Power station bus voltage switching device

Abstract

The invention discloses a power station bus voltage switching device, and relates to the technical field of power station equipment.The switching device comprises a first switch and a second switch, the input end and the output end of the first switch are connected with the input end of a first bus and the input end of a load respectively, and the output end of the second switch is connected with the output end of a second bus; the input end and the output end of the second switch are respectively connected with the second bus and the input end of the load; a first switch control circuit and a second switch control circuit, the first switch control circuit is connected with and controls the first switch, and the second switch control circuit is connected with and controls the second switch; and the locking circuit is respectively connected with the first switch control circuit and the second switch control circuit. When the first switch control circuit and the second switch control circuit receive starting signals, the first switch control circuit controls the first switch to be closed, and the locking circuit forcibly controls the second switch to be opened through the second switch control circuit, so that mutual influence between different power grids is avoided.

Description

Technical Field

[0001] This invention relates to the field of power plant equipment technology, and in particular to a power plant bus voltage switching device. Background Technology

[0002] In a double-busbar power system, each busbar segment is equipped with a voltage transformer. When one busbar voltage transformer is taken out of service for maintenance or other reasons, the secondary voltage of the taken-out busbar voltage transformer needs to be replaced by the voltage of another busbar segment to ensure voltage correspondence between the primary and secondary systems. However, for hydropower stations that are connected to both domestic and international power grids, there are objective constraints such as sovereignty, affiliation, and dispatch authority. It is absolutely forbidden for any electrical connection between the relevant electrical equipment of the power station and the power grids of two different countries, and there should be a clearly visible disconnection point. Therefore, the first step in achieving rapid grid switching is to quickly switch between different voltage levels of domestic and international power grids while avoiding incorrect paralleling of secondary voltage levels. Summary of the Invention

[0003] The purpose of this invention is to provide a switching device for the bus voltage of a power station. When both the first switch control circuit and the second switch control circuit receive a start signal, the first switch control circuit controls the first switch to close, and the locking circuit forces the second switch to open through the second switch control circuit to avoid mutual interference between different power grids.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: One aspect of this invention provides a switching device for a power station bus voltage. The switching device includes: a first switch and a second switch, wherein the input and output terminals of the first switch are respectively connected to a first bus and the input terminal of a load, and the input and output terminals of the second switch are respectively connected to a second bus and the input terminal of a load; a first switch control circuit and a second switch control circuit, wherein the first switch control circuit controls the first switch, and the second switch control circuit controls the second switch; and a latching circuit, wherein the latching circuit is connected to both the first switch control circuit and the second switch control circuit. When both the first switch control circuit and the second switch control circuit receive a start signal, the first switch control circuit controls the first switch to close, the latching circuit controls the second switch control circuit to close, and the second switch to open.

[0005] In some embodiments, the switching device further includes a first startup circuit connected to the first switch control circuit, a second startup circuit connected to the second switch control circuit, and a control module. The first startup circuit and the second startup circuit have the same circuit structure. The first startup circuit includes a first NPN transistor, a first PNP transistor, a first resistor, a second resistor, and a third resistor. The collector of the first NPN transistor and the base of the first PNP transistor are connected to a power supply through the first resistor. The emitter of the first PNP transistor is connected to a power supply through the second resistor. The collector of the first PNP transistor is connected to one end of the third resistor and the base of the first NPN transistor. The emitter of the first NPN transistor is used to connect to the first switch control circuit. The other end of the third resistor is connected to the control module.

[0006] In some embodiments, the first startup circuit further includes a fifth resistor, one end of which is connected to the other end of the third resistor. The latching circuit includes a second NPN transistor, a first diode, a second diode, and a sixth resistor. The base of the second NPN transistor is connected to the cathode of the first diode, and the anode of the first diode is connected to the other end of the fifth resistor to obtain a working signal through the fifth resistor. The collector of the second NPN transistor is connected to the cathode of the second diode, and the anode of the second diode is connected to the working signal of the second startup circuit.

[0007] In some embodiments, the first startup circuit further includes a third NPN transistor, a second PNP transistor, a seventh resistor, an eighth resistor, a ninth resistor, and a tenth resistor. The emitter of the second PNP transistor is connected to a power supply through the seventh resistor. The base of the second PNP transistor is connected to the control module and one end of the eighth resistor. The other end of the eighth resistor is connected to a power supply. The collector of the second PNP transistor is connected to the other end of the third resistor and the collector of the third NPN transistor. The base of the third NPN transistor is connected to the control module and one end of the tenth resistor. The emitter of the third NPN transistor is connected to one end of the ninth resistor. The other ends of the ninth resistor and the other end of the tenth resistor are grounded.

