JP2015050881A - Power factor automatic adjuster - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to significantly reduce loss of electrical energy and suppress burden of a power consumer side as much as possible by enabling power factor automatic adjustment from an electric power supply source in a cubicle type high voltage power incoming installation.SOLUTION: A cubicle type high voltage power incoming installation P includes: a high voltage load switchgear 1 for receiving high voltage power from a power supply source; a power side capacitor 2 for electric power storage; a single phase transformer 3 and a three-phase transformer 4 connected with the power side capacitor 2 in parallel; a circuit breaker 6 for a lamp circuit wiring of a low voltage distribution board 5 connected with the single phase transformer 3; and a circuit breaker 7 for a motor circuit wiring of a low voltage distribution board 5 connected with the three phase transformer 4. Reactive power detection means A (reactive power detection unit) and power factor automatic adjustment means B (power factor automatic adjustment section) are installed for the low voltage side of at least one transformer of the installation P.

Description

  The present invention relates to a power factor automatic adjustment device installed for a transformer in a cubicle type high-voltage power receiving facility.

  2. Description of the Related Art Conventionally, a high-voltage power receiving facility called a so-called cubicle in which a set of devices for receiving power at a high voltage is housed in a metal outer box has been widely used. In other words, it is widely used as a substation facility for small and medium-sized facilities with a receiving capacity of 50 kVA or more and 4,000 kVA or less. Electricity received at a nominal voltage of about 6,600 V from a high-voltage distribution pole (power supply source side) Is transformed into 100V or 200V in a cubicle installed on the ground and supplied to each facility. The cubicle uses a small PF-S type that uses a high-voltage current-limiting fuse and a high-voltage AC load switch as the main circuit breaker when the power receiving equipment capacity is 300 kVA or less, and when the power receiving equipment capacity is 4,000 kVA or less. The CB type using a circuit breaker is used for the main circuit breaker.

Moreover, most of the conventional power factor automatic adjustment devices are mainly equipped with a phase advance capacitor in a load device such as an electric light or an electric motor at the end or a power panel. That is, the reactive power in the electric power system is generally a lagging power factor, and when this reactive power exceeds a predetermined limit, a phase advance capacitor (which has a function of advancing the phase of current by 90 ° from the phase of voltage in alternating current) is inserted. A power factor automatic adjustment method is adopted that improves the power factor (the ratio between the apparent power and the active power) of the power system by shutting off the phase advance capacitor when it falls below a predetermined limit.
In general, reactive currents such as motors are lagging currents, and by connecting a phase advance capacitor in parallel to the load, the current flowing into the capacitor becomes a leading current in the opposite direction to the load. By canceling out, the apparent current is reduced, approaching the value of the effective current only, and the power factor is improved.

  For example, as disclosed in Patent Document 1, there is an automatic power factor adjustment device that can change a power factor adjusting capacitor input point and a cutoff point for each of an upper limit mode, a center mode, and a lower limit mode for a control reference line. Exists. This is because the reactive power is detected by the reactive power detector based on the output of the measuring transformer and current transformer provided in the electric circuit, the capacitor capacity and the target power factor value set by the setting unit, and the control standard Based on the control reference line set by the line setting unit and the target value shift amount setting unit and the shift amount, the CPU calculates the capacitor insertion point and the cutoff point, and controls the capacitor so that it falls within this range. ing.

  Further, as disclosed in Patent Document 2, the reactive signal of the electric circuit is detected, and when the detected reactive power exceeds the set target power factor and the input point, a control signal for connecting a capacitor to the electric circuit There is also an automatic power factor adjustment device that outputs a control signal for disconnecting the capacitor from the electric circuit when the detected reactive power exceeds the cutoff point.

Japanese Patent Laid-Open No. 6-22457 JP-A-6-67743

  As mentioned above, most of the conventional power factor automatic adjustment devices are mainly equipped with phase-advancing capacitors in the load equipment such as lamps and motors at the end and in the power panel. There has never been a technology in which an automatic power factor adjustment device is installed for a transformer in a power receiving facility.

  In addition, since the phase-advancing capacitor is attached to each individual load device such as an electric light and an electric motor as in the past, the loss of electric power energy increases and the cost of home appliances and installation greatly increases for each individual load device. This increases the burden on the power consumer side.

  Therefore, the present invention was created in view of the existing circumstances as described above. By enabling automatic power factor adjustment from a power source in a cubicle type high-voltage power receiving facility, the loss of power energy is greatly reduced. It is an object of the present invention to provide an automatic power factor adjustment device that can improve the power consumption of the power consumer side as much as possible.

  In order to solve the above-described problems, in the power factor automatic adjustment device according to the present invention, a high-voltage load switching device that receives high voltage from a power supply source, a power-side capacitor for power storage, and a parallel connection to the power-side capacitor A single-phase transformer and a three-phase transformer, a circuit breaker for lighting circuit wiring of a low-voltage distribution board connected to the single-phase transformer, and a circuit breaker for power circuit wiring of a low-voltage distribution board connected to the three-phase transformer, In the cubicle type high-voltage power receiving equipment provided, reactive power detection means and power factor automatic adjustment means are installed on the low-voltage side of at least one transformer.

  The reactive power detection means includes a calculation means for detecting a voltage fluctuating with respect to the load and calculating a fluctuation value of the reactive power based on the detected voltage.

  The power factor automatic adjusting means is characterized in that the power factor can be automatically adjusted in accordance with the variable reactive voltage calculated by the calculating means.

  The power factor automatic adjustment means is connected to the secondary side of the transformer via the first switching element, and connected to the secondary side of the transformer via the second switching element, A reactor connected in parallel with the capacitor, and a control unit for controlling the first switching element and the second switching element in accordance with the output on the primary side of the transformer are provided.

  The power factor automatic adjustment means is wirelessly connected to a personal computer via a serial communication standard wireless unit so that bidirectional communication is possible, and the reactive power value detected by the reactive power detection means and the fluctuation invalid calculated by the calculation means The power factor automatically adjusted by the power and power factor automatic adjusting means can be constantly monitored in real time.

  According to the present invention, by enabling automatic power factor adjustment from a power source in a cubicle type high-voltage power receiving facility, loss of power energy can be greatly improved and the burden on the power consumer side can be minimized. be able to.

  For example, conventionally, when power is supplied from the transformer of the high-voltage power receiving equipment toward the load side (for example, 100 kW work), a 120 kW power transmission loss from the transformer and an output loss on the load side are generated and sufficient power is generated. Energy cannot be obtained efficiently. On the other hand, in the present invention, the reactive power detection means and the power factor automatic adjustment means are installed on the low voltage side of at least one transformer in the cubicle type high voltage power receiving equipment. In addition, about 7 to 15% of wasted power, which becomes an output loss on the load side, is cut to about 111 to 102 kW, which can greatly improve the loss of power energy. Moreover, in addition to the reduction of power loