Opening and closing control circuit with switch fault maloperation prevention function and power system switch equipment

Abstract

The invention discloses an opening and closing control circuit with a switch fault maloperation prevention function and power system switch equipment, which are applied to the field of power switches and comprise an opening and closing control circuit and a switch fault maloperation prevention circuit. The switch fault maloperation prevention circuit comprises a single-pole double-throw relay and a switch button. Under the protection and clamping of a switch button in the switch fault maloperation prevention circuit, when the opening and closing control circuit works normally, the contacts of the single-pole double-throw relay are closed, and the opening and closing control circuit controls the opening and closing of the electric power system switch according to the braking of the forward rotation relay or the reverse rotation relay. When the forward rotation relay or the reverse rotation relay is abnormally opened and closed due to contact faults or manual maloperation, due to the existence of the switch button, the single-pole double-throw relay is powered off, and the opening and closing control circuit is disconnected, so that abnormal opening and closing of the power system switch under the condition of not passing electrical five-prevention verification are avoided; the problem of abnormal switching on and switching off of the electrical system switch under the condition of relay damage or manual maloperation is solved.

Description

Technical Field

[0001] The invention relates to the field of power switches, and in particular to a switching control circuit with switch fault prevention and malfunction prevention and a power system switch device. Background Art

[0002] As the control circuit of important switchgear in the power system, the operation status of the separation and combination control circuit directly affects the transmission and distribution of electric energy and the safe and reliable operation of the system. The switchgear of the power system includes: isolating switches and grounding switches. The isolating switches can electrically isolate the busbars, circuit breakers and other electrical equipment under maintenance from the voltage lines, and provide a safe and visible insulation gap that meets the requirements for the equipment under maintenance and the maintenance personnel. The function of the grounding switch is to reliably ground certain parts of the power-off equipment in situations such as equipment maintenance. At present, most separation and combination control circuits on the market do not have a design to prevent false operation, such as Figure 1 As shown, the multiple contacts of the relay are in a unified braking relationship. When the forward relay K1 contact is closed, the motor rotates forward, and when the reverse relay K2 contact is closed, the motor rotates reversely. The motor can only have one rotation state at a time. When the motor needs to stop the forward operation but the forward relay K1 node is stuck or malfunctioned by human beings, and the contact fails to open normally; or when the motor needs to reverse operation but the reverse relay K2 is stuck or malfunctioned by human beings, and the contact fails to close normally, it is possible that a serious accident of abnormal opening and closing of the power system switch may occur without the electrical five-protection verification.

[0003] At the same time, the failure of the separation and combination control circuit may cause bus voltage fluctuations, thus affecting the normal operation of multiple transmission lines connected to the bus. It may cause the protection devices of multiple lines to operate, causing large-scale power outages and affecting the power supply stability of the entire power grid.

[0004] It can be seen from this that how to solve the abnormal separation and combination of electrical system switches due to failure of the separation and combination control circuit or human error is a technical problem that needs to be urgently solved by personnel in the power field. Summary of the invention

[0005] In view of this, the purpose of this application is to provide a switch disconnection and connection control circuit and power system switch equipment with switch fault prevention function, which solves the problem of abnormal disconnection and connection of electrical system switches due to fault jamming or human error in the disconnection and connection control circuit. The specific scheme is as follows:

[0006] In a first aspect, the present application provides a separation and combination control circuit with switch fault prevention and malfunction protection, including a separation and combination control circuit, characterized in that it also includes a switch fault prevention and malfunction protection circuit, the switch fault prevention and malfunction protection circuit includes: a single-pole double-throw relay and a switch button;

[0007] The single-pole double-throw relay comprises a coil, a first contact and a second contact;

[0008] The first end of the coil is connected in series with the first contact of the forward relay and the first contact of the reverse relay in sequence and then connected to the positive electrode;

[0009] The first end of the coil is connected in series with the first contact and then connected to the positive electrode;

[0010] The second end of the coil is connected to the first end of the switch button, and the second end of the switch button is connected to the negative electrode;

[0011] The first end of the second contact is connected to the positive electrode, and the second end of the second contact is connected to the positive input end of the separation and combination control circuit.

[0012] Optionally, the switch fault prevention circuit further includes:

[0013] A forward rotation indicating circuit is connected between the positive electrode and the negative electrode.

[0014] Optionally, the forward rotation indication circuit comprises: a forward rotation indication circuit indicator light and a second contact of a forward rotation relay;

[0015] The first end of the second contact of the forward relay is connected to the positive electrode;

[0016] The second end of the second contact of the forward relay is connected to the first end of the indicator light of the forward indication circuit;

[0017] The second end of the indicator light of the forward rotation indicating circuit is connected to the negative electrode.

[0018] Optionally, the switch fault prevention circuit further includes:

[0019] A reversal indicating circuit is connected between the positive electrode and the negative electrode.

[0020] Optionally, the reversing indication circuit comprises: a reversing indication circuit indicator light and a second contact of a forward and reversing relay;

[0021] The first end of the second contact of the reversing relay is connected to the positive electrode;

[0022] The second end of the second contact of the reversing relay is connected to the first end of the indicator light of the reversing indication circuit;

[0023] The second end of the indicator light of the reversal indication circuit is connected to the negative electrode.

[0024] Optionally, the forward relay includes: an auxiliary normally open contact;

[0025] The auxiliary normally open contact is closed after the coil of the forward relay is energized, so that the contact of the forward relay is maintained in an energized state.

[0026] Optionally, the reversing relay includes: an auxiliary normally open contact;

[0027] The auxiliary normally open contact is closed after the coil of the reversing relay is energized, so that the contact of the reversing relay is maintained in an energized state.

[0028] Optionally, the confirmation button is a spring reset button.

[0029] Optionally, it includes: the forward relay and the reverse relay form an interlocking structure, wherein the normally closed contact of the forward relay is connected in series in the coil power supply circuit of the reverse relay, and the normally closed contact of the reverse relay is connected in series in the coil power supply circuit of the forward relay.

[0030] In a second aspect, the present application provides a power system switch device, including the above-mentioned opening and closing control circuit with switch fault protection function.

[0031] It can be seen that the separation and combination control circuit in the present application is protected by the switch button in the switch fault prevention and malfunction circuit. When it works normally, the first contact of the single-pole double-throw relay and the second contact of the single-pole double-throw relay are both closed, and the separation and combination control circuit controls the separation and combination of the power system switch according to the braking of the forward relay or the reverse relay. When the forward relay or the reverse relay is abnormally separated and combined due to contact failure or human malfunction, due to the presence of the switch button, the single-pole double-throw relay is powered off, and the separation and combination control circuit is disconnected, avoiding abnormal separation and combination of the power system switch without the five electrical protection verification, and solving the problem of abnormal separation and combination of the electrical system switch due to relay damage or human malfunction. 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 drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0033] Figure 1 A separation and combination control circuit diagram provided for related technologies;

[0034] Figure 2 A switching control circuit diagram with switch fault prevention and malfunction prevention is provided in an embodiment of the present application. DETAILED DESCRIPTION

[0035] 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 described embodiments 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 creative work are within the scope of protection of the present invention.

[0036] The core of the present application is to provide a switching control circuit with switch fault prevention and malfunction prevention.

[0037] In order to enable those skilled in the art to better understand the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0038] As the control circuit of important switchgear in power system, the operation status of the separation and combination control circuit directly affects the transmission and distribution of electric energy and the safe and reliable operation of the system. The switchgear of power system includes: isolating switch and grounding knife switch. The isolating switch can electrically isolate the busbar, circuit breaker and other electrical equipment under maintenance from the voltage line, and provide a safe and visible insulation gap that meets the requirements for the equipment under maintenance and the maintenance personnel. The function of the grounding knife switch is to reliably ground certain parts of the power-off equipment in the case of equipment maintenance. At present, most of the separation and combination control circuits on the market have no anti-false operation design. When the motor M needs to stop the forward operation but the forward relay K1 node is stuck or artificially malfunctioned, the contact fails to open normally; or when the motor M needs to reverse operation but the reverse relay K2 is stuck or artificially malfunctioned, the contact fails to close normally, it is possible that the power system switch is abnormally separated and combined without the five electrical protection verification.

[0039] At the same time, the failure of the separation and combination control circuit may cause bus voltage fluctuations, thus affecting the normal operation of multiple transmission lines connected to the bus. It may cause the protection devices of multiple lines to operate, causing large-scale power outages and affecting the power supply stability of the entire power grid.