[0008] In some embodiments, the switching device further includes a first shutdown circuit connected to the first switch control circuit and a second shutdown circuit connected to the second switch control circuit. The first shutdown circuit and the second shutdown circuit have the same circuit structure. The first shutdown circuit includes a fourth NPN transistor, a fifth NPN transistor, a third PNP transistor, a fourth PNP transistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fifteenth resistor, and a sixteenth resistor. The collector of the fourth NPN transistor and the base of the third PNP transistor are connected to a power supply through the eleventh resistor, and the emitter of the third PNP transistor is connected to a power supply through the eleventh resistor. The 12th resistor is connected to the power supply. The collector of the third PNP transistor is connected to the base of the fourth NPN transistor and one end of the 13th resistor. The emitter of the fourth NPN transistor is used to connect to the first switch control circuit. The other end of the 13th resistor is connected to the emitters of the fifth NPN transistor and the fourth PNP transistor. The collector of the fifth NPN transistor is connected to the power supply through the 15th resistor. The base of the fifth NPN transistor is connected to the control module. The collector of the fourth PNP transistor is grounded through the 16th resistor. The base of the fourth PNP transistor is connected to the control module.

[0009] In some embodiments, the first switch control circuit and the second switch control circuit have the same circuit structure. The first switch control circuit includes a first start switch, a first freewheeling diode, a first turn-off switch, a second freewheeling diode, a fourth resistor, a fourteenth resistor, and a seventeenth resistor. The first switch, the second switch, the first start switch, and the first turn-off switch are all relays. One end of the coil of the first start switch is connected to the emitter of the first NPN transistor and the cathode of the first freewheeling diode. The other end of the coil of the first start switch is connected to the anode of the first freewheeling diode and one end of the fourth resistor. The other end of the fourth resistor is grounded. One end of the coil of the first turn-off switch is connected to the emitter of the fourth NPN transistor and the cathode of the second freewheeling diode. The other end of the coil of the first turn-off switch is connected to the anode of the second freewheeling diode and one end of the fourteenth resistor. The other end of the fourteenth resistor is grounded. One end of the contactor of the first start switch is connected to the power supply, the other end of the contactor of the first start switch is connected to one end of the coil of the first switch, the other end of the coil of the first switch is connected to one end of the contactor of the first stop switch, the other end of the contactor of the first stop switch is grounded through the seventeenth resistor, and the two ends of the contactor of the first switch are respectively connected to the first bus and the input terminal of the load.

[0010] In some embodiments, the switching device further includes a third start circuit and a third stop circuit connected to the first switch control circuit, and a fourth start circuit and a fourth stop circuit connected to the second switch control circuit. The third start circuit includes a third start switch, the third stop circuit includes a third stop switch, the contactor of the third start switch is disposed between the contactor of the first start switch and the coil terminal of the first switch, and the contactor of the third stop switch is connected in parallel with the contactor of the first stop switch.

[0011] In some embodiments, the latching circuit further includes a third diode and a fourth diode, wherein the cathode of the third diode is connected to the base of the second NPN transistor, the anode of the third diode is connected to the operating signal of the third startup circuit, the cathode of the fourth diode is connected to the collector of the second NPN transistor, and the anode of the fourth diode is connected to the operating signal of the fourth startup circuit.

[0012] In some embodiments, the switching device further includes a start-up-side reset circuit, which includes a sixth NPN transistor, a reset relay, a fifth diode, a sixth diode, a twentieth resistor, a twenty-first resistor, a twenty-second resistor, and an energy storage capacitor. One end of the coil of the reset relay is connected to the contactors of the first and third off switches, and the other end of the coil is connected to the seventeenth resistor. The anode of the fifth diode is connected to the base of the fifth NPN transistor and the control module. The anode of the sixth diode is connected to the third off circuit and the control module. The cathodes of the fifth and sixth diodes are used to transmit power to the control module. The two output shutdown signals are connected as follows: the negative terminals of the fifth and sixth diodes are connected to one end of the twenty-first resistor and the base of the sixth NPN transistor through the twentyth resistor; the collector of the sixth NPN transistor is connected to the power supply through the twenty-second resistor; the emitter of the sixth NPN transistor is connected to the positive terminal of the energy storage capacitor, one end of the first contactor of the reset relay, and one end of the second contactor of the reset relay; the other end of the twenty-first resistor and the negative terminal of the energy storage capacitor are grounded; the other end of the first contactor of the reset relay is connected to the base of the third NPN transistor in the first startup circuit; and the other end of the second contactor of the reset relay is connected to the third startup circuit.

