A power supply control circuit for a coal mill oil station

Abstract

A coal mill oil station power supply control circuit is composed of a first switching circuit composed of a first main power supply control circuit and a first standby power supply control circuit, a second switching circuit composed of a second main power supply control circuit and a second standby power supply control circuit, the first main power supply control circuit is electrically connected with a boiler safety MCCA section, the first standby power supply control circuit is electrically connected with a boiler safety MCC B section to supply power for a bus A end, the second main power supply control circuit is electrically connected with the boiler safety MCC B section, and the second standby power supply control circuit is electrically connected with the boiler safety MCC A section to supply power for a bus B end. The coal mill oil station is realized to be supplied with power in groups, when one group of power supply circuits fails or the standby power supply control circuit is switched, another switching circuit can normally supply power for another group of coal mill oil stations, so that the coal mill can normally operate, the unit is prevented from being tripped and tripped due to insufficient power supply of the coal mill oil station, and the stability of unit operation is improved.

Description

Technical Field

[0001] This invention belongs to the field of coal mill power supply technology, and specifically relates to a power control circuit for a coal mill oil station. Background Technology

[0002] The power supply for the A, B, and F pulverizer motors in the power plant furnace is drawn from the 10kV A section, while the power supply for the C, D, and E pulverizer motors is drawn from the 10kV B section. The power supply for the boiler safety motor control center MCC A section is drawn from the 10kV A section, and the power supply for the boiler safety motor control center MCC B section is drawn from the 10kV B section. The control power supply 1 for the 6 pulverizer oil station control cabinets is drawn from the boiler safety motor control center MCC A section, and the control power supply 2 is drawn from the boiler safety motor control center MCC B section. During normal operation, the oil station control cabinet control power supply 1 is the main power supply, and the oil station control cabinet control power supply 2 is the backup power supply.

[0003] When the boiler safety MCC A section experiences a power outage, all six coal mill oil station control cabinets lose power (control power supply 1). Although control power supply 2 successfully switches over, it experiences a brief power outage. This causes all six coal mill oil station control cabinets to trip, resulting in the tripping of all six coal mills. Ultimately, this will lead to unit disconnection and unplanned shutdown. This power switching method reduces the unit's operational stability. Summary of the Invention

[0004] In view of the above problems, the present invention proposes a power control circuit for a coal mill oil station, which can solve the problem that a power supply failure in a coal mill oil station causes multiple coal mill oil stations to trip, ultimately leading to the disconnection of the unit and unplanned shutdown.

[0005] This invention provides a power control circuit for a coal mill oil station, comprising:

[0006] The busbar and at least two sets of switching circuits, wherein the switching circuits include at least one main power control circuit and one backup power control circuit;

[0007] The switching circuit is electrically connected to the bus; the main power supply control circuit is electrically connected to the bus, and the backup power supply control circuit is electrically connected to the bus.

[0008] At least one set of coal mill oil station control cabinets is connected to the A end of the busbar, and at least one set of coal mill oil station control cabinets is connected to the B end of the busbar.

[0009] Furthermore, the switching circuit includes:

[0010] A first switching circuit and a second switching circuit; wherein, the first switching circuit includes a first main power control circuit and a first backup power control circuit, and the second switching circuit includes a second main power control circuit and a second backup power control circuit.

[0011] The first switching circuit and the second switching circuit are switching circuits with the same structure and symmetrical connection.

[0012] Furthermore, the first switching circuit and the second switching circuit are respectively electrically connected to the busbar;

[0013] Specifically, the first main power supply control circuit is electrically connected to bus A, and the first backup power supply control circuit is electrically connected to bus A; the second main power supply control circuit is electrically connected to bus B, and the second backup power supply control circuit is electrically connected to bus B.

[0014] Furthermore, the main power supply control circuit includes:

[0015] The first main circuit is connected to the main contacts of the first circuit breaker MK1 and the first contactor 1KM. The first main circuit is connected to the boiler safety MCC section A, and the first backup circuit is connected to the boiler safety MCC section B.

