High-voltage power distribution system capable of automatically switching double power supplies

Abstract

The utility model relates to a high-voltage power distribution system capable of automatically switching double power supplies, which comprises a plurality of switch cabinets, and the double power supplies comprise a main power supply and a standby power supply. When the section from the main switch to the current transmitter of the main power supply circuit breaks down, the standby power supply is automatically switched to supply power to the current transmitter; wherein when the section from the main power supply air switch upper port to the main power supply main switch of one switch cabinet has a fault, the main power supply main switch trips, and the standby power supply supplies power to the current transmitter of each switch cabinet; when the section from the lower opening of the main power supply air switch of one switch cabinet to the current transmitter breaks down, the main power supply air switch of the switch cabinet trips, the standby power supply supplies power to the current transmitter of the switch cabinet, and the main power supply still supplies power to the current transmitters of the other switch cabinets. Under the two conditions, the DCS detects that the output current of the current transmitter of the switch cabinet is a stable numerical value, so that interlocking shutdown of the switch cabinet of the system is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of dual power supply automatic switching, in particular to a high-voltage power distribution system for dual power supply automatic switching. Background Art

[0002] In the high-voltage power supply and distribution system, DCS centralized control system has been widely used in production. As a high-precision signal conversion unit, the current transmitter can convert DC current or AC current into a constant current loop standard signal for use by the on-site 10KV high-voltage motor unit controller or the DCS computer in the main control room. At present, the current transmitter is installed in the corresponding 10KV high-voltage switch cabinet secondary room and powered by the DC panel. The current data of the current transmitter is one of the main operating indicators in the DCS interlocking trip logic. Most units directly define the loss of current data as a unit trip fault. In actual operation, it was found that each high-voltage switch cabinet is equipped with an independent current transmitter DC small air switch, which can deal with problems such as short circuit at the lower end of the DC small air switch and perform tripping protection on an air switch cabinet; if the fault occurs in the section from the upper end of the DC small air switch to the DC panel main switch, the DC panel main switch will perform tripping protection; when the tripping protection occurs, it will cause the power supply of multiple current transmitters powered by the main power supply to lose power and have no output, resulting in the loss of current data involved in DCS control, thereby causing a shutdown due to non-unit faults. If the on-site operator makes a wrong judgment, it may even cause accidents such as process interlocking shutdown, posing a huge safety hazard. Utility Model Content

[0003] The utility model aims to solve the above problems, thereby providing a power supply mode that changes the power supply of the current transmitter into a dual power supply and automatically switches, and ensures the stable power supply of the current transmitter when a fault occurs in the section from the upper port of the small switch in the switch cabinet to the main switch of the DC panel.

[0004] The utility model solves the above problems and adopts the following technical solutions:

[0005] A high-voltage power distribution system with automatic dual power supply switching includes a plurality of switch cabinets, a dual power supply is provided, the dual power supply includes a main power supply and a backup power supply, and a main switch is provided on the power supply lines of the main power supply and the backup power supply respectively.

[0006] Each switch cabinet is equipped with two air switches, contactors and current transmitters. The upper ports of the two air switches are respectively connected to the lower ports of the two main switches. The lower port of the air switch connected to the main power supply through the main switch is connected to the control coil of the contactor. The lower ports of the two air switches are respectively connected to the input ends of the normally open contacts and normally closed contacts of the contactor. The output ends of the normally open contacts and normally closed contacts of the contactor are both connected to the power supply end of the current transmitter; the signal output end of the current transmitter is connected to the DCS controller.

[0007] Compared with the prior art, the utility model adopting the above technical solution has the following beneficial effects:

[0008] The current transmitters of each switch cabinet in this system adopt dual power switching power supply, and a contactor is added as a switching power supply device. When the main switch of the main power line to the current transmitter fails, the backup power supply is automatically switched to supply power to the current transmitter; when a fault occurs in the section from the upper port of the main power air switch of one switch cabinet to the main power main switch, the main power switch trips, and the backup power supply supplies power to the current transmitters of each switch cabinet; when a fault occurs in the section from the lower port of the main power air switch of one switch cabinet to the current transmitter, the main power air switch of the switch cabinet trips, and the backup power supply supplies power to the current transmitter of the switch cabinet, and the current transmitters of the remaining switch cabinets are still powered by the main power supply. In the above two situations, the DCS control system detects that the output current of the current transmitter of the switch cabinet is a stable value, thereby avoiding the interlocking and parking of the switch cabinet of the system, maximizing the reliability of the power supply of the current transmitter, reducing the operation risk to the minimum, and ensuring production safety.