[0013] In some embodiments, the switching device further includes a shutdown-side reset switch, one end of which is connected to the base of the fourth PNP transistor, and the other end of which is used to receive a shutdown-side reset signal.

[0014] According to an embodiment of the present invention, a power station bus voltage switching device has at least the following beneficial effects: When the first starting circuit, the second starting circuit, the third starting circuit, and the fourth starting circuit all receive a starting signal, the first starting circuit and the third starting circuit control the first switch to close through the first switch control circuit, and the second NPN transistor to conduct, pulling down the operating signals of the second starting circuit and the fourth starting circuit, forcibly controlling the second switch to open, so as to avoid mutual interference between different power grids. Both the first switch control circuit and the second switch control circuit are provided with two series-connected starting switches, reducing false closing caused by switch unreliability; both the first switch control circuit and the second switch control circuit are provided with two parallel-connected shut-off switches, reducing false tripping caused by switch unreliability. When both the first and third shut-off switches are open, the coil of the reset relay is not energized, and the two contactors of the reset relay return to their normally closed state, thus de-energizing the first and third starting circuits in the same group. This application uses a storage capacitor to output a reset signal on the starting side to de-energize the first and third starting circuits. The de-energizing action stops after the storage capacitor has discharged completely, which can prevent the first and third starting circuits from failing to start on the next startup.

[0015] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this disclosure. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic block diagram of the switching device according to an embodiment; Figure 2 This is a schematic diagram of the first startup circuit according to an embodiment; Figure 3 This is a schematic diagram of the latching circuit according to an embodiment; Figure 4 This is a schematic diagram of the first shutdown circuit according to an embodiment; Figure 5 This is a schematic diagram of the first switch control circuit according to an embodiment; Figure 6 This is a schematic diagram of the startup-side reset circuit according to an embodiment. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0020] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0021] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that the description of this disclosure will be more complete and fully convey the concept of the exemplary embodiments to those skilled in the art. The drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted.

[0022] The technical solutions of the embodiments of this application are briefly described below: According to some embodiments, such as Figure 1 As shown, this application provides a switching device for a power station bus voltage, the switching device comprising: The first switch and the second switch, the input terminal and the output terminal of the first switch KS1 are respectively connected to the first bus and the input terminal of the load; the input terminal and the output terminal of the second switch are respectively connected to the second bus and the input terminal of the load. A first switch control circuit and a second switch control circuit, wherein the first switch control circuit is connected to control the first switch KS1 and the second switch control circuit is connected to control the second switch; A locking circuit is connected to the first switch control circuit and the second switch control circuit respectively. The working principle of the above embodiment is as follows: when both the first switch control circuit and the second switch control circuit receive start signal 101 and start signal 102 respectively, the first switch control circuit controls the first switch KS1 to close, the latching circuit controls the second switch control circuit to close, the second switch opens, and power is supplied to the load from the first bus. This prevents the first bus and the second bus from being connected simultaneously, avoiding mutual interference between different power grids.

[0023] The following is in conjunction with the appendix to this instruction manual. Figures 1 to 6 The preferred embodiments of this disclosure will be further described in detail below.

[0024] According to some embodiments, such as Figure 1 As shown, the switching device also includes a first start-up circuit connected to the first switch control circuit, a second start-up circuit connected to the second switch control circuit, and a control module. The first start-up circuit and the second start-up circuit have the same circuit structure. The first start-up circuit includes a first NPN transistor QN1, a first PNP transistor QP1, a first resistor R1, a second resistor R2, and a third resistor R3, and its specific connection method is as follows. like Figure 2 As shown, the collector of the first NPN transistor QN1 and the base of the first PNP transistor QP1 are connected to the power supply through the first resistor R1. The emitter of the first PNP transistor QP1 is connected to the power supply through the second resistor R2. The collector of the first PNP transistor QP1 is connected to one end of the third resistor R3 and the base of the first NPN transistor QN1. The emitter of the first NPN transistor QN1 is used to connect to the first switch control circuit. The other end of the third resistor R3 is connected to the control module.

[0025] The working principle of the above embodiment is as follows: when it is necessary to control the first switch KS1 to close, the control module outputs a high-level start signal 101 to the base of the first NPN transistor QN1, the first NPN transistor QN1 is turned on, the first switch control circuit is powered on, the first switch KS1 is closed, the base level of the first PNP transistor QP1 is pulled low by the first NPN transistor QN1, the first PNP transistor QP1 is turned on, after the start signal 101 is turned off, the first NPN transistor QN1 and the first PNP transistor QP1 form a self-locking, continuously conduct, the first switch control circuit is continuously powered on, and the first switch KS1 is continuously closed.

