TW202103406A - Uninterruptible power supply characterized in that the uninterruptible power supply can also deal with various system abnormalities other than the voltage dip including an instantaneous voltage dip and the frequency fluctuation - Google Patents

Abstract

The present invention provides an uninterruptible power supply which can also deal with various system abnormalities other than the voltage dip including an instantaneous voltage dip and the frequency fluctuation. An uninterruptible power supply (100) is disposed between a commercial power system (10) and an important load (30) and supplies AC power for the important load (30). The uninterrupted power supply (100) includes: a power portion (2) including an energy storage device (21) connected to an electric line (L1), wherein the electric line (L1) is used to supply electricity for the important load (30) from the commercial power system (10); a circuit breaker (3) which is disposed on the electric line (L1) to be closer to the side of the commercial power system (10) than the power portion (2) and allows the electric line (L1) to be opened or closed; a system abnormality detection portion (5) detecting system abnormalities, wherein the system abnormality is also at least one of voltage rise, phase fluctuation, voltage unbalance, high-order harmonic abnormality and flicker other than at least one of the voltage dip including an instantaneous voltage dip and the frequency fluctuation, and the instantaneous voltage dip is generated at the side closer to the commercial power system than the circuit breaker (3); and a controlling portion (6) used to break the circuit breaker (3) so as to supply AC power for the important load (30) from the power portion (2), when the detected system abnormality exceeds the tolerance of the important load (30) or the power portion (2) to the system abnormality.

Description

Uninterruptible power supply device

The present invention relates to an uninterruptible power supply device in a usual commercial power supply mode.

The uninterruptible power supply device of the usual commercial power supply system is a device that compensates for the instantaneous voltage drop or frequency fluctuation of the system voltage of the commercial power system. For example, as shown in Patent Document 1, the power supply unit is connected in parallel with the load. A switch is provided on the upper part of the component, and the power supply unit includes a battery and a parallel inverter (inverter). Furthermore, when the system voltage of the commercial power system exceeds the prescribed allowable voltage range, the switch is opened, and the power storage unit, which is an energy storage device, supplies power to the load.

However, in the conventional uninterruptible power supply device of the usual commercial power supply system, only the instantaneous voltage drop and frequency fluctuation compensation operation can be performed to the load, and the compensation operation for other system abnormalities cannot be performed. In addition, the consideration of system abnormalities is only for the load, but not for the energy storage device. [Prior Art Literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 2005-229662

[The problem to be solved by the invention]

Therefore, the present invention was completed in order to solve the above-mentioned problems, and its main subject is to provide an uninterruptible power supply device that can also cope with various system abnormalities other than voltage drops including instantaneous voltage drops and frequency fluctuations. [Means to solve the problem]

That is, the uninterrupted power supply device of the present invention is an uninterrupted power supply device that is installed between a commercial power system and an important load, and supplies AC power to the important load. It includes a power supply unit, including an energy storage connected to a power line. Device, the power line is used to supply power from the power system to the important load; an opening switch is provided on the power line on the side of the commercial power system than the power supply unit, so that The power line is open or closed; the system abnormality detection unit detects system abnormalities. The system abnormality is not only at least one of voltage drop including instantaneous voltage drop or frequency fluctuation, but also voltage rise, phase change, and voltage At least one of unbalance, high-order harmonic abnormality, or flicker, the instantaneous voltage drop is generated on the side of the commercial power system closer to the circuit breaker; and the control unit, when the detected system When the abnormality is greater than the tolerance of the important load or the power supply unit to the abnormality of the system, the disconnect switch is disconnected, and AC power is supplied from the power supply unit to the important load.

