Bus backup power automatic throw-in system and method

Abstract

The application provides a bus backup power automatic input system and method, which comprises multiple buses and backup power; each bus is provided with an incoming line switch; the buses are provided with a tie switch; the backup power is connected with the buses; further comprising a relay and a monitoring system; the bus is installed with a bus no-voltage relay; the incoming line switch cabinet of the bus is installed with an incoming line no-current relay; the incoming line side of the backup power is installed with an incoming line no-voltage relay; the monitoring system is used for obtaining relay signals and switch states, and determining whether to input the backup power based on the relay signals and the switch states; the relay signals comprise no-voltage signals sent by the bus no-voltage relay, no-current signals sent by the incoming line no-current relay and no-voltage signals sent by the incoming line no-voltage relay; the switch states comprise opening and closing states of the incoming line switch and opening and closing states of the tie switch; so as to reduce the cost of the backup power automatic input device and reduce the uncertainty caused by human factors.

Description

Technical Field

[0001] This invention relates to the field of power distribution network control technology, and more specifically, to a system and method for automatically switching on a bus backup power supply. Background Technology

[0002] Large power plants have numerous and widely distributed auxiliary power loads, and the reliability of the auxiliary power system directly affects the stable operation of the generating units. To ensure the reliability of auxiliary power supply, the auxiliary power system generally needs to have an automatic backup power transfer function. Traditionally, the automatic backup power transfer function of auxiliary power systems is achieved by complete sets of automatic transfer switches (ATS). These ATS sets are relatively expensive, and maintenance units need to regularly inspect and maintain them. Depending on the actual site conditions, different quantities of spare ATS modules need to be stocked. The installation of ATS requires additional installation cabinets, resulting in high on-site usage and maintenance costs. For ATS devices equipped with an ATS action output pressure plate, there are problems such as accidental activation or deactivation of the pressure plate due to human error, leading to malfunctions or failures to activate the ATS.

[0003] In view of this, the present invention provides a bus backup power automatic switching system and method to reduce the cost of switching on the backup power device and reduce the uncertainty caused by human factors. Summary of the Invention

[0004] The purpose of this invention is to provide an automatic switching system for a busbar backup power supply, comprising multiple busbars and a backup power supply; each busbar is equipped with an incoming line switch; interconnecting switches are provided between the busbars; the backup power supply is connected to the busbars; the system also includes relays and a monitoring system; a busbar no-voltage relay is installed on each busbar; an incoming line no-current relay is installed in the incoming line switch cabinet of each busbar; an incoming line no-voltage relay is installed on the incoming side of the backup power supply; the monitoring system is used to acquire relay signals and switch states, and based on the relay signals and switch states, to determine whether to switch on the backup power supply; the relay signals include a no-voltage signal sent by the busbar no-voltage relay, a no-current signal sent by the incoming line no-current relay, and a no-voltage signal sent by the incoming line no-voltage relay; the switch states include the open / closed state of the incoming line switch and the open / closed state of the interconnecting switch.

[0005] Furthermore, there are two busbars, namely a first busbar I and a second busbar II; the first busbar is equipped with a first busbar no-voltage relay and a first incoming line switch 1QF; the second busbar is equipped with a second busbar no-voltage relay and a second incoming line switch 2QF; a tie switch 3QF is provided between the first busbar and the second busbar; the backup power supply includes a first backup power supply, which is connected to the first busbar via a first backup switch; determining whether to activate the backup power supply includes: judging whether a first no-voltage signal and a first incoming line no-current signal are received from the first busbar; if not, the automatic backup power supply activation process is not activated; if yes, the automatic backup power supply activation process is activated, and it is judged whether the duration of the first no-voltage signal and the first incoming line signal is greater than a first preset time t1; if not, the automatic backup power supply activation process is deactivated. The activation process is as follows: If yes, the external load switch on the first busbar is tripped; it is determined whether the duration of the first no-voltage signal and the first incoming signal is greater than the second preset time t2; the second preset time t2 is longer than the first preset time t1; if no, the tripped external load switch is maintained; if yes, it is determined whether the first incoming switch of the first busbar performs a protection device operation; if yes, no action is taken; if no, it is determined whether no-voltage signals from the second busbar and the backup power supply are received; the second busbar is adjacent to the first busbar, and the first backup power supply is a backup power supply connected to the first busbar; if the second busbar sends a no-voltage signal and the first backup power supply does not send a no-voltage signal, the first backup power supply is activated; if the second busbar does not send a no-voltage signal, the second busbar is activated as a backup power supply.

