A high-voltage switch cabinet for nuclear power plants and an arc fault clearing device thereof

Abstract

The present application relates to a kind of nuclear power plant high voltage switch cabinet and its arc fault removal device, belong to high voltage distribution technical field.The device includes cable chamber, bus chamber and handcar room pressure switch, first arc fault removal circuit and second arc fault removal circuit;Each pressure switch is respectively arranged in the top of the pressure release channel of corresponding interval room, can be displaced when arc fault occurs in corresponding interval room;First arc fault removal circuit and second arc fault removal circuit do not include software program, and arc fault removal is realized by setting circuit hardwiring, both solve the problem that the device containing software program must be made strict program authentication, it is simple and reliable again, and cost is greatly reduced compared with traditional arc protection device, so that switch cabinet is rapidly removed fault interval in the moment of arc, reduce the scope of failure, maximum limit guarantee the safety of personnel and equipment.

Description

Technical Field

[0001] This invention relates to a high-voltage switchgear for nuclear power plants and its arc fault isolation device, belonging to the field of high-voltage power distribution technology. Background Technology

[0002] Currently, arcing faults in conventional power plant high-voltage switchgear mainly rely on arc protection devices and arc protection sensors installed inside the switchgear to clear the fault. The arc protection sensor detects the arcing situation inside the switchgear and transmits this information to the arc protection device. The arc protection device's internal software program then makes a judgment and issues an alarm or action signal. For example, Chinese utility model patent CN207925942U discloses an intelligent fast-switching armored withdrawable switchgear with arc protection, including a switchgear shell, a high-voltage vacuum circuit breaker, a high-voltage busbar, and high-voltage cables. The switchgear shell is divided into a high-voltage busbar compartment, a high-voltage circuit breaker compartment, a secondary instrument compartment, and a high-voltage cable compartment. Each high-voltage electrical component is installed in its corresponding compartment. The switchgear also includes arc protection detection sensors and an arc protection central processing unit. Arc protection detection sensors are installed in the high-voltage busbar compartment, the high-voltage circuit breaker compartment, and the high-voltage cable compartment, and each arc protection detection sensor is connected to the arc protection central processing unit via optical fiber. Once a flashover occurs, the arc flash protection detection sensor transmits a signal to the arc flash protection central processing unit, which then controls the high-voltage circuit breaker to quickly disconnect the faulty power supply.

[0003] It is evident that conventional power plants typically employ arc flash protection devices with embedded software programs for arc fault isolation, and design units and owners generally do not have specific requirements for the verification and validation of the internal software programs of these devices. However, in the nuclear power sector, nuclear power projects have stringent requirements for devices containing software programs. Whether it's regulations (HAF 003, HAF102), guidelines (HAD102 / 10, HAD 102 / 16), or national / industry standards (NB / T 20448, GB / T 41145), regulatory authorities mandate that devices with embedded programs (including software / firmware / programmable hardware) in nuclear power plants must undergo V&V certification. This requirement necessitates that arc flash protection manufacturers submit their devices to a third party for professional verification and validation of the internal programs, in accordance with regulations or standards, before they can be deployed in the nuclear power market. Currently, no major domestic arc flash protection manufacturers have publicly disclosed their nuclear safety-grade V&V certification status.

[0004] Because the application of arc flash protection devices from conventional power plants to nuclear power plants requires rigorous testing of the devices' procedures, the application of these devices in the nuclear power field faces numerous difficulties, making it challenging to guarantee the safety, reliability, and stability of the equipment. This necessitates finding a new solution that ensures reliable circuit disconnection in the event of an arcing fault in the high-voltage switchgear of a nuclear power plant while avoiding the impact of program issues on the device's reliability and stability. Summary of the Invention

[0005] The purpose of this invention is to provide a high-voltage switchgear for nuclear power plants and an arc fault clearing device thereof, in order to solve the problem that the application of conventional arc fault clearing devices in high-voltage switchgear for nuclear power plants is difficult due to internal program issues, making it difficult to ensure the safe, reliable, and stable clearing of the fault circuit after an arc fault occurs in the nuclear power plant.

[0006] To address the aforementioned technical problems, the first aspect of this invention provides a nuclear power plant high-voltage switchgear arc fault clearing device. This device includes a cable compartment pressure switch, a busbar compartment pressure switch, a handcart compartment pressure switch, a first arc fault clearing circuit, and a second arc fault clearing circuit. Each pressure switch is respectively installed at the top of the pressure relief channel of its corresponding compartment and can change position when an arc fault occurs in the corresponding compartment. The first arc fault clearing circuit includes a circuit breaker tripping circuit containing a circuit breaker switchgear, and the auxiliary contacts of the cable compartment pressure switch in the circuit breaker switchgear are connected to the circuit breaker in the circuit breaker switchgear. The second arc fault clearing circuit includes a series circuit and the circuit breaker tripping circuit of the incoming line cabinet. The series circuit is composed of the auxiliary contacts of the bus compartment pressure switch and the truck compartment pressure switch of all switchgear containing circuit breakers, as well as the auxiliary contacts of the cable compartment pressure switch, bus compartment pressure switch and truck compartment pressure switch of switchgear without circuit breakers. The series circuit is interlocked with the circuit breaker tripping circuit of the incoming line cabinet through the first intermediate relay. It is used to conduct the circuit breaker tripping circuit of the incoming line cabinet to clear the arc fault when the state of the series circuit changes due to an arc fault in the compartment.