[0040] It can be seen from this that how to solve the abnormal separation and combination of electrical system switches due to failure of the separation and combination control circuit or human error is a technical problem that needs to be urgently solved by personnel in the power field.

[0041] See also Figure 2 As shown, in order to solve the above problems, this embodiment discloses a separation and combination control circuit with switch fault prevention malfunction, including a separation and combination control circuit, characterized in that it also includes a switch fault prevention malfunction circuit, the switch fault prevention malfunction circuit includes: a single-pole double-throw relay and a switch button SW;

[0042] The single-pole double-throw relay comprises a coil BH, a first contact BH-1 and a second contact BH-2;

[0043] The first end of the coil BH is connected in series with the first contact K1-1 of the forward relay and the first contact K1-1 of the reverse relay in sequence and then connected to the positive electrode;

[0044] The first end of the coil BH is connected in series with the first contact BH-1 and then connected to the positive electrode;

[0045] The second end of the coil BH is connected to the first end of the switch button SW, and the second end of the switch button SW is connected to the negative electrode;

[0046] A first end of the second contact BH- 2 is connected to the positive electrode, and a second end of the second contact BH- 2 is connected to the positive input end of the separation and combination control circuit.

[0047] As shown in the figure, the switch button SW is connected to the coil BH of the single-pole double-throw relay. In a specific embodiment, only after the switch button SW is manually pressed, the coil BH of the single-pole double-throw relay can be energized, so that the first contact BH-1 of the normally open single-pole double-throw relay and the second contact BH-2 of the single-pole double-throw relay are closed, and the power supply can be sent to the separation and closing control circuit, and then the relay to be closed can be selected in the forward and reverse relay control circuit containing the forward relay coil and the reverse relay coil. When the power system switch is selected to rotate forward, the third contact K1-3 of the forward relay, the fourth contact K1-4 of the forward relay and the fifth contact K1-5 of the forward relay are closed, and the motor M runs in the forward direction; when the power system switch is selected to rotate reversely, the third contact K2-3 of the reverse relay, the fourth contact K2-4 of the reverse relay and the fifth contact K2-5 of the reverse relay are closed, and the motor M runs in the reverse direction.

[0048] In a specific embodiment, the power system switch is a grounding switch. Figure 2 When the switch fault protection opening and closing control circuit is applied to the main circuit of the grounding knife switch motor M, if the forward relay contacts are damaged, stuck, or the nodes are adhered, and the forward relay fails when the third contact K1-3, the fourth contact K1-4, and the fifth contact K1-5 of the forward relay are in the energized state, it is the most dangerous state. Figure 1 As shown, at this moment, the fifth contact K1-5 of the forward relay, the fourth contact K1-4 of the forward relay, and the third contact K1-3 of the forward relay are in a closed state. After the grounding knife switch motor M is powered, the motor M will rotate forward and the grounding knife switch will be closed without the control circuit. This will lead to a vicious accident of the grounding knife switch being mistakenly closed without the five electrical protection verification. In the embodiment of the present application, Figure 2As shown, if the contacts of the forward relay are damaged, stuck, or the nodes are stuck in the energized state, the first contact K1-1 of the forward relay is in the open state, and the coil BH of the single-pole double-throw relay cannot be energized. The first contact BH-1 of the single-pole double-throw relay and the second contact BH-2 of the single-pole double-throw relay return to the normally open state, and the opening and closing control circuit cannot be energized, so the grounding switch cannot be opened and closed.

[0049] It is understandable that after the grounding knife switch is connected to the power supply, if due to human error, such as on-site working tools, human error, safety helmets, etc., the forward relay K1 or reverse relay K2 is malfunctioned, the Figure 1 The circuit design shown will cause the grounding knife switch to be opened or closed by mistake. In the embodiment of the present application, when a human error occurs, the first contact K1-1 of the forward relay is in the open state, the coil BH of the single-pole double-throw relay cannot be energized, the first contact BH-1 of the single-pole double-throw relay and the second contact BH-2 of the single-pole double-throw relay are opened, and the opening and closing control circuit cannot be energized, so it can effectively prevent the relay from being damaged or the node from sticking, and the grounding knife switch from being closed or opened by mistake.

