JP2005218200A - Common standby uninterruptible power supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a reverse converter from being overloaded when a normal uninterruptible power supply is switched from UPS operation to bypass operation, and to prevent a standby uninterruptible power supply from being overloaded. To provide an uninterruptible power supply system.
SOLUTION: One standby uninterruptible power supply 12 is provided for a plurality of regular uninterruptible power supplies 11a to 11n, and the standby uninterruptible power supply 11a to 11n is subjected to maintenance inspection or failure. Power is supplied from the power supply device 12 to the common uninterruptible power supply devices 11a to 11n. The uninterruptible switching circuits 16a to 16n of the service uninterruptible power supply devices 11a to 11n are switched from a UPS operation in which power is supplied from the reverse converters 15a to 15n to a bypass operation in which power is supplied from the bypass circuits 24a to 24n. Reactors 28a to 28n are provided for suppressing the cross current that flows instantaneously.
[Selection] Figure 1

Description

  The present invention relates to a common backup uninterruptible power supply system in which an uninterruptible power supply is supplied from a backup uninterruptible power supply when the normal uninterruptible power supply is inspected or malfunctioned.

  For example, since a power source of an important load such as a computer is not allowed to have an instantaneous power failure, an uninterruptible power supply (UPS) is often used. The uninterruptible power supply unit converts commercial power into direct current with a forward converter and converts it into desired alternating current with a reverse converter and supplies it to the load. In the unlikely event of a power failure in the commercial power supply Is configured to supply a continuous power supply to a load through a reverse converter using DC power from a storage battery.

  In the common standby uninterruptible power supply system, one standby uninterruptible power supply is provided for the plurality of regular uninterruptible power supplies that supply power to the load, and maintenance and inspection of the normal uninterruptible power supply is not possible. Sometimes it is configured to supply power from a standby uninterruptible power supply to the permanent uninterruptible power supply.

  The standby uninterruptible power supply device is a forward converter that converts the alternating current input from the commercial power source into a direct current and outputs it, an inverse converter that converts the direct current output from the forward converter again into alternating current, and outputs it, A storage battery that supplies DC power to the reverse converter during a power failure of the commercial power supply, a bypass circuit that bypasses the forward converter and the reverse converter, and supplies AC from the commercial power supply, and the reverse converter and bypass circuit And an uninterruptible switching circuit for switching when the power is cut off, and supplies power to the continuous uninterruptible power supply at the time of maintenance inspection or failure of any of the plurality of permanent uninterruptible power supplies.

  The regular uninterruptible power supply is configured in almost the same way as the standby uninterruptible power supply. It converts the AC input from the commercial power source into DC and outputs it, and the DC output from the forward converter becomes AC again. Inverter that converts and outputs, storage battery that supplies DC power to the inverter in the event of a power failure of the commercial power supply, and bypass that supplies power from the standby uninterruptible power supply by bypassing the forward converter and reverse converter The circuit is configured to include an uninterruptible switching circuit for switching between the inverter and the bypass circuit without instantaneous disconnection. In other words, the bypass circuit is different from the standby uninterruptible power supply in that power from the standby uninterruptible power supply is supplied instead of the commercial power supply.

As such a common standby uninterruptible power supply system, in a state where the normal uninterruptible power supply is load-fed, the forward converter and the reverse converter of the standby uninterruptible power supply are stopped and the standby uninterruptible power supply is When the failure signal from the normal uninterruptible power supply is received, the load is temporarily supplied from the standby uninterruptible power supply to the load by the commercial power supply, and in the meantime In some cases, the forward converter and the reverse converter of the standby uninterruptible power supply are automatically operated to automatically switch from bypass power supply to UPS power supply to supply UPS power to the load (for example, Patent Document 1).
JP 2003-87798 A

  However, in Patent Document 1, when the common uninterruptible power supply is load-fed, the forward converter and reverse converter of the standby uninterruptible power supply are stopped and the standby uninterruptible power supply is bypassed. The operation loss can be minimized because the system is kept on standby with no-load operation, but at the moment when the regular uninterruptible power supply switches from UPS operation to bypass operation, the impedance of the standby uninterruptible power supply There is a possibility that a cross current flows due to the difference, and when the cross current flows, there is a concern that the reverse converter is overloaded.

