JP7760486B2 - Uninterruptible power supply systems and test methods for uninterruptible power supply systems - Google Patents

Description

This disclosure relates to an uninterruptible power supply system and a method for testing an uninterruptible power supply system.

Uninterruptible power supply systems require high reliability, so even if a failure occurs in the uninterruptible power supply unit, it is necessary for the uninterruptible power supply unit to continue supplying power to the load. For this reason, it has traditionally been common to combine multiple uninterruptible power supply units to create a redundant uninterruptible power supply system.

As an example of such a redundant uninterruptible power supply system, Japanese Patent Application Laid-Open No. 2005-218200 (Patent Document 1) discloses an uninterruptible power supply system consisting of multiple regular uninterruptible power supplies configured to constantly supply power to loads, and a standby uninterruptible power supply provided as a common backup for these regular uninterruptible power supplies.

A redundant uninterruptible power supply system generally consists of one standby uninterruptible power supply for multiple normal uninterruptible power supplies. The output of the standby uninterruptible power supply is input to each of the multiple normal uninterruptible power supplies as a bypass input power source. In the event of maintenance or inspection of one normal uninterruptible power supply or a malfunction, the output of the standby uninterruptible power supply becomes the bypass input power source for that normal uninterruptible power supply, and power is supplied to the load via the bypass circuit of that normal uninterruptible power supply.

Japanese Patent Application Laid-Open No. 2005-218200

In an uninterruptible power supply system equipped with a standby uninterruptible power supply, when a normal uninterruptible power supply is updated or added, a combination test is conducted between the new normal uninterruptible power supply and the standby uninterruptible power supply. During the combination test, to prevent an interruption in the power supply to the load equipment, there is a period during which both the standby uninterruptible power supply and the new uninterruptible power supply supply power to the load. If the characteristics of the new normal uninterruptible power supply differ from those of the standby uninterruptible power supply at this time, an abnormality may occur in the new normal uninterruptible power supply or the standby uninterruptible power supply, causing the power supply to the load to stop.

Therefore, the object of this disclosure is to provide an uninterruptible power supply system and a test method for an uninterruptible power supply system that can reduce the possibility of power supply to a load being stopped when testing a combination of a new mains uninterruptible power supply and a standby uninterruptible power supply.

The uninterruptible power supply system disclosed herein comprises: a first normal uninterruptible power supply including a bypass input terminal and an AC output terminal; a standby uninterruptible power supply including a first AC output terminal connectable to a first node to which generated AC power is output and a first test terminal block; a first AC input terminal connectable to the first AC output terminal of the standby uninterruptible power supply; a second AC input terminal connectable to the AC output terminal of the first normal uninterruptible power supply; a first switch having a first end connected to the first AC input terminal; a second switch having a first end connected to the second AC input terminal; and an AC output terminal to which the second end of the first switch and the second end of the second switch are connected and to which a load can be connected; and a switch box including a first terminal, a second terminal, and a switch and a fuse connected in series between the first and second terminals. The first test terminal block includes a first terminal, a second terminal, and a third terminal. The first terminal of the first test terminal block is configured to be connectable to the first terminal of the switch box and is connected to a first node. The second terminal of the first test terminal block is configured to be connectable to the second terminal of the switch box and is connected to a second node. The third terminal of the first test terminal block is connected to the second node and is configured to be connectable to a bypass input terminal of the first utility uninterruptible power supply.

The above-described uninterruptible power supply system testing method includes the steps of turning on the first switch of the first output branch panel, replacing the first normal uninterruptible power supply, connecting the first terminal of the first test terminal block to the first terminal of the switch box, connecting the second terminal of the first test terminal block to the second terminal of the switch box, and connecting the third terminal of the first test terminal block to the bypass input terminal of the replaced first normal uninterruptible power supply, and turning on the second switch of the first output branch panel.

This disclosure reduces the possibility of power supply to the load being stopped when testing a combination of a new mains uninterruptible power supply and a standby uninterruptible power supply.

FIG. 1 is a diagram showing the configuration of an uninterruptible power supply system according to a reference example. FIG. 10 is a diagram showing the states of switches during a first combination test in a reference example. FIG. 10 is a diagram showing the states of the switches during a second combination test in the reference example. 1 is a diagram showing the configuration of an uninterruptible power supply system according to a first embodiment; 10 is a flowchart showing a procedure of a first combination test in the first embodiment. FIG. 10 is a diagram showing switch states during a first combination test in the first embodiment. 10 is a flowchart showing a procedure of a second combination test in the first embodiment. FIG. 10 is a diagram showing switch states during a second combination test in the first embodiment.

Embodiments of the present invention will now be described in detail with reference to the drawings. Note that identical or corresponding parts will be designated by the same reference numerals and their descriptions will not be repeated.

(Reference example)
First, an uninterruptible power supply system according to a reference example will be described.

Figure 1 shows the configuration of an uninterruptible power supply system for reference purposes.

The uninterruptible power supply system of the reference example includes a first normal uninterruptible power supply unit 20A, a second normal uninterruptible power supply unit 20B, a standby uninterruptible power supply unit 20P, a first normal output branch panel 40A, a switch SA1, a second normal output branch panel 40B, a switch SB1, a switch SP1, and storage batteries 2A, 2B, and 2P.

We will now explain the first common system. The second common system is similar to the first common system, so we will not repeat the explanation.

The first normal uninterruptible power supply 20A includes a first normal UPS 11A and a first normal input/output panel 21A. The second normal uninterruptible power supply 20B includes a second normal UPS 11B and a second normal input/output panel 21B. The standby uninterruptible power supply 20P includes a standby UPS 11P and a standby input/output panel 21P.

In the following explanation, the first normal system UPS 11A, the first normal system input/output panel 21A, the first normal system output branch panel 40A, the switch SA1, and the storage battery 2A will be referred to as the first normal system, the second normal system UPS 11B, the second normal system input/output panel 21B, the second normal system output branch panel 40B, the switch SB1, and the storage battery 2B will be referred to as the second normal system, and the standby system UPS 11P, the standby system input/output panel 21P, the switch SP1, and the storage battery 2P will be referred to as the standby system.

The first normal UPS 11A includes a battery terminal T0, input terminal T1, input terminal T2, output terminal T3, converter 3, inverter 4, bypass circuit 6, and bypass switching circuit 5. The first normal input/output panel 21A includes switches S2 to S8, AC input terminal T5, AC output terminal T9, bypass input terminal T4, output terminals T6 and T7, and input terminal T8.

The AC input terminal T5 can be connected to the commercial AC power supply 1 via switch SA1.

The converter 3 and inverter 4 are arranged in series between the AC input terminal T5 and the AC output terminal T9 via switch S5, output terminal T7, and input terminal T2, and output terminal T3, input terminal T8, switch S7, and switch S8.

Bypass circuit 6 is arranged between node N1 (third node) and AC output terminal T9 via switch S4, output terminal T6, and input terminal T1, and output terminal T3, input terminal T8, switch S7, and switch S8.

The bypass switching circuit 5 switches between the output of the inverter 4 and the output of the bypass circuit 6.

The input terminal T1 is connected to the output terminal T6 and to the bypass circuit 6. The input terminal T2 is connected to the output terminal T7 and to the input node of the converter 3.

Battery terminal T0 is connected to a DC circuit (DC link) between the output node of converter 3 and the input node of inverter 4, and is also connected to storage battery 2A.

Converter 3 receives commercial frequency AC power from commercial AC power supply 1. During normal operation, when AC power is supplied from commercial AC power supply 1, converter 3 converts the AC power into DC power. Converter 3 is controlled so that the DC voltage supplied to the DC circuit remains constant.

Storage battery 2A is connected to the DC circuit between converter 3 and inverter 4 via battery terminal T0. Under normal circumstances, storage battery 2A stores DC power generated by converter 3, and supplies DC power to inverter 4 during a power outage when the supply of AC power from commercial AC power source 1 is stopped.

Inverter 4 is connected to the DC circuit. Under normal conditions, inverter 4 converts the DC power generated by converter 3 into AC power at the commercial frequency, and during a power outage, converts the DC power from storage battery 2A into AC power at the commercial frequency. The output node of inverter 4 is connected to output terminal T3.

The bypass circuit 6 is connected between the input terminal T1 and the bypass switching circuit 5. The bypass switching circuit 5 is connected between the bypass circuit 6 and the output terminal T3. The bypass switching circuit 5 switches between electrical connection and disconnection between the bypass circuit 6 and the output terminal T3. Specifically, the bypass switching circuit 5 includes a switch connected between the bypass circuit 6 and the output terminal T3. The switch is in a non-conductive (off) state when power is supplied from the inverter 4, and in a conductive (on) state when power is supplied from the bypass circuit 6.

The control unit controls the converter 3 and the inverter 4 to generate AC power. During a power outage, the control unit stops the converter 3 and controls the inverter 4 to generate AC power. The control unit determines whether AC power is being supplied normally from the commercial AC power supply 1 based on the voltage at the input terminal T2 (i.e., the AC voltage supplied from the commercial AC power supply 1). The control unit controls the converter 3 and the inverter 4 based on the determination result. If the control unit detects a fault in the inverter 4, it controls the bypass switching circuit 5 to electrically connect the bypass circuit 6 and the output terminal T3.

The AC input terminal T5 can be connected to the first terminal of the switch SA1. The second terminal of the switch SA1 is connected to the commercial AC power supply 1.

Output terminal T6 can be connected to input terminal T1. Output terminal T7 can be connected to input terminal T2. Input terminal T8 can be connected to output terminal T3.

Switch S2 (first switch) is arranged between bypass input terminal T4 and node N1 (third node). Switch S3 (second switch) is arranged between AC input terminal T5 and node N1 (third node). When one of switches S2 and S3 is on, the other is off.

Switch S4 is arranged between node N1 and output terminal T6. Switch S5 is arranged between AC input terminal T5 and output terminal T7. Switch S6 is arranged between node N1 and node N2. Switch S7 is arranged between input terminal T8 and node N2. Switch S8 is arranged between node N2 and AC output terminal T9.

The first utility output branch panel 40A has switches S9 and S10, a first AC input terminal T10, a second AC input terminal T11, and AC output terminals T12 and T13.

The first AC input terminal T10 can be connected to the first AC output terminal TP9 of the standby uninterruptible power supply 20P. The second AC input terminal T11 can be connected to the AC output terminal T9 of the first normal uninterruptible power supply 20A.

The first terminal of switch S9 (first switch) is connected to the first AC input terminal T10. The second terminal of switch S9 (first switch) is connected to node N3. The first terminal of switch S10 (second switch) is connected to the second AC input terminal T11. The second terminal of switch S10 (second switch) is connected to node N3.

The AC output terminal T12 is connected to the second end of the switch S9 and the second end of the switch S10 via the node N3, and can be connected to a load LA1. The AC output terminal T13 is connected to the second end of the switch S9 and the second end of the switch S10 via the node N3, and can be connected to a load LA2.

Switches SA1, S2, S3, S4, S5, S6, S8, S9, and S10 are trip switches that automatically turn off when excessive current flows.

The standby UPS 11P includes a battery terminal TP0, input terminals TP1 and TP2, an output terminal TP3, a converter 3P, an inverter 4P, a bypass circuit 6P, and a bypass switching circuit 5P. The standby output branch panel 40P includes switches SP4, SP7, and SP8, switches 33 and 34, a switch 31 (first switch), a switch 32 (second switch), an AC input terminal TP5, output terminals TP6 and TP7, an input terminal TP8, a first AC output terminal TP9, a second AC output terminal TP10, and output terminals TP11 and TP12.

The AC input terminal TP5 can be connected to the commercial AC power supply 1 via the switch SP1.

Converter 3P and inverter 4P are arranged in series between AC input terminal TP5 and node NP1 (first node) via switch SP5, output terminal TP7, and input terminal TP2, and output terminal TP3, input terminal TP8, and switch SP7.

The bypass circuit 6P has a path in parallel between the AC input terminal TP5 and node NP1 (first node), which includes the converter 3P and inverter 4P via the switch SP4, output terminal TP6, and input terminal TP1, and the output terminal TP3, input terminal TP8, and switch SP7.

The bypass switching circuit 5P switches between the output of the inverter 4P and the output of the bypass circuit 6P.

Input terminal TP1 is connected to output terminal TP6 and to bypass circuit 6P. Input terminal TP2 is connected to output terminal TP7 and to the input node of converter 3P.

Battery terminal TP0 is connected to a DC circuit (DC link) between the output node of converter 3P and the input node of inverter 4P, and is also connected to storage battery 2P.

Converter 3P receives commercial frequency AC power from commercial AC power supply 1. During normal operation, when AC power is supplied from commercial AC power supply 1, converter 3P converts the AC power into DC power. Converter 3P is controlled so that the DC voltage supplied to the DC circuit is a constant voltage.

The storage battery 2P is connected to the DC circuit between the converter 3P and the inverter 4P via the battery terminal TP0. Under normal circumstances, the storage battery 2P stores the DC power generated by the converter 3P, and supplies DC power to the inverter 4P during a power outage when the supply of AC power from the commercial AC power source 1 is stopped.

Inverter 4P is connected to the DC circuit. Under normal conditions, inverter 4P converts DC power generated by converter 3P into AC power at the commercial frequency, and during a power outage, converts DC power from storage battery 2P into AC power at the commercial frequency. The output node of inverter 4P is connected to output terminal TP3.

The bypass circuit 6P is connected between the input terminal TP1 and the bypass switching circuit 5P. The bypass switching circuit 5P is connected between the bypass circuit 6P and the output terminal TP3. The bypass switching circuit 5P switches between electrical connection and disconnection between the bypass circuit 6P and the output terminal TP3. Specifically, the bypass switching circuit 5P includes a switch connected between the bypass circuit 6P and the output terminal TP3. The switch is non-conductive (off) when power is supplied from the inverter 4P, and is conductive (on) when power is supplied from the bypass circuit 6P.

The control unit controls the converter 3P and the inverter 4P to generate AC power. During a power outage, the control unit stops the converter 3P and controls the inverter 4P to generate AC power. The control unit determines whether AC power is being supplied normally from the commercial AC power supply 1 based on the voltage at the input terminal TP2 (i.e., the AC voltage supplied from the commercial AC power supply 1). The control unit controls the converter 3P and the inverter 4P based on the determination result. If the control unit detects a fault in the inverter 4P, it controls the bypass switching circuit 5P to electrically connect the bypass circuit 6P to the output terminal TP3.

The AC input terminal T5 can be connected to the first terminal of the switch SP1. The second terminal of the switch SP1 is connected to the commercial AC power supply 1.

Output terminal TP6 can be connected to input terminal TP1. Output terminal TP7 can be connected to input terminal TP2. Input terminal TP8 can be connected to output terminal TP3.

Switch SP4 is arranged between AC input terminal TP5 and output terminal T6. Switch SP5 is arranged between AC input terminal TP5 and output terminal T7. AC power generated by standby uninterruptible power supply 20P is output to node NP1 (first node). Switch SP6 is arranged between AC input terminal TP5 and node NP1 (first node). Switch SP7 is arranged between input terminal TP8 and node NP1 (first node).

Switch 33 is arranged between node NP1 (first node) and first AC output terminal TP9. Switch 34 is arranged between node NP1 (first node) and second AC output terminal TP10.

Switch 31 is arranged between node NP1 (first node) and output terminal TP12. Switch 32 is arranged between node NP1 (first node) and output terminal TP11.

Switches SP1, SP4, SP5, SP6, 31, 32, 33, and 34 are trip switches that automatically turn off when excessive current flows.

(Operation of the reference example)
Next, in the reference example, a method for replacing the first normal uninterruptible power supply 20A and performing a combination test (first combination test) of the new first normal uninterruptible power supply 20A and the standby uninterruptible power supply 20P will be described.

Figure 2 shows the switch states during the first combination test in the reference example.

In the standby system, switches SP1, SP4, SP5, SP7, 31, 33, and 34 are set on, and switches SP6 and 32 are set off. In the first normal system, switch S9 is set on. In the second normal system, switches SB1, S3, S4, S5, S7, and S8 are set on, and switches S2 and S6 are set off.

Replace the first normal uninterruptible power supply 20A. That is, remove the old first normal uninterruptible power supply 20A from the uninterruptible power supply system and connect the new first normal uninterruptible power supply 20A to the uninterruptible power supply system.

In the first normal system, switches S2, S4, S5, S7, S8, and S10 are set to on, and switches SA1, S3, and S6 are set to off.

As a result, both switches S9 and S10 are turned on simultaneously in the first normal output branch panel 40A. The AC power generated by the standby uninterruptible power supply 20P is supplied to loads LA1 and LA2 via the first AC output terminal TP9 of the standby uninterruptible power supply 20P, the first AC input terminal T10 of the first normal output branch panel 40A, and switch S9. The AC power generated by the standby uninterruptible power supply 20P is further supplied to loads LA1 and LA2 via the output terminal TP12 of the standby uninterruptible power supply 20P, the bypass input terminal T4, switch S2, switch S4, bypass circuit 6, output terminal T3, input terminal T8, switch S7, switch S8, and AC output terminal T9 of the first normal uninterruptible power supply 20A, the second AC input terminal T11 of the first normal output branch panel 40A, and switch S10.

Switches S9 and S10 are set to ON simultaneously because if there is even a short period of time when both switches are OFF when switching from switch S9 to switch S10, power supply to loads LA1 and LA2 will be stopped.

While switches S9 and S10 are set to on, node N3 receives voltage V1 from the standby uninterruptible power supply 20P and voltage V2 from the first normal uninterruptible power supply 20A. When the old first normal uninterruptible power supply 20A before switching is connected, the voltage characteristics of V1 and V2 are the same.

If the model or specifications of the new first normal uninterruptible power supply 20A after the switchover are the same as the model or specifications of the old first normal uninterruptible power supply 20A before the switchover, the voltage characteristics of V1 and V2 will be the same. In this case, no abnormalities will occur, so switch S9 is set to OFF, and the first combination test ends.

If the model or specifications of the new first normal uninterruptible power supply 20A after the switchover differ from the model or specifications of the old first normal uninterruptible power supply 20A before the switchover, the voltage characteristics of V1 and V2 may differ. If the voltage characteristics of V1 and V2 differ, a large current may be generated in the standby uninterruptible power supply 20P, causing failure of one or both of the first normal uninterruptible power supply 20A and the standby uninterruptible power supply 20P, or a situation may arise in which the first normal uninterruptible power supply 20A must be operated using commercial AC power from commercial AC power source 1. As a result, problems such as an interruption in the power supply to loads LA1 and LA2 may occur.