[0006] Furthermore, the step of activating the second bus as a backup power source includes: determining whether a trip signal from the first incoming switch of the first bus is received after a third duration t3; if not, exiting the automatic backup power activation process; if so, closing the connection switch between the adjacent bus and the first bus.

[0007] Furthermore, the step of activating the first backup power supply includes: determining whether a trip signal from the first incoming switch of the first bus is received after a third duration t3; if not, exiting the automatic backup power supply activation process; if yes, closing the backup power supply and the first backup switch of the first bus.

[0008] The present invention aims to provide a method for automatically switching on a busbar backup power supply, comprising: determining whether a first no-voltage signal and a first incoming line no-current signal are received on a first busbar; if not, then not initiating the automatic backup power supply switching process; if yes, then initiating the automatic backup power supply switching process, and determining whether the duration of the first no-voltage signal and the first incoming line signal is greater than a first preset time t1; if not, then exiting the automatic backup power supply switching process; if yes, then disconnecting the external load switch on the first busbar; determining whether the duration of the first no-voltage signal and the first incoming line signal is greater than a second preset time t2; the second preset time t... 2. If the time is longer than the first preset time t1; if not, then keep the external load switch tripped; if yes, then determine whether the first incoming switch of the first busbar has performed a protection device operation; if yes, then do not do anything; if no, then determine whether a no-voltage signal has been received from the adjacent busbar and the first backup power supply; the adjacent busbar is another busbar adjacent to the first busbar, and the first backup power supply is the backup power supply of the first busbar; if both adjacent buses send no-voltage signals and the first backup power supply does not send a no-voltage signal, then the first backup power supply is put into operation; if the adjacent busbar does not send a no-voltage signal, then the adjacent busbar is put into operation as a backup power supply.

[0009] Furthermore, this includes: when the external load switch on the first busbar is tripped and the voltage of the first busbar recovers, the automatic backup power supply switching process is terminated.

[0010] Furthermore, the step of using the adjacent bus as a backup power source includes: determining whether a trip signal from the first incoming switch of the first bus is received after a third duration t3; if not, exiting the automatic backup power source activation process; if yes, closing the connection switch between the adjacent bus and the first bus.

[0011] Furthermore, the step of activating the first backup power supply includes: determining whether a position signal from the first incoming switch of the first bus is received after a third duration t3; if not, exiting the automatic backup power supply activation process; if yes, closing the backup power supply and the backup switch of the first bus.

[0012] Furthermore, the monitoring system remotely controls the external load switch, the first incoming line switch, the tie switch, and the standby switch.

[0013] Furthermore, it also includes confirming whether the no-voltage signal of the first bus has been restored after the first backup power supply or the adjacent bus is put into operation. If the no-voltage signal of the first bus has not been restored, it is determined that the backup power supply has failed to be put into operation, and the automatic backup power supply process is exited.

[0014] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects:

[0015] This invention fully utilizes the 10kV switch position information to send to the monitoring system, adds bus no-voltage and incoming line no-current signals, and adds the startup and operation logic of backup power supply to the monitoring system, thus solving the problems of high investment cost, high maintenance cost, large installation space, and low device reliability caused by human factors in traditional automatic transfer switch devices. Attached Figure Description

[0016] Figure 1 A schematic diagram of an automatic bus backup power supply switching system provided by the present invention;

[0017] Figure 2 The automatic backup power supply self-starting logic diagram provided by the present invention;

[0018] Figure 3 This is an exemplary flowchart of a method for automatically switching on a backup power supply to a busbar, provided by the present invention. Detailed Implementation

[0019] 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, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0020] Figure 1 This is a schematic diagram of an automatic bus backup power supply switching system provided by the present invention.

[0021] like Figure 1 As shown, the automatic switching system for backup power supply of a busbar includes multiple busbars and a backup power supply; each busbar is equipped with an incoming line switch; interconnecting switches are installed between the busbars; the backup power supply is connected to the busbar; it also includes relays and a monitoring system; a busbar de-voltage relay is installed on each busbar; an incoming line de-current relay is installed in the incoming line switch cabinet of each busbar; an incoming line de-voltage relay is installed on the incoming side of the backup power supply; the monitoring system is used to acquire relay signals and switch status, and based on the relay signals and switch status, determines whether to activate the backup power supply; the relay signals include a de-voltage signal sent by the busbar de-voltage relay, a de-current signal sent by the incoming line de-current relay, and a de-voltage signal sent by the incoming line de-voltage relay; the switch status includes the open / closed state of the incoming line switch and the open / closed state of the interconnecting switch.