  Also, the maintenance uninterruptible power supply is operated with the standby uninterruptible power supply carrying the load of the normal uninterruptible power supply during maintenance and inspection of the normal uninterruptible power supply. Is switched from the UPS operation to the bypass operation, the standby uninterruptible power supply is already carrying the load of the normal uninterruptible power supply. As a result, the backup uninterruptible power supply may be overloaded.

  The purpose of the present invention is to prevent the reverse converter from becoming overloaded when the normal uninterruptible power supply switches from UPS operation to bypass operation, and to prevent the backup uninterruptible power supply from becoming overloaded. It is to provide a common standby uninterruptible power system that can.

  In the common standby uninterruptible power supply system according to the invention of claim 1, one standby uninterruptible power supply unit is provided for a plurality of regular uninterruptible power supply units. In the common standby uninterruptible power supply system in which power is supplied from the standby uninterruptible power supply to the normal uninterruptible power supply, the standby uninterruptible power supply converts the alternating current input from the commercial power source into direct current. A forward converter for outputting, a reverse converter for converting the direct current output from the forward converter to alternating current again, and a storage battery for supplying direct current to the reverse converter during a power failure of the commercial power source, A bypass circuit that bypasses the forward converter and the reverse converter and supplies alternating current from the commercial power supply, and an uninterruptible switching circuit for switching the inverse converter and the bypass circuit without instantaneous interruption, Said always The uninterruptible power supply includes a forward converter that converts alternating current input from a commercial power source into direct current, outputs, a reverse converter that converts direct current output from the forward converter back into alternating current, and the commercial converter. A storage battery for supplying DC power to the reverse converter in the event of a power failure, a bypass circuit for bypassing the forward converter and the reverse converter and supplying power from the backup uninterruptible power supply, and the reverse converter And an uninterruptible switching circuit for switching between an uninterruptible power supply and a bypass circuit, and the uninterruptible switching circuit of the service uninterruptible power supply is configured to bypass the bypass operation from a UPS operation in which power is supplied from the inverse converter. A reactor for suppressing a cross current flowing at the moment of switching to a bypass operation in which power is supplied from the circuit is provided.

  A common standby uninterruptible power supply system according to a second aspect of the present invention is the common standby uninterruptible power supply system according to the first aspect of the present invention, wherein the common uninterruptible power supply is switched for connecting the commercial power input to the forward converter to the bypass circuit. A switch is provided.

  The common standby uninterruptible power supply system according to the invention of claim 3 is the common standby uninterruptible power supply system according to the invention of claim 2, wherein the common uninterruptible power supply unit is connected to all other uninterruptible uninterruptible power supplies when it switches from UPS operation to bypass operation. When it is notified to the power supply and the fact that the UPS operation is switched to the bypass operation is received from any of the other uninterruptible uninterruptible power supply devices, its own bypass circuit is connected to the spare uninterruptible power supply device. The disconnecting switch is closed and connected to the commercial power source.

  The common backup uninterruptible power supply system according to the invention of claim 4 is the common standby uninterruptible power supply system according to claim 2, wherein the common uninterruptible power supply is changed to a standby uninterruptible power supply when the UPS is switched from the UPS operation to the bypass operation. When this is reported, and when any other permanent uninterruptible power supply has been switched from UPS operation to bypass operation from the standby uninterruptible power supply, its own bypass circuit is connected to the spare uninterruptible power supply. Disconnect from the power failure power supply and close the switching switch and connect to the commercial power supply, and when the standby uninterruptible power supply is switched from UPS operation to bypass operation, This is reported to the remaining normal uninterruptible power supply.

  A common standby uninterruptible power supply system according to a fifth aspect of the invention is the common standby uninterruptible power supply system according to the second aspect of the invention, wherein the common uninterruptible power supply device issues a notification to the control panel when it switches from UPS operation to bypass operation. When it is received from the control panel that any other permanent uninterruptible power supply has been switched from UPS operation to bypass operation, its own bypass circuit is disconnected from the backup uninterruptible power supply and the switching open / close The controller is closed and connected to the commercial power source, and the control panel issues a notification to the remaining normal uninterruptible power supply units when any of the regular uninterruptible power supply units switches from UPS operation to bypass operation. It is characterized by reporting.

  According to the present invention, since the cross current can be suppressed by the reactor of the uninterruptible switching circuit when the normal uninterruptible power supply device is switched from the UPS operation to the bypass operation, the reverse converter can be prevented from being overloaded. In addition, when the standby uninterruptible power supply becomes the load of the normal uninterruptible power supply, the remaining normal uninterruptible power supply is disconnected from the standby uninterruptible power supply and its bypass circuit becomes commercial power. Since it is connected, even if another normal uninterruptible power supply is switched from the UPS operation to the bypass operation, the standby uninterruptible power supply is not overloaded.

  FIG. 1 is a configuration diagram of a common standby uninterruptible power supply system according to the first embodiment of the present invention. One backup uninterruptible power supply 12 is provided for the plurality of common uninterruptible power supplies 11a to 11n. Operation stop of the service uninterruptible power supply devices 11a to 11n is given to the forward converters 14a to 14n, the reverse converters 15a to 15n, and the uninterruptible switching circuits 16a to 16n via the control circuits 13a to 13n. Done. Similarly, when the standby uninterruptible power supply 12 is stopped, commands are given to the forward converter 14, the reverse converter 15 and the uninterruptible switching circuit 16 through the control circuit 13, and the normal uninterruptible power supply 11a. This is performed by giving a command to the selection circuit 17 for selecting ˜11n.

  During normal operation, the service uninterruptible power supply devices 11a to 11n convert the AC input 19 from the commercial power source 18 into DC by the forward converters 14a to 14n via the AC input switches 20a to 20n, and then perform reverse conversion. UPS operation which reversely converts into alternating current with unit 15a-15n and obtains a UPS power supply is performed. The obtained USP power supply is supplied to the loads 21a to 21n as an AC output via the uninterruptible switching circuits 16a to 16n. Further, the forward converters 14a to 14n store DC energy in the storage batteries 23a to 23n, which are energy storage units, via the DC input circuit breakers 22a to 22n.

  When a power failure occurs in the commercial power supply 18, the reverse converters 15 a to 15 n convert the DC energy of the storage batteries 23 a to 23 n to AC and are supplied with USP power, and continuously supply the loads 21 a to 21 n as AC output. The bypass circuits 24a to 24n are connected to the output terminal of the standby uninterruptible power supply 12, and the uninterruptible switching circuits 16a to 16n are connected to the output signal of the standby uninterruptible power supply 12 via the bypass input switches 25a to 25n. To enter.

  The bypass circuits 24a to 24n are provided with switching switches 26a to 26n for connecting the commercial power source 18 input to the forward converters 14a to 14n to the bypass circuits 24a to 24n. ˜26n are opened / closed by the sequence control circuits 27a˜27n. The opening / closing of the switching switches 26a to 26n by the sequence control circuits 27a to 27n will be described later.

  Switching between UPS feeding by the inverse converters 15a to 15n and bypass feeding by the bypass circuits 24a to 24n is performed manually or automatically by the uninterruptible switching circuits 16a to 16n. The uninterruptible switching circuits 16a to 16n have a hybrid type changeover switch composed of a thyristor and a switch, and reactors 28a to 28n are connected between the thyristor and the switch of the hybrid type changeover switch. The reactors 28a to 28n suppress the cross current flowing at the moment when the UPS operation in which power is supplied from the inverters 15a to 15n is switched to the bypass operation in which power is supplied from the bypass circuits 24a to 24n.

  On the other hand, in the standby uninterruptible power supply 12, the forward converter 14 and the reverse converter 15 are stopped during normal operation, and the bypass input from the commercial power supply 18 is bypassed via the bypass input switch 25. Is supplied to the uninterruptible switching circuit 16 and is output to the service uninterruptible power supply devices 11a to 11n via the selection circuit 17. When any one of the normal uninterruptible power supply devices 11 a to 11 n is switched from the UPS operation to the bypass operation, the selection circuit 17 connects the standby uninterruptible power supply device 12 to the normal uninterruptible power supply device 11. As a result, the standby uninterruptible power supply 12 supplies the load 21 with the bypass power supply from the commercial power supply temporarily, and the forward converter 14 and the reverse converter 15 of the standby uninterruptible power supply 12 that are stopped are supplied during this period. The operation is switched from the bypass power supply to the UPS power supply, and the UPS power supply is supplied to the load 21.

  When the self-switching operation from the UPS operation to the bypass operation is performed, the sequence control circuits 27a to 27n of the service uninterruptible power supply devices 11a to 11n issue notifications to all other service uninterruptible power supply devices 11. Further, when it is received from any other uninterruptible power supply 11 that the UPS operation has been switched to the bypass operation, the bypass input switch 25 is opened and the self-bypass circuit 24 is set as a spare uninterruptible power supply. 12, and the switching switch 26 is closed and connected to the commercial power source 18.