In the case of such an uninterruptible power supply device, the system abnormality detection unit detects system abnormalities. The system abnormalities are not only voltage drops including instantaneous voltage drops or at least one of frequency fluctuations, but also voltages. At least one of rise, phase change, voltage imbalance, high-order harmonic abnormality, or flicker. When the detected system abnormality is an important load or the power supply unit's tolerance to the system abnormality or more, the circuit breaker can be disconnected. Respond to various system abnormalities other than voltage drops including instantaneous voltage drops and frequency fluctuations. In addition, not only the tolerance of the important load against system abnormalities is used as a parameter, but also the tolerance of the power supply unit against system abnormalities is used as a parameter to open the circuit breaker. Therefore, it can not only deal with system abnormalities in consideration of important loads, but also Deal with system abnormalities in consideration of the power supply unit.

Here, it can be read from the interconnection rules. As system abnormalities, the phase fluctuations, voltage imbalances, high-order harmonic abnormalities, or flicker can be considered. However, if the three-phase system voltage is further subjected to three-phase-two-phase In the complex number obtained by conversion (α-β-0 conversion), the expression of the α component (set it as a real number component) and β component (set it as an imaginary number component) can be expressed by Equation 1.

此處，各要素如下。 v：系統電壓 V₁ ＝系統電壓振幅 f：系統電壓頻率 θ：與系統電壓相位、相位躍進的相位變動是所述要素的變化。 Σ_{n ≠ 1} v_n ：具有基本波正相成分以外的成分、n=﹣1的逆相成分與|n|≠1的高次諧波成分。 再者，閃爍是V₁ 的數赫茲（Hz）至數十赫茲的低週期變動。[Numerical formula 1]

Here, the elements are as follows. v: system voltage V ₁ = system voltage amplitude f: system voltage frequency θ: the phase change with the system voltage phase and the phase jump is the change of the above-mentioned element. Σ _{n ≠ 1} v _n : It has components other than the normal phase component of the fundamental wave, the reverse phase component of n=﹣1, and the higher harmonic component of |n|≠1. Furthermore, the flicker is _{a low period variation of V 1} from a few hertz (Hz) to several tens of hertz.

As a result of adding system abnormal elements based on this investigation, the uninterrupted power supply device of the usual commercial power supply method can also deal with the uninterrupted power supply device of the more expensive usual inverter power supply method, including transients. System abnormal elements such as voltage drop including voltage drop and voltage increase other than frequency fluctuation, phase fluctuation, voltage imbalance, harmonic abnormality or flicker. As an example, as shown in the below-mentioned "Simulation of the first embodiment", an abnormality of the uninterruptible power supply device (in the simulation, an important load with interconnected inverters is dropped due to abnormal overcurrent) Prevent it from happening.

As a specific embodiment, it is desirable that the power supply unit is to withstand the limit of the important load or the power supply unit with a smaller tolerance to the abnormality of the system when the disconnect switch is disconnected. Operate independently within the scope of the volume.

In order to reduce the frequency of shifting to independent operation with high running cost, it is desirable for the control unit to detect that the system abnormality detected by the system abnormality detection unit is less abnormal than the important load or the power supply. The power supply unit performs a compensation operation for the system abnormality when the tolerance to the system abnormality is greater than or equal to the predetermined threshold value.

In order to cope with the prolonged independent operation time, it is desirable to include a power generating device which is connected to the power line separately from the power source. [Effects of the invention]

According to the present invention configured as described above, it is possible to provide an uninterruptible power supply device, which can also cope with various system abnormalities other than voltage drops including instantaneous voltage drops and frequency fluctuations.

<The first embodiment> Hereinafter, the first embodiment of the uninterruptible power supply device of the present invention will be described with reference to the drawings.

The uninterruptible power supply device 100 of the first embodiment is shown in FIG. 1 and is a device of the usual commercial power supply method. It is installed between the commercial power system 10 and the important load 30. When the commercial power system 10 is abnormal, the important load 30 Supply electricity. Furthermore, in addition to the commercial power system 10, the uninterruptible power supply device 100 may also be installed between the upper power supply side power system of the self-operated line and the important load 30.