Next, in the reference example, we will explain how to replace the second regular uninterruptible power supply 20B and perform a combination test (second combination test) of the new second regular uninterruptible power supply 20B and standby uninterruptible power supply 20P.

Figure 3 shows the switch states during the second combination test in the reference example.

In the standby system, switches SP1, SP4, SP5, SP7, 32, 33, and 34 are set on, and switches SP6 and 31 are set off. In the second normal system, switch S9 is set on. In the first normal system, switches SA1, S3, S4, S5, S7, and S8 are set on, and switches S2 and S6 are set off.

Replace the second normal uninterruptible power supply 20B. That is, remove the old second normal uninterruptible power supply 20B from the uninterruptible power supply system and connect the new second normal uninterruptible power supply 20B to the uninterruptible power supply system.

In the second normal system, switches S2, S4, S5, S7, S8, and S10 are set to on, and switches SB1, S3, and S6 are set to off.

As a result, both switches S9 and S10 are turned on simultaneously in the second normal output branch panel 40B. The AC power generated by the standby uninterruptible power supply 20P is supplied to loads LB1 and LB2 via the second AC output terminal TP10 of the standby uninterruptible power supply 20P, the first AC input terminal T10 of the second normal output branch panel 40B, and switch S9. The AC power generated by the standby uninterruptible power supply 20P is further supplied to loads LB1 and LB2 via the output terminal TP11 of the standby uninterruptible power supply 20P, the bypass input terminal T4, switch S2, switch S4, bypass circuit 6, output terminal T3, input terminal T8, switch S7, switch S8, and AC output terminal T9 of the second normal output branch panel 40B, and the second AC input terminal T11 and switch S10 of the second normal output branch panel 40B.

Switches S9 and S10 are set to ON simultaneously because if there is even a short period of time when both switches are OFF when switching from switch S9 to switch S10, power supply to loads LB1 and LB2 will be stopped.

While switches S9 and S10 are set to on, node N3 receives voltage V1 from standby uninterruptible power supply 20P and voltage V2 from second normal uninterruptible power supply 20B. When the old second normal uninterruptible power supply 20B before switching is connected, the voltage characteristics of V1 and V2 are the same.

If the model or specifications of the new second normal uninterruptible power supply 20B after the switchover are the same as those of the old second normal uninterruptible power supply 20B before the switchover, the voltage characteristics of V1 and V2 will be the same. In this case, no abnormalities will occur, so switch S9 is set to OFF, and the second combination test ends.

If the model or specifications of the new second normal uninterruptible power supply 20B after the switchover differ from the model or specifications of the old second normal uninterruptible power supply 20B before the switchover, the voltage characteristics of V1 and V2 may differ. If the voltage characteristics of V1 and V2 differ, a large current may be generated in the standby uninterruptible power supply 20P, causing failure of either or both of the second normal uninterruptible power supply 20B and the standby uninterruptible power supply 20P, or a situation may arise in which the second normal uninterruptible power supply 20B must be operated using commercial AC power from commercial AC power supply 1. As a result, problems such as an interruption in the power supply to loads LB1 and LB2 may occur.

Embodiment 1.
(Uninterruptible power supply system according to the first embodiment)
FIG. 4 is a diagram showing the configuration of the uninterruptible power supply system according to the first embodiment.

The uninterruptible power supply system of embodiment 1 differs from the uninterruptible power supply system of the reference example in that the uninterruptible power supply system of embodiment 1 includes a switch box 60.

In this embodiment, the standby system input/output board 21P further includes a first test terminal block 50 and a second test terminal block 51. The first test terminal block 50 includes a first terminal 51X, a second terminal 51Y, and a third terminal 51Z. The second test terminal block 51 includes a first terminal 51X, a second terminal 51Y, and a third terminal 51Z.

The switch box 60 includes a first terminal 61, a second terminal 62, a switch 65, and a fuse 70. The switch 65 and fuse 70 are connected in series between the first terminal 61 and the second terminal 62.

The first terminal 50X of the first test terminal block 50 is connected to node NP1 (first node) and is connectable to the first terminal 61 of the switch box 60. The second terminal 50Y of the first test terminal block 50 is connected to node NP4 (second node) and is connectable to the second terminal 62. The third terminal 50Z of the first test terminal block 50 is connected to node NP4 (second node) and is connectable to the bypass input terminal T4 of the first normal system input/output panel 21A. The switch 31 is disposed between nodes NP1 and NP4.

The first terminal 51X of the second test terminal block 51 is connected to node NP1 (first node) and is connectable to the first terminal 61 of the switch box 60. The second terminal 51Y of the second test terminal block 51 is connected to node NP5 (fourth node) and is connectable to the second terminal 62. The third terminal 51Z of the second test terminal block 51 is connected to node NP5 (fourth node) and is connectable to the bypass input terminal T4 of the second normal system input/output panel 21B. The switch 32 is disposed between nodes NP1 and NP5.

(First Test Method for Uninterruptible Power Supply System of First Embodiment)
Next, a method for replacing the first normal uninterruptible power supply 20A and performing a combination test (first combination test) of the new normal uninterruptible power supply 20A and the standby uninterruptible power supply 20P will be described.

Figure 5 is a flowchart showing the procedure for the first combination test in embodiment 1. Figure 6 is a diagram showing the switch states during the first combination test in embodiment 1.

In step S101, multiple switches are set to on/off.

In the standby system, switches SP1, SP4, SP5, SP7, 33, and 34 are set on, and switches SP6, 31, and 32 are set off. In the first normal system, switch S9 is set on. In the second normal system, switches SB1, S3, S4, S5, S7, and S8 are set on, and switches S2 and S6 are set off.

In step S102, the first normal uninterruptible power supply 20A is replaced. That is, the old first normal uninterruptible power supply 20A is removed from the uninterruptible power supply system, and a new first normal uninterruptible power supply 20A is connected to the uninterruptible power supply system.

In step S103, the first terminal 50X of the first test terminal block 50 is connected to the first terminal 61 of the switch box 60, the second terminal 50Y of the first test terminal block 50 is connected to the second terminal 62 of the switch box 60, and the third terminal 50Z of the first test terminal block 50 is connected to the bypass input terminal T4 of the new, replaced first normal uninterruptible power supply 20A.

In step S104, in the first normal system, switches S2, S4, S5, S7, S8, and S10 are set to ON, and switches SA1, S3, and S6 are set to OFF.

As a result, the AC power generated by the standby uninterruptible power supply 20P and output to node NP1 is sent to the bypass input terminal T4 of the first normal uninterruptible power supply 20A via the first terminal 50X of the first test terminal block 50, the first terminal 61, switch 65, fuse 70, and second terminal 62 of the switch box 60, the second terminal 51Y of the first test terminal block 50, node NP4 of the standby uninterruptible power supply 20P, and the third terminal 51Z of the first test terminal block 50. If a large current flows through node NP1 of the standby uninterruptible power supply 20P, the fuse 70 of the switch box 60 will blow. As a result, the supply of AC power from standby uninterruptible power supply 20P to first normal uninterruptible power supply 20A is stopped, preventing a situation in which one or both of first normal uninterruptible power supply 20A and standby uninterruptible power supply 20P fail, or in which first normal uninterruptible power supply 20A has to be operated using commercial AC power from commercial AC power supply 1. As a result, the possibility of power supply to loads LA1 and LA2 being stopped can be reduced.

If the fuse 70 in the switch box 60 is not blown in step S105, processing proceeds to step S106.

In step S106, switch S9 on the first normal system output distribution board 40A is set to OFF.

In step S107, the connection between the first terminal 50X of the first test terminal block 50 and the first terminal 61 of the switch box 60 is disconnected, and the connection between the second terminal 50Y of the first test terminal block 50 and the second terminal 62 of the switch box 60 is connected.

Next, we will explain how to replace the second regular uninterruptible power supply 20B and perform a combination test (second combination test) of the new regular uninterruptible power supply 20B and standby uninterruptible power supply 20P.

Figure 7 is a flowchart showing the procedure for the second combination test in embodiment 1. Figure 8 is a diagram showing the switch states during the second combination test in embodiment 1.

In step S201, multiple switches are set to on/off.

In the standby system, switches SP1, SP4, SP5, SP7, 33, and 34 are set on, and switches SP6, 31, and 32 are set off. In the second normal system, switch S9 is set on. In the first normal system, switches SA1, S3, S4, S5, S7, and S8 are set on, and switches S2 and S6 are set off.

In step S202, the second normal uninterruptible power supply 20B is replaced. That is, the old second normal uninterruptible power supply 20B is removed from the uninterruptible power supply system, and a new second normal uninterruptible power supply 20B is connected to the uninterruptible power supply system.

In step S203, the first terminal 51X of the second test terminal block 51 is connected to the first terminal 61 of the switch box 60, the second terminal 51Y of the second test terminal block 51 is connected to the second terminal 62 of the switch box 60, and the third terminal 51Z of the second test terminal block 51 is connected to the bypass input terminal T4 of the new, replaced second normal uninterruptible power supply 20B.

In step S204, in the second normal system, switches S2, S4, S5, S7, S8, and S10 are set to ON, and switches SB1, S3, and S6 are set to OFF.

As a result, the AC power generated by the standby uninterruptible power supply 20P and output to node NP1 is sent to the bypass input terminal T4 of the second normal uninterruptible power supply 20B via the first terminal 51X of the second test terminal block 51, the first terminal 61, switch 65, fuse 70, and second terminal 62 of the switch box 60, the second terminal 51Y of the second test terminal block 51, node NP4 of the standby uninterruptible power supply 20P, and the third terminal 51Z of the second test terminal block 51. If a large current flows through node NP1 of the standby uninterruptible power supply 20P, the fuse 70 of the switch box 60 will blow. As a result, the supply of AC power from standby uninterruptible power supply 20P to second normal uninterruptible power supply 20B is stopped, preventing a situation in which one or both of second normal uninterruptible power supply 20B and standby uninterruptible power supply 20P fail, or in which second normal uninterruptible power supply 20B must be operated using commercial AC power from commercial AC power supply 1. This reduces the possibility of power supply to loads LB1 and LB2 being stopped.

If the fuse 70 in the switch box 60 is not blown in step S205, processing proceeds to step S206.

In step S206, switch S9 on the second regular system output distribution board 40B is set to OFF.

In step S207, the connection between the first terminal 51X of the second test terminal block 51 and the first terminal 61 of the switch box 60 is disconnected, and the connection between the second terminal 51Y of the second test terminal block 51 and the second terminal 62 of the switch box 60 is connected.

As described above, according to this embodiment, by providing test terminal blocks 50, 51 and switch box 60, it is possible to reduce the possibility of power supply to the load being stopped during a combined test of a regular uninterruptible power supply to be updated or expanded with an existing standby uninterruptible power supply. Furthermore, because combined testing is possible by connecting an external switch box to the standby uninterruptible power supply, the switch box can be reused for combined testing of multiple systems. As a result, costs can also be reduced.

The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The present invention is defined by the claims rather than the above description, and it is intended to include all modifications within the meaning and scope of the claims.

1 Commercial AC power supply, 2A, 2B, 2P Storage battery, 3, 3P Converter, 4, 4P Inverter, 5, 5P Bypass switching circuit, 6, 6P Bypass circuit, 20A, 20B, 20P Uninterruptible power supply, 21A First normal system input/output panel, 21B Second normal system input/output panel, 21P Standby system input/output panel, 31, 32, 33, 34, 65, S2, S3, S4, S5, S6, S7, S8, S9, S10, SA1, SB1, SP1, SP4, SP5, SP6, SP7, SP8 Switch, 40A First normal system output branch panel, 40B Second normal system output branch panel, 40P Standby system output branch panel, 50 First test terminal block, 50X, 51X, 61 First terminals, 50Y, 51Y, 62 Second terminals, 50Z, 51Z Third terminal, 51 Second test terminal block, 60 Switch box, 70 Fuses, LA1, LA2, LB1, LB2 Load, T0, TP0 Battery terminals, T1, T2, T8, TP1, TP2, TP8 Input terminals, T3, T6, T7, TP3, TP6, TP7, TP11, TP12 Output terminal, T4 Bypass input terminals, T5, TP5 AC input terminals, T9, T12, T13 AC output terminal, T10 First AC input terminal, T11 Second AC input terminal, TP9 First AC output terminal, TP10 Second AC output terminal, 11A First regular UPS, 11B Second regular UPS, 11P Standby UPS.

Claims (11)