[0026] When the first startup circuit needs to be restored to power-off state, the control module outputs a low-level startup-side reset signal 201 to the base of the first NPN transistor QN1. The first NPN transistor QN1 is turned off, the first switch control circuit is de-energized, the first switch KS1 is restored to open state, the base level of the first PNP transistor QP1 is pulled high by the first resistor R1, the first PNP transistor QP1 is turned off, after the startup-side reset signal 201 is turned off, the first startup circuit and the first switch control circuit are restored to power-off state, and the first switch KS1 is restored to open state.

[0027] According to some embodiments, such as Figures 2 to 3 As shown, the first startup circuit also includes a fifth resistor R5, one end of which is connected to the other end of the third resistor R3. The latching circuit includes a second NPN transistor QN2, a first diode D1, a second diode D2, and a sixth resistor R6, with the specific connection method as follows. The base of the second NPN transistor QN2 is connected to the cathode of the first diode D1, and the anode of the first diode D1 is connected to the other end of the fifth resistor R5 so as to obtain the working signal 301 through the fifth resistor R5. The collector of the second NPN transistor QN2 is connected to the cathode of the second diode D2, and the anode of the second diode D2 is connected to the working signal 302 of the second start-up circuit.

[0028] The working principle of the above embodiment is as follows: when the first startup circuit and the second startup circuit receive startup signals 101 and 102 respectively, the second NPN transistor QN2 is turned on, pulling down the operating signal 302 of the second startup circuit. The second startup circuit is forcibly turned off, the second switch is opened, and the first startup circuit controls the first switch KS1 to close through the first switch control circuit, so that power is supplied to the load from the first bus. This is to prevent the first bus and the second bus from being connected at the same time and to avoid mutual interference between different power grids.

[0029] According to some embodiments, such as Figure 2 As shown, the first startup circuit also includes a third NPN transistor QN3, a second PNP transistor QP2, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, and a tenth resistor R10, with the specific connection method as follows. The emitter of the second PNP transistor QP2 is connected to the power supply through the seventh resistor R7. The base of the second PNP transistor QP2 is connected to the control module and one end of the eighth resistor R8. The other end of the eighth resistor R8 is connected to the power supply. The collector of the second PNP transistor QP2 is connected to the other end of the third resistor R3 and the collector of the third NPN transistor QN3. The base of the third NPN transistor QN3 is connected to the control module and one end of the tenth resistor R10. The emitter of the third NPN transistor QN3 is connected to one end of the ninth resistor R9. The other ends of the ninth resistor R9 and the other ends of the tenth resistor R10 are grounded.

[0030] The working principle of the above embodiment is as follows: when it is necessary to control the first switch KS1 to close, the control module outputs a low-level start signal 101 to the base of the second PNP transistor QP2, the second PNP transistor QP2 is turned on, the base of the first NPN transistor QN1 receives a high-level signal through the second PNP transistor QP2, the first NPN transistor QN1 is turned on, the first switch control circuit is powered on, the first switch KS1 is closed, the base level of the first PNP transistor QP1 is pulled low by the first NPN transistor QN1, the first PNP transistor QP1 is turned on, after the start signal 101 is turned off, the first NPN transistor QN1 and the first PNP transistor QP1 form a self-locking, continuously conducting, the first switch control circuit is continuously powered on, and the first switch KS1 is continuously closed.

[0031] When the first startup circuit needs to be restored to power-off state, the control module outputs a high-level startup-side reset signal 201 to the base of the third NPN transistor QN3. The third NPN transistor QN3 is turned on, and the base of the first NPN transistor QN1 receives a low-level signal through the third NPN transistor QN3. The first NPN transistor QN1 is turned off, the first switch control circuit is de-energized, the first switch KS1 is restored to open state, the base level of the first PNP transistor QP1 is pulled high by the first resistor R1, the first PNP transistor QP1 is turned off, after the startup-side reset signal 201 is turned off, the first startup circuit and the first switch control circuit are restored to power-off state, and the first switch KS1 is restored to open state.