[0016] Furthermore, the main power supply control circuit also includes:

[0017] The first control circuit includes: a third contactor 3KM and a first fuse 1FU.

[0018] Wherein, the first end of the first fuse 1FU is connected to phase C1 of the first main circuit, the second end of the first fuse 1FU is electrically connected to the first end of the coil of the third contactor 3KM, the second end of the coil of the third contactor 3KM is electrically connected to the second end of the second fuse 2FU, and the first end of the second fuse 2FU is connected to phase A1 of the first main circuit.

[0019] Furthermore, the first control circuit also includes:

[0020] Third fuse 3FU, fourth fuse 4FU;

[0021] The first end of the third fuse 3FU is connected to phase C1 of the first main circuit, the second end of the third fuse 3FU is electrically connected to the first end of the normally closed contact of the second contactor 2KM, and the second end of the normally closed contact of the second contactor 2KM is electrically connected to the first end of the coil of the first contactor 1KM.

[0022] The second end of the coil of the first contactor 1KM is electrically connected to the first end of the normally open contact of the third contactor 3KM. The second end of the normally open contact of the third contactor 3KM is electrically connected to the second end of the fourth fuse 4FU. The first end of the fourth fuse 4FU is connected to phase B1 of the first main circuit.

[0023] Furthermore, the backup power control circuit includes:

[0024] The second main circuit is connected to the main contacts of the second circuit breaker MK2 and the second contactor 2KM. The second main circuit is connected to the boiler safety MCC B section.

[0025] Furthermore, the backup power control circuit also includes:

[0026] A second control circuit, the second control circuit comprising:

[0027] The fifth fuse 5FU and the sixth fuse 6FU are provided. The first end of the fifth fuse 5FU is connected to phase A2 of the second main circuit, and the second end of the fifth fuse 5FU is electrically connected to the first end of the normally closed contact of the first contactor 1KM. The second end of the normally closed contact of the first contactor 1KM is electrically connected to the first end of the coil of the second contactor 2KM.

[0028] The second end of the coil of the second contactor 2KM is electrically connected to the second end of the normally closed contact of the third contactor 3KM; the first end of the normally closed contact of the third contactor 3KM is electrically connected to the second end of the sixth fuse 6FU, and the first end of the sixth fuse 6FU is connected to phase C2 of the second main circuit.

[0029] Furthermore, the first switching circuit is connected to the A end of the busbar, and the A end of the busbar is connected to the control cabinet of the first group of coal mill oil stations. The main power control circuit in the first switching circuit is connected to the A end of the busbar, and the control cabinet of the first group of coal mill oil stations includes at least two or more coal mill oil stations.

[0030] Furthermore, the second switching circuit is connected to bus B, which is connected to the second set of coal mill oil station control cabinets. The main power control circuit in the second switching circuit is connected to bus B, and the second set of coal mill oil station control cabinets includes at least two or more coal mill oil stations.

[0031] The beneficial effects of this invention are:

[0032] Based on the above technical solution, the present invention sets up a first switching circuit composed of a first main power supply control circuit and a first backup power supply control circuit, and a second switching circuit composed of a second main power supply control circuit and a second backup power supply control circuit. The first main power supply control circuit is electrically connected to the boiler safety MCC A section, and the first backup power supply control circuit is electrically connected to the boiler safety MCC B section to supply power to the bus A end. The second main power supply control circuit is electrically connected to the boiler safety MCC B section, and the second backup power supply control circuit is electrically connected to the boiler safety MCC A section to supply power to the bus B end. Thus, the above technical solution realizes grouped power supply for the coal mill oil station, which can ensure that when one group of power supply circuits fails, or when switching the backup power supply control circuit, the other switching circuit can normally supply power to the other group of coal mill oil stations, so that the coal mill can operate normally and prevent the entire unit from tripping due to insufficient power supply to the coal mill oil station, thus improving the stability of the unit operation.

[0033] The switching circuit is electrically connected to the bus; the main power supply control circuit is electrically connected to the bus, and the backup power supply control circuit is electrically connected to the bus.

[0034] At least one set of coal mill oil station control cabinets is connected to the A end of the busbar, and at least one set of coal mill oil station control cabinets is connected to the B end of the busbar.

[0035] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 The main schematic diagram of the power control circuit for the coal mill oil station of the present invention is shown.

[0038] Figure 2 A schematic diagram of the power control circuit for the coal mill oil station of the present invention is shown;

[0039] Figure 3 The electrical control diagram of the first switching circuit of the coal mill oil station power control circuit of the present invention is shown;

[0040] Figure 4 The electrical control diagram of the second switching circuit of the coal mill oil station power control circuit of the present invention is shown. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0042] It should be noted that the terms "first," "second," etc., used in this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," "longitudinal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings.

[0043] This invention primarily addresses the problem that during power plant operation, a power outage or malfunction in the coal mill oil station can cause a short-term power loss, leading to the coal mill oil station tripping and failing to operate normally. This in turn prevents the normal supply of coal for power generation, resulting in the unit being disconnected and affecting production.

[0044] This invention provides a power control circuit for a coal mill oil station, see below. Figure 1 ,include:

[0045] The busbar and at least two sets of switching circuits 101, wherein the switching circuit 101 includes at least one main power control circuit 102 and one backup power control circuit 103;

[0046] The switching circuit 101 is electrically connected to the bus; the main power control circuit 102 is electrically connected to the bus; and the backup power control circuit 103 is electrically connected to the bus.

[0047] At least one set of coal mill oil station control cabinets is connected to the A end of the busbar, and at least one set of coal mill oil station control cabinets is connected to the B end of the busbar.

[0048] It should be noted that the power supply for the existing coal mill oil stations in the power plant is directly supplied to the control cabinets of six coal mill oil stations (A, B, C, D, E, and F) through the main power control circuit 102. When the main power control circuit 102 fails to supply power normally, it is necessary to switch the six coal mill oil stations (A, B, C, D, E, and F) to the backup power control circuit 103 for power supply. However, there will be a short-term power outage during the switch from the main power control circuit 102 to the backup power control circuit 103, which cannot guarantee the normal operation of the units.

[0049] Specifically, see Figure 2 This invention employs at least two sets of switching circuits, each supplying power to a different portion of the coal mill oil station control cabinets. For example, switching circuit A supplies power to control cabinets a, b, and c; switching circuit B supplies power to control cabinets d, e, and f; and switching circuit C supplies power to control cabinets g, h, and i. When any one or any two of the three switching circuits (A, B, and C) experience a power supply failure—such as a failure in A, B, and C, or failures in A and B, B and C, or A and C—at least one switching circuit will still provide normal power, ensuring the coal mill oil station can operate normally, guaranteeing uninterrupted unit operation and normal running.

[0050] Specifically, the switching circuit includes:

[0051] A first switching circuit 201 and a second switching circuit 301; wherein, the first switching circuit 201 includes a first main power control circuit 202 and a first backup power control circuit 203, and the second switching circuit 301 includes a second main power control circuit 302 and a first backup power control circuit 303.

[0052] The first switching circuit 201 and the second switching circuit 301 are switching circuits with the same structure and symmetrical connection.

[0053] In some optional embodiments, the first switching circuit 201 and the second switching circuit 301 are electrically connected to the busbar, respectively.

[0054] Specifically, the first main power control circuit 202 is electrically connected to the A end of the busbar, and the first backup power control circuit 203 is electrically connected to the A end of the busbar; the second main power control circuit 302 is electrically connected to the B end of the busbar, and the first backup power control circuit 303 is electrically connected to the B end of the busbar.