[0050] In another specific embodiment, the power system switch is an isolating switch. When the contacts of the reversing relay K2 are damaged, stuck, or the nodes are adhered, and the reversing relay fails while the third contact K2-3, the fourth contact K2-4, and the fifth contact K2-5 of the reversing relay are in the energized state, this is the most dangerous state. Figure 1 As shown, at this moment, the fifth contact K2-5 of the reversing relay, the fourth contact K2-4 of the reversing relay, and the third contact K2-3 of the reversing relay are in a closed state. When the opening and closing control circuit is energized, the motor M will not be reversed through the control circuit, and the disconnector will be opened. This will lead to a serious accident of opening and closing the disconnector with load without the five electrical protection verification. In the embodiment of the present application, Figure 2 As shown, the first contact K2-1 of the reversing relay is in the open state, the coil BH of the single-pole double-throw relay cannot be energized, the first contact BH-1 of the single-pole double-throw relay and the second contact BH-2 of the single-pole double-throw relay return to the normally open state, the separation and closing control circuit cannot be energized, and therefore the isolating switch cannot be separated or closed.

[0051] It can be understood that after the isolating switch is connected to the power supply, if the forward relay or the reverse relay is operated due to human error, such as on-site work tools, human errors, safety helmets, etc., the first contact K2-1 of the reverse relay is in the open state, and the coil BH of the single-pole double-throw relay cannot be energized. The first contact BH-1 of the single-pole double-throw relay and the second contact BH-2 of the single-pole double-throw relay are opened, and the separation and closing control circuit cannot be energized. Therefore, it can effectively prevent relay damage or node adhesion, and mis-closing or mis-opening of the isolating switch.

[0052] In this embodiment, when the contact of the forward relay K1 or the reverse relay K2 fails, and the third contact, the fourth contact and the fifth contact of any of the forward relay K1 or the reverse relay K2 are disconnected, it will not cause a vicious accident of mistakenly closing the grounding knife switch under power without the five electrical protection verification or a vicious accident of opening and closing the disconnector under load. At this time, the power system switch will not perform the action corresponding to the instruction, and the operator can judge the fault of the relay switch at this time from the state of the power system switch.

[0053] It can be seen that the separation and combination control circuit in the present application is protected by the switch button in the switch fault prevention and malfunction circuit. When it works normally, the first contact of the single-pole double-throw relay and the second contact of the single-pole double-throw relay are both closed, and the separation and combination control circuit separates and combines according to the brake control of the forward relay or the reverse relay. When the forward relay or the reverse relay is abnormally separated and combined due to contact failure or human malfunction, due to the presence of the switch button, the coil of the single-pole double-throw relay is de-energized, and the separation and combination control circuit is disconnected, thereby avoiding abnormal separation and combination of the power system switch without the electrical five-protection verification, and solving the problem of abnormal separation and combination of the electrical system switch due to relay damage or human malfunction.

[0054] According to the above embodiment, this embodiment provides a specific solution, the switch fault prevention circuit further includes:

[0055] A forward rotation indicating circuit is connected between the positive pole and the negative pole.

[0056] The forward indication circuit is a circuit that is reflected when the motor M receives the forward instruction. It is convenient to verify whether the instruction is accurately transmitted when operating the power system switch, and is used to check whether the contacts of the forward relay are in the normally open state when the separation and closing control circuit is energized.

[0057] According to the above embodiment, this embodiment provides a specific solution, the forward indication circuit includes: a forward indication circuit indicator light L1 and a second contact K1-2 of the forward relay;

[0058] A first end of the second contact K1-2 of the forward relay is connected to the positive electrode;

[0059] The second end of the second contact K1-2 of the forward relay is connected to the first end of the indicator light L1 of the forward indication circuit;

[0060] The second end of the indicator light L1 of the forward indication circuit is connected to the negative electrode.