[0007] In one possible implementation, the auxiliary contacts of the pressure switch in the cable compartment of the switchgear without circuit breakers are normally closed contacts, the auxiliary contacts of the pressure switch in the cable compartment of the switchgear with circuit breakers are normally open contacts, and the auxiliary contacts of the pressure switch in the bus compartment and the pressure switch in the truck compartment of each switchgear are normally closed contacts.

[0008] In one possible implementation, each auxiliary contact in the series circuit is also connected in series with the relay coil of the first intermediate relay. The normally closed contact of the first intermediate relay, the normally open auxiliary contact of the overcurrent protection in the integrated protection device of the incoming line cabinet, and the relay coil of the second intermediate relay are connected in series to form a control circuit. The normally open contact of the second intermediate relay is connected in series with the circuit breaker tripping circuit of the incoming line cabinet.

[0009] In one possible implementation, when the integrated protection device of the incoming line cabinet detects that the incoming line current value is greater than the overcurrent protection threshold, the normally open auxiliary contact of the overcurrent protection closes.

[0010] In one possible implementation, the normally open contact of the second intermediate relay is connected in parallel with the normally open auxiliary contact of the pressure switch in the cable compartment of the switchgear containing the circuit breaker. The normally open contact of the second intermediate relay and the normally open auxiliary contact of the pressure switch in the cable compartment of the switchgear containing the circuit breaker are then connected in series with the circuit breaker tripping circuit of the incoming line cabinet.

[0011] In one possible implementation, the overcurrent protection in the integrated protection device of the incoming line cabinet has two normally open auxiliary contacts, and the two normally open auxiliary contacts are connected in parallel and then connected in series with the relay coil of the second intermediate relay. In the event of an arcing fault, one normally open auxiliary contact is used to trip the working incoming line, and the other normally open auxiliary contact is used to trip the backup incoming line.

[0012] In one possible implementation, the switchgear without circuit breakers includes busbar PT cabinets.

[0013] In one possible implementation, the switchgear containing the circuit breaker includes a working incoming line cabinet, a standby incoming line cabinet, and a feeder cabinet.

[0014] In one possible implementation, the circuit breaker tripping circuit of the circuit breaker switchgear includes a tripping coil, and the auxiliary contact of the cable compartment pressure switch in the circuit breaker switchgear being connected in series with the circuit breaker tripping circuit means that the auxiliary contact of the cable compartment pressure switch in the circuit breaker switchgear is connected in series with the tripping coil in the circuit breaker tripping circuit of the circuit breaker switchgear.

[0015] To address the aforementioned technical problems, a second aspect of the present invention provides a high-voltage switchgear for a nuclear power plant. This high-voltage switchgear includes switchgear with and without circuit breakers. Each switchgear has three compartments: a cable compartment, a busbar compartment, and a truck compartment. The high-voltage switchgear also includes an arc fault clearing device, comprising a cable compartment pressure switch, a busbar compartment pressure switch, a truck compartment pressure switch, a first arc fault clearing circuit, and a second arc fault clearing circuit. Each pressure switch is respectively located at the top of the pressure relief channel in its corresponding compartment and can change position when an arc fault occurs in that compartment. The first arc fault clearing circuit includes a circuit breaker in the switchgear containing the circuit breaker. The tripping circuit includes an auxiliary contact of the cable compartment pressure switch in the circuit breaker switchgear connected in series with the circuit breaker tripping circuit of the switchgear containing the circuit breaker; the second arc fault clearing circuit includes a series circuit and the circuit breaker tripping circuit of the incoming line cabinet. The series circuit is composed of the auxiliary contacts of the bus compartment pressure switches and truck compartment pressure switches of all switchgear containing circuit breakers, as well as the auxiliary contacts of the cable compartment pressure switches, bus compartment pressure switches, and truck compartment pressure switches of switchgear not containing circuit breakers connected in series; the series circuit is interlocked with the circuit breaker tripping circuit of the incoming line cabinet through a first intermediate relay, which is used to conduct the circuit breaker tripping circuit of the incoming line cabinet to clear the arc fault when an arc fault occurs in the compartment causing a change in the state of the series circuit.

[0016] In one possible implementation, the auxiliary contacts of the pressure switch in the cable compartment of the switchgear without circuit breakers are normally closed contacts, the auxiliary contacts of the pressure switch in the cable compartment of the switchgear with circuit breakers are normally open contacts, and the auxiliary contacts of the pressure switch in the bus compartment and the pressure switch in the truck compartment of each switchgear are normally closed contacts.

[0017] In one possible implementation, each auxiliary contact in the series circuit is also connected in series with the relay coil of the first intermediate relay. The normally closed contact of the first intermediate relay, the normally open auxiliary contact of the overcurrent protection in the integrated protection device of the incoming line cabinet, and the relay coil of the second intermediate relay are connected in series to form a control circuit. The normally open contact of the second intermediate relay is connected in series with the circuit breaker tripping circuit of the incoming line cabinet.

[0018] In one possible implementation, when the integrated protection device of the incoming line cabinet detects that the incoming line current value is greater than the overcurrent protection threshold, the normally open auxiliary contact of the overcurrent protection closes.

[0019] In one possible implementation, the normally open contact of the second intermediate relay is connected in parallel with the normally open auxiliary contact of the pressure switch in the cable compartment of the switchgear containing the circuit breaker. The normally open contact of the second intermediate relay and the normally open auxiliary contact of the pressure switch in the cable compartment of the switchgear containing the circuit breaker are then connected in series with the circuit breaker tripping circuit of the incoming line cabinet.

[0020] In one possible implementation, the overcurrent protection in the integrated protection device of the incoming line cabinet has two normally open auxiliary contacts, and the two normally open auxiliary contacts are connected in parallel and then connected in series with the relay coil of the second intermediate relay. In the event of an arcing fault, one normally open auxiliary contact is used to trip the working incoming line, and the other normally open auxiliary contact is used to trip the backup incoming line.

[0021] In one possible implementation, the switchgear without circuit breakers includes busbar PT cabinets.

[0022] In one possible implementation, the switchgear containing the circuit breaker includes a working incoming line cabinet, a standby incoming line cabinet, and a feeder cabinet.

[0023] In one possible implementation, the circuit breaker tripping circuit of the circuit breaker switchgear includes a tripping coil, and the auxiliary contact of the cable compartment pressure switch in the circuit breaker switchgear being connected in series with the circuit breaker tripping circuit means that the auxiliary contact of the cable compartment pressure switch in the circuit breaker switchgear is connected in series with the tripping coil in the circuit breaker tripping circuit of the circuit breaker switchgear.

[0024] The beneficial effects of the present invention are as follows: The nuclear power plant high-voltage switchgear arc fault clearing device of the present invention does not require software programs, but achieves arc fault clearing by setting up hard wiring and mechanical switching devices. This solves the problem of the stringent program certification required for devices containing software programs, while being simple and reliable, and significantly reducing the cost compared to traditional arc protection devices. It enables the switchgear to quickly clear the fault interval at the moment of arcing, reducing the scope of the fault and maximizing the safety of personnel and equipment. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the cable compartment pressure switch, busbar compartment pressure switch, and handcart compartment pressure switch of the present invention; Figure 2 This is a structural diagram of the pressure switch of the present invention; Figure 3 This is a circuit diagram of the series circuit in the nuclear power plant high-voltage switchgear arc fault clearing device of the present invention; Figure 4 This is a circuit diagram of the first arc fault clearing circuit in the arc fault clearing device for high-voltage switchgear of nuclear power plants of the present invention; Figure 5 This is a circuit diagram of the control circuit of the second arc fault clearing circuit and the circuit breaker tripping circuit of the incoming line cabinet in the arc fault clearing device of the nuclear power plant high-voltage switchgear of the present invention. Figure 6 This is a circuit diagram of the arc fault clearing circuit in the high-voltage switchgear arc fault clearing device for nuclear power plants of the present invention. In the diagram, -F16 is an air switch, -S31 is a cable compartment pressure switch, -S32 is a busbar compartment pressure switch, -S33 is a truck compartment pressure switch, 008BN is a terminal block, -K11, -K12, -K13, -K52, -K70, and -K71 are intermediate relays, -K16 is a monitoring relay, -F61 is a microprocessor protection device, -Q11 is a circuit breaker, -S11 is a circuit breaker auxiliary switch, CZ is a circuit breaker secondary connector, -F11 is a circuit breaker tripping coil, PE is a grounding symbol, and -S21, -S22, -S23, and -S24 are function activation / deactivation pressure plates. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0027] The basic idea of ​​this invention is that the nuclear power plant high-voltage switchgear arc fault clearing device of this invention does not require software programs. Instead, it achieves arc fault clearing by setting up hard-wired circuits and mechanical switching devices. This solves the problem of the stringent program certification required for devices containing software programs. At the same time, it is simple and reliable, and the cost is significantly reduced compared to traditional arc protection devices. This allows the switchgear to quickly clear the fault interval at the moment of arcing, reduce the scope of the fault, and maximize the safety of personnel and equipment.

[0028] Implementation method of arc fault isolation device for high-voltage switchgear in nuclear power plants: Figure 3 An embodiment of a nuclear power plant high-voltage switchgear is shown, comprising 23 switchgear units: a standby incoming line cabinet (01 cabinet), a working incoming line cabinet (02 cabinet), a busbar PT cabinet (03 cabinet), and various feeder cabinets (04~23 cabinets). Figure 1 Each switchgear includes three compartments: a cable compartment, a busbar compartment, and a handcart compartment. The arcing fault signal comes from each compartment of the high-voltage switchgear in the power distribution room.

[0029] To address the stringent program certification requirements for devices containing software programs in nuclear power projects, such as... Figure 1 , 2 As shown, the present invention provides cable compartment pressure switches, busbar compartment pressure switches, and handcart compartment pressure switches respectively in the cable compartment, busbar compartment, and handcart compartment of each switchgear, and respectively installed on the top of the pressure relief channel of each compartment. When an arcing fault occurs in any compartment, the arcing pressure will quickly impact the pressure relief channel cover plate of that compartment. After the pressure relief channel cover plate is opened, the pressure switch installed on the top of the pressure relief channel will change position under the action of the cover plate (from open to closed or from closed to open).

[0030] Therefore, as Figure 3, 6 As shown, the nuclear power plant high-voltage switchgear arc fault clearing device of the present invention includes a cable compartment pressure switch, a busbar compartment pressure switch, a truck compartment pressure switch, and an arc fault clearing circuit. The cable compartment pressure switch is installed at the top of the pressure relief channel in the cable compartment, the busbar compartment pressure switch is installed at the top of the pressure relief channel in the busbar compartment, and the truck compartment pressure switch is installed at the top of the pressure relief channel in the truck compartment. Each pressure switch can perform a displacement action when an arc fault occurs in the corresponding compartment and the arc pressure breaks open the pressure relief channel cover. The arc fault clearing circuit includes a first arc fault clearing circuit and a second arc fault clearing circuit. The first arc fault clearing circuit includes a circuit breaker tripping circuit (e.g., a circuit breaker switchgear) containing a circuit breaker switchgear. Figure 4 As shown), the auxiliary contacts of the pressure switch in the cable compartment of the circuit breaker switchgear are connected in series with the circuit breaker tripping circuit of the circuit breaker switchgear; the second arc fault clearing circuit includes a series circuit and the tripping circuit of the incoming line cabinet circuit breaker (as shown). Figure 5 As shown, the series circuit is composed of the auxiliary contacts of the busbar compartment pressure switch and the truck compartment pressure switch of the switchgear containing the circuit breaker, as well as the auxiliary contacts of the cable compartment pressure switch, the busbar compartment pressure switch, and the truck compartment pressure switch of the switchgear without the circuit breaker, connected in series. The series circuit is interlocked with the circuit breaker tripping circuit of the incoming line cabinet through an intermediate relay. It is used to conduct the circuit breaker tripping circuit of the incoming line cabinet when the state of the series circuit changes due to an arcing fault in each compartment, so as to trip the circuit breaker of the incoming line cabinet and isolate the arcing fault.

[0031] In a preferred embodiment, the auxiliary contacts of the pressure switches in the cable compartment of the switchgear without circuit breakers are normally closed contacts, while the auxiliary contacts of the pressure switches in the cable compartment of the switchgear with circuit breakers are normally open contacts. The auxiliary contacts of the busbar compartment pressure switches and the auxiliary contacts of the truck compartment pressure switches in each switchgear (both without and with circuit breakers) are normally closed contacts. When the high-voltage switchgear of the nuclear power plant is operating normally, the normally open / normally closed auxiliary contacts of the cable compartment pressure switches, the normally closed auxiliary contacts of the busbar compartment pressure switches, and the normally closed auxiliary contacts of the truck compartment pressure switches all remain unchanged. When an arcing fault occurs in any compartment of the switchgear, the auxiliary contacts of the pressure switches in that compartment change position (the normally open auxiliary contacts of the cable compartment pressure switches change from open to closed, and the normally closed contacts change from closed to open; the normally closed auxiliary contacts of the busbar compartment pressure switches and the normally closed auxiliary contacts of the truck compartment pressure switches change from closed to open).

[0032] As one embodiment of the second arc fault clearing circuit, such as Figure 6As shown, the second arc fault clearing circuit also includes a control circuit. The relay coil of the first intermediate relay is connected in series in the series circuit. The control circuit is composed of the normally closed contact of the first intermediate relay, the normally open auxiliary contact of the overcurrent protection in the integrated protection device of the incoming line cabinet, and the relay coil of the second intermediate relay connected in series. The normally open contact of the second intermediate relay is connected in series with the circuit breaker tripping circuit of the incoming line cabinet.

[0033] like Figure 6 As shown, the normally open contact of the second intermediate relay is also connected in parallel to the normally open auxiliary contact of the cable compartment pressure switch of the switchgear containing the circuit breaker. The normally open contact of the second intermediate relay and the normally open auxiliary contact of the cable compartment pressure switch are respectively connected in series with the circuit breaker tripping circuit of the incoming line cabinet.

[0034] like Figure 6 As shown, the integrated protection device for the incoming line cabinet has two normally open auxiliary contacts for overcurrent protection, and these two normally open auxiliary contacts are connected in parallel and then connected in series with the relay coil of the second intermediate relay. In the event of an arcing fault, one of the two normally open auxiliary contacts is used to trip the working incoming line, and the other is used to trip the backup incoming line, thereby ensuring that both power supplies are disconnected.

[0035] The working principle of the nuclear power plant high-voltage switchgear arc fault isolation device of the present invention is as follows: like Figure 4 , 6 As shown, when an arcing fault occurs in the cable compartment of a switchgear containing a circuit breaker, the arcing pressure will rapidly impact the pressure relief channel cover in the cable compartment, forcing it open. This will activate the cable compartment pressure switch on the pressure relief channel cover, causing its normally open auxiliary contact to change position (from open to closed). Since the normally open auxiliary contact of the cable compartment pressure switch is connected in series with the circuit breaker tripping circuit in this switchgear, as... Figure 3 As shown, when the normally open auxiliary contact of the cable compartment pressure switch closes, it will conduct the circuit breaker tripping circuit in this switchgear, energizing the tripping coil and causing the circuit breaker in the switchgear to trip, allowing the switchgear to quickly disconnect the faulty compartment at the moment of arcing. When the switchgear containing the circuit breaker is operating normally, the cable compartment pressure switch in this switchgear does not operate and remains in the open state. The circuit breaker tripping circuit in this switchgear is disconnected, the tripping coil is de-energized, and the circuit breaker in the switchgear does not trip.

[0036] When an arcing fault occurs in the busbar compartment or truck compartment of a switchgear containing a circuit breaker, the arcing pressure will rapidly impact the pressure relief channel cover in that compartment, forcing it open. This will activate the pressure switch on the pressure relief channel cover, changing the state of the series circuit. This state change interlocks and activates the circuit breaker tripping circuit of the incoming line cabinet, energizing the tripping coil and tripping the circuit breaker, thus isolating the arcing fault. When a switchgear without a circuit breaker is operating normally, the pressure switches in the busbar compartment and truck compartment do not activate. The auxiliary contacts of both the busbar compartment and truck compartment pressure switches remain in their current states, maintaining the current state of the series circuit. This does not interlock and activate the circuit breaker tripping circuit of the incoming line cabinet, de-energizing the tripping coil and preventing the circuit breaker from tripping.

[0037] like Figure 5 , 6 As shown, when an arcing fault occurs in any compartment of a switchgear without a circuit breaker, the arcing pressure will rapidly impact the pressure relief channel cover in that compartment, forcing it open. The pressure switch on the pressure relief channel cover will then activate, changing the state of the series circuit. This state change interlocks with the circuit breaker tripping circuit of the incoming line cabinet, energizing the circuit breaker's tripping coil and tripping the circuit breaker, thus isolating the arcing fault. When the switchgear without a circuit breaker is operating normally, the pressure switches in each compartment do not activate, and the auxiliary contacts of each pressure switch remain in their current state. The series circuit remains in its current state and does not interlock with the circuit breaker tripping circuit of the incoming line cabinet. The circuit breaker's tripping coil is de-energized, and the circuit breaker does not trip.

[0038] This invention provides an optimal implementation of a switchgear arc fault isolation device, such as... Figure 3-6 As shown, the optimal implementation method is as follows: Each incoming line cabinet, standby incoming line cabinet, busbar PT cabinet, and feeder cabinet is equipped with a cable compartment, busbar compartment, and handcart compartment. A busbar compartment pressure switch is installed at the top of the pressure relief channel in the busbar compartment, a handcart compartment pressure switch is installed at the top of the pressure relief channel in the handcart compartment, and a cable compartment pressure switch is installed at the top of the pressure relief channel in the cable compartment. The cable compartment pressure switches in the incoming line cabinet, standby incoming line cabinet, and busbar PT cabinet are all equipped with normally open auxiliary contacts (S31), the cable compartment pressure switches in the busbar PT cabinet are all equipped with normally closed auxiliary contacts (S31), the busbar compartment pressure switches in the incoming line cabinet, standby incoming line cabinet, busbar PT cabinet, and feeder cabinet are all equipped with normally closed auxiliary contacts (S32), and the handcart compartment pressure switches in the incoming line cabinet, standby incoming line cabinet, busbar PT cabinet, and feeder cabinet are all equipped with normally closed auxiliary contacts (S33). The switchgear arc fault clearing device includes pressure switches installed in each compartment of each switchgear and an arc fault clearing circuit. The arc fault clearing circuit includes a first arc fault clearing circuit and a second arc fault clearing circuit. The first arc fault clearing circuit includes the circuit breaker tripping circuit of the switchgear containing the circuit breaker. The auxiliary contacts of the pressure switch in the cable compartment of the switchgear containing the circuit breaker are connected in series with the circuit breaker tripping circuit. The busbar PT cabinet does not contain a circuit breaker, while the working incoming line cabinet, the standby incoming line cabinet, and the feeder cabinet all contain circuit breakers. The second arc fault clearing circuit includes a series circuit, a control circuit, and the circuit breaker tripping circuit of the incoming line cabinet. The auxiliary contacts of the pressure switches in the three compartments of the busbar PT cabinet, as well as the auxiliary contacts of the busbar compartment pressure switches and the auxiliary contacts of the handcart compartment pressure switches in the working incoming line cabinet, the standby incoming line cabinet, and each feeder cabinet, are connected in series to form a series circuit. Figure 3 , 6 As shown, the normally closed auxiliary contacts - S32 of the busbar compartment pressure switch and - S33 of the truck compartment pressure switch of the working incoming line cabinet, the standby incoming line cabinet, and each feeder cabinet, as well as the normally closed auxiliary contacts - S31, - S32, and - S33 of the cable compartment pressure switch of the busbar PT cabinet, are connected in series to form a series circuit. This series circuit is also interlocked with the circuit breaker tripping circuit of the incoming line cabinet through an intermediate relay, such as... Figure 6 As shown, the relay coil of intermediate relay K71 is also connected in series in the series circuit.

[0039] The control circuit consists of the relay coil of intermediate relay K70, the normally closed contact of intermediate relay K71, and the normally open auxiliary contact of the overcurrent protection of the integrated protection device of the incoming line cabinet connected in series. The normally open contact of intermediate relay K70 is connected in parallel with the normally open auxiliary contact of the cable compartment pressure switch S31 of the incoming line cabinet, forming a parallel circuit. This parallel circuit is connected in series with the circuit breaker tripping circuit of the incoming line cabinet. The circuit breaker tripping circuit of the incoming line cabinet includes the circuit breaker auxiliary switch S11 and the tripping coil F11, which are connected in series.

[0040] The working principle of the above-mentioned switchgear arc fault isolation device is as follows: like Figure 6 As shown, under normal circumstances (without arcing faults), the normally closed auxiliary contact -S31 of the cable compartment pressure switch in the busbar PT cabinet cable compartment, the normally closed auxiliary contact -S32 of the busbar compartment pressure switch in each switchgear, and the normally closed auxiliary contact -S33 of the handcart compartment pressure switch in each switchgear all remain closed, the series circuit is in a closed state, the relay coil of the intermediate relay -K71 connected in series in the series circuit is energized, the normally closed contact 1 / 9 of the intermediate relay -K71 in the control circuit remains open, the relay coil of the intermediate relay -K70 is de-energized, the normally open contact 5 / 9 of the intermediate relay -K70 remains open, the normally open auxiliary contact -S31 of the cable compartment pressure switch in the incoming line cabinet remains open, the trip coil -F11 in the circuit breaker tripping circuit of the incoming line cabinet is de-energized, and the circuit breaker of the incoming line cabinet will not trip.

[0041] When an arcing fault occurs in any compartment of the busbar PT cabinet, the arcing pressure will quickly impact the pressure relief channel cover. When the pressure relief channel cover is blown open, the pressure switch on the pressure relief channel cover will perform a corresponding action, and then the normally closed contact of the pressure switch in that compartment will change from the closed state to the open state. Then, the series circuit changes from the conducting state during normal operation to the open state. The relay coil of intermediate relay-K71 is de-energized, and the normally closed contact 1 / 9 of intermediate relay-K71 closes. The overcurrent protection in the integrated protection device of the incoming line cabinet is activated. When the detected current value is greater than the overcurrent protection threshold, the normally open contact 517 / 518 of the overcurrent protection closes, and the control circuit is turned on. The relay coil of intermediate relay-K70 is energized, and the normally open contact 5 / 9 of intermediate relay-K70 closes. The circuit breaker auxiliary switch S11 is in the closed state when it is closed. Therefore, the circuit breaker tripping circuit of the incoming line cabinet is turned on, and the tripping coil-F11 is energized, thus forming the entire arc protection tripping circuit. The circuit breaker of the incoming line cabinet trips, quickly isolates the faulty line, protects the entire busbar, and effectively reduces the scope of the fault.

[0042] When an arcing fault occurs in the busbar compartment or handcart compartment of any of the switch cabinets, including the working incoming line cabinet, the standby incoming line cabinet, or any of the feeder cabinets, the arcing pressure will rapidly impact the pressure relief channel cover. When the pressure relief channel cover is blown open, the pressure switch on the pressure relief channel cover will perform a corresponding action, and the normally closed contact of the pressure switch in that compartment will change position from closed to open. Then, the series circuit changes from the conducting state during normal operation to the open state. The relay coil of intermediate relay-K71 is de-energized, and the normally closed contact 1 / 9 of intermediate relay-K71 closes. The overcurrent protection in the integrated protection device of the incoming line cabinet is activated. When the detected current value is greater than the overcurrent protection threshold, the normally open contact 517 / 518 of the overcurrent protection closes, and the control circuit is turned on. The relay coil of intermediate relay-K70 is energized, and the normally open contact 5 / 9 of intermediate relay-K70 closes. The circuit breaker auxiliary switch S11 is in the closed state when it is closed. Therefore, the circuit breaker tripping circuit of the incoming line cabinet is turned on, and the tripping coil-F11 is energized, thus forming the entire arc protection tripping circuit. The circuit breaker of the incoming line cabinet trips, quickly isolates the faulty line, protects the entire busbar, and effectively reduces the scope of the fault.

[0043] When an arcing fault occurs in the cable compartment of any of the switchgear cabinets (including the working incoming cabinet, standby incoming cabinet, and feeder cabinets), the arcing pressure will rapidly impact the pressure relief channel cover. When the pressure relief channel cover is breached, the cable compartment pressure switch on the cover will activate accordingly. Consequently, the normally open contact -S31 of the cable compartment pressure switch will change position from open to closed. Since the normally open contact -S31 of the cable compartment pressure switch is connected in series with the circuit breaker tripping circuit within this switchgear, when the normally open contact -S31 of the cable compartment pressure switch closes, it will conduct the circuit breaker tripping circuit within this switchgear, energizing the tripping coil -F11. This causes the circuit breaker in this switchgear to trip, allowing the switchgear to quickly disconnect the faulty compartment at the moment of arcing. When the working incoming line cabinet, the standby incoming line cabinet, and each feeder cabinet are normal, the pressure switches in each compartment do not operate, and the auxiliary contacts of each pressure switch remain in the normal operating state (the normally open contact -S31 of the pressure switch in the cable compartment remains open, the normally closed contact -S32 of the pressure switch in the busbar compartment remains closed, and the normally closed contact -S33 of the pressure switch in the truck compartment remains closed). The circuit breaker tripping circuits of the working incoming line cabinet, the standby incoming line cabinet, and each feeder cabinet are disconnected, the tripping coils are de-energized, and the circuit breakers will not trip.

[0044] Implementation method of high-voltage switchgear in nuclear power plants: like Figure 3 , 6As shown, the high-voltage switchgear of a nuclear power plant includes switchgear with circuit breakers and switchgear without circuit breakers. Each switchgear has three compartments: a cable compartment, a busbar compartment, and a truck compartment. A busbar compartment pressure switch is installed at the top of the pressure relief channel in the busbar compartment, a truck compartment pressure switch is installed at the top of the pressure relief channel in the truck compartment, and a cable compartment pressure switch is installed at the top of the pressure relief channel in the cable compartment. Each pressure switch can change position (from open to closed or from closed to open) when an arcing fault occurs in the corresponding compartment and the arcing pressure opens the pressure relief channel cover. The high-voltage switchgear also includes an arcing fault isolation circuit, which includes a first arcing fault isolation circuit and a second arcing fault isolation circuit. The first arcing fault isolation circuit includes the circuit breaker tripping circuit of the switchgear with circuit breakers (e.g.,...). Figure 4 As shown), the auxiliary contacts of the pressure switch in the cable compartment of the switchgear containing the circuit breaker are connected in series with the circuit breaker tripping circuit. The second arc fault clearing circuit includes a series circuit and the circuit breaker tripping circuit of the incoming cabinet (such as...). Figure 5 As shown, the series circuit is composed of the auxiliary contacts of the pressure switches installed in all compartments of the switchgear without circuit breakers, and the auxiliary contacts of the pressure switches in the bus compartment and the handcart compartment of the switchgear containing circuit breakers, connected in series. The series circuit is interlocked with the circuit breaker tripping circuit of the incoming line cabinet through an intermediate relay. It is used to conduct the circuit breaker tripping circuit of the incoming line cabinet when an arcing fault occurs in any compartment, causing a change in the state of the series circuit, so as to trip the circuit breaker of the incoming line cabinet and isolate the arcing fault.

[0045] In a preferred embodiment, the auxiliary contacts of the cable compartment pressure switch in the busbar PT cabinet are normally closed contacts, while the auxiliary contacts of the cable compartment pressure switches in the working incoming cabinet, standby incoming cabinet, and each feeder cabinet are normally open contacts. The auxiliary contacts of the busbar compartment pressure switches and the auxiliary contacts of the truck compartment pressure switches in the busbar PT cabinet, working incoming cabinet, standby incoming cabinet, and each feeder cabinet are all normally closed contacts. When the high-voltage switchgear of the nuclear power plant is operating normally, the normally open / normally closed auxiliary contacts of the cable compartment pressure switch, the normally closed auxiliary contacts of the busbar compartment pressure switch, and the normally closed auxiliary contacts of the truck compartment pressure switch all remain unchanged. When an arcing fault occurs in any compartment of the switchgear, the auxiliary contacts of the pressure switches installed in that compartment change position (the normally open auxiliary contact of the cable compartment pressure switch changes from open to closed, and the normally closed contact changes from closed to open; the normally closed auxiliary contacts of the busbar compartment pressure switch and the normally closed auxiliary contacts of the truck compartment pressure switch change from closed to open).

[0046] As one embodiment of the second arc fault clearing circuit, such as Figure 6As shown, the second arc fault clearing circuit also includes a control circuit. The relay coil of the first intermediate relay is connected in series in the series circuit. The control circuit is composed of the normally closed contact of the first intermediate relay, the normally open auxiliary contact of the overcurrent protection in the integrated protection device of the incoming line cabinet, and the relay coil of the second intermediate relay connected in series. The normally open contact of the second intermediate relay is connected in series with the circuit breaker tripping circuit of the incoming line cabinet.

[0047] like Figure 6 As shown, the normally open contact of the second intermediate relay is connected in parallel with the normally open auxiliary contact of the pressure switch in the cable compartment of the switchgear containing the circuit breaker. The normally open contact of the second intermediate relay and the normally open auxiliary contact of the pressure switch in the cable compartment are connected in series with the circuit breaker tripping circuit of the incoming line cabinet.

[0048] like Figure 6 As shown, the integrated protection device for the incoming line cabinet has two normally open auxiliary contacts for overcurrent protection, and these two normally open auxiliary contacts are connected in parallel and then connected in series with the relay coil of the second intermediate relay. In the event of an arcing fault, one normally open auxiliary contact is used to trip the working incoming line, and the other normally open auxiliary contact is used to trip the backup incoming line, thereby ensuring that both power supplies are disconnected.

[0049] As one embodiment of a switchgear without circuit breakers, the switchgear without circuit breakers includes a busbar PT cabinet.

[0050] As one embodiment of a switchgear containing a circuit breaker, the switchgear containing a circuit breaker includes a working incoming line cabinet, a standby incoming line cabinet, and a feeder cabinet.

[0051] The specific working principle of the arc fault isolation device in the high-voltage switchgear of the nuclear power plant mentioned above is described in the above embodiment of the arc fault isolation device in the high-voltage switchgear of the nuclear power plant, and will not be described in detail here.