[0055] The switching circuits involved in this invention include, but are not limited to, the first switching circuit 201 and the second switching circuit 301. When the installed capacity of the unit is large, a third switching circuit, a fourth switching circuit, or even more switching circuits can be set to supply power to the coal mill oil stations of different groups, ensuring that the coal mills under large-capacity units can supply coal normally.

[0056] The present invention takes the first switching circuit 201 and the second switching circuit 301 as an example of supplying power to the control cabinets of six coal mill oil stations, and provides a specific illustrative description.

[0057] In the first switching circuit 201, section A of the boiler safety MCC is connected. The boiler safety MCC is the power output terminal of the power plant, which can be considered as an equivalent power source. The busbar is the power supply terminal of the coal mill oil station. Through this invention, the power generated by the boiler safety MCC is distributed to the busbar. The coal mill oil station connects to the busbar to obtain power. The busbar is divided into busbar A and busbar B. If busbar A and busbar B cannot supply power normally, the capacity can be expanded to busbar C or even more by setting up a switching circuit. In the second switching circuit 301, section B of the boiler safety MCC is connected. The first switching circuit 201 is connected to busbar A, where busbar A is a three-phase four-wire system. Specifically, the first main circuit of the first main power control circuit 202 in the first switching circuit 201 is connected to busbar A, and the first main circuit is a three-phase four-wire circuit. The second main circuit of the first backup power control circuit 203 is connected to busbar A, and the second main circuit is a three-phase four-wire circuit. The operation of the second switching circuit 301 is the same as that of the first switching circuit 201, and will not be described again here.

[0058] During normal operation, the first main power control circuit 202 supplies power from the boiler safety MCC A section to the bus A terminal, and the second main power control circuit 302 supplies power from the boiler safety MCC B section to the bus B terminal. When the first main power control circuit 202 malfunctions, the boiler safety MCC A section cannot supply power normally, but the boiler safety MCC B section can supply power normally. At this time, the first main power control circuit 202 in the first switching circuit 201 can switch to the first backup power control circuit 203 to supply power to the bus A terminal. At the same time, the second main power control circuit 302 can supply power to the bus B terminal to ensure the normal operation of the coal mill oil station, so that the coal mill oil station can work without interruption.

[0059] When the second main power control circuit 302 fails to supply power to the B end of the bus, the boiler safety MCCB section cannot be powered normally, but the boiler safety MCC A section can be powered normally. At this time, the second main power control circuit 302 in the second switching circuit 301 can switch to the first backup power control circuit 303 to supply power to the B end of the bus. At the same time, when there is a fault, the first main power control circuit 202 can supply power to the A end of the bus to ensure the normal operation of the coal mill oil station, so that the coal mill oil station can work without interruption.

[0060] This invention mainly uses the electrical control schematic diagram to realize the switching of power supply for the coal mill oil station. The circuit components and electrical control schematic diagram in this invention will be described in detail below.

[0061] In some alternative embodiments, see Figure 3 The main power supply control circuit includes:

[0062] The first main circuit is connected to the main contacts of the first circuit breaker MK1 and the first contactor 1KM. The first main circuit is connected to the boiler safety MCC section A, and the first backup circuit is connected to the boiler safety MCC section B.

[0063] Specifically, the main power supply control circuit also includes:

[0064] The first control circuit includes: a third contactor 3KM and a first fuse 1FU.

[0065] Wherein, the first end of the first fuse 1FU is connected to phase C1 of the first main circuit, the second end of the first fuse 1FU is electrically connected to the first end of the coil of the third contactor 3KM, the second end of the coil of the third contactor 3KM is electrically connected to the second end of the second fuse 2FU, and the first end of the second fuse 2FU is connected to phase A1 of the first main circuit.