[0009] As a preferred embodiment, a further technical solution of the utility model is:

[0010] Each switch cabinet is equipped with an instrument room, a trolley room and a cable room. Current transmitters, contactors and air switches are installed in the instrument room, circuit breakers are installed in the trolley room, and high-voltage busbars, current transformers and high-voltage cables are installed in the cable room. The high-voltage busbar is connected to the circuit breaker, and the circuit breaker is connected to external electrical equipment through high-voltage cables, and the high-voltage cables pass through the current transformer. The circuit breaker plays the role of switch and protection in the high-voltage line, and the current transformer converts the detected large current into a small current and transmits it to the instrument for current monitoring.

[0011] The power supply is a DC power supply powered by a DC panel, and the air switch connected to the DC panel is a small DC air switch; the backup power supply is an AC power supply powered by an AC panel, and the air switch connected to the AC panel is a small AC air switch. Set the AC power supply as the backup power supply to avoid the main power supply and the backup power supply failing to power the current transmitter when the DC power supply main circuit fails.

[0012] A power busbar room is also provided in the switch cabinet and above the instrument room, which is used to place the DC busbar and the AC busbar. The DC busbar and the AC busbar are respectively connected to the lower ports of the main switches of the DC panel and the AC panel. A wire passing hole is provided between the instrument room and the power busbar room. The DC busbar and the AC busbar are respectively connected to the DC small air switch and the AC small air switch through the wire passing hole.

[0013] The inner wall of the instrument room is provided with a guide rail, and the current transmitter, contactor, DC small air switch and AC small air switch are fixed on the guide rail. Through the above structure, the current transmitter, contactor and air switch can be quickly installed in the instrument room.

[0014] The instrument room is also provided with a terminal block, the signal input end and the signal output end of the current transmitter are connected to the terminals on one side of the terminal block, and the corresponding terminals on the other side of the terminal block are connected to the DCS controller. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the electrical principle of dual power supply of the utility model;

[0016] Figure 2 It is a structural front view of each switch cabinet of the utility model;

[0017] Figure 3 It is a side view of the internal structure of the switch cabinet of the utility model;

[0018] Figure 4 This is a schematic diagram of the internal structure of the instrument room of the utility model;

[0019] In the figure: 1. DC panel; 2. AC panel; 3. Main switch; 4. DC small busbar; 5. AC small busbar; 6. DC small air switch; 7. AC small air switch; 8. Switch cabinet; 81. Power small busbar room; 82. Instrument room; 83. Cart room; 831. Circuit breaker; 84. Cable room; 841. High-voltage busbar; 842. Current transformer; 843. High-voltage cable; 9. Contactor; 10. Current transmitter; 11. Guide rail; 12. Terminal block; 13. Wire hole; 14. Through-wall terminal. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with embodiments, the purpose of which is only to provide a better understanding of the content of the present invention. Therefore, the examples given do not limit the protection scope of the present invention.

[0021] See attached Figure 1-4 , this embodiment discloses a high-voltage power distribution system with automatic dual power supply switching, including a plurality of switch cabinets 8, a dual power supply is provided, the dual power supply includes a main power supply and a backup power supply, and a main switch 3 is provided on the output power lines of the main power supply and the backup power supply respectively;

[0022] Each switch cabinet 8 is provided with two air switches, a contactor 9 and a current transmitter 10. The upper ports of the two air switches are respectively connected to the lower ports of the two main switches 3. The lower port of the air switch connected to the main power line through the main switch is connected to the control coil of the contactor 9. The lower ports of the two air switches are respectively connected to the input ends of the normally open contact and the normally closed contact of the contactor 9. The output ends of the normally open contact and the normally closed contact of the contactor 9 are both connected to the power supply end of the current transmitter 10; the signal output end of the current transmitter 10 is connected to the DCS controller.

[0023] In this embodiment, each switch cabinet 8 is provided with an instrument room 82, a trolley room 83 and a cable room 84. The current transmitter 10, the contactor 9 and the air switch are arranged in the instrument room 82. The switch cabinet 8 indicating instrument is also arranged on the cabinet body at the front end of the instrument room 82, which is used to display the operating data of each electrical component in the switch cabinet 8; a circuit breaker 831 is arranged in the trolley room 83, a circuit breaker 831 trolley is fixed under the circuit breaker 831, and a guide rail is fixed in the trolley room 83 so that the circuit breaker 831 can be moved in the trolley room 83; a high-voltage bus 841, a current transformer 842 and a high-voltage cable 843 are arranged in the cable room 84. The high-voltage bus 841 It is a three-phase high-voltage AC busbar, which is connected to the upper terminal of the circuit breaker 831 through the busbar branch. The lower terminal of the circuit breaker 831 is connected to the external electrical equipment through the high-voltage cable 843 to supply power. The circuit breaker 831 plays the role of switch and protection in the high-voltage line; and the three-phase high-voltage AC busbar passes through the current transformer 842. Under normal circumstances, the vector sum of the three-phase current is zero. When single-phase grounding occurs, the secondary coil will have an induced current, which is judged as a fault, and cooperates with the protection circuit and the circuit breaker 831 to disconnect the high-voltage line. In addition, the current transformer 842 can also convert the detected large current into a small current and transmit it to the instrument for current monitoring.

[0024] In this embodiment, the main power supply is a DC power supply supplied by the DC panel 1, and the air switch connected to the DC panel 1 is a small DC air switch 6 (a small DC air switch); the backup power supply is an AC power supply supplied by the AC panel 2, and the air switch connected to the AC panel 2 is a small AC air switch 7 (a small AC air switch). The AC power supply is set as the backup power supply to avoid the situation where both power supplies cannot supply power to the current transmitter 10 when a fault occurs in the DC power supply main circuit.

[0025] In this embodiment, a power busbar chamber 81 is further provided above the instrument chamber 82 in the switch cabinet 8, for placing the DC busbar 4 and the AC busbar 5. A through-wall terminal 14 is fixed on the wall of the power busbar chamber 81, and the outer terminal of the through-wall terminal 14 is connected to the lower port of the main switch 3 of the DC panel 1 and the AC panel 2. The DC busbar 4 is connected to the inner terminal of the DC panel 1 corresponding to the through-wall terminal 14, and the AC busbar 5 is connected to the inner terminal of the AC panel 2 corresponding to the through-wall terminal 14; a through-wire hole 13 is provided between the instrument chamber 82 and the power busbar chamber 81, and the branch lines of the DC busbar 4 and the AC busbar 5 are respectively connected to the upper ports of the DC small air switch 6 and the AC small air switch 7 in the switch cabinet through the through-wire hole 13.

[0026] In this embodiment, a guide rail 11 is provided on the inner wall of the instrument room 82, and the current transmitter 10, the contactor 9, the DC small air switch 6 and the AC small air switch 7 are fixed on the guide rail 11. Through the above structure, it is convenient to quickly install the current transmitter 10, the contactor 9, the DC small air switch 6 and the AC small air switch 7 in the instrument room 82.

[0027] In this embodiment, a terminal block 12 is further provided in the instrument room 82. The signal input end and the signal output end of the current transmitter 10 are connected to the terminals on one side of the terminal block 12, and the terminals on the other side are connected to the DCS controller. Specifically, terminals 1 and 2 of the terminal block 12 are connected to the two signal input ends of the current transmitter 10, and the two signal output ends of the current transmitter 10 are connected to terminals 19 and 20. The DCS controller is connected to the terminals 19 and 20 on the other side corresponding to the terminal block 12. The current transmitter 10 and the DCS controller are connected through the terminal block 12, and the output current of the current transmitter 10 is transmitted to the external DCS controller.

[0028] In this embodiment, the contactor 9 adopts a 4P contactor; the current transmitter 10 adopts a transmitter with model PD60031-1B1, signal input O-5A, signal output 4-20mA, and accuracy 0.5%FS, and the power supply end supports DC or AC power input.