a first utility uninterruptible power supply including a bypass input terminal and an AC output terminal;
a standby uninterruptible power supply including a first AC output terminal connectable to a first node to which the generated AC power is output, and a first test terminal block;
a first output branch panel including: a first AC input terminal connectable to the first AC output terminal of the standby uninterruptible power supply; a second AC input terminal connectable to the AC output terminal of the first normal uninterruptible power supply; a first switch having a first end connected to the first AC input terminal; a second switch having a first end connected to the second AC input terminal; and an AC output terminal to which a second end of the first switch and a second end of the second switch are connected and to which a load can be connected;
a switch box including a first terminal, a second terminal, and a switch and a fuse connected in series between the first terminal and the second terminal;
the first test terminal block includes a first terminal, a second terminal, and a third terminal;
the first terminal of the first test terminal block is configured to be connectable to the first terminal of the switch box and is connected to the first node;
the second terminal of the first test terminal block is configured to be connectable to the second terminal of the switch box and is connected to a second node;
An uninterruptible power supply system, wherein the third terminal of the first test terminal block is connected to the second node and is configured to be connectable to the bypass input terminal of the first normal uninterruptible power supply. The standby uninterruptible power supply device is
2. The uninterruptible power supply system according to claim 1, further comprising a first switch disposed between said first node and said second node. The first normal uninterruptible power supply further comprises:
an AC input terminal connectable to an AC power source;
a converter and an inverter arranged in series between the AC input terminal and the AC output terminal;
a bypass circuit disposed between a third node and the AC output terminal;
a bypass switching circuit for switching between the output of the inverter and the output of the bypass circuit;
a storage battery connected to a DC circuit between the converter and the inverter;
a first switch disposed between the bypass input terminal and the third node;
a second switch disposed between the AC input terminal and the third node;
2. The uninterruptible power supply system according to claim 1, wherein when one of the first switch and the second switch is on, the other is off. the standby uninterruptible power supply further includes a second AC output terminal connectable to the first node and a second test terminal block;
The uninterruptible power supply system comprises:
a second normal uninterruptible power supply including a bypass input terminal and an AC output terminal;
a second output branch panel including a first AC input terminal connectable to the second AC output terminal of the standby uninterruptible power supply, a second AC input terminal connectable to the AC output terminal of the second normal uninterruptible power supply, a first switch having a first end connected to the first AC input terminal, a second switch having a first end connected to the second AC input terminal, and an AC output terminal to which a second end of the first switch and a second end of the second switch are connected and to which a load can be connected,
the second test terminal block includes a first terminal, a second terminal, and a third terminal;
the first terminal of the second test terminal block is configured to be connectable to the first terminal of the switch box and is connected to the first node;
the second terminal of the second test terminal block is configured to be connectable to the second terminal of the switch box and is connected to a fourth node;
2. The uninterruptible power supply system according to claim 1, wherein the third terminal of the second test terminal block is connected to the fourth node and is configured to be connectable to the bypass input terminal of the second normal uninterruptible power supply. The standby uninterruptible power supply device is
5. The uninterruptible power supply system according to claim 4, further comprising a second switch disposed between said first node and said fourth node. The second normal uninterruptible power supply further comprises:
an AC input terminal connectable to an AC power source;
a converter and an inverter arranged in series between the AC input terminal and the AC output terminal;
a bypass circuit disposed between a third node and the AC output terminal;
a bypass switching circuit for switching between the output of the inverter and the output of the bypass circuit;
a storage battery connected to a DC circuit between the converter and the inverter;
a first switch disposed between the bypass input terminal and the third node;
a second switch disposed between the AC input terminal and the third node;
5. The uninterruptible power supply system according to claim 4, wherein when one of the first switch and the second switch is on, the other is off. The standby uninterruptible power supply device is
an AC input terminal connectable to an AC power source;
a converter and an inverter arranged in series between the AC input terminal and the first node;
a bypass circuit arranged between the AC input terminal and the first node in parallel with a path in which the converter and the inverter are arranged;
a bypass switching circuit for switching between the output of the inverter and the output of the bypass circuit;
2. The uninterruptible power supply system according to claim 1, further comprising: a storage battery connected to a DC circuit between said converter and said inverter. 2. A method for testing an uninterruptible power supply system according to claim 1, comprising:
turning on the first switch of the first output branch panel;
replacing the first utility uninterruptible power supply;
connecting the first terminal of the first test terminal block to the first terminal of the switch box, connecting the second terminal of the first test terminal block to the second terminal of the switch box, and connecting the third terminal of the first test terminal block to the bypass input terminal of the replaced first normal uninterruptible power supply;
and turning on the second switch of the first output branch panel. turning off the first switch of the first output branch panel when the fuse of the switch box is not blown as a result of the connecting step;
9. The method for testing an uninterruptible power supply system according to claim 8, further comprising the steps of: disconnecting the first terminal of the first test terminal block from the first terminal of the switch box; and disconnecting the second terminal of the first test terminal block from the second terminal of the switch box. 5. A method for testing an uninterruptible power supply system according to claim 4, comprising:
turning on the first switch of the second output branch panel;
replacing the second normal uninterruptible power supply;
connecting the first terminal of the second test terminal block to the first terminal of the switch box, connecting the second terminal of the second test terminal block to the second terminal of the switch box, and connecting the third terminal of the second test terminal block to the bypass input terminal of the replaced second normal uninterruptible power supply;
and turning on the second switch of the second output branch panel. turning off the first switch of the second output branch panel when the fuse of the switch box is not blown as a result of the connecting step;
11. The method for testing an uninterruptible power supply system according to claim 10, further comprising the steps of: disconnecting the connection between the first terminal of the second test terminal block and the first terminal of the switch box; and disconnecting the connection between the second terminal of the second test terminal block and the second terminal of the switch box.