[0066] Specifically, the first control circuit further includes:

[0067] Third fuse 3FU, fourth fuse 4FU;

[0068] The first end of the third fuse 3FU is connected to phase C1 of the first main circuit, the second end of the third fuse 3FU is electrically connected to the first end of the normally closed contact of the second contactor 2KM, and the second end of the normally closed contact of the second contactor 2KM is electrically connected to the first end of the coil of the first contactor 1KM.

[0069] The second end of the coil of the first contactor 1KM is electrically connected to the first end of the normally open contact of the third contactor 3KM. The second end of the normally open contact of the third contactor 3KM is electrically connected to the second end of the fourth fuse 4FU. The first end of the fourth fuse 4FU is connected to phase B1 of the first main circuit.

[0070] In some optional embodiments, the backup power control circuit includes:

[0071] The second main circuit is connected to the main contacts of the second circuit breaker MK2 and the main contacts of the second contactor 2KM. The second main circuit is connected to the boiler safety MCC B section.

[0072] Specifically, the backup power control circuit further includes:

[0073] A second control circuit, the second control circuit comprising:

[0074] The fifth fuse 5FU and the sixth fuse FU, the first end of the fifth fuse 5FU is connected to phase A2 of the second main circuit, the second end of the fifth fuse 5FU is electrically connected to the first end of the normally closed contact of the first contactor 1KM; the second end of the normally closed contact of the first contactor 1KM is electrically connected to the first end of the coil of the second contactor 2KM.

[0075] The second end of the coil of the second contactor 2KM is electrically connected to the second end of the normally closed contact of the third contactor 3KM; the first end of the normally closed contact of the third contactor 3KM is electrically connected to the second end of the sixth fuse 6FU, and the first end of the sixth fuse 6FU is connected to phase C2 of the second main circuit.

[0076] It should be noted that contactors are low-voltage electrical appliances. To ensure normal operation when connected to the main circuit, a fuse is usually connected to the contactor to protect the appliance. The working principle of the specific device is explained in detail below.

[0077] Because the coil of the third contactor 3KM is energized, the normally open contact of the third contactor 3KM closes and the normally open contact opens. When the main contact of the first circuit breaker MK1 is closed, the first main circuit of the first main power control circuit 202 is connected, and the boiler safety MCC A section is connected to the first main circuit of A1, B1, and C1. At this time, because the coil of the first contactor 1KM is energized, the normally closed contact of the first contactor 1KM opens and the normally open contact of the first contactor 1KM closes. The first main power control circuit 202 connects the power supply of the boiler safety MCC A section to the A end of the bus.

[0078] Simultaneously, the coil of the third contactor 3KM is energized, and the normally closed contact of the third contactor 3KM opens. In the first backup power control circuit 203, the coil of the second contactor 2KM cannot be energized, and the normally open contact of the second contactor 2KM on the second main circuit cannot close, causing the first backup power control circuit 203 to fail to operate. When the first main circuit in the first main power control circuit 202 fails to operate, the normally open contact of the second relay MK2 in the first backup power control circuit 203 closes. Due to the failure of the first main circuit, the coils of the first contactor 1KM and the third contactor 3KM are de-energized, causing the normally closed contacts of the first contactor 1KM and the third contactor 3KM to close. The coil of the second contactor 2KM is energized, and the normally open contact of the second contactor 2KM closes. The boiler safety MCC B section is connected to the second main circuit of A2, B2, and C2 to supply power to the B end of the bus.

[0079] In some optional embodiments, the first switching circuit 201 is connected to the A end of the bus, and the A end of the bus is connected to the control cabinet of the first group of coal mill oil stations. The main power control circuit in the first switching circuit 201 is connected to the A end of the bus, and the control cabinet of the first group of coal mill oil stations includes at least two or more coal mill oil stations.

[0080] In some optional embodiments, the second switching circuit 301 is connected to the B end of the bus, and the B end of the bus is connected to the control cabinet of the second set of coal mill oil stations. The main power control circuit in the second switching circuit 301 is connected to the B end of the bus, and the control cabinet of the second set of coal mill oil stations includes at least two or more coal mill oil stations.

[0081] It should be noted that in this invention, the first set of coal mill oil station control cabinets includes coal mill oil stations A, B, and F, and the second set of coal mill oil station control cabinets includes coal mill oil stations C, D, and E. The six coal mill oil stations are divided into two groups of three, each powered separately. If one group fails, the other group can continue to operate normally. When the circuit supplying power to the faulty group switches to the backup circuit, the two groups are still powered separately, ensuring the uninterrupted normal operation of the coal mill oil stations.

[0082] The second switching circuit 301 involved in this invention, see [link to relevant documentation]. Figure 4 Its electrical structure is the same as that of the first switching circuit 201. Its working principle can be understood by referring to the first switching circuit 201, so it will not be repeated here. The connection relationship of the second switching circuit 301 will be explained in detail below.

[0083] In the second switching circuit 301, the second main power control circuit 302 is connected to the boiler safety MCC B section and supplies power to the bus B end through the boiler safety MCC B section. The first backup power control circuit 303 is connected to the boiler safety MCC A section.

[0084] It should be noted that in the first switching circuit 201 of the present invention, A1, B1, and C1 of the first main power control circuit 202 are connected to the boiler safety MCC section A. The first main power control circuit 202 supplies power to the A end of the busbar, and the A end of the busbar is connected to the coal mill oil stations A, B, and F. In the first backup power control circuit 203, A2, B2, and C2 are connected to the boiler safety MCC section B. The first backup power supply serves as the backup power supply in the first switching circuit 201. The first backup power supply is electrically connected to the A end of the busbar. When the first main power control circuit 202 fails, the circuit switches to the first backup power control circuit 203, which supplies power to the coal mill oil stations A, B, and F through the boiler safety MCC section B.

[0085] In the second switching circuit 301, A2, B2, and C2 of the second main power control circuit 302 are connected to the boiler safety MCC section B. The second main power control circuit 302 supplies power to the B end of the busbar, which is connected to the coal mill oil stations C, D, and E. In the first backup power control circuit 303, A1, B1, and C1 are connected to the boiler safety MCC section A. The second backup power supply serves as the backup power supply in the second switching circuit 301. The second backup power supply is electrically connected to the A end of the busbar. When the second main power control circuit 302 fails, it switches to the first backup power control circuit 303, which supplies power to the coal mill oil stations C, D, and E through the boiler safety MCC section A.

[0086] Based on the above technical solution, the present invention sets up a first switching circuit 201 composed of a first main power control circuit 202 and a first backup power control circuit 203, and a second switching circuit 301 composed of a second main power control circuit 302 and a first backup power control circuit 303. The first main power control circuit 202 is electrically connected to the boiler safety MCC A section, and the first backup power control circuit 203 is electrically connected to the boiler safety MCC B section to supply power to the A end of the bus. The second main power control circuit 302 is electrically connected to the boiler safety MCC B section, and the first backup power control circuit 303 is electrically connected to the boiler safety MCC A section to supply power to the B end of the bus. Thus, the above technical solution realizes grouped power supply for the coal mill oil station, which can ensure that when one group of power supply circuits fails, or when switching the backup power control circuit, the other switching circuit can normally supply power to the other group of coal mill oil stations, so that the coal mill can operate normally and prevent the entire unit from tripping due to insufficient power supply to the coal mill oil station, thus improving the stability of the unit operation.