[0061] When the switch button SW is manually pressed, the coil BH of the single-pole double-throw relay is energized, the first contact BH-1 of the single-pole double-throw relay and the second contact BH-2 of the single-pole double-throw relay are closed, and the power is sent to the separation and closing control circuit. At this time, if there is no operation on the forward and reverse relay control circuit where the forward relay coil is located, the indicator light L1 of the forward indication circuit is not on. When the coil of the forward relay K1 is energized in the forward and reverse relay control circuit, the second contact K1-2 of the forward relay is closed, and the indicator light L1 of the forward indication circuit is on. This is the working state of the forward indication circuit under normal working conditions. When the contact of the forward relay K1 cannot be disconnected in time due to contact damage, jamming, and node adhesion in the attracted state, at this time, there is no closing instruction for the power system switch, the switch button SW is disconnected, the coil BH of the single-pole double-throw relay is not energized, the second contact BH-2 of the single-pole double-throw relay is disconnected, and the separation and closing control circuit is powered off, which prevents the abnormal separation and closing of the power system switch due to contact failure or human error. This embodiment is mainly used in the case of abnormal closing of the grounding knife switch.

[0062] According to the above embodiment, this embodiment provides a specific solution, the switch fault prevention circuit further includes:

[0063] A reversing indication circuit is connected between the positive pole and the negative pole.

[0064] The reversing indication circuit is a circuit that is reflected when the motor M receives a reversing instruction. It is convenient to verify whether the instruction is accurately transmitted when operating the power system switch, and is used to check whether the contacts of the reversing relay K2 are in the normally open state when the separation and closing control circuit is energized.

[0065] According to the above embodiment, this embodiment provides a specific solution, the reversing indication circuit includes: a reversing indication circuit indicator light L2 and a second contact K1-2 of a forward and reverse relay;

[0066] A first end of the second contact K1-2 of the reversing relay is connected to the positive electrode;

[0067] The second end of the second contact K1-2 of the reversing relay is connected to the first end of the indicator light L2 of the reversing indicating circuit;

[0068] The second end of the indicator light L2 of the reverse indication circuit is connected to the cathode.

[0069] When the switch button SW is manually pressed, the coil BH of the single-pole double-throw relay is energized, the first contact BH-1 of the single-pole double-throw relay and the second contact BH-2 of the single-pole double-throw relay are closed, and the power is sent to the separation and closing control circuit. At this time, if the forward and reverse relay control circuit where the coil of the reversing relay K2 is located is not operated, the indicator light L2 of the reversing indication circuit is not lit. When the coil of the reversing relay K2 is energized in the forward and reverse relay control circuit, the second contact K1-2 of the reversing relay is closed, and the indicator light L2 of the reversing indication circuit is lit. This is the working state of the reversing indication circuit under normal working conditions. When the reversing relay K2 is in the energized state, the contact is damaged, stuck, or the node is adhered, and the contact of the reversing relay cannot be disconnected in time. At this time, there is no instruction for the power system switch to open, the switch button SW is disconnected, the coil BH of the single-pole double-throw relay is not energized, the second contact BH-2 of the single-pole double-throw relay is disconnected, and the separation and closing control circuit is powered off, which prevents contact failure or human error from causing abnormal separation and closing of the power system switch. This embodiment is mainly used in the case of abnormal opening of the isolating switch.

[0070] According to the above embodiment, this embodiment provides a specific solution, the forward relay K1 includes: an auxiliary normally open contact; the reverse relay K2 includes: an auxiliary normally open contact;

[0071] The auxiliary normally open contact closes after the coil of the forward relay K1 is energized, so that the contact of the forward relay K1 remains in the energized state.

[0072] The auxiliary normally open contact closes after the coil of the reversing relay K2 is energized, so that the contact of the reversing relay K2 remains in the energized state.

[0073] When the coil of the forward relay K1 or the coil of the reverse relay K2 in the forward and reverse relay control circuit is energized, the normally open contacts of the forward relay K1 or the reverse relay K2 remain in the closed state, and the normally closed contacts remain in the conducting state. This ensures that the power system switch is opened or closed normally when the opening and closing control circuit is energized.

[0074] According to the above embodiment, this embodiment provides a specific solution, in which the confirmation button SW is a spring reset button.

[0075] In a specific embodiment, when operating the closing or opening action, the operator needs to hold the confirmation button SW with one hand to ensure that the circuit where the confirmation button SW is located is turned on, and control the closing and opening buttons with the other hand. The operator's action of keeping the confirmation button closed can effectively avoid the accidental touch of the forward relay K1 or the reverse relay K2 in the opening and closing control circuit by this hand, and can also avoid the continuous impact of the wrong operation. At the same time, the spring reset button has a clear state, which helps the operator to accurately judge the operating state of the equipment and improve the safety and reliability of equipment operation.

