Converting capacitor charging power supply of high-voltage direct-current circuit breaker and control method

Abstract

The invention provides a high-voltage direct-current circuit breaker commutation capacitor charging power supply and a control method. The high-voltage direct-current circuit breaker commutation capacitor charging power supply comprises a charging power supply module, a relay module, a signal processing module and a capacitor, the charging power supply module is connected with the relay module, the relay module is connected with the capacitor, one end of the signal processing module is connected with the relay module, and the other end of the signal processing module is connected with the capacitor; the charging power supply module is connected with a direct-current power supply outside the high-voltage direct-current circuit breaker commutation capacitor charging power supply; the signal processing module is in communication connection with a main control system outside the high-voltage direct-current circuit breaker commutation capacitor charging power supply; the converter capacitor charging power supply of the high-voltage direct-current circuit breaker is provided with the signal processing module, transmission of a driving relay closing instruction and a driving relay opening and closing instruction can be achieved, and the reliability and flexibility of a system are improved; when a DC system fails, the capacitor in the commutation capacitor charging power supply of the high-voltage DC circuit breaker can perform reverse charging, so that the charging power supply is prevented from being damaged.

Description

Technical Field

[0001] The present application belongs to the technical field of high-voltage charging capacitor control, and specifically relates to a high-voltage DC circuit breaker commutation capacitor charging power supply and control method. Background Art

[0002] In recent years, with the development of power electronics technology, DC grids have broad application prospects in high-voltage flexible transmission, renewable energy access, rail traction, and future urban distribution networks. As important control and protection devices, DC circuit breakers are crucial for the safety of DC grid power supply.

[0003] The key to different DC circuit breaker designs lies in the design of the commutation branch. Capacitor-commutated hybrid DC circuit breakers are currently the most widely used design. This design's commutation branch consists of a charging power supply module, commutation capacitors, bypass thyristors, and other components. During normal operation of the DC system, the capacitor charging power supply pre-charges the commutation capacitors. However, in the event of a DC system fault, the short-circuit current reverse-charges the commutation capacitors, forcing the charging power supply to withstand the reverse voltage.

[0004] like Figure 1 The figure shows a high-voltage capacitor charging circuit module for general applications, including a high-voltage charging power supply module and current-limiting resistor R1. The charging power supply module converts the external input voltage to the required high voltage through voltage conversion, and controls the charging current and time through current-limiting resistor R1.

[0005] The capacitor charging power supply has the following problems: (1) the main circuit has no communication interface, and the control signal cannot be transmitted; (2) the power supply cannot withstand high reverse impact voltage, and excessive reverse voltage will damage the internal components of the charging power supply; Summary of the Invention

[0006] In order to overcome the above-mentioned deficiencies of the prior art, the present invention patent application proposes a high-voltage DC circuit breaker commutation capacitor charging power supply, comprising: a charging power supply module, a relay module, a signal processing module and a capacitor;

[0007] The charging power module is connected to the relay module, the relay module is connected to the capacitor, one end of the signal processing module is connected to the relay module, and the other end of the signal processing module is connected to the capacitor;

[0008] The charging power supply module is connected to a DC power supply outside the high-voltage DC circuit breaker converter capacitor charging power supply, and the signal processing module is communicatively connected to a main control system outside the high-voltage DC circuit breaker converter capacitor charging power supply;

[0009] When the DC system operates normally, the signal processing module receives a driving relay closing instruction from the main control system. The relay module is placed in a closed state under the action of the driving relay closing instruction. The charging power supply module converts the DC voltage of the DC power supply into a high voltage and charges the capacitor through the closed relay module.

[0010] When a fault occurs in the DC system, the output of the DC power supply is turned off, and the driving relay separation instruction of the main control system is received through the signal processing module. The relay module is placed in an open circuit state under the action of the driving relay separation and closing instruction, and the capacitor is reversely charged through the relay module in the open circuit state.