Here, the commercial power system 10 is a power supply network of a power company (power supplier), and includes a power station, a power supply system, and a power distribution system. In addition, the important load 20 is a load for supplying electric power stably even when the system is abnormal such as a power outage or instantaneous drop. There is one in FIG. 1, but there may be more than one.

Specifically, the uninterruptible power supply device 100 includes: a power supply unit 2; a disconnect switch 3, which connects the commercial power system 10 with the power supply unit 2 and an important load 30; and a system-side voltage detection unit 4, which detects more reliably than the disconnect switch 3. The voltage on the side of the commercial power system 10; the system abnormality detection section 5, which detects system abnormalities based on the detection voltage of the system-side voltage detection section 4; and the control section 6, the disconnection switch 3 by the detection signal of the system abnormality detection section 5 Open circuit.

The power supply unit 2 is connected to a power line L1 that is used to supply power from the commercial power system 10 to the important load 30. The power supply unit 2 is a component interconnected with the commercial power system 10 and includes an energy storage device 21 such as a secondary battery (battery) and a power converter (power conditioner) 22.

The disconnect switch 3 is a member that is provided on the power line L1 on the side of the commercial power system 10 than the connection point of the power supply unit 2 to open or close the power line L1. For example, a semiconductor switch or a hybrid switch can be used. A non-momentary switch capable of high-speed switching. The hybrid switch is a combination of a semiconductor switch and a mechanical switch. For example, in the case of using a semiconductor switch, the switching time can be set to two milliseconds or less, and the switch can be cut regardless of the zero point. In addition, in the case of using a hybrid switch, not only can the switching time be set to two milliseconds or less, the cut-off can be performed regardless of the zero point, and the energization loss can be set to zero. Furthermore, the disconnect switch 3 is controlled by the control unit 6 to open or close.

The system-side voltage detection unit 4 is a component that detects the voltage on the power line L1 that is closer to the commercial power system 10 than the disconnect switch 3 via the meter transformer 41. Specifically, the system-side voltage detection unit 4 is connected to the side of the commercial power system 10 rather than the disconnect switch 3 via the meter transformer 41.

The system abnormality detection unit 5 is a component that detects abnormalities in each system on the side of the commercial power system 10 relative to the disconnect switch 3 based on the detection voltage detected by the system-side voltage detection unit 4. The system abnormalities of the present embodiment include voltage drop, voltage rise, frequency fluctuation, phase fluctuation, voltage imbalance, abnormal harmonics, and flicker including instantaneous drop.

Therefore, the system abnormality detection unit 5 includes: a voltage drop detection unit 51 that detects a voltage drop including an instantaneous drop; a frequency fluctuation detection unit 52 that detects frequency fluctuations; a voltage rise detection unit 53 that detects a voltage rise; and a phase fluctuation detection unit 54 , Detects the phase change; the voltage unbalance detection section 55, detects the voltage imbalance; the abnormal harmonic detection section 56, detects the abnormal high harmonics; and the flicker detection section 57, detects flicker.

The voltage drop detection unit 51 is a member that detects a voltage drop by comparing the detection voltage of the system-side voltage detection unit 4 with a predetermined set value. Here, the set value used to detect the voltage drop is the voltage value used to detect the instantaneous drop, for example, the remaining voltage is 20%.

The frequency fluctuation detection unit 52 is a component that detects frequency fluctuations (on frequency, OF) and frequency down (under frequency, UF) based on the detection voltage of the system-side voltage detection unit 4. Furthermore, the frequency fluctuation is, for example, a step Rise or slope up and down.

The voltage increase detection unit 53 is a member that detects a voltage increase by comparing the detection voltage of the system-side voltage detection unit 4 with a predetermined set value. Here, the set value for detecting the increase in voltage is, for example, a voltage of 107% relative to the system voltage.

The phase change detection unit 54 is a member that detects a phase change such as a phase jump of 10° based on the phase of the detection voltage of the system-side voltage detection unit 4.