[0032] According to some embodiments, such as Figure 4 As shown, the switching device also includes a first shutdown circuit connected to the first switch control circuit and a second shutdown circuit connected to the second switch control circuit. The circuit structures of the first shutdown circuit and the second shutdown circuit are the same. The first shutdown circuit includes a fourth NPN transistor QN4, a fifth NPN transistor QN5, a third PNP transistor QP3, a fourth PNP transistor QP4, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fifteenth resistor R15, and a sixteenth resistor R16. Its specific connection method is as follows. The collector of the fourth NPN transistor QN4 and the base of the third PNP transistor QP3 are connected to the power supply through the eleventh resistor R11. The emitter of the third PNP transistor QP3 is connected to the power supply through the twelfth resistor R12. The collector of the third PNP transistor QP3 is connected to the base of the fourth NPN transistor QN4 and one end of the thirteenth resistor R13. The emitter of the fourth NPN transistor QN4 is used to connect to the first switch control circuit. The other end of the thirteenth resistor R13 is connected to the emitter of the fifth NPN transistor QN5 and the emitter of the fourth PNP transistor QP4. The collector of the fifth NPN transistor QN5 is connected to the power supply through the fifteenth resistor R15. The base of the fifth NPN transistor QN5 is connected to the control module. The collector of the fourth PNP transistor QP4 is grounded through the sixteenth resistor R16. The base of the fourth PNP transistor QP4 is connected to the control module.

[0033] Furthermore, such as Figure 5 As shown, the first switch control circuit and the second switch control circuit have the same circuit structure. The first switch control circuit includes a first start switch K11, a first freewheeling diode KD1, a first turn-off switch K12, a second freewheeling diode KD2, a fourth resistor R4, a fourteenth resistor R14, and a seventeenth resistor R17. Their specific connection method is as follows: The first switch KS1, the second switch, the first start switch K11, and the first stop switch K12 are all relays. One end of the coil of the first start switch K11 is connected to the emitter of the first NPN transistor QN1 and the cathode of the first freewheeling diode KD1. The other end of the coil of the first start switch K11 is connected to the anode of the first freewheeling diode KD1 and one end of the fourth resistor R4. The other end of the fourth resistor R4 is grounded. One end of the coil of the first stop switch K12 is connected to the emitter of the fourth NPN transistor QN4 and the cathode of the second freewheeling diode KD2. The other end of the coil of the first stop switch K12 is connected to the anode of the second freewheeling diode KD2 and one end of the fourteenth resistor R14. The other end of the fourteenth resistor R14 is grounded. One end of the contactor of the first start switch K11 is connected to the power supply, and the other end of the contactor of the first start switch K11 is connected to one end of the coil of the first switch KS1. The other end of the coil of the first switch KS1 is connected to one end of the contactor of the first stop switch K12. The other end of the contactor of the first stop switch K12 is grounded through the seventeenth resistor R17. The two ends of the contactor of the first switch KS1 are respectively connected to the first bus and the input terminal of the load.

[0034] Among them, the first shut-off switch K12 is a normally closed switch.

[0035] The working principle of the above embodiments is as follows: Figures 4 to 5As shown, when it is necessary to control the first switch KS1 to be turned off, the control module outputs a high-level turn-off signal 401 to the base of the fifth NPN transistor QN5, the fifth NPN transistor QN5 is turned on, the base of the fourth NPN transistor QN4 receives a high-level signal through the fifth NPN transistor QN5, the fourth NPN transistor QN4 is turned on, the first turn-off switch K12 is turned off, the coil terminal of the first switch KS1 is not energized, the first switch KS1 is turned off, the base level of the third PNP transistor QP3 is pulled low by the fourth NPN transistor QN4, the third PNP transistor QP3 is turned on, after the turn-off signal 401 is cut off, the fourth NPN transistor QN4 and the third PNP transistor QP3 form a self-locking, continuously conduct, the first switch control circuit is continuously de-energized, and the first switch KS1 is continuously turned off.

[0036] When the first shutdown circuit needs to be restored to power-off state, the control module outputs a low-level shutdown-side reset signal 501 to the base of the fourth PNP transistor QP4. The fourth PNP transistor QP4 is turned on, and the base of the fourth NPN transistor QN4 receives a low-level signal through the fourth PNP transistor QP4. The fourth NPN transistor QN4 is turned off, the first shutdown switch K12 is reopened, the base level of the third PNP transistor QP3 is pulled high by the eleventh resistor R11, the third PNP transistor QP3 is turned off, and after the shutdown-side reset signal 501 is turned off, the first shutdown circuit is restored to power-off state.

[0037] According to some embodiments, such as Figure 1 As shown, the switching device also includes a third start circuit and a third stop circuit connected to the first switch control circuit, and a fourth start circuit and a fourth stop circuit connected to the second switch control circuit.

[0038] like Figure 5 As shown, the third start circuit includes a third start switch K31, and the third stop circuit includes a third stop switch K32. The contactor of the third start switch K31 is located between the contactor of the first start switch K11 and the coil terminal of the first switch KS1. The contactor of the third stop switch K32 is connected in parallel with the contactor of the first stop switch K12.

[0039] like Figure 5 As shown, this application sets a first start switch K11 and a third start switch K31 connected in series, which can reduce false closing caused by unreliable start switches. It also sets a first stop switch K12 and a third stop switch K32 connected in parallel, which can reduce false tripping caused by unreliable stop switches.

[0040] Furthermore, such as Figure 3 As shown, the latching circuit also includes a third diode D3 and a fourth diode D4, and their specific connection method is as follows. The cathode of the third diode D3 is connected to the base of the second NPN transistor QN2, and the anode of the third diode D3 is connected to the operating signal 303 of the third startup circuit. The cathode of the fourth diode D4 is connected to the collector of the second NPN transistor QN2, and the anode of the fourth diode D4 is connected to the operating signal 304 of the fourth startup circuit.

[0041] The working principle of the above embodiment is as follows: when the first, second, third, and fourth starting circuits receive starting signals 101, 102, 103, and 104 respectively, the second NPN transistor QN2 is turned on, pulling down the operating signals 302 and 304 of the second and fourth starting circuits, forcibly turning them off. This forces the second switch to open, and the first and third starting circuits control the first switch KS1 to close via the first switch control circuit, allowing power to be supplied to the load from the first bus. This prevents the first and second bus from being connected simultaneously, avoiding mutual interference between different power grids.

[0042] According to some embodiments, such as Figure 2 , Figure 4 , Figure 5 , Figure 6 As shown, the switching device also includes a startup-side reset circuit, which includes a sixth NPN transistor QN6, a reset relay K13, a fifth diode D5, a sixth diode D6, a twentieth resistor R20, a twenty-first resistor R21, a twenty-second resistor R22, and an energy storage capacitor C. Its specific connection method is as follows: One end of the coil of reset relay K13 is connected to the contactors of the first off switch K12 and the third off switch K32. The other end of the coil of reset relay K13 is connected to the seventeenth resistor R17. The anode of the fifth diode D5 is connected to the base of the fifth NPN transistor QN5 and the control module. The anode of the sixth diode D6 is connected to the third off circuit and the control module. The cathodes of the fifth diode D5 and the sixth diode D6 are used to transmit the two off signals 401 and 403 output by the control module, respectively. The cathodes of the fifth diode D5 and the sixth diode D6 are connected to the twenty-first resistor R2 through the twentieth resistor R20. One end of resistor 1 is connected to the base of the sixth NPN transistor QN6. The collector of the sixth NPN transistor QN6 is connected to the power supply through the twenty-second resistor R22. The emitter of the sixth NPN transistor QN6 is connected to the positive terminal of the energy storage capacitor C, one end of the first contactor K131 of the reset relay K13, and one end of the second contactor K132 of the reset relay K13. The other end of the twenty-first resistor R21 is connected to the negative terminal of the energy storage capacitor C and grounded. The other end of the first contactor K131 of the reset relay K13 is connected to the base of the third NPN transistor QN3 in the first starting circuit. The other end of the second contactor K132 of the reset relay K13 is connected to the third starting circuit.

[0043] Among them, the reset relay K13 is normally closed.

[0044] The working principle of the above embodiments is as follows: Figure 4 As shown, when the first switch KS1 needs to be turned off, the first and third shutdown circuits are sequentially energized. When the first shutdown circuit is energized, the control module outputs a high-level shutdown signal 401 to the base of the fifth NPN transistor QN5 in the first shutdown circuit. Figure 4 , Figure 6As shown, the shutdown signal 401 is also output to the base of the sixth NPN transistor QN6 through the fifth diode D5, turning on the sixth NPN transistor QN6 and charging the energy storage capacitor C. At the same time, after the base of the fifth NPN transistor QN5 receives the high-level shutdown signal 401, the first shutdown switch K12 is opened. When the third shutdown circuit is powered on, the control module outputs a high-level shutdown signal 403 to the third shutdown circuit. The shutdown signal 403 of the third shutdown circuit is output to the base of the sixth NPN transistor QN6 through the sixth diode D6, charging the energy storage capacitor C. At the same time, the third shutdown switch K32 is opened. At this time, both the first shutdown switch K12 and the third shutdown switch K32 are open, the reset relay K13 is not powered on, the reset relay K13 returns to its normally closed state, and the energy storage capacitor C outputs a high-level start-up side reset signal 201 to the first start-up circuit and the third start-up circuit, turning off the power-on state of the first start-up circuit and the third start-up circuit. This application uses the energy storage capacitor C to output a start-side reset signal 201 to shut off the power-on state of the first start-up circuit and the third start-up circuit. After the energy storage capacitor C has finished discharging, the shutdown action stops, which can prevent the first start-up circuit and the third start-up circuit that control the first switch control circuit from failing to start on the next start-up.

