Double-power-supply switching system with over-temperature protection based on PLC (Programmable Logic Controller) module

Abstract

The utility model discloses a PLC module-based dual power supply switching system with overtemperature protection, which comprises a no-voltage relay, a sensor instrument, a bus 1, a bus 2, an interbus and a PLC module, and is characterized in that the bus 1 and the bus 2 are respectively connected with two paths of power supply incoming lines through a circuit breaker QF1 and a circuit breaker QF3; the interbus is connected with the two buses through a circuit breaker or an isolating switch; each circuit breaker is connected with the PLC module, the no-voltage relay collects the voltage of a power supply bus, and when one power supply bus loses voltage, the PLC module controls the corresponding circuit breaker to be switched off and controls the circuit breaker on the interbus to be switched on, so that normal operation of all loads of the two buses is ensured; the sensor instrument comprises a temperature sensor instrument which is used for acquiring the contact temperature of the circuit breaker QF1 and the circuit breaker QF3; when the contact of one circuit breaker is overheated or the temperature difference of the three contacts of the circuit breaker is detected to be too large, the PLC module selects overtemperature protection logic work. The system is simple in structure, convenient to operate, low in manufacturing cost, high in expansibility and high in power supply reliability, and has a protection function.

Description

Technical Field

[0001] The utility model relates to the technical field of low-voltage power supply systems, and more particularly to a dual-power supply switching system with over-temperature protection based on a PLC module. Background Art

[0002] With the rapid economic development of my country, electricity has become the primary energy source and driving force for modern industrial production, and modern enterprises are increasingly demanding higher power supply quality. Currently, power outages caused by power supply network anomalies or equipment overheating or fire within an enterprise have become a significant factor impacting production efficiency. Currently, the primary approach for industrial enterprises to ensure power supply reliability is to utilize dual or multiple power supply lines in the primary system, supplemented by dual power switching capabilities in the secondary system for rapid switching. Therefore, the stability, reliability, and scalability of the dual power switching system are crucial.

[0003] At present, most dual-power switching devices have a single switching logic and do not have over-temperature and fire protection functions. The reason is that the points of the dual-power switching devices are fixed, and the number of collected electrical parameters is also relatively fixed. It is impossible to increase the switching logic according to the complex situation on site. Therefore, it does not have over-temperature and fire protection functions, and cannot adapt well to all possible power grid and power supply equipment failures.

[0004] Therefore, how to design a dual power switching system that is multi-logic adjustable, has over-temperature and fire protection, and is scalable is a problem that technicians in this field urgently need to solve. Utility Model Content

[0005] In view of this, the utility model provides a dual power switching system with over-temperature protection based on a PLC module, which is used to solve the technical problem that the existing dual-circuit power automatic control system only has undervoltage switching but no over-temperature protection.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A dual power switching system based on PLC module, bus 1, bus 2, connecting bus, pressure loss relay, sensor instrument and PLC module,

[0008] The busbar 1 and busbar 2 are connected to the incoming lines of the two power supplies through circuit breaker QF1 and circuit breaker QF3 respectively;

[0009] The interconnecting busbar is connected to the busbar 1 and busbar 2 via circuit breakers QF2 and QF4 respectively;

[0010] The switch states of circuit breakers QF1, QF2, QF3, and QF4 are electrically interlocked. At most three circuit breakers can be in the closed state at any state, and each circuit breaker is connected to the PLC module for data exchange.

[0011] The pressure loss relay is provided in plurality, and is used to collect the bus voltages at both ends of the bus 1 and bus 2, as well as the voltage on the interconnecting bus;

[0012] When busbar 1 loses pressure, the PLC module controls circuit breaker QF1 to open and circuit breakers QF2 and QF4 to close, and busbar 2 simultaneously bears the entire load of busbar 1 and busbar 2. Similarly, when busbar 2 loses pressure, circuit breaker QF3 opens, and circuit breakers QF2 and QF4 close, and busbar 1 simultaneously bears the entire load of busbar 1 and busbar 2.

[0013] The sensor instrument includes a temperature sensor instrument, at least two of which are provided for real-time acquisition of the contact temperature of the circuit breakers QF1 and QF3; each temperature sensor instrument is connected to the serial port of the PLC module via an RS485 cable; when the contact temperature of one of the busbar circuit breakers exceeds the temperature or the temperature difference between the three contacts of the detection circuit breaker is too large, the PLC module selects the over-temperature protection logic of the dual power switching for control.