[0022] For example, there are two busbars, namely the first busbar I and the second busbar II; the first busbar is equipped with a first busbar no-voltage relay and a first incoming line switch 1QF; the second busbar is equipped with a second busbar no-voltage relay and a second incoming line switch 2QF; a tie switch 3QF is provided between the first busbar and the second busbar; the backup power supply includes a first backup power supply, which is connected to the first busbar via the first backup switch; when the 10kV system is operating normally, the two busbars I and II operate separately, with the first busbar incoming line switch 1QF closed; the second busbar incoming line switch 2QF closed; the tie switch 3QF between the first and second busbars open; and the backup power supply switch 4QF open (if present). Determining whether to activate the backup power supply includes: judging whether a first no-voltage signal and a first incoming line no-current signal from the first busbar are received; if not, the automatic backup power supply activation process is not initiated; if yes, the automatic backup power supply activation process is initiated, and the first no-voltage signal is judged. If the duration of the first incoming signal is greater than a first preset time t1, then exit the automatic backup power supply switching process; if yes, then disconnect the external load switch on the first bus. Determine if the duration of the first no-voltage signal and the first incoming signal is greater than a second preset time t2; the second preset time t2 is longer than the first preset time t1; if no, maintain the disconnected external load switch state; if yes, determine if the first incoming switch of the first bus executes a protection device action; if yes, do not process; if no, determine if a no-voltage signal from the second bus and the backup power supply is received; the second bus is adjacent to the first bus, and the first backup power supply is a backup power supply connected to the first bus; if the second bus sends a no-voltage signal and the first backup power supply does not send a no-voltage signal, then connect the first backup power supply; if the second bus does not send a no-voltage signal, then connect the second bus as a backup power supply. For more information on connecting the second bus as a backup power supply and connecting the first backup power supply, see [link to relevant documentation]. Figure 3 And its related descriptions.

[0023] Figure 2 The present invention provides an automatic backup power supply switching and self-starting logic diagram.

[0024] The monitoring system can monitor the LCU (Logic Control Unit) system. The monitoring LCU system's automatic switchover and automatic start-up logic is as follows: Figure 2As shown: Install busbar de-voltage relays on Bus I and Bus II, and install incoming line de-voltage relays (if applicable) on the backup power supply incoming line side. The voltage circuit of the de-voltage relays adopts the line voltage connection method to prevent the busbar de-voltage relays from operating when a single phase ground fault occurs in the 10kV system. The operating contacts of the above de-voltage relays are sent to the monitoring LCU system. Install incoming line current-free relays in the incoming switch cabinets of Bus I and Bus II, and send the operating contacts of the incoming line current-free relays to the monitoring LCU system. The automatic power supply start-up conditions for Bus I and Bus II backup power supply are: the monitoring LCU system does not receive a busbar de-voltage signal from Bus I or Bus II; the automatic power supply start-up function of Bus I and Bus II backup power supply is activated; Bus I incoming line switch 1QF is closed; Bus II incoming line switch 2QF is closed; Bus I and Bus II tie switch 3QF is open.

[0025] Figure 3 This is an exemplary flowchart of a method for automatically switching on a backup power supply to a busbar, provided by the present invention.

[0026] like Figure 3 As shown, the automatic switching method for the bus backup power supply includes:

[0027] Determine whether the first no-voltage signal from the first bus and the first no-current signal from the first incoming line have been received; if not, the automatic backup power supply switching process is not activated.

[0028] If so, the automatic backup power supply process is activated, and it is determined whether the duration of the first no-voltage signal and the first incoming signal is greater than the first preset time t1; if not, the automatic backup power supply process is exited.

[0029] If so, the external load switch on the first busbar will be tripped. If the voltage on the first busbar recovers after the external load switch on the first busbar is tripped, the automatic backup power supply connection process will be terminated.

[0030] Determine whether the duration of the first no-voltage signal and the first incoming signal is greater than the second preset time t2; the second preset time t2 is longer than the first preset time t1; if not, maintain the state of tripping the external load switch.

[0031] If yes, then determine whether the first incoming switch of the first busbar has activated the protection device; if yes, then do not take any action.

[0032] If not, determine whether a no-voltage signal is received from the adjacent bus and the first backup power supply; the adjacent bus is another bus adjacent to the first bus, and the first backup power supply is the backup power supply of the first bus.

[0033] If both adjacent buses send a no-voltage signal and the first backup power supply does not send a no-voltage signal, then the first backup power supply is activated, including: determining whether the first incoming switch of the first bus is received after a third duration t3; if not, then exiting the automatic backup power supply activation process; if yes, then closing the backup power supply and the backup switch of the first bus.