[0011] Preferably, the signal processing module includes: an optical fiber communication module, a controller and a voltage sampling module;

[0012] The controller is connected to the optical fiber communication module and the voltage sampling module respectively;

[0013] The controller is connected to the relay module, and the voltage sampling module is connected to the capacitor;

[0014] The optical fiber communication module is communicatively connected with the main control system;

[0015] The optical fiber communication module receives a voltage sampling instruction from the main control system and sends it to the controller. The controller forwards the voltage sampling instruction to the voltage sampling module. The voltage sampling module collects the charging voltage of the capacitor according to the voltage sampling instruction and sends it to the optical fiber communication module via the controller. The optical fiber communication module feeds back the charging voltage to the main control system.

[0016] Preferably, the relay module comprises: a high voltage reed relay and a drive circuit;

[0017] The driving circuit is connected to the high-voltage reed relay and the controller respectively;

[0018] The drive circuit receives a driving relay closing instruction sent by the controller, and places the high-voltage reed relay in a closed state under the action of the driving relay closing instruction;

[0019] Alternatively, the drive circuit receives a drive relay separation instruction sent by the controller, and places the high-voltage reed relay in an open-circuit state under the action of the drive relay separation instruction.

[0020] Preferably, the high-voltage reed relay includes: two groups of normally open contacts; when the two groups of normally open contacts are closed, the relay module is placed in a closed state; when the two groups of normally open contacts are disconnected, the relay module is placed in an open state.

[0021] Preferably, the charging power supply module includes: a PWM control chip;

[0022] The DC voltage of the DC power supply is converted into high voltage through the PWM control chip.

[0023] Preferably, the controller includes: an FPGA chip;

[0024] The FPGA chip processes and transmits the driving relay closing instruction, the driving relay separating instruction and the voltage sampling instruction received by the controller.

[0025] Based on the same inventive concept, the present invention patent application also provides a method for controlling a charging power supply for a high-voltage DC circuit breaker converter capacitor, comprising:

[0026] When the DC system operates normally, the signal processing module receives a driving relay closing instruction from the main control system. Under the action of the driving relay closing instruction, the relay module is placed in a closed state, the DC voltage of the DC power supply is converted into high voltage through the charging power supply module, and the capacitor is charged through the closed relay module;

[0027] When a fault occurs in the DC system, the output of the DC power supply is turned off, and the driving relay separation instruction of the main control system is received through the signal processing module. Under the action of the driving relay separation and connection instruction, the relay module is placed in an open circuit state, and the capacitor is reversely charged through the relay module in the open circuit state.

[0028] Preferably, it also includes:

[0029] The optical fiber communication module in the signal processing module receives the voltage sampling instruction of the main control system and sends it to the controller in the signal processing module, and the controller forwards the voltage sampling instruction to the voltage sampling module in the signal processing module;

[0030] The voltage sampling module collects the charging voltage of the capacitor using a resistor voltage divider according to the voltage sampling instruction, and sends it to the optical fiber communication module through the controller, and then feeds the charging voltage back to the main control system through the optical fiber communication module.

[0031] Preferably, the relay module is placed in an open circuit state under the action of the driving relay opening and closing instruction, including:

[0032] Under the action of the driving relay opening and closing instruction, the high-voltage reed relay in the relay module is placed in an open circuit state through the driving circuit in the relay module.

[0033] Preferably, placing the high-voltage reed relay in the relay module in an off-circuit state through a driving circuit in the relay module comprises:

[0034] The two groups of normally open contacts of the high-voltage reed relay in the relay module are disconnected through the driving circuit in the relay module.

[0035] Compared with the closest prior art, the patent application of this invention has the following beneficial effects:

[0036] The present invention patent application provides a high-voltage DC circuit breaker commutation capacitor charging power supply and control method, including: a charging power supply module, a relay module, a signal processing module and a capacitor; the charging power supply module is connected to the relay module, the relay module is connected to the capacitor, one end of the signal processing module is connected to the relay module, and the other end of the signal processing module is connected to the capacitor; the charging power supply module is connected to a DC power supply outside the high-voltage DC circuit breaker commutation capacitor charging power supply, and the signal processing module is communicatively connected to a main control system outside the high-voltage DC circuit breaker commutation capacitor charging power supply; when the DC system is operating normally, the signal processing module receives a driving relay closing instruction of the main control system, and the relay module is placed in a closed state under the action of the driving relay closing instruction. The charging power supply module converts the DC voltage of the DC power supply into high voltage and charges the capacitor through the closed relay module. When a DC system fault occurs, the output of the DC power supply is turned off, and the signal processing module receives the drive relay separation instruction of the main control system. The relay module is placed in an open circuit state under the action of the drive relay separation instruction, and the capacitor is reversely charged through the open circuit relay module. The high-voltage DC circuit breaker commutation capacitor charging power supply of the present application has a signal processing module that can realize the transmission of the drive relay separation instruction and the drive relay separation instruction, thereby improving the reliability and flexibility of the system. When the DC system faults, the capacitor in the high-voltage DC circuit breaker commutation capacitor charging power supply of the present application can be reversely charged, thereby avoiding damage to the charging power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A schematic diagram of a capacitor charging power supply for general applications provided for the patent application of this invention;

[0038] Figure 2 A schematic diagram of a high-voltage DC circuit breaker commutation capacitor charging power supply provided for the patent application of the present invention;

[0039] Figure 3 A diagram of a capacitor charging power supply module provided for the patent application of this invention;

[0040] Figure 4 A flow chart of a control method for a high-voltage DC circuit breaker commutation capacitor charging power supply provided in the patent application of the present invention. DETAILED DESCRIPTION

[0041] The specific implementation methods of the patent application of the present invention are further described in detail below with reference to the accompanying drawings.

[0042] Example 1:

[0043] The present invention provides a high voltage DC circuit breaker commutation capacitor charging power supply. Figure 2 As shown, it includes: a charging power module, a relay module, a signal processing module and a capacitor;

[0044] The charging power module is connected to the relay module, the relay module is connected to the capacitor, one end of the signal processing module is connected to the relay module, and the other end of the signal processing module is connected to the capacitor;

[0045] The charging power supply module is connected to a DC power supply outside the high-voltage DC circuit breaker converter capacitor charging power supply, and the signal processing module is communicatively connected to a main control system outside the high-voltage DC circuit breaker converter capacitor charging power supply;

[0046] When the DC system operates normally, the signal processing module receives a driving relay closing instruction from the main control system. The relay module is placed in a closed state under the action of the driving relay closing instruction. The charging power supply module converts the DC voltage of the DC power supply into a high voltage and charges the capacitor through the closed relay module.

[0047] When a fault occurs in the DC system, the output of the DC power supply is turned off, and the driving relay separation instruction of the main control system is received through the signal processing module. The relay module is placed in an open circuit state under the action of the driving relay separation and closing instruction, and the capacitor is reversely charged through the relay module in the open circuit state.

[0048] Figure 2 The DC circuit breaker commutation capacitor charging power supply shown in the figure can charge the capacitor and withstand the reverse surge voltage generated by the short-circuit current on the capacitor during a DC system fault, thus preventing damage to the charging power supply. The addition of a fiber-optic communication module enables effective electrical isolation control and real-time transmission of control commands and charging voltage samples, improving system reliability and flexibility.

[0049] In one implementation, the signal processing module includes: an optical fiber communication module, a controller, and a voltage sampling module;

[0050] The controller is connected to the optical fiber communication module and the voltage sampling module respectively;

[0051] The controller is connected to the relay module, and the voltage sampling module is connected to the capacitor;

[0052] The optical fiber communication module is communicatively connected with the main control system;

[0053] The optical fiber communication module receives a voltage sampling instruction from the main control system and sends it to the controller. The controller forwards the voltage sampling instruction to the voltage sampling module. The voltage sampling module collects the charging voltage of the capacitor according to the voltage sampling instruction and sends it to the optical fiber communication module via the controller. The optical fiber communication module feeds back the charging voltage to the main control system.

[0054] In this implementation, the charging voltage can be detected in real time through the optical fiber communication module, thereby improving the accuracy of the charging voltage.

[0055] The relay module includes: a high-voltage reed relay and a drive circuit;

[0056] The driving circuit is connected to the high-voltage reed relay and the controller respectively;

[0057] The drive circuit receives a driving relay closing instruction sent by the controller, and places the high-voltage reed relay in a closed state under the action of the driving relay closing instruction;

[0058] Alternatively, the drive circuit receives a drive relay separation instruction sent by the controller, and places the high-voltage reed relay in an open-circuit state under the action of the drive relay separation instruction.

[0059] For example, the high-voltage reed relay includes: two groups of normally open contacts; when the two groups of normally open contacts are closed, the relay module is placed in a closed state; when the two groups of normally open contacts are disconnected, the relay module is placed in an open state.

[0060] The charging power supply module includes: a PWM control chip;

[0061] The DC voltage of the DC power supply is converted into high voltage through the PWM control chip.

[0062] The controller includes: an FPGA chip;

[0063] The FPGA chip processes and transmits the driving relay closing instruction, the driving relay separating instruction and the voltage sampling instruction received by the controller.

[0064] The high-voltage DC circuit breaker commutation capacitor charging power supply of the present application can control the charging process and detect the capacitor charging voltage through optical fiber communication, and can withstand reverse charging voltages of up to 5kV; this improves the reliability of the charging power supply and makes the charging process controllable and monitorable; the present application realizes a high-voltage DC circuit breaker commutation capacitor charging power supply capable of real-time communication with a main control system, realizes communication functions through an optical fiber communication module, and electrically isolates the main control system from the main circuit of the high-voltage DC circuit breaker, thereby improving reliability; the voltage acquisition module proposed in the present application realizes real-time monitoring of the capacitor charging voltage and feeds back the signal of the optical fiber communication module to the main control system, thereby realizing remote monitoring of the capacitor charging process; the present invention realizes the control function of the capacitor charging interface switch through a relay module, can realize the charging power supply to withstand reverse charging voltage, and improves the reliability of the charging power supply.

[0065] Example 2:

[0066] The present invention provides a specific embodiment of a high-voltage DC circuit breaker commutation capacitor charging power supply, as follows:

[0067] The DC circuit breaker commutation capacitor charging power supply proposed by the present invention has a DC 24V input, a DC output voltage of DC300V to DC3000V, and a rated output power of 150W. Figure 3 As shown, a high-voltage DC circuit breaker commutation capacitor charging power supply consists of a charging power supply module, a relay module, a controller module, an optical fiber communication module, a capacitor C1 and a voltage sampling module.

[0068] The charging power module is connected to an external 24V DC power supply. The other end of the DC power supply is connected to the DC system outside the high-voltage DC circuit breaker commutation capacitor charging power supply. The PWM control chip generates a drive signal, which is then converted to a 3000V high-voltage output by a high-frequency transformer. The charging power module is connected to the relay module, which consists of a high-voltage reed relay and a drive circuit. Figure 2 In Figure 1, S1 and S2 are the two normally open contacts of a high-voltage reed relay. The controller generates the open / close signals for the drive circuit. Under normal circumstances, S1 and S2 are closed, allowing the charging power module to charge the capacitor. In the event of a DC system fault, the DC power supply shuts off, and S1 and S2 open. This prevents short-circuit current from causing reverse charging voltage to the capacitor and potentially damaging the power supply, improving the charger's ability to withstand high reverse voltages.

[0069] The fiber optic communication module is connected to the controller and the external main control system. The fiber optic communication module completes the transmission of control instructions from the main control system and returns the capacitor voltage measurement value to the main control system. The control instructions include: driving relay closing instructions, driving relay opening instructions, and voltage sampling instructions.

[0070] The voltage sampling module is connected to both ends of the capacitor's charging power supply, tests the charging voltage through resistor voltage division, and then converts the voltage signal into a digital signal and transmits it to the controller.