[0014] Furthermore, one of the circuit breakers QF2 or QF4 is replaced by a "manual disconnector", which is normally closed.

[0015] Furthermore, the sensor instrument also includes two smoke sensor instruments YW1 and YW2, which are respectively arranged in two busbar circuit breaker cabinets to detect smoke information; the two smoke sensor instruments YW1 and YW2 are connected to the serial port of the PLC module via RS485 communication; when smoke appears in one of the two busbar circuit breaker cabinets, the PLC module selects fire protection logic for control.

[0016] Furthermore, it also includes a time delay relay, and the normally closed contacts of each pressure loss relay are connected to a time delay relay coil; the function of the time delay relay is to protect against malfunction caused by instantaneous failure of the power supply network.

[0017] Furthermore, the number of undervoltage relays and time delay relays is increased by one or two so that the number of undervoltage relays and time delay relays is consistent with the total number of circuit breakers used; the increased undervoltage relays and time delay relays respectively monitor the voltage of the two sections of the interconnecting busbars including the circuit breakers QF2 and QF4, and perform delay control on the corresponding busbar circuit breakers.

[0018] Furthermore, it also includes output relays K11 to K18, and the PLC module controls the opening and closing states of a circuit breaker through two of the output relays; the two output relays are respectively connected to the opening coil and closing coil of the circuit breaker to be controlled.

[0019] Furthermore, it also includes a touch screen HMI, the touch screen HMI is connected to the serial port of the PLC module;

[0020] The touch screen HMI is used to display the current system screen and system parameters, including the status of each circuit breaker, each bus power parameter, important data curves and function buttons; the touch screen HMI remotely controls different circuit breakers through the function buttons.

[0021] Furthermore, a system switch SW is included, and the system switch SW is connected to the Ethernet interface of the PLC module and the touch screen HMI respectively, for realizing data communication between the touch screen HMI and the PLC module.

[0022] Furthermore, it also includes an auxiliary power supply and a system power supply PS, the system power supply converts the 220V AC voltage provided by the auxiliary power supply into a 24V DC voltage; the system power supply PS supplies power to the PLC module, the touch screen HMI and the DI feedback loop of the PLC module, and the supply voltage is 24V; the points I0.0~i2.5 in the DI feedback loop of the PLC module are respectively connected to the automatic start and reset, automatic start and manual reset, remote, opening, closing, fault and undervoltage signals of the circuit breakers QF1~QF4.

[0023] Furthermore, it also includes a multifunctional meter, which is a PM, used to collect the current and voltage of bus 1, bus 2 and the interconnecting bus; connected to the system power supply; its RS485 A1 and B1 ports are correspondingly connected to the serial port of the PLC module; the multifunctional meter PM transmits the real-time collected voltage and current data of bus 1, bus 2 and the interconnecting bus to the PLC module.

[0024] The utility model discloses a dual power supply switching system with over-temperature protection based on a PLC module, which has the following beneficial effects:

[0025] (1) Compared with the ordinary dual power switching system, it not only has the function of ordinary dual power switching, but also solves the problem of busbar circuit breaker contact over-temperature protection that the ordinary dual power switching system does not have.

[0026] (2) The utility model designs a dual power switching system based on the PLC module, which has strong scalability. When new protection functions need to be added in the later stage, it is only necessary to add a new sensor type at the appropriate location, connect it with the point of the PLC module, and modify the control logic. There is no need for repeated investment, the system cost is low, and at the same time, unnecessary repeated construction of multiple systems is avoided.

[0027] (3) The utility model adds a network port connection between the touch screen and the PLC module, so that the dual power switching system based on the PLC module with over-temperature protection has the functions of alarming and recording alarm information, which makes it convenient for users to select the corresponding switching protection logic and remotely control the circuit breaker status.

[0028] (4) The utility model is based on a dual power switching system with over-temperature protection of a PLC module, and uses output relays to control the status of each circuit breaker, and its operation is convenient.

[0029] (5) The utility model is based on a dual power switching system with over-temperature protection of the PLC module, which realizes data communication between the touch screen and the PLC module through the system switch, ensuring the data communication effect and security.

[0030] (6) The utility model is based on a dual power switching system with over-temperature protection for the PLC module, and uses the system power supply to supply 24V voltage to the PLC module, the touch screen and the DI feedback loop of the PLC module, ensuring that when the two power supplies are abnormal or a fault occurs, it will not affect the operation of the system protection logic.