[0034] If the adjacent bus does not send a no-voltage signal, then the adjacent bus is put into use as a backup power supply, including: determining whether the first incoming switch of the first bus is received after the third duration t3; if not, then exit the automatic backup power supply process; if yes, then close the connection switch between the adjacent bus and the first bus.

[0035] The monitoring system controls the off-site load switch, the first incoming line switch, the tie switch, and the standby switch remotely.

[0036] It also includes confirming whether the no-voltage signal of the first bus has been restored after the first backup power supply or adjacent bus is put into operation. If the no-voltage signal of the first bus has not been restored, it is determined that the backup power supply has failed to be put into operation and the automatic backup power supply process is exited.

[0037] Example 1:

[0038] The automatic switching procedure for the backup power supply of the monitoring LCU system is as follows: Figure 3 The following describes the automatic backup power supply operation procedure (taking Bus I as an example): When Bus I and Bus II of the 10kV plant power system are operating normally in sections, if the monitoring system receives a no-voltage signal on Bus I and a no-current signal on incoming switch 1QF, and the duration of the no-voltage signal on Bus I and the no-current signal on incoming switch 1QF is greater than time t1, the monitoring LCU system will trip the external load switch with a high failure rate (if there is an external power supply load); if the duration of the no-voltage signal on Bus I and the no-current signal on incoming switch 1QF is greater than time t2 (t2>t1), and the monitoring LCU system does not receive an action signal from the protection device of incoming switch 1QF on Bus I, and does not receive a no-voltage signal on Bus II, then the incoming switch 1QF on Bus I will trip. After a delay of t3, after receiving the disconnection signal from incoming switch 1QF on Bus I, the interconnection switch 3QF between Bus I and Bus II will be closed. At this time, Bus I and Bus II are in communication operation, the no-pressure signal of Bus I is restored, and the automatic power supply activation process for Bus I and Bus II ends. If any of the above conditions are not met, the process will exit prematurely. The power supply activation process when Bus II loses pressure is the same as when Bus I loses pressure.

[0039] Example 2:

[0040] When there are two power sources on the bus, the automatic backup power supply activation procedure (taking Bus II as an example) is as follows: When Bus I and Bus II of the 10kV plant power system are operating normally in sections, when the monitoring system receives the bus II bus no-voltage signal and the incoming switch 2QF incoming line no-current signal, if the duration of the bus II bus no-voltage signal and the incoming switch 2QF incoming line no-current signal is greater than time t1, the monitoring LCU system will trip the switch of the off-site power supply load with a high failure rate (if there is an off-site power supply load); if the duration of the bus II bus no-voltage signal and the incoming switch 2QF incoming line no-current signal is greater than time t2 (t2>t1), and the monitoring LCU system does not receive the action signal of the protection device of the incoming switch 2QF of Bus II, but the monitoring LCU system receives the bus I bus no-voltage signal and does not receive the backup power supply no-voltage signal, then the incoming switch 2QF of Bus II will trip, and after a delay of t3, after receiving the vacancy signal of the incoming switch 2QF of Bus II, the backup power supply switch 4QF on Bus II will be closed.

[0041] A button for activating the bus backup power supply is added to the monitoring LCU system. Operators can enable or disable this function on the monitoring system. When operators manually open the bus incoming switch to de-energize the bus, they can disable the backup power supply activation function on the monitoring system to prevent accidental activation of the backup power supply during manual de-energization.

