JP2011041427A - Power unit for uninterruptible power work - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein a load may stop for an influence of an overcurrent, or the like, of a three-phase power load when switching a power supply in a different system in interruptible power supply construction work that uses two instantaneous change-over switches. <P>SOLUTION: In a power unit, an inverter power supply, which uses an electric double-layer capacitor (EDLC), capable of discharging electricity in a short time as an energy source, is used, and transitional voltage compensation in switching is performed only for a short time, thus preventing disturbance of a three-phase load; and hence, attaining an uninterruptible power supply work, without having to stop the load, even when the power load is included. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power supply device for uninterruptible construction that supplies power to a customer on a low-voltage load side uninterruptibly when replacing a pole transformer for power distribution.

  Conventionally, when replacing a pole transformer for distribution that is connected to a high-voltage distribution line, it is necessary to carry out the low-voltage distribution line without power failure in order to prevent the low-voltage distribution line in the system under construction from powering out. There is.

  In this type of construction, the power supply of the low-voltage distribution line of the construction target system is switched from the power supply of the construction target system to the power supply of another system without interruption, and after construction is completed and switched to the opposite, the conventional method is instantaneous. A power switching device for low voltage distribution line construction using a switching switch is used. In addition, when there is no power source of another system nearby, a proposal has been made regarding a power supply device for uninterruptible construction that feeds power to a construction target house during power distribution work from an inverter power generation type power car (generator car) or the like. (Japanese Patent Laid-Open No. 2001-224133)

FIG. 5 shows an example of a conventional configuration in which two commercial power sources are switched using two instantaneous switching switches using bidirectional semiconductor switches. 1 is an A system (construction target) commercial power system, 2 is a B system (sound) commercial power system, 3 and 4 are A / B primary cutout switches, 5 is a pole transformer for replacement work, and 6 is B system pole transformer, 7 is an A system instantaneous switching switch, 8 is a B system instantaneous switching switch, 9 is an A system load group, and 10 is a B system load group.

FIG. 6 shows a detailed circuit diagram of the contents of the instantaneous switching switches 7 and 8. 11 is an MCCB for overcurrent protection, 12 is a bidirectional semiconductor switch such as a triac, and 13 is an electromagnetic switch. The instantaneous switching opening / closing shown in FIG. 6 generally has a voltage detection function and can prevent erroneous connection when performing construction.

A conventional operation and its procedure will be described with reference to FIGS. The A-system instantaneous switching switch 7 and the B-system instantaneous switching switch 8 are used only for construction work, are temporarily installed on a pillar or the like, and are connected by cables. When replacing the pole transformer 5 of one A system of both A and B systems, the power supply to the load group 9 on the A system side is instantaneously switched from the B system (healthy). During the construction of the A system, the power is stably supplied to the load group 9. After the construction is completed, the power supply to the load group 9 is switched back from the B system side to the A system side.

The procedure for exchanging the pole transformer of No. 5 is to open the A-system instantaneous switching switch 7 that is in the on state and shut off the input from the A system to the load group 9. The B system instantaneous switching switch 8 detects no voltage of the A system load group voltage, and the B system instantaneous switching switch 8 is turned on within 1/2 cycle, and the power is supplied to the load group 9 from the B system. . When the replacement work of the pole transformer 5 is completed, when the B system instantaneous switching switch 8 in the on state is opened, the A system instantaneous switching switch 7 detects the A system load group no-voltage, and 1 / Within two cycles, the system A instantaneous switching switch 7 is turned on and the power is supplied to the system A load group 9 to return to the normal state and the construction is completed.

JP 2001-224133 A

  When a power load is connected, such as a motor with a three-phase circuit, when switching to an uninterruptible power supply, depending on the construction site, there are conditions in which the phases differ between the two power sources. Even if the power supply of the system can be switched within 1/2 cycle of the commercial frequency, a transient disturbance of the voltage waveform occurs. For this reason, power loads such as air conditioner compressors and rotary presses sometimes stop automatically due to overcurrent or torque fluctuation. Moreover, even if it can be said that switching can be performed within a half cycle (about 10 msec) depending on the customer, a slight instantaneous interruption between switching and switching back may be affected.

  In order to solve the above-mentioned problem, the present invention converts a direct current equipped with an electric storage element such as an electric double layer capacitor into an alternating current with an inverter, and outputs it via an interconnection transformer. Distribution lines affected by switching work to eliminate transient voltage fluctuations when switching from A system to B system and switching back from B system to A system for about 1/2 cycle. Connected to the system, and after establishing the interconnection operation with the same phase and amplitude as the system, the system A instantaneous switching switch is turned off and the output of the inverter power supply is about 1 second so that it is the same as the phase and amplitude of the B system. The system is equipped with means for gradually controlling the voltage and automatically turning on the B-system instantaneous switching switch and stopping the inverter when the difference between the voltage values of the power supply side and the load side becomes 5% or less. It is characterized by that.

  According to the above power supply device, even when uninterruptible power supply construction between different phase power supplies is performed, there is no transient voltage fluctuation, so there is no torque fluctuation of the power load and almost no transient overcurrent flows, so stable voltage supply is performed I can do it.

  Further, by adopting the above-described configuration, the bidirectional semiconductor switch can be replaced with a general electromagnetic switch, so that the cost is reduced and the device is made compact. Further, in the above device, since the output of the inverter is as short as about 1 second, an electric double layer capacitor or the like can be used for the power storage unit. Since it is not necessary to use a lead battery, it is environmentally friendly and easy to maintain.

FIG. 1 shows an embodiment of the present invention. FIG. 2 is a diagram showing details of the switching switches 7 and 8. FIG. 3 is a flowchart of the present invention. FIG. 4 is a time chart of the present invention. FIG. 5 shows a conventional example. FIG. 6 is a diagram showing details of a conventional switching switch.

  The uninterruptible power supply device of the present invention eliminates a bidirectional semiconductor switch from a conventional instantaneous switching switch, and switches to a switching switch that is turned on and off by a normal electromagnetic switch. Can be used to eliminate uninterruptible power supply without stopping the power load even under conditions where a power load is connected.

The configuration of the present invention will be described with reference to FIGS. FIG. 1 is an embodiment of the present invention. The present invention has a configuration in which an inverter power supply 14 is added to the conventional configuration shown in FIG. From the A system switching switch 7 and the B system switching switch 8, the power supply side voltages VA and VB and the auxiliary contacts of the electromagnetic switches of the A system and B system are input. Details of the switching switch are shown in FIG. The conventional switching switch is an expensive device using the bidirectional semiconductor switch 12, but can be replaced with a general electromagnetic switch (MC) 13 by switching in-phase / same amplitude. Since it does not need to be used, it is possible to use a low-cost and compact switching switch (FIG. 2).

The inverter power supply 14 includes a storage element 17 that can supply power to a load for about 1 to 2 seconds at rated power. As the storage element 17, an electric double layer capacitor or a secondary battery such as a lithium ion battery can be used. The inverter power supply 14 is configured to output a three-phase sine wave alternating current by inputting a predetermined control signal. Inverter power supply 14 is operated from the commercial power connection mode with the same phase and the same amplitude by charging from the connected A-system commercial power supply before power switching so that the commercial power supply can be switched without interruption. Is doing.

  The operation of the present invention will be described using the flowchart of FIG. 3 and the time chart of FIG. When the A system switching switch 7 is opened, the inverter power supply 14 switches from the commercial power supply interconnection mode to the constant voltage output mode, and after the set timer time (0.1 second in this embodiment) has elapsed, Synchronize voltage and phase to the power supply. That is, the output voltage amplitude value is changed from VArms to VBrms, and the phase is changed from VuA to VuB in about 1 second. Generally, the power supply frequency can be tolerated up to + -1% of the rating. In the case of 60 Hz, the frequency range is 59.4 to 60.6 Hz. When there is a phase difference of 120 ° between the A system and the B system, if it is changed by 3.6 ° in one cycle, 120 / 3.6 = 34. That is, the phase is synchronized with the B-system commercial power supply in 34 cycles (about 0.57 seconds).

  The B system switching switch 8 is automatically turned on when the voltage difference between the input and output falls within an allowable value (in this embodiment, about 5% of the rated voltage), and the A system load group from the B system commercial power supply. 9 is supplied with electric power. During the pole transformer replacement work, power will continue to be supplied from the B system commercial power supply. Since it is not necessary to start the inverter during this construction, the inverter is stopped by the contact signal of the B system switching switch. After the completion of construction, this time, switching from B-system commercial power supply to A-system commercial power supply in the same procedure will eliminate the occurrence of transient voltage disturbance as in the past. On the other hand, the influence of overcurrent or the like is reduced.

1 System A high voltage power supply 2 System B high voltage power supply 3 System A primary cutout switch 4 System B primary cutout switch 5 System A pole transformer 6 System B pole transformer 7 System A instantaneous switching switch 8 System B Instantaneous switching switch 9 System A load group 10 System B load group 11 MCCB (wiring breaker)
12 Bidirectional semiconductor switch 13 MC (Electromagnetic switch)
14 Inverter power supply 15 Interconnection transformer 16 Inverter 17 Storage element (electric double layer capacitor, etc.)

Claims (2)

In uninterruptible electrical work using two systems using two instantaneous switching switches, an inverter power supply is connected to the distribution line A system to be constructed, and after establishing an interconnection operation with the same phase and amplitude as the system, A The system instantaneous switching switch is turned OFF, and the inverter power supply output is gradually synchronized in about 1 second so that the phase and amplitude of the B system are the same, and the voltage value difference between each phase on the power supply side and the load side Power supply device for uninterruptible construction characterized by having means for automatically turning on the B-system instantaneous switching switch and stopping the inverter when the battery becomes 5% or less The inverter power supply is an uninterruptible power supply unit characterized in that an electric storage element such as an electric double layer capacitor as an energy source is connected to the interconnection transformer via an inverter

Images