[0031] (7) The utility model is based on a dual power switching system with over-temperature protection of a PLC module, and uses a multi-function instrument to facilitate the collection of current and voltage of bus 1, bus 2 and the interconnecting bus, facilitates remote communication between the three mutually self-locking circuit breakers and the PLC module, and facilitates the system power supply to the PLC module, the touch screen and the DI feedback loop of the PLC module. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0033] Figure 1 This is a schematic diagram of the overall structure of a dual power switching system with over-temperature protection based on a PLC module provided by the present invention;

[0034] Figure 2A primary system diagram of an embodiment provided by the utility model;

[0035] Figure 3 A primary principle diagram of an embodiment provided by the utility model;

[0036] Figure 4-Figure 7 A secondary principle diagram of an embodiment provided by the utility model;

[0037] Figure 8 This is the secondary principle diagram of the PLC module of this utility model. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0039] See also Figure 1 As shown, the utility model discloses a dual power switching system with over-temperature protection based on a PLC module, comprising a PLC module, a busbar 1, a busbar 2 and a connecting busbar;

[0040] Busbar 1 is connected to the power supply line through circuit breaker QF1;

[0041] Busbar 2 is connected to the power supply line through circuit breaker QF4;

[0042] The interconnecting busbar is connected to busbar 1 through circuit breaker QF2, and the interconnecting busbar is connected to busbar 2 through circuit breaker QF3;

[0043] The switch states of circuit breakers QF1, QF2, QF3, and QF4 are electrically interlocked. At any given time, only three circuit breakers can be closed. Each circuit breaker is connected to the PLC module for data exchange.

[0044] At least two undervoltage relays are provided, one for collecting the bus voltage at both ends of bus 1 and bus 2 respectively. In this embodiment, a total of four undervoltage relays are provided, namely KV1 to KV4, which collect the voltage at both ends of the four circuit breaker circuits respectively. In another embodiment, three undervoltage relays may be provided to measure the voltage at both ends of bus 1, bus 2 and the interconnecting bus circuit breaker. In this case, circuit breaker QF2 or QF4 is replaced by a "manual isolating switch".

[0045] In all embodiments, the following is included: when busbar 1 loses pressure, the PLC module controls circuit breaker QF1 to open, and controls circuit breakers QF2 and QF4 to close, and busbar 2 simultaneously bears the entire load of busbar 1 and busbar 2; similarly, when busbar 2 loses pressure, circuit breaker QF3 is opened, and circuit breakers QF2 and QF4 are closed, and busbar 1 simultaneously bears the entire load of busbar 1 and busbar 2;

[0046] The sensor instrument includes a temperature sensor instrument. In this embodiment, two are set, namely T1 and T2, for collecting the contact temperature of circuit breakers QF1 and QF3; each temperature sensor instrument is connected to the serial port of the PLC module via an RS485 cable; when the contact of one of the busbar circuit breakers is overheated or the temperature difference between the three contacts of the detection circuit breaker is too large, the PLC module selects the over-temperature protection logic of the dual power switching.

[0047] The sensor instruments also include two smoke sensors, YW1 and YW2, installed in two busbar circuit breaker cabinets to detect smoke. These smoke sensors, YW1 and YW2, are connected to the serial port of a PLC module via RS485 communication. When smoke appears in one of the two busbar circuit breaker cabinets, the PLC module selects fire protection logic for control. In other embodiments, different types of sensor instruments can be added to expand protection functionality.

[0048] In this embodiment, time delay relays 1KT1 to 4KT1 are also included, and the normally closed contact of each pressure loss relay is connected to a time delay relay coil.

[0049] In other embodiments, the number of undervoltage relays and time-delay relays is consistent with the total number of circuit breakers used, and is used for voltage monitoring and delay control of the circuit breakers; in addition to detecting the voltage of the busbar circuit breaker, the undervoltage relay can also detect and delay the voltage of the bus tie circuit breaker QF2 or QF4.

[0050] That is to say, in this embodiment, there are four circuit breakers, so there are four pressure loss relays, four time delay relays and four temperature sensor meters; while in another embodiment, since there are three circuit breakers, there are three pressure loss relays, time delay relays and temperature sensor meters, and even three smoke sensor meters.

[0051] In this embodiment, eight output relays are included. Each PLC module controls the opening and closing states of a circuit breaker via two output relays. The two output relays are connected to the opening and closing coils of the circuit breaker to be controlled, respectively. In other embodiments, the number of output relays may be four or six, depending on the total number of circuit breakers used in the system.