[0052] This invention establishes an internal arc fault isolation device within the switchgear, enabling the switchgear to rapidly disconnect the faulty compartment the instant an arc occurs. This effectively reduces the scope of the fault and maximizes the safety of personnel and equipment. The device has a simple structure, low cost, and is easy to inspect and maintain.

Claims

1. A device for isolating arc faults in a high-voltage switchgear of a nuclear power plant, characterized in that, The device includes a cable compartment pressure switch, a busbar compartment pressure switch, a truck compartment pressure switch, a first arc fault clearing circuit, and a second arc fault clearing circuit. Each pressure switch is installed at the top of the pressure relief channel of its corresponding compartment and can change position when an arc fault occurs in the corresponding compartment. The first arc fault clearing circuit includes a circuit breaker tripping circuit of a switchgear containing a circuit breaker, with the auxiliary contacts of the cable compartment pressure switch in the switchgear containing the circuit breaker connected in series with the circuit breaker tripping circuit of the switchgear containing the circuit breaker. The second arc fault clearing circuit includes a series circuit and a circuit breaker tripping circuit of the incoming line cabinet. The series circuit is composed of the auxiliary contacts of the busbar compartment pressure switches and truck compartment pressure switches of all switchgear containing circuit breakers, as well as the auxiliary contacts of the cable compartment pressure switches, busbar compartment pressure switches, and truck compartment pressure switches of switchgear not containing circuit breakers, connected in series. The series circuit is interlocked with the circuit breaker tripping circuit of the incoming line cabinet through a first intermediate relay, which is used to activate the circuit breaker tripping circuit of the incoming line cabinet when an arc fault occurs in the compartment, causing a change in the state of the series circuit, thereby clearing the arc fault.

2. The nuclear power plant high-voltage switchgear arc fault isolation device according to claim 1, characterized in that, The auxiliary contacts of the pressure switches in the cable compartment of switchgear excluding circuit breaker switchgear are normally closed contacts, while the auxiliary contacts of the pressure switches in the cable compartment of switchgear including circuit breaker switchgear are normally open contacts. The auxiliary contacts of the pressure switches in the bus compartment and the auxiliary contacts of the pressure switches in the truck compartment of each switchgear are normally closed contacts.

3. The nuclear power plant high-voltage switchgear arc fault isolation device according to claim 1, characterized in that, Each auxiliary contact in the series circuit is also connected in series with the relay coil of the first intermediate relay. The normally closed contact of the first intermediate relay, the normally open auxiliary contact of the overcurrent protection in the integrated protection device of the incoming line cabinet, and the relay coil of the second intermediate relay are connected in series to form a control circuit. The normally open contact of the second intermediate relay is connected in series with the circuit breaker tripping circuit of the incoming line cabinet.

4. The nuclear power plant high-voltage switchgear arc fault isolation device according to claim 3, characterized in that, When the integrated protection device of the incoming line cabinet detects that the incoming line current value is greater than the overcurrent protection threshold, the normally open auxiliary contact of the overcurrent protection closes.

5. The nuclear power plant high-voltage switchgear arc fault isolation device according to claim 3, characterized in that, The normally open contact of the second intermediate relay is connected in parallel with the normally open auxiliary contact of the pressure switch in the cable compartment of the switchgear containing the circuit breaker. After the normally open contact of the second intermediate relay and the normally open auxiliary contact of the pressure switch in the cable compartment of the switchgear containing the circuit breaker are connected in parallel, they are connected in series with the circuit breaker tripping circuit of the incoming line cabinet.

6. The nuclear power plant high-voltage switchgear arc fault isolation device according to claim 3, characterized in that, The integrated protection device for incoming line cabinet has two normally open auxiliary contacts for overcurrent protection. The two normally open auxiliary contacts are connected in parallel and then connected in series with the relay coil of the second intermediate relay. In the event of an arcing fault, one normally open auxiliary contact is used to trip the working incoming line, and the other normally open auxiliary contact is used to trip the backup incoming line.

7. The nuclear power plant high-voltage switchgear arc fault isolation device according to claim 1, characterized in that, Switchgear excluding circuit breakers includes busbar PT cabinets.

8. The nuclear power plant high-voltage switchgear arc fault isolation device according to claim 1, characterized in that, Switchgear containing circuit breakers includes working incoming line cabinets, standby incoming line cabinets, and feeder cabinets.

9. The nuclear power plant high-voltage switchgear arc fault isolation device according to claim 1, characterized in that, The circuit breaker tripping circuit of a switchgear containing a circuit breaker includes a tripping coil. The auxiliary contact of the pressure switch in the cable compartment of the switchgear containing a circuit breaker being connected in series with the circuit breaker tripping circuit of the switchgear containing a circuit breaker means that the auxiliary contact of the pressure switch in the cable compartment of the switchgear containing a circuit breaker is connected in series with the tripping coil in the circuit breaker tripping circuit of the switchgear containing a circuit breaker.

10. A high-voltage switchgear for a nuclear power plant, comprising switchgear with circuit breakers and switchgear without circuit breakers, each switchgear having three compartments: a cable compartment, a busbar compartment, and a handcart compartment, characterized in that, The nuclear power plant high-voltage switchgear also includes the nuclear power plant high-voltage switchgear arc fault isolation device as described in any one of claims 1 to 9.

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