[0042] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An automatic switching system for backup power supply to a busbar, comprising multiple busbars and a backup power supply; each busbar is equipped with an incoming line switch; interconnecting switches are provided between the busbars; the backup power supply is connected to the busbar; characterized in that, It also includes relays and monitoring systems; A busbar no-voltage relay is installed on the busbar; an incoming line no-current relay is installed in the incoming switch cabinet of the busbar. An incoming line voltage-free relay is installed on the incoming line side of the backup power supply; The monitoring system is used to acquire relay signals and switch status, and based on the relay signals and switch status, determine whether to activate the backup power supply; the relay signals include the no-voltage signal sent by the bus no-voltage relay, the no-current signal sent by the incoming line no-current relay, and the no-voltage signal sent by the incoming line no-voltage relay; the switch status includes the open / closed status of the incoming line switch and the open / closed status of the tie switch. The busbars are two, namely a first busbar I and a second busbar II; the first busbar is equipped with a first busbar no-voltage relay and a first incoming switch 1QF; the second busbar is equipped with a second busbar no-voltage relay and a second incoming switch 2QF; a tie switch 3QF is provided between the first busbar and the second busbar; the backup power supply includes a first backup power supply, which is connected to the first busbar via a first backup switch; determining whether to activate the backup power supply includes: Determine whether the first no-voltage signal from the first bus and the first no-current signal from the first incoming line have been received; if not, the automatic backup power supply switching process is not activated. If so, the automatic backup power supply procedure is activated, and it is determined whether the duration of the first no-voltage signal and the first incoming line no-current signal is greater than a first preset time. If not, then exit the automatic backup power supply process. If so, then disconnect the external load switch on the first busbar; Determine whether the duration of the first no-voltage signal and the first input no-current signal is greater than a second preset time. The second preset time Longer than the first preset time If not, then keep the aforementioned off-site load switch in the open state; If yes, then determine whether the first incoming switch of the first busbar has activated the protection device; if yes, then do nothing. If not, determine whether a no-voltage signal is received from the second bus and the backup power supply; the second bus is adjacent to the first bus, and the first backup power supply is a backup power supply connected to the first bus. If the second bus sends a no-voltage signal and the first backup power supply does not send a no-voltage signal, then the first backup power supply is activated. If the second bus does not send a no-voltage signal, then the second bus will be put into operation as a backup power source.

2. The automatic bus backup power supply switching system according to claim 1, characterized in that, The step of activating the second busbar as a backup power source includes: Determine the duration in the third time If the first incoming switch of the first busbar is not received, the automatic backup power supply process is exited. If so, then close the connection switch between the adjacent bus and the first bus.

3. The automatic switching system for bus backup power supply according to claim 2, characterized in that, The step of activating the first backup power supply includes: Determine the duration in the third time If the first incoming switch of the first busbar is not received, the automatic backup power supply process is exited. If so, then close the aforementioned backup power supply and the first backup switch of the first bus.

4. A method for automatically switching on a busbar backup power supply, applied to the automatic switching system for a busbar backup power supply as described in any one of claims 1-3, characterized in that, include: Determine whether the first no-voltage signal from the first bus and the first no-current signal from the first incoming line have been received; If not, the automatic backup power supply process will not be activated; If so, the automatic backup power supply procedure is activated, and it is determined whether the duration of the first no-voltage signal and the first incoming line no-current signal is greater than a first preset time. If not, then exit the automatic backup power supply process. If so, then disconnect the external load switch on the first busbar; Determine whether the duration of the first no-voltage signal and the first input no-current signal is greater than a second preset time. The second preset time Longer than the first preset time If not, then keep the aforementioned off-site load switch in the open state; If yes, then determine whether the first incoming switch of the first busbar has activated the protection device; if yes, then do nothing. If not, determine whether a no-voltage signal is received from the adjacent bus and the first backup power supply; the adjacent bus is another bus adjacent to the first bus, and the first backup power supply is the backup power supply of the first bus. If both adjacent buses send a no-voltage signal and the first backup power supply does not send a no-voltage signal, then the first backup power supply is activated. If the adjacent bus does not send a no-voltage signal, then the adjacent bus is put into operation as a backup power source.

5. The method for automatically switching on a backup power supply to a busbar according to claim 4, characterized in that, This includes: when the external load switch on the first busbar is tripped and the voltage of the first busbar recovers, the automatic backup power supply switching process is exited.

6. The method for automatically switching on a backup power supply to a busbar according to claim 4, characterized in that, The step of using the adjacent busbar as a backup power source includes: Determine the duration in the third time If the first incoming switch of the first busbar is not received, the automatic backup power supply process is exited. If so, then close the connection switch between the adjacent bus and the first bus.

7. The method for automatically switching on a backup power supply to a busbar according to claim 4, characterized in that, The step of activating the first backup power supply includes: Determine the duration in the third time If the first incoming switch of the first busbar is not received, the automatic backup power supply process is exited. If so, then close the backup power supply and the backup switch of the first bus.

8. The method for automatically switching on a busbar backup power supply according to any one of claims 4-7, characterized in that, The monitoring system controls the off-site load switch, the first incoming line switch, the tie switch, and the standby switch remotely.

9. The method for automatically switching on a backup power supply to a busbar according to claim 4, characterized in that, It also includes confirming whether the no-voltage signal of the first bus has been restored after the first backup power supply or adjacent bus is put into operation. If the no-voltage signal of the first bus has not been restored, it is determined that the backup power supply has failed to be put into operation and the automatic backup power supply process is exited.

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