The voltage unbalance detection unit 55 is a member that detects the magnitude of the amplitude or the phase difference of 120° between the three phases in different states based on the detection voltage of the system-side voltage detection unit 4.

The abnormal harmonic detection unit 56 is a component that detects the harmonic voltage based on the detection voltage of the system-side voltage detection unit 4. The flicker detection unit 57 is a member that detects voltage fluctuation (flicker) based on the detection voltage of the system-side voltage detection unit 4.

The control unit 6 is a member that outputs a control signal to the disconnect switch 3 based on the detection signals detected by the system abnormality detection unit 5 to disconnect the disconnect switch 3. The control unit 6 of the present embodiment receives the detection signals from the detection units 51 to 57, and when any of the detection signals meets a predetermined condition (or (OR) condition), the disconnect switch 3 is opened.

Specifically, when at least one of the system abnormalities detected by the detection units 51 to 57 is greater than or equal to the critical load 30 or the power supply unit 2’s tolerance to each system abnormality, the control unit 6 turns the disconnect switch 3 Open circuit.

2, the operation of the power supply unit 2 will be described together with the specific opening or closing control of the disconnect switch 3 of the control unit 6.

The uninterruptible power supply device 100 normally closes the disconnect switch 3, and the power supply unit 2 and the important load 30 are in a state of being connected to the commercial power system 10 via the disconnect switch 3.

(1) When the detected system abnormalities are smaller than the system abnormal tolerance of the power supply unit 2 and the important load 30 (Figure 2 (1)), the control unit 6 maintains the disconnection The state where the switch 3 is turned on. At this time, the power supply unit 2 continues to operate following the system abnormality of the commercial power system 10.

(2) When the detected system abnormality is greater than the system abnormality tolerance of the smaller of the power supply unit 2 and the important load 30 (Figure 2 (2)), the control unit 6 turns the disconnect switch 3 Open circuit. In this state, the power supply unit 2 continues to operate within the range of the critical load 30 or the limit tolerance of the system abnormality tolerance of the power supply unit 2 (independent operation of the power supply unit 2).

Furthermore, each detection unit 51 to detection unit 57 detects an abnormality of each system of the commercial power system 10 regardless of whether the disconnect switch 3 is opened or closed. The control unit 6 detects that the abnormality of each system of the commercial power system 10 is not as small as the above-mentioned abnormality. When the person’s system is abnormally tolerated, the disconnect switch 3 is closed.

<Simulation of the first embodiment> As an example of a system abnormality, the influence of a phase jump (a phase jump of 10°) on the power supply unit in a commercial power system has been simulated. FIG. 3 shows the simulated system model and the monitoring control model of the phase jump Δθ of the voltage v at the switch output point.

Fig. 4 shows the voltage v, the current i, and the phase jump Δθ at the switch output point when the disconnecting switch is not operated. At time 0.5 seconds, a 10° phase jump occurs in the commercial power system, followed by an overcurrent with a constant amplitude of twice the current i of the pole-changing switch (PCS) flowing to the important load.

Fig. 5 shows the voltage v, the current i, and the phase jump Δθ at the switch output point when the disconnect switch is operated. A phase jump of 10° is generated in the commercial power system at time 0.5 second, and the disconnect switch is opened after two milliseconds by detecting the phase jump. In addition, it is assumed that the phase jump detection control is not performed during the opening of the switch.

From the above simulation results, it can be seen that the voltage fluctuation when the phase jump occurs is about 10% of the voltage amplitude, but an overcurrent occurs. In this case, as long as the phase jump is monitored and the circuit breaker is opened before the phase jump is substantially performed, it can prevent important loads when the PCS (inverter) overcurrent withstand capacity of the important load is twice or less. The load is disconnected (dropped) due to overcurrent (conversely, if the corresponding operation is not performed, important loads will be dropped due to overcurrent). It can be seen from the simulation results that the phase jump detection is effective, and only the voltage drop detection function including the instantaneous voltage drop cannot cope with system abnormalities.