[0045] According to some embodiments, such as Figure 4 As shown, the switching device also includes a shutdown-side reset switch S. One end of the shutdown-side reset switch S is connected to the base of the fourth PNP transistor QP4, and the other end of the shutdown-side reset switch S is used to receive the shutdown-side reset signal 501.

[0046] Specifically, the shutdown-side reset switch S is a relay. The coil of the shutdown-side reset switch S is connected to the control module, and the other end of the shutdown-side reset switch S is grounded. When the first shutdown circuit needs to be restored to its de-energized state, the control module briefly energizes the coil of the shutdown-side reset switch S, the contactor of the shutdown-side reset switch S is energized, the base of the fourth PNP transistor QP4 receives a low-level shutdown-side reset signal 501, the fourth PNP transistor QP4 is turned on, the base of the fourth NPN transistor QN4 receives a low-level signal through the fourth PNP transistor QP4, the fourth NPN transistor QN4 is turned off, the first shutdown switch K12 is restored to its closed state, the base level of the third PNP transistor QP3 is pulled high by the eleventh resistor R11, the third PNP transistor QP3 is turned off, and after the coil of the shutdown-side reset switch S is de-energized, the first shutdown circuit is restored to its de-energized state.

[0047] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0048] Although this disclosure has been described with reference to several typical embodiments, it should be understood that the terminology used is descriptive and exemplary, and not restrictive. Because this disclosure can be embodied in many forms without departing from the spirit or substance of this application, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims. Therefore, all variations and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A switching device for a power station bus voltage, characterized in that, The switching device includes: A first switch and a second switch, wherein the input and output terminals of the first switch are respectively connected to the first bus and the input terminal of the load, and the input and output terminals of the second switch are respectively connected to the second bus and the input terminal of the load; A first switch control circuit and a second switch control circuit, wherein the first switch control circuit is connected to control the first switch and the second switch control circuit is connected to control the second switch; A locking circuit, wherein the locking circuit is respectively connected to the first switch control circuit and the second switch control circuit; When both the first switch control circuit and the second switch control circuit receive a start signal, the first switch control circuit controls the first switch to close, the locking circuit controls the second switch control circuit to close, and the second switch to open.

2. The switching device according to claim 1, characterized in that, The switching device further includes a first start-up circuit connected to the first switch control circuit, a second start-up circuit connected to the second switch control circuit, and a control module. The first start-up circuit and the second start-up circuit have the same circuit structure. The first start-up circuit includes a first NPN transistor, a first PNP transistor, a first resistor, a second resistor, and a third resistor. The collector of the first NPN transistor and the base of the first PNP transistor are connected to the power supply through the first resistor. The emitter of the first PNP transistor is connected to the power supply through the second resistor. The collector of the first PNP transistor is connected to one end of the third resistor and the base of the first NPN transistor. The emitter of the first NPN transistor is used to connect to the first switch control circuit. The other end of the third resistor is connected to the control module.

3. The switching device according to claim 2, characterized in that, The first startup circuit further includes a fifth resistor, one end of which is connected to the other end of the third resistor. The latching circuit includes a second NPN transistor, a first diode, a second diode, and a sixth resistor. The base of the second NPN transistor is connected to the cathode of the first diode, and the anode of the first diode is connected to the other end of the fifth resistor to obtain a working signal through the fifth resistor. The collector of the second NPN transistor is connected to the cathode of the second diode, and the anode of the second diode is connected to the working signal of the second startup circuit.

4. The switching device according to claim 3, characterized in that, The first startup circuit further includes a third NPN transistor, a second PNP transistor, a seventh resistor, an eighth resistor, a ninth resistor, and a tenth resistor. The emitter of the second PNP transistor is connected to the power supply through the seventh resistor. The base of the second PNP transistor is connected to the control module and one end of the eighth resistor. The other end of the eighth resistor is connected to the power supply. The collector of the second PNP transistor is connected to the other end of the third resistor and the collector of the third NPN transistor. The base of the third NPN transistor is connected to the control module and one end of the tenth resistor. The emitter of the third NPN transistor is connected to one end of the ninth resistor. The other ends of the ninth resistor and the other end of the tenth resistor are grounded.