[0087] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A power control circuit for a coal mill oil station, characterized in that, include: The busbar and at least two sets of switching circuits, wherein the switching circuits include at least one main power control circuit and one backup power control circuit; The main power supply control circuit includes: a first main circuit, wherein the main contacts of the first circuit breaker MK1 are electrically connected to the main contacts of the first contactor 1KM, the first main circuit is connected to boiler safety MCC segment A, and the first backup circuit is connected to boiler safety MCC segment B; the backup power supply control circuit includes: a second main circuit, wherein the main contacts of the second circuit breaker MK2 are electrically connected to the main contacts of the second contactor 2KM, the second main circuit is connected to boiler safety MCC segment B, and the second backup circuit is connected to boiler safety MCC segment A; The switching circuit is electrically connected to the bus; the main power supply control circuit is electrically connected to the bus, and the backup power supply control circuit is electrically connected to the bus. At least one set of coal mill oil station control cabinets is connected to end A of the busbar, and at least one set of coal mill oil station control cabinets is connected to end B of the busbar; wherein: The switching circuit includes a first switching circuit and a second switching circuit; the first switching circuit includes a first main power control circuit and a first backup power control circuit, and the second switching circuit includes a second main power control circuit and a second backup power control circuit; the first switching circuit and the second switching circuit are switching circuits with the same structure and symmetrical connection. The first switching circuit and the second switching circuit are electrically connected to the busbar respectively; including the first main power control circuit electrically connected to the A end of the busbar, the first backup power control circuit electrically connected to the A end of the busbar; the second main power control circuit electrically connected to the B end of the busbar, and the second backup power control circuit electrically connected to the B end of the busbar.

2. The control circuit according to claim 1, characterized in that, The main power supply control circuit also includes: The first control circuit includes: a third contactor 3KM and a first fuse 1FU. Wherein, the first end of the first fuse 1FU is connected to phase C1 of the first main circuit, the second end of the first fuse 1FU is electrically connected to the first end of the coil of the third contactor 3KM, the second end of the coil of the third contactor 3KM is electrically connected to the second end of the second fuse 2FU, and the first end of the second fuse 2FU is connected to phase A1 of the first main circuit.

3. The control circuit according to claim 2, characterized in that, The first control circuit further includes: Third fuse 3FU, fourth fuse 4FU; The first end of the third fuse 3FU is connected to phase C1 of the first main circuit, the second end of the third fuse 3FU is electrically connected to the first end of the normally closed contact of the second contactor 2KM, and the second end of the normally closed contact of the second contactor 2KM is electrically connected to the first end of the coil of the first contactor 1KM. The second end of the coil of the first contactor 1KM is electrically connected to the first end of the normally open contact of the third contactor 3KM. The second end of the normally open contact of the third contactor 3KM is electrically connected to the second end of the fourth fuse 4FU. The first end of the fourth fuse 4FU is connected to phase B1 of the first main circuit.

4. The control circuit according to claim 1, characterized in that, The backup power control circuit also includes: A second control circuit, the second control circuit comprising: The fifth fuse 5FU and the sixth fuse 6FU are provided. The first end of the fifth fuse 5FU is connected to phase A2 of the second main circuit, and the second end of the fifth fuse 5FU is electrically connected to the first end of the normally closed contact of the first contactor 1KM. The second end of the normally closed contact of the first contactor 1KM is electrically connected to the first end of the coil of the second contactor 2KM. The second end of the coil of the second contactor 2KM is electrically connected to the second end of the normally closed contact of the third contactor 3KM; the first end of the normally closed contact of the third contactor 3KM is electrically connected to the second end of the sixth fuse 6FU, and the first end of the sixth fuse 6FU is connected to phase C2 of the second main circuit.

5. The control circuit according to claim 1, characterized in that, The first switching circuit is connected to the A end of the busbar, and the A end of the busbar is connected to the control cabinet of the first group of coal mill oil stations. The main power control circuit in the first switching circuit is connected to the A end of the busbar, and the control cabinet of the first group of coal mill oil stations includes at least two or more coal mill oil stations.

6. The control circuit according to claim 1, characterized in that, The second switching circuit is connected to the B end of the busbar, and the B end of the busbar is connected to the control cabinet of the second set of coal mill oil stations. The main power control circuit in the second switching circuit is connected to the B end of the busbar, and the control cabinet of the second set of coal mill oil stations includes at least two or more coal mill oil stations.

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