<Effects of the first embodiment> According to the uninterruptible power supply device 100 of the first embodiment configured as described above, the system abnormality detection unit detects system abnormalities, except for voltage drops including instantaneous voltage drops or frequency fluctuations. In addition to at least one of, it is also at least one of voltage rise, phase change, voltage imbalance, higher harmonic abnormality, or flicker. When the detected system abnormality is the critical load 30 or the power supply unit 2’s tolerance to system abnormality When the amount exceeds the amount, the circuit breaker 3 is opened, so that various system abnormalities other than voltage drops including instantaneous voltage drops and frequency fluctuations can also be dealt with. In addition, not only the tolerance of the important load to system abnormalities is used as a parameter, but also the tolerance of the power supply unit 2 to system abnormalities is used as a parameter to open the circuit breaker 3, so that not only can the important load 30 be taken into consideration for system abnormalities , And can cope with system abnormalities in consideration of the power supply unit 2.

<Second Embodiment> Next, the second embodiment of the uninterruptible power supply device of the present invention will be described.

As shown in FIG. 6, the uninterruptible power supply device of the second embodiment is different from the above-mentioned embodiment in the configuration of the control unit 6 and the operation of the power supply unit 2.

That is, in the control unit 6 of the second embodiment, in addition to the above-mentioned embodiment, at least one of the abnormalities detected by each of the detection units 51 to 57 is a system smaller than the important load 30 or the power supply unit 2. When the abnormal tolerance is more than the predetermined threshold value, the disconnect switch 3 is not opened, and the power supply unit 2 performs the compensation operation for each system abnormality.

7, the operation of the power supply unit 2 will be described together with the specific opening or closing control of the disconnect switch 3 of the control unit 6.

The uninterruptible power supply device 100 normally closes the disconnect switch 3, and the power supply unit 2 and the important load 30 are connected to the commercial power system 10 via the disconnect switch 3.

(1) When the detected system abnormality is less than the predetermined threshold value (FIG. 7 (1 )), the control unit 6 maintains the state in which the disconnect switch 3 is turned on. At this time, the power supply unit 2 continues to operate following the system abnormality of the commercial power system 10.

(2) When the detected system abnormality is greater than or equal to the predetermined threshold value (FIG. 7(2)), the control unit 6 maintains the state where the disconnect switch 3 is turned on. At this time, the power supply unit 2 performs a compensation operation for a system abnormality of the commercial power system (a change reduction operation of a system abnormality). Furthermore, at this time, the premise is that the detected system abnormality is less than the system abnormality tolerance of the power supply unit 2 and the important load 30.

(3) When the detected system abnormality is greater than that of the system abnormality tolerance of the power supply unit 2 and the important load 30 (Fig. 7(3)), the control unit 7 turns the disconnect switch 3 Open circuit. In this state, the power supply unit 2 continues to operate (independent operation) within the limit tolerance range of the important load 30 or the power supply unit 2 whose system abnormality tolerance is smaller.

<Effects of the second embodiment> According to the uninterruptible power supply device 100 of the second embodiment configured as described above, in addition to the effects of the first embodiment, it is possible to reduce the frequency of shifting to independent operation where the running cost is high.

<Other Modified Implementation Modes> In addition, the present invention is not limited to the above-mentioned embodiment.

For example, as shown in FIG. 8, a power generation device (generator) 7 connected to the power line L1 separately from the power supply unit 2 may also be included. The power generation device 7 is connected to the side closer to the important load 30 than the disconnect switch 3. With the above configuration, it is possible to cope with the prolonged independent operation time (when the system is out of power).

In addition, in each of the above-mentioned embodiments, the disconnect switch 3 is disconnected when any of the system abnormalities meets the condition, but it can also be set to disconnect the disconnect switch 3 when a combination of two or more system abnormalities meets a predetermined condition. .