[0052] In this embodiment, a touch screen HMI is further included, and the touch screen HMI is connected to the serial port of the PLC module;

[0053] The touch screen HMI is used to display the current system screen and system parameters, including the status of each circuit breaker, each bus power parameter, important data curves and function buttons; the touch screen HMI remotely controls different circuit breakers through the function buttons.

[0054] In this embodiment, a system switch SW is further included. The system switch SW is connected to the Ethernet interfaces of the PLC module and the touch screen respectively, and is used to realize data communication between the touch screen and the PLC module.

[0055] In this embodiment, an auxiliary power supply and a system power supply PS are also included. The system power supply converts the 220V AC voltage provided by the auxiliary power supply into a 24V DC voltage. The system power supply PS supplies power to the PLC module, the touch screen HMI, and the DI feedback loop of the PLC module. Points I0.0 to i2.5 in the DI feedback loop of the PLC module are respectively connected to the automatic start and reset, automatic start and manual reset, remote control, opening, closing, fault, and undervoltage signals of the circuit breakers QF1 to QF4.

[0056] In this embodiment, a multifunctional instrument is also included, which is a PM, which is used to collect the current and voltage of bus 1, bus 2 and the interconnecting bus; it is connected to the system power supply; its RS485 A1 and B1 ports are correspondingly connected to the serial port of the PLC module; the multifunctional instrument PM transmits the real-time collected voltage and current data of bus 1, bus 2 and the interconnecting bus to the PLC module;

[0057] Attachment Figure 3 In the embodiment, the multi-function instrument PM is connected to an auxiliary power supply, which can be a UPS power supply or other types of auxiliary power supplies. It can provide 220V AC power to the control circuit in the dual power switching system disclosed in this embodiment. The purpose is to provide power to the control system when the entire power supply system loses power.

[0058] The overall structural diagram of this embodiment is as follows Figure 1 As shown; For the primary system diagram of this embodiment, please refer to Figure 2 ;

[0059] In another embodiment, one of the circuit breakers on the interconnecting busbar can be replaced by a "manual disconnector", which is usually closed and manually disconnected in special circumstances;

[0060] The multifunctional instrument PM collects the voltage and current data of the three buses, and is connected to the serial port of the PLC module through the instrument ports A1 and B1, and is connected to the auxiliary power supply. The auxiliary power supply is connected to the system power supply PS. For details, please refer to the attached Figure 3A schematic diagram of the first understanding;

[0061] Before the system is put into use, 1: Check that the circuit breakers QF1 to QF4 are all in the working position and the manual position, among which, the circuit breakers QF1 and QF3 are both in the closed position, and the circuit breakers QF2 and QF4 are both in the open position;

[0062] 2: Turn all circuit breakers to remote status;

[0063] 3: Set the system status to automatic transfer and automatic recovery state on the touch screen;

[0064] 4: The current status is that bus 1 and bus 2 are supplying power to their respective loads, and the interconnecting bus is in a non-energized state.

[0065] After the system is used, it has three switching logics: loss of voltage dual power supply switching logic, dual power supply switching over-temperature protection logic and fire protection logic;

[0066] The logic flow of switching between dual power supplies during voltage loss also includes:

[0067] 5: When bus 1 loses power, the pressure loss relay drives the delay relay to operate. When the PLC receives the power loss signal, it determines whether the power supply of bus 2 is normal. If it is normal, the PLC will issue an opening command to the QF1 circuit breaker after 2 seconds. When the PLC receives the opening signal feedback from QF1, it starts timing 6 seconds and then issues a closing command to QF2 and QF4.

[0068] 6: In the current power supply status, bus 1 loses power and QF1 is disconnected; bus 2 is energized and supplies power to the loads of both bus 2 and bus 1; F2, QF3, and QF4 are all in the closed position;

[0069] 7: When the busbar is restored to power, the pressure loss relay drives the delay relay to operate. When the power loss signal disappears, the PLC issues a trip command to QF2 and QF4 after a delay of 2 seconds. When the PLC receives the trip signal feedback from QF2 and QF4, it starts timing for 6 seconds and then issues a closing command to QF1. The busbar is restored to power;

[0070] 8: The current system status is that busbar 1 and busbar 2 are supplying power to their loads independently, and the connecting circuit breakers QF2 and QF4 are in the open state;

[0071] 9: Complete the entire process of automatic switching to automatic recovery of dual power supplies;

[0072] The switching process when busbar 2 loses power is exactly the same as that of busbar 1.

[0073] In this embodiment, the selection of over-temperature protection and fire protection logic for the dual power switching is based on data collected in real time by the PLC module through sensor instruments. If the collected information indicates that the contacts of busbar 1 or 2 are over-temperature, or that the temperature difference between the three contact items is too large, the PLC module selects the over-temperature protection logic for the dual power switching. If the collected information indicates that there is smoke in the circuit breaker cabinet of busbar 1 or 2, the PLC module selects the fire protection logic for the dual power switching.

[0074] The over-temperature protection process for dual power switching includes the following steps in addition to the four steps before the system is put into operation:

[0075] 5: When the contact of busbar 1 circuit breaker QF1 overheats or a large temperature difference is detected among the three contacts, the system triggers the over-temperature protection logic to determine whether the power supply of busbar 2 is normal. If normal, the PLC module issues an opening command to circuit breaker QF1 after 2 seconds. When the PLC module receives the opening feedback signal of circuit breaker QF1, it times for 6 seconds and issues closing commands to circuit breakers QF2 and QF4. At the same time, the touch screen prompts a high-temperature alarm for the contact of circuit breaker QF1 and records the alarm data.

[0076] 6: Current power supply status: Circuit breaker QF1 is disconnected, bus 1 is not energized, bus 2 is energized, bus 2 supplies power to all loads on both bus 2 and bus 1, and circuit breakers QF2, QF3, and QF4 are all in the closed position;

[0077] 7: Before maintenance, switch the control mode of circuit breaker QF1 to the maintenance position. After maintenance, push it into the working position, switch the control mode back to the remote position, and manually reset the over-temperature alarm on the touch screen. At this time, the PLC module will check the status of the equipment in the system and the incoming voltage of bus 1. If both are normal, the PLC module will issue an opening command to circuit breakers QF2 and QF4 after 2 seconds. After the PLC module receives the opening signal feedback from circuit breakers QF2 and QF4, the PLC module will issue a closing command to circuit breaker QF1 after 6 seconds, and the power supply to bus 1 will be restored;

[0078] 8: The current system status is that busbar 1 and busbar 2 are independently supplying power to their loads, and the circuit breakers QF2 and QF4 of the connecting busbar are in the open state;

[0079] 9: Complete the entire process of automatic switching to automatic recovery due to over-temperature failure of dual power supplies;

[0080] The switching process for busbar 2 over-temperature is exactly the same as that for busbar 1.

[0081] In this embodiment, the dual power switching fire protection logic includes the following specific steps in addition to the four steps before the system is put into operation:

[0082] 5: When the smoke sensor in the circuit breaker QF1 cabinet is triggered, the fire signal is transmitted to the PLC module in real time for judgment. When the fire protection logic is triggered, the PLC module sends a trip command to the circuit breakers QF1 and QF3, and the touch screen issues a fire alarm and records the fire.

[0083] 6: Current power supply status: busbar 1 circuit breaker QF1 is disconnected, busbar 2 circuit breaker QF3 is disconnected, and bus tie circuit breakers QF2 and QF4 are both in the open position;

[0084] 7: After the fire is extinguished and all equipment is repaired, push circuit breakers QF1 to QF4 to the working position, set the control status to local, and manually reset the fire alarm on the touch screen. At this time, the PLC module will check the status of the equipment in the system. If the status is normal, manually close circuit breakers QF1 and QF3 to restore power, and then set the control status of circuit breakers QF1 to QF4 to remote;

[0085] 8: The current system status is that busbar 1 and busbar 2 are supplying power to their loads independently, and the connecting circuit breakers QF2 and QF4 are in the open state;

[0086] 9: Complete the entire process of automatic power off and manual recovery in case of dual power supply fire failure;

[0087] The fire protection process of busbar 2 is exactly the same as that of busbar 1.

[0088] In this embodiment, the PLC module used has strong scalability. When new protection needs to be added in the later stage, it is only necessary to add corresponding sensors at appropriate locations and connect them to the corresponding points of the PLC module. Modification of the control logic only requires reprogramming the PLC, without the need for repeated investment.

[0089] In this embodiment, the remote control mode includes two types: remote automatic restoration and manual restoration.