[0076] According to the above embodiment, this embodiment provides a specific solution, in which the forward relay K1 and the reverse relay K2 form an interlocking structure, wherein the normally closed contact of the forward relay K1 is connected in series in the coil power supply circuit of the reverse relay K2, and the normally closed contact of the reverse relay K2 is connected in series in the coil power supply circuit of the forward relay K1.

[0077] Depend on Figure 2 It can be seen that the normal opening or closing of the power system switch is completed by the same motor M. If the forward relay K1 or the reverse relay K2 in the opening and closing control circuit is accidentally touched, causing the forward relay K1 or the reverse relay K2 to be closed at the same time, it will cause a short circuit in the opening and closing control circuit, causing a huge short-circuit current in the circuit. At the same time, the motor M winding is subjected to an excessively high current density, causing certain damage to the motor M.

[0078] Finally, this embodiment provides a power system switch device, including the above-mentioned switching control circuit with switch fault protection function.

[0079] The above is a detailed introduction to the separation and combination control circuit with switch fault protection and malfunction protection and the power system switchgear provided by the present application. The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referenced to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

[0080] It should also be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

Claims

1. A separation and combination control circuit with switch fault prevention and malfunction prevention, comprising a separation and combination control circuit, characterized in that: It also includes a switch fault prevention circuit, which includes a single-pole double-throw relay and a switch button; The device comprises a coil, a first contact and a second contact; The first end of the coil is connected in series with the first contact of the forward relay and the first contact of the reverse relay in sequence and then connected to the positive electrode; The first end of the coil is connected in series with the first contact and then connected to the positive electrode; The second end of the coil is connected to the first end of the switch button, and the second end of the switch button is connected to the negative electrode; The first end of the second contact is connected to the positive electrode, and the second end of the second contact is connected to the positive input end of the separation and combination control circuit.

2. The on-off control circuit with switch fault prevention function according to claim 1, characterized in that: The switch fault prevention circuit also includes: A forward rotation indicating circuit is connected between the positive electrode and the negative electrode.

3. The on-off control circuit with switch fault prevention function according to claim 1, characterized in that: The forward rotation indication circuit comprises: a forward rotation indication circuit indicator light and a second contact of a forward rotation relay; The first end of the second contact of the forward relay is connected to the positive electrode; The second end of the second contact of the forward relay is connected to the first end of the indicator light of the forward indication circuit; The second end of the indicator light of the forward rotation indicating circuit is connected to the negative electrode.

4. The on-off control circuit with switch fault prevention function according to claim 1, characterized in that: The switch fault prevention circuit also includes: A reversal indicating circuit is connected between the positive electrode and the negative electrode.

5. The on-off control circuit with switch fault prevention function according to claim 1, characterized in that: The reverse indication circuit comprises: a reverse indication circuit indicator light and a second contact of a forward and reverse relay; The first end of the second contact of the reversing relay is connected to the positive electrode; The second end of the second contact of the reversing relay is connected to the first end of the indicator light of the reversing indication circuit; The second end of the indicator light of the reversal indication circuit is connected to the negative electrode.

6. The on-off control circuit with switch fault prevention function according to any one of claims 1 to 5, characterized in that: The forward relay comprises: an auxiliary normally open contact; The auxiliary normally open contact is closed after the coil of the forward relay is energized, so that the contact of the forward relay is maintained in an energized state.

7. The on-off control circuit with switch fault prevention function according to any one of claims 1 to 5, characterized in that: The reversing relay comprises: an auxiliary normally open contact; The auxiliary normally open contact is closed after the coil of the reversing relay is energized, so that the contact of the reversing relay is maintained in an energized state.

8. The on-off control circuit with switch fault prevention function according to any one of claims 1 to 5, characterized in that: include: The forward relay and the reverse relay form an interlocking structure, wherein the normally closed contact of the forward relay is connected in series in the coil power supply circuit of the reverse relay, and the normally closed contact of the reverse relay is connected in series in the coil power supply circuit of the forward relay.

9. The on-off control circuit with switch fault prevention function according to claim 1, characterized in that: The confirmation button is a spring reset button.

10. A power system switchgear, characterized in that: The invention comprises a switching control circuit with switch fault prevention and malfunction prevention as described in any one of claims 1 to 9.

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