[0071] The controller is connected to the optical fiber communication module, the relay module, and the voltage sampling module. The controller uses an FPGA chip to complete the processing of communication signals, relay drive signals, and DC voltage sampling signals.

[0072] In the embodiment of the present invention, the DC circuit breaker commutation capacitor charging power supply includes a charging power supply module, a relay module, a controller module, an optical fiber communication module and a voltage sampling module. The charging power supply module is used to convert the power supply voltage, which is boosted from an external DC 24V to a DC 3000V. The driving signal is generated by the PWM driving chip, and a high-voltage output is generated through a high-frequency transformer. The relay module is connected to the output of the charging power supply module and is connected in parallel with the charging capacitor to realize the relay-controlled capacitor charging start and stop function. The controller module is connected to the optical fiber communication module, the relay module and the voltage sampling module to complete the processing of the communication signal, the relay driving signal and the DC voltage sampling signal. Therefore, the embodiment of the present invention improves the reliability and flexibility of the system.

[0073] Example 3:

[0074] Based on the same inventive concept, the present invention patent application also provides a flow chart of a method for controlling a high-voltage DC circuit breaker commutation capacitor charging power supply. Figure 4 As shown, including:

[0075] Step 1: When the DC system is operating normally, the signal processing module receives a driving relay closing instruction from the main control system. Under the action of the driving relay closing instruction, the relay module is placed in a closed state, the DC voltage of the DC power supply is converted into high voltage through the charging power supply module, and the capacitor is charged through the closed relay module;

[0076] Step 2: When a fault occurs in the DC system, the output of the DC power supply is turned off, and the driving relay separation instruction of the main control system is received through the signal processing module. Under the action of the driving relay separation and closing instruction, the relay module is placed in an open circuit state, and the capacitor is reversely charged through the relay module in the open circuit state.

[0077] Preferably, it also includes:

[0078] The optical fiber communication module in the signal processing module receives the voltage sampling instruction of the main control system and sends it to the controller in the signal processing module, and the controller forwards the voltage sampling instruction to the voltage sampling module in the signal processing module;

[0079] The voltage sampling module collects the charging voltage of the capacitor using a resistor voltage divider according to the voltage sampling instruction, and sends it to the optical fiber communication module through the controller, and then feeds the charging voltage back to the main control system through the optical fiber communication module.

[0080] Preferably, the relay module is placed in an open circuit state under the action of the driving relay opening and closing instruction, including:

[0081] Under the action of the driving relay opening and closing instruction, the high-voltage reed relay in the relay module is placed in an open circuit state through the driving circuit in the relay module.

[0082] Preferably, placing the high-voltage reed relay in the relay module in an off-circuit state through a driving circuit in the relay module comprises:

[0083] The two groups of normally open contacts of the high-voltage reed relay in the relay module are disconnected through the driving circuit in the relay module.

[0084] It will be understood by those skilled in the art that the embodiments of the present invention patent application may be provided as a method, system, or computer program product. Therefore, the present invention patent application may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention patent application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0085] The present invention patent application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present invention patent application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0086] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0087] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 The steps for the function specified in one or more boxes.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the patent application of the present invention and are not intended to limit its scope of protection. Although the patent application of the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that after reading the patent application of the present invention, those skilled in the art can still make various changes, modifications or equivalent substitutions to the specific implementation methods of the application, but these changes, modifications or equivalent substitutions are all within the scope of protection of the claims to be approved.

Claims

1. A high-voltage DC circuit breaker commutation capacitor charging power supply, characterized in that: include: Charging power module, relay module, signal processing module and capacitor; The charging power module is connected to the relay module, the relay module is connected to the capacitor, one end of the signal processing module is connected to the relay module, and the other end of the signal processing module is connected to the capacitor; The charging power supply module is connected to a DC power supply outside the high-voltage DC circuit breaker converter capacitor charging power supply, and the signal processing module is communicatively connected to a main control system outside the high-voltage DC circuit breaker converter capacitor charging power supply; When the DC system operates normally, the signal processing module receives a driving relay closing instruction from the main control system. The relay module is placed in a closed state under the action of the driving relay closing instruction. The charging power supply module converts the DC voltage of the DC power supply into a high voltage and charges the capacitor through the closed relay module. When a fault occurs in the DC system, the output of the DC power supply is turned off, and the driving relay separation instruction of the main control system is received through the signal processing module. The relay module is placed in an open circuit state under the action of the driving relay separation and closing instruction, and the capacitor is reversely charged through the relay module in the open circuit state.