  FIG. 2 is a flowchart showing the processing contents of the sequence control circuit 27a of the first uninterruptible power supply 11a. FIG. 2 shows a case where determination is made as to whether or not the normal uninterruptible power supply devices 11a to 11n are out of order as determination for switching from UPS operation to bypass operation. First, it is determined whether or not the self-use uninterruptible power supply 11a is out of order (S1). When it is a failure, the fact is notified to the other regular uninterruptible power supply devices 11b to 11n (S2). This notification is performed by contact output. Therefore, the service uninterruptible power supply 11a has contacts for the other service uninterruptible power supplies 11b to 11n.

  On the other hand, when the own uninterruptible power supply 11a is not out of order, it is determined whether or not the second uninterruptible power supply 11b is out of order (S3). It is determined whether or not the device 11c is out of order (S4), and similarly, it is determined whether or not the common uninterruptible power supply 11n of the n-th unit is out of order (Sn). On the other hand, when any one of the uninterruptible uninterruptible power supply devices 11b to 11n of No. 2 to No. n is out of order, the bypass input switch 25a is opened and the switching switch 26a is closed (S0). In this case, the commercial power supply 18 is supplied to the bypass circuit 24a. However, since the uninterruptible switching circuit 16a is not performing a switching operation, the load 21a is not supplied with the commercial power supply 18 but the UPS from the inverter 15a. Power is supplied.

  FIG. 3 is a flowchart showing the processing contents of the sequence control circuit 27b of the second uninterruptible uninterruptible power supply 11b. FIG. 3 shows a case where determination is made as to whether or not the normal uninterruptible power supply devices 11a to 11n are out of order as determination for switching from UPS operation to bypass operation. Also in this case, as in the case of the first unit, first, it is determined whether or not the own uninterruptible power supply 11b is out of order (S1), and then the other uninterruptible power supply 11a, 11c to 11n are It is determined whether or not there is a failure (S3 to Sn). Then, when the uninterruptible uninterruptible power supply 11a, 11c to 11n of any of the first unit, the third unit to the nth unit other than the own unit is out of order, the bypass input switch 25b is opened and the switching switch 26b is closed (S0). . The same applies to the sequence control circuits 27c to 11n of the common uninterruptible power supply devices 11c to 11n of No. 3 to No. n.

  Therefore, when a certain common uninterruptible power supply 11 is switched from UPS operation to bypass operation, the other regular uninterruptible power supply 11 switches the bypass circuit 24 to the commercial power supply 18, so that the standby uninterruptible power supply 11 12 is already carrying the load 21 of the service uninterruptible power supply 11 and does not bear the load of another service uninterruptible power supply 11, so that the backup uninterruptible power supply 12 is overloaded. There is no.

  According to the first embodiment, when the normal uninterruptible power supply devices 11a to 11n are switched from the UPS operation to the bypass operation, the reactors 28a to 28n of the uninterruptible switching circuits 16a to 16n are used for the standby uninterruptible power supply. The cross current flowing between the power supply device 12 and the service uninterruptible power supply device 11 can be suppressed. Therefore, it is possible to prevent the inverse converters 15a to 15n from being overloaded. Further, when the standby uninterruptible power supply 12 is in a state of carrying the loads 21a to 21n of the regular uninterruptible power supply 11a to 11n, the remaining normal uninterruptible power supplies 11a to 11n are used as standby uninterruptible power supplies. 12 and the bypass circuits 24a to 24n are connected to the commercial power supply 18. Therefore, even if another normal uninterruptible power supply 11a to 11n is switched from the UPS operation to the bypass operation, the standby uninterruptible power supply 12 Will not be overloaded.

  FIG. 4 is a configuration diagram of a common standby uninterruptible power supply system according to the second embodiment of the present invention. The second embodiment divides the functions of the sequence control circuits 27a to 27n with respect to the first embodiment shown in FIG. Are divided into the sequence control circuits 30a to 30n of the common uninterruptible power supply devices 11a to 11n. The same elements as those in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.

  In FIG. 4, the sequence control circuit 29 of the standby uninterruptible power supply 12 receives that the normal uninterruptible power supply 11 a to 11 n has switched from the UPS operation to the bypass operation, and any of the normal uninterruptible power supply 11 a. When .about.11n is switched from the UPS operation to the bypass operation, it has a function of notifying all other uninterruptible power supply devices 11 to that effect. Further, the sequence control circuits 30a to 30n of the respective uninterruptible power supply devices 11a to 11n are arranged so that the sequence of the standby uninterruptible power supply device 12 when the own uninterruptible power supply device 11 is switched from the UPS operation to the bypass operation. It has a function of notifying the control circuit 29 to that effect and a function of disconnecting its own bypass circuit 24 from the backup uninterruptible power supply 12 and connecting it to the commercial power supply 18.

  FIG. 5 is a flowchart showing the processing contents of the sequence control circuits 30a to 30n of the service uninterruptible power supply devices 11a to 11n in the second embodiment. FIG. 5 shows a case where determination is made as to whether or not the normal uninterruptible power supply devices 11a to 11n are out of order as determination for switching from UPS operation to bypass operation. Hereinafter, a case where the self-use uninterruptible power supply is the first useless uninterruptible power supply 11a will be described. First, it is determined whether a failure signal of any one of the other uninterruptible uninterruptible power supply devices 11b to 11n has been transmitted from the sequence control circuit 29 of the standby uninterruptible power supply device 12 (S1). When any one of the uninterruptible uninterruptible power supplies 11b to 11n is out of order, the bypass input switch 25a is opened and the switching switch 26a is closed (S2).

  As a result, the commercial power supply 18 is supplied to the bypass circuit 24a, and the uninterruptible switching circuit 16a does not perform the switching operation. Therefore, the UPS 21 from the inverter 15 is not supplied to the load 21a but the commercial power supply 18. Still supplied. In this state, even if the self-use uninterruptible power supply 11a breaks down and the UPS operation is switched to the bypass operation, the power is supplied from the commercial power supply 18 instead of the power supply from the standby uninterruptible power supply 12. The backup uninterruptible power supply 12 is not overloaded.

  On the other hand, when none of the uninterruptible power supply apparatuses 11b to 11n is in failure, it is determined whether or not the own uninterruptible power supply apparatus 11a is in failure (S3). When the self-use uninterruptible power supply 11a is out of order, the fact is notified to the sequence control circuit 29 of the backup uninterruptible power supply 12 (S4). This notification is performed by contact output. Therefore, since the common uninterruptible power supply 11a needs only to have a contact with the standby uninterruptible power supply 12, there is only one contact.

  FIG. 6 is a flowchart showing the processing contents of the sequence control circuit 29 of the backup uninterruptible power supply 12 in the second embodiment. The backup uninterruptible power supply 12 determines whether a failure signal has been transmitted from each of the regular uninterruptible power supplies 11a to 11n. First, it is determined whether or not a failure signal has been transmitted from the first unit uninterruptible power supply 11a (S1). If no failure signal has been transmitted, a failure signal is transmitted from the second unit uninterruptible power supply 11b. It is determined whether or not it has been transmitted (S2). Similarly, it is determined whether or not a failure signal has been transmitted from the normal uninterruptible power supply 11n of the n-th unit (Sn). When any of the normal uninterruptible power supply units 11a to 11n in Units 1 to n is out of order, it is a failure for all the uninterruptible power supply units 11 other than the normal uninterruptible power supply unit 11 that has failed. A signal is issued (S0).

  In the above description, the sequence control circuit 29 for notifying all of the other uninterruptible power supply devices 11 that any one of the uninterruptible power supply devices 11a to 11n has switched from the UPS operation to the bypass operation is used as a spare. Although provided in the power failure power supply device 12, it may be provided in a control panel independent of the backup uninterruptible power supply device 12. In this case, the sequence control circuit 29 is housed in an independent control panel, so that the entanglement of the control power source configured by the backup uninterruptible power supply 12 can be made independent.

  According to the second embodiment, in addition to the effects of the first embodiment, the failure output of the normal uninterruptible power supply 11a to 11n is sent to the standby uninterruptible power supply 12 or the sequence control circuit 29 in the control panel. Since only the notification is made, only one contact point of the failure output of the normal uninterruptible power supply devices 11a to 11n is required, and it becomes possible to flexibly cope with the future expansion of the normal uninterruptible power supply device 11.

The block diagram of the common backup uninterruptible power supply system concerning the 1st Embodiment of this invention. The flowchart which shows the processing content of the sequence control circuit of the common uninterruptible power supply of No. 1 machine in the 1st Embodiment of this invention. The flowchart which shows the processing content of the sequence control circuit of the common uninterruptible power supply apparatus of No. 2 in the 1st Embodiment of this invention. The block diagram of the common backup uninterruptible power supply system concerning the 2nd Embodiment of this invention. The flowchart which shows the processing content of the sequence control circuit of the regular uninterruptible power supply in the 2nd Embodiment of this invention. The flowchart which shows the processing content of the sequence control circuit of the backup uninterruptible power supply in the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Regular uninterruptible power supply device, 12 ... Standby uninterruptible power supply device, 13 ... Control circuit, 14 ... Forward converter, 15 ... Reverse converter, 16 ... Uninterruptible switching circuit, 17 ... Selection circuit, 18 ... Commercial Power source, 19 ... AC input, 20 ... AC input switch, 21 ... Load, 22 ... DC input circuit breaker, 23 ... Storage battery, 24 ... Bypass circuit, 25 ... Bypass input switch, 26 ... Switching switch, 27 ... Sequence Control circuit 28 ... Reactor 29 ... Sequence control circuit 30 ... Sequence control circuit

Claims (5)

  One standby uninterruptible power supply unit is provided for multiple normal uninterruptible power supply units. When the maintenance or inspection of the normal uninterruptible power supply unit fails, the standby uninterruptible power supply unit supplies power to the normal uninterruptible power supply unit. In the common standby uninterruptible power supply system, the standby uninterruptible power supply device includes a forward converter that converts alternating current input from a commercial power source into direct current, and a direct current from the forward converter. An inverter that converts the output to AC again and outputs the output, a storage battery that supplies DC power to the inverter in the event of a power failure of the commercial power supply, and the commercial power supply that bypasses the forward converter and the reverse converter And a non-instantaneous uninterruptible switching circuit for switching between the inverter and the bypass circuit without interruption, and the uninterruptible uninterruptible power supply is an alternating current input from a commercial power source. The direct current A forward converter for converting and outputting; an inverse converter for converting and outputting a direct current output from the forward converter to alternating current; and a storage battery for supplying direct current power to the reverse converter during a power failure of the commercial power source; A bypass circuit that bypasses the forward converter and the reverse converter and supplies power from the backup uninterruptible power supply, and an uninterruptible switching for switching the inverse converter and the bypass circuit without instantaneous interruption The uninterruptible switching circuit of the normal uninterruptible power supply is a cross current that flows at the moment of switching from UPS operation to which power is supplied from the reverse converter to bypass operation to which power is supplied from the bypass circuit. Common standby uninterruptible power supply system characterized by having a reactor for suppressing   2. The common backup uninterruptible power supply system according to claim 1, wherein the common uninterruptible power supply apparatus includes a switching switch for connecting a commercial power input to the forward converter to the bypass circuit.   When the self-operating uninterruptible power supply switches from UPS operation to bypass operation, it notifies all other normal uninterruptible power supply devices, and UPS from any other uninterruptible power supply When receiving a notification that the operation has been switched to the bypass operation, the bypass circuit is disconnected from the standby uninterruptible power supply device, the switching switch is closed, and the commercial power supply is connected. 2. Common standby uninterruptible power supply system according to 2.   When the self-operating uninterruptible power supply switches from UPS operation to bypass operation, it notifies the standby uninterruptible power supply to that effect and any other uninterruptible uninterruptible power supply When it is received that the power supply device has switched from UPS operation to bypass operation, disconnect its own bypass circuit from the backup uninterruptible power supply device, close the switching switch and connect to the commercial power supply, 3. The uninterruptible power supply for an operation notifies the remaining uninterruptible power supply to the remaining uninterruptible power supply when any of the normal uninterruptible power supplies switches from a UPS operation to a bypass operation. Common standby uninterruptible power system as described. When the self-operating uninterruptible power supply is switched from UPS operation to bypass operation, the control panel notifies the control panel, and any other uninterruptible power supply apparatus operates from the UPS operation to bypass operation. When the switchboard is received, the self-bypass circuit is disconnected from the backup uninterruptible power supply, the switching switch is closed and connected to the commercial power supply, and the control panel is connected to the utility uninterruptible power supply. 3. The common standby uninterruptible power supply system according to claim 2, wherein when any of the devices switches from UPS operation to bypass operation, the remaining normal uninterruptible power supply device is notified.

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