[0090] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0091] The above description of the disclosed embodiments will enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A dual power switching system with over-temperature protection based on a PLC module, characterized in that: Including bus 1, bus 2, interconnecting bus, pressure loss relay, sensor instrument and PLC module, The busbar 1 and busbar 2 are connected to the incoming lines of the two power supplies through circuit breaker QF1 and circuit breaker QF3 respectively; The interconnecting busbar is connected to the busbar 1 and busbar 2 via circuit breakers QF2 and QF4 respectively; The switch states of circuit breakers QF1, QF2, QF3, and QF4 are electrically interlocked. At most three circuit breakers can be in the closed state at any state, and each circuit breaker is connected to the PLC module for data exchange. At least two pressure loss relays are provided, each for collecting the bus voltage at both ends of the bus 1 and the bus 2; When busbar 1 loses pressure, the PLC module controls circuit breaker QF1 to open and circuit breakers QF2 and QF4 to close, and busbar 2 simultaneously bears the entire load of busbar 1 and busbar 2. Similarly, when busbar 2 loses pressure, circuit breaker QF3 opens, and circuit breakers QF2 and QF4 close, and busbar 1 simultaneously bears the entire load of busbar 1 and busbar 2. The sensor instrument includes a temperature sensor instrument, at least two of which are set to respectively collect the contact temperatures of circuit breakers QF1 and QF3; each temperature sensor instrument is connected to the serial port of the PLC module via an RS485 cable; when the contact temperature of one of the busbar circuit breakers exceeds the temperature or the temperature difference between the three contacts of the detection circuit breaker is too large, the PLC module selects the over-temperature protection logic of the dual power switching for control.

2. The dual power switching system with over-temperature protection based on PLC module according to claim 1 is characterized in that: One of the circuit breakers QF2 or QF4 is replaced by a "manual disconnect switch".

3. The dual power switching system with over-temperature protection based on PLC module according to claim 1 or 2, characterized in that: The sensor instrument also includes at least two smoke sensor instruments, which are respectively arranged in each circuit breaker cabinet for detecting smoke information; each smoke sensor instrument is connected to the serial port of the PLC module via RS485 communication; when smoke appears in one of the two busbar circuit breaker cabinets, the PLC module selects fire protection logic for control.

4. The dual power switching system with over-temperature protection based on PLC module according to claim 3 is characterized in that: It also includes a time delay relay, and the normally closed contact of each pressure loss relay is connected to a time delay relay coil.

5. The dual power switching system with over-temperature protection based on PLC module according to claim 4 is characterized in that: The number of pressure loss relays and time delay relays is set to three or four, which is consistent with the total number of circuit breakers used; Includes voltage detection and delay control for circuit breakers on the interconnecting busbar.

6. The dual power switching system with over-temperature protection based on PLC module according to claim 1 is characterized in that: It also includes output relays. The PLC module controls the opening and closing states of a circuit breaker through two output relays; the two output relays are respectively connected to the opening coil and the closing coil of the circuit breaker to be controlled.

7. The dual power switching system with over-temperature protection based on PLC module according to claim 1 is characterized in that: Also comprising a touch screen, the touch screen is connected to the serial port of the PLC module; The touch screen is used to display the current system screen and system parameters, including the status of each circuit breaker, each busbar power parameter, important data curves and function buttons; the touch screen remotely controls different circuit breakers through the function buttons.

8. The dual power switching system with over-temperature protection based on PLC module according to claim 7 is characterized in that: It also includes a system switch, which is connected to the Ethernet interface of the PLC module and the touch screen respectively, and is used to realize data communication between the touch screen and the PLC module.

9. The dual power switching system with over-temperature protection based on PLC module according to claim 7, characterized in that: It also includes an auxiliary power supply and a system power supply. The system power supply converts the 220V AC voltage provided by the auxiliary power supply into a 24V DC voltage to power the PLC module, the touch screen and the DI feedback loop of the PLC module; wherein the points I0.0 to i2.5 in the DI feedback loop of the PLC module are respectively connected to the automatic start and automatic recovery, automatic start and manual recovery, remote control, opening, closing, fault and undervoltage signals of the circuit breakers QF1 to QF4.

10. The dual power switching system with over-temperature protection based on PLC module according to claim 1, characterized in that: It also includes a multifunctional meter, which is a PM, used to collect the current and voltage of the busbar 1, busbar 2 and the connecting busbar; connected to the auxiliary power supply; The RS485 A1 and B1 ports are connected to the serial port of the PLC module; the multifunctional meter PM transmits the voltage and current data of bus 1, bus 2 and interconnecting bus collected in real time to the PLC module.

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