2. The power supply according to claim 1, wherein: The signal processing module includes: an optical fiber communication module, a controller and a voltage sampling module; The controller is connected to the optical fiber communication module and the voltage sampling module respectively; The controller is connected to the relay module, and the voltage sampling module is connected to the capacitor; The optical fiber communication module is communicatively connected with the main control system; The optical fiber communication module receives a voltage sampling instruction from the main control system and sends it to the controller. The controller forwards the voltage sampling instruction to the voltage sampling module. The voltage sampling module collects the charging voltage of the capacitor according to the voltage sampling instruction and sends it to the optical fiber communication module via the controller. The optical fiber communication module feeds back the charging voltage to the main control system.

3. The power supply according to claim 2, wherein: The relay module includes: a high-voltage reed relay and a drive circuit; The driving circuit is respectively connected to the high-voltage reed relay and the controller; The drive circuit receives a drive relay closing instruction sent by the controller, and places the high-voltage reed relay in a closed state under the action of the drive relay closing instruction; Alternatively, the drive circuit receives a drive relay separation instruction sent by the controller, and places the high-voltage reed relay in an open circuit state under the action of the drive relay separation instruction.

4. The power supply according to claim 3, wherein: The high-voltage reed relay includes: two groups of normally open contacts; when the two groups of normally open contacts are closed, the relay module is placed in a closed state; when the two groups of normally open contacts are disconnected, the relay module is placed in an open state.

5. The power supply according to claim 1, wherein: The charging power supply module includes: a PWM control chip; The DC voltage of the DC power supply is converted into high voltage through the PWM control chip.

6. The power supply according to claim 2, wherein: The controller includes: an FPGA chip; The FPGA chip processes and transmits the driving relay closing instruction, the driving relay separating instruction and the voltage sampling instruction received by the controller.

7. A method for controlling a charging power supply for a high-voltage DC circuit breaker commutation capacitor, characterized in that: include: When the DC system operates normally, the signal processing module receives a driving relay closing instruction from the main control system. Under the action of the driving relay closing instruction, the relay module is placed in a closed state, the DC voltage of the DC power supply is converted into high voltage through the charging power supply module, and the capacitor is charged through the closed relay module; When a fault occurs in the DC system, the output of the DC power supply is turned off, and the driving relay separation instruction of the main control system is received through the signal processing module. Under the action of the driving relay separation and connection instruction, the relay module is placed in an open circuit state, and the capacitor is reversely charged through the relay module in the open circuit state.

8. The control method according to claim 7, wherein: Also includes: The optical fiber communication module in the signal processing module receives the voltage sampling instruction of the main control system and sends it to the controller in the signal processing module, and the controller forwards the voltage sampling instruction to the voltage sampling module in the signal processing module; The voltage sampling module collects the charging voltage of the capacitor using a resistor voltage divider according to the voltage sampling instruction, and sends it to the optical fiber communication module through the controller, and then feeds the charging voltage back to the main control system through the optical fiber communication module.

9. The control method according to claim 7, wherein: The relay module is placed in an open circuit state under the action of the driving relay opening and closing instruction, including: Under the action of the driving relay opening and closing instruction, the high-voltage reed relay in the relay module is placed in an open circuit state through the driving circuit in the relay module.

10. The control method according to claim 9, wherein: Placing the high-voltage reed relay in the relay module into an open-circuit state through a driving circuit in the relay module includes: The two groups of normally open contacts of the high-voltage reed relay in the relay module are disconnected through the driving circuit in the relay module.

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