[0029] In this embodiment, each switch cabinet 8 current transmitter 10 of this system is powered by dual power automatic switching, and a contactor 9 is added as a switching power supply device to close the DC small air switch 6 and the AC small air switch 7. During normal operation, after the contactor 9 control coil is energized, an electromagnetic attraction is generated and drives the iron core to move so that the normally open contact is closed and the normally closed contact is disconnected. At this time, the section from the DC screen 1 to the current transmitter 10 is a passage, and the DC screen 1 supplies power to the current transmitter 10; when a fault occurs at the upper or lower port of the DC small air switch 6, the control coil loses power, the electromagnetic attraction disappears, the iron core returns to its position, the normally open contact is disconnected, and the normally closed contact is closed. At this time, the AC screen 2 supplies power to the current transmitter 10, which includes two situations. In this case, when a fault occurs from the upper port of the DC small air breaker 6 of one switch cabinet 8 to the DC screen section 1, the main switch of the DC screen 1 trips. At this time, no current passes from the DC screen 1 to the current transmitter 10 of each switch cabinet 8, the control coil loses power, the normally open contact is disconnected, and the normally closed contact is closed. At this time, the AC screen 2 supplies power to each current transmitter 10; when a fault occurs from the lower port of the DC small air breaker 6 of one switch cabinet 8 to the current transmitter 10, the DC small air breaker 6 of the switch cabinet 8 trips, the control coil loses power, the normally open contact is disconnected, and the normally closed contact is closed. At this time, the AC screen 2 supplies power to the current transmitter 10 of the switch cabinet 8, and the current transmitters 10 of the remaining switch cabinets 8 are still powered by the DC screen 1. In the above two cases, the output current of the current transmitter 10 of the switch cabinet 8 detected by the DCS control system is a stable value, thereby avoiding the interlocking and parking of the switch cabinet 8 of the system, maximizing the reliability of the power supply of the current transmitter 10, reducing the operation risk to the minimum, and ensuring production safety.

[0030] The above description is only a preferred feasible embodiment of the present utility model, and does not limit the scope of rights of the present utility model. All equivalent changes made using the contents of the present utility model specification and its drawings are included in the scope of rights of the present utility model.

Claims

1. A high voltage power distribution system with automatic dual power supply switching, comprising a plurality of switch cabinets (8), characterized in that: A dual power supply is provided, the dual power supply includes a main power supply and a backup power supply, and the output ends of the main power supply and the backup power supply are respectively provided with a main switch (3); Each switch cabinet (8) is provided with two air switches, a contactor (9) and a current transmitter (10); the upper ports of the two air switches are respectively connected to the lower ports of the two main switches (3); the lower port of the air switch connected to the main power supply via the main switch (3) is connected to the control coil of the contactor (9); the lower ports of the two air switches are respectively connected to the input ends of the normally open contact and the normally closed contact of the contactor (9); the output ends of the normally open contact and the normally closed contact of the contactor (9) are both connected to the power supply end of the current transmitter (10); and the signal output end of the current transmitter (10) is connected to the DCS controller.

2. The high-voltage power distribution system with automatic dual power supply switching according to claim 1 is characterized in that: Each switch cabinet (8) is provided with an instrument room (82), a trolley room (83) and a cable room (84). The current transmitter (10), the contactor (9) and the air switch are arranged in the instrument room (82). The trolley room (83) is provided with a circuit breaker (831). The cable room (84) is provided with a high-voltage busbar (841), a current transformer (842) and a high-voltage cable (843). The high-voltage busbar (841) is connected to the circuit breaker (831). The circuit breaker (831) is connected to an external electrical device via a high-voltage cable (843), and the high-voltage cable passes through the current transformer (842).

3. The high-voltage power distribution system with automatic dual power supply switching according to claim 2 is characterized in that: The main power supply is a DC power supply supplied by a DC panel (1), and the air switch connected to the DC panel (1) is a small DC air switch (6); the backup power supply is an AC power supply supplied by an AC panel (2), and the air switch connected to the AC panel (2) is a small AC air switch (7).

4. The high-voltage power distribution system with automatic dual power supply switching according to claim 3 is characterized in that: A power busbar chamber (81) is also provided above the instrument chamber (82) in the switch cabinet (8) for accommodating a DC busbar (4) and an AC busbar (5). The DC busbar (4) and the AC busbar (5) are connected to the lower ports of the main switches of the DC panel (1) and the AC panel (2), respectively. A wire-through hole (13) is provided between the instrument chamber (82) and the power busbar chamber (81). The DC busbar (4) and the AC busbar (5) are connected to the DC air switch (6) and the AC air switch (7) respectively through the wire-through hole (13).

5. The high-voltage power distribution system with automatic dual power supply switching according to claim 3 is characterized in that: A guide rail (11) is arranged on the inner wall of the instrument room (82), and the current transmitter (10), the contactor (9), the DC small air switch (6) and the AC small air switch (7) are fixed on the guide rail (11).

6. The high-voltage power distribution system with automatic dual power supply switching according to claim 2 is characterized in that: A terminal block (12) is also provided in the instrument room (82); a signal input end and a signal output end of the current transmitter (10) are connected to terminals on one side of the terminal block (12); and corresponding terminals on the other side of the terminal block (12) are connected to a DCS controller.

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