5. The switching device according to claim 4, characterized in that, The switching device further includes a first shutdown circuit connected to the first switch control circuit and a second shutdown circuit connected to the second switch control circuit. The first shutdown circuit and the second shutdown circuit have the same circuit structure. The first shutdown circuit includes a fourth NPN transistor, a fifth NPN transistor, a third PNP transistor, a fourth PNP transistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fifteenth resistor, and a sixteenth resistor. The collector of the fourth NPN transistor and the base of the third PNP transistor are connected to the power supply through the eleventh resistor, and the emitter of the third PNP transistor is connected through the twelfth resistor. The power supply is connected. The collector of the third PNP transistor is connected to the base of the fourth NPN transistor and one end of the thirteenth resistor. The emitter of the fourth NPN transistor is used to connect to the first switch control circuit. The other end of the thirteenth resistor is connected to the emitter of the fifth NPN transistor and the emitter of the fourth PNP transistor. The collector of the fifth NPN transistor is connected to the power supply through the fifteenth resistor. The base of the fifth NPN transistor is connected to the control module. The collector of the fourth PNP transistor is grounded through the sixteenth resistor. The base of the fourth PNP transistor is connected to the control module.

6. The switching device according to claim 5, characterized in that, The first switch control circuit and the second switch control circuit have the same circuit structure. The first switch control circuit includes a first start switch, a first freewheeling diode, a first turn-off switch, a second freewheeling diode, a fourth resistor, a fourteenth resistor, and a seventeenth resistor. The first switch, the second switch, the first start switch, and the first turn-off switch are all relays. One end of the coil of the first start switch is connected to the emitter of the first NPN transistor and the cathode of the first freewheeling diode. The other end of the coil of the first start switch is connected to the anode of the first freewheeling diode and one end of the fourth resistor. The other end of the fourth resistor is grounded. One end of the coil of the first turn-off switch is connected to the emitter of the fourth NPN transistor and the cathode of the second freewheeling diode. The other end of the coil of the first turn-off switch is connected to the anode of the second freewheeling diode and one end of the fourteenth resistor. The other end of the fourteenth resistor is grounded. One end of the contactor of the first start switch is connected to the power supply, the other end of the contactor of the first start switch is connected to one end of the coil of the first switch, the other end of the coil of the first switch is connected to one end of the contactor of the first stop switch, the other end of the contactor of the first stop switch is grounded through the seventeenth resistor, and the two ends of the contactor of the first switch are respectively connected to the first bus and the input terminal of the load.

7. The switching device according to claim 6, characterized in that, The switching device further includes a third start circuit and a third stop circuit connected to the first switch control circuit, and a fourth start circuit and a fourth stop circuit connected to the second switch control circuit. The third start circuit includes a third start switch, and the third stop circuit includes a third stop switch. The contactor of the third start switch is disposed between the contactor of the first start switch and the coil terminal of the first switch. The contactor of the third stop switch is connected in parallel with the contactor of the first stop switch.

8. The switching device according to claim 7, characterized in that, The locking circuit further includes a third diode and a fourth diode. The cathode of the third diode is connected to the base of the second NPN transistor, and the anode of the third diode is connected to the operating signal of the third startup circuit. The cathode of the fourth diode is connected to the collector of the second NPN transistor, and the anode of the fourth diode is connected to the operating signal of the fourth startup circuit.

9. The switching device according to claim 6, characterized in that, The switching device further includes a start-up-side reset circuit, which comprises a sixth NPN transistor, a reset relay, a fifth diode, a sixth diode, a twentieth resistor, a twenty-first resistor, a twenty-second resistor, and an energy storage capacitor. One end of the coil of the reset relay is connected to the contactors of the first and third off switches, and the other end is connected to the seventeenth resistor. The anode of the fifth diode is connected to the base of the fifth NPN transistor and the control module. The anode of the sixth diode is connected to the third off circuit and the control module. The cathodes of the fifth and sixth diodes are used to transmit the outputs of the control module. Two shutdown signals are provided. The negative terminals of the fifth and sixth diodes are connected to one end of the twenty-first resistor and the base of the sixth NPN transistor through the twentyth resistor. The collector of the sixth NPN transistor is connected to the power supply through the twenty-second resistor. The emitter of the sixth NPN transistor is connected to the positive terminal of the energy storage capacitor, one end of the first contactor of the reset relay, and one end of the second contactor of the reset relay. The other end of the twenty-first resistor and the negative terminal of the energy storage capacitor are grounded. The other end of the first contactor of the reset relay is connected to the base of the third NPN transistor in the first startup circuit. The other end of the second contactor of the reset relay is connected to the third startup circuit.

10. The switching device according to claim 5, characterized in that, The switching device further includes a shutdown-side reset switch, one end of which is connected to the base of the fourth PNP transistor, and the other end of which is used to receive a shutdown-side reset signal.

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