normally open auxiliary contact (K2) of the zero-sequence overcurrent protection relay connected to the positive terminal of the DC power supply, a tripping coil (YO) and a first normally open contact (Q1) connected in sequence to the zero-sequence overcurrent protection relay, the other end of the first normally open contact being connected to the negative terminal of the DC power supply, and the normally open auxiliary contact (K2) of the zero-sequence overcurrent protection relay being energized by a relay (K8) connected to the zero-sequence overcurrent protection control terminal; The switch closing indication circuit includes: a closing indicator light connected to the positive terminal of the DC power supply, the closing indicator light connected to the second normally open contact (Q3), and the other end of the second normally open contact connected to the negative terminal of the DC power supply; The circuit breaker tripping indicator circuit includes: a tripping indicator light connected to the positive terminal of the DC power supply, the tripping indicator light connected to the second normally closed contact (Q4), and the other end of the second normally closed contact connected to the negative terminal of the DC power supply; The switch opening and closing energy storage circuit includes: an energy storage motor connected to the positive terminal of a DC power supply, the energy storage motor being connected to an auxiliary contact (S33M / 1) of the energy storage circuit via a fuse, and the other end of the auxiliary contact of the energy storage circuit being connected to the negative terminal of the DC power supply.

2. The security box as described in claim 1, characterized in that, in: The AC power input terminal of the microcomputer protection module is used to connect to the output terminal of the first micro-break switch (QF1) through multiple fuses to collect the voltage of the main circuit. The current input terminal of the microcomputer protection module is used to collect the current of the main circuit through multiple current transformers; The microcomputer protection module is further used to determine whether there is a fault in the main circuit based on the collected main circuit voltage and current.

3. The security box as described in claim 2, characterized in that, The signal output port communicates with the substation monitoring and control device via cable transmission or fiber optic network communication, and is displayed on the monitoring and control screen of the substation monitoring and control device.

4. The security box as described in any one of claims 1 to 3, characterized in that, Its main busbar uses flame-retardant insulated copper busbars, and its grounding uses grounding copper busbars.

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