Furthermore, in the above embodiment, a secondary battery or other storage battery is used as the energy storage device, but in addition to this, it may also be a pumped power generation method, a compressed air storage method, a superconductivity storage method, a flywheel, an electric double layer capacitor, etc. .

In addition, it goes without saying that the present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the scope of the gist. [Industrial availability]

According to the present invention, an uninterruptible power supply device can be provided, which can also cope with various system abnormalities other than voltage drops including instantaneous voltage drops and frequency fluctuations.

2: Distributed power supply 3: Disconnect switch 4: System side voltage detection section 5: System anomaly detection department 6: Control Department 7: Power generation device (generator) 10: Commercial power system (upper power supply side power system) 21: Energy storage device 22: Power converter (power conditioner) 30: important load 41: Instrument transformer 51: Voltage drop detection unit 52: Frequency variation detection department 53: Voltage rise detection unit 54: Phase fluctuation detection section 55: Voltage unbalance detection unit 56: Abnormal harmonic detection department 57: Flicker detection section 100: Uninterruptible power supply device i: current L1: Power line v: The voltage of the switch output point Δθ: Phase jump

Fig. 1 is a schematic diagram showing the configuration of the uninterruptible power supply device of the first embodiment. Fig. 2 is a table showing a list of operating states when the system of the first embodiment is abnormal. Fig. 3 is a diagram showing a simulation model of a compensation operation during a phase jump. Fig. 4 is a diagram showing a simulation result when the disconnect switch is not operating. Fig. 5 is a diagram showing a simulation result when the disconnect switch has been operated. Fig. 6 is a schematic diagram showing the configuration of an uninterruptible power supply device according to a second embodiment. Fig. 7 is a table showing a list of operating states when the system of the second embodiment is abnormal. Fig. 8 is a schematic diagram showing the configuration of an uninterruptible power supply device according to another modified embodiment.

2: Distributed power supply

3: Disconnect switch

4: System side voltage detection section

5: System anomaly detection department

6: Control Department

10: Commercial power system

21: Energy storage device

22: Power converter (power conditioner)

30: important load

41: Instrument transformer

51: Voltage drop detection unit

52: Frequency variation detection department

53: Voltage rise detection unit

54: Phase fluctuation detection section

55: Voltage unbalance detection unit

56: Abnormal harmonic detection department

57: Flicker detection section

100: Uninterruptible power supply device

L1: Power line

Claims (4)

An uninterruptible power supply device is arranged between the upper power supply side power system of a commercial or self-operated line and an important load, and supplies AC power to the important load. The uninterrupted power supply device includes: The power supply unit includes an energy storage device connected to a power line, and the power line is used to supply power from the power system to the important load; A circuit breaker is arranged on the power line on the side of the power system closer to the power supply unit to open or close the power line; The system abnormality detection unit detects system abnormalities. The system abnormalities are not only at least one of voltage drops or frequency fluctuations including instantaneous voltage drops, but also voltage increases, phase fluctuations, voltage imbalances, and harmonic abnormalities. Or at least one of flicker, the instantaneous voltage drop is generated on the side of the power system closer to the power system than the disconnect switch; and The control unit, when the detected system abnormality is the important load or the power supply unit's tolerance to the system abnormality or more, disconnects the disconnect switch and supplies power to the important load from the power supply unit AC power. The uninterruptible power supply device described in the first item of the scope of patent application, wherein the power supply unit is in a state where the disconnect switch has been disconnected, and the important load or the power supply unit is abnormal to the system The one with the smaller tolerance will operate independently within the range of the limit tolerance. The uninterruptible power supply device described in item 1 or item 2 of the scope of the patent application, wherein the system abnormality detected by the control unit at the system abnormality detection unit is an abnormal degree less than the important load or the When the power supply unit's tolerance to the system abnormality exceeds the threshold value, the power supply unit performs a compensation operation for the system abnormality. The uninterruptible power supply device described in any one of items 1 to 3 of the scope of the patent application includes: a power generation device, which is connected to the power line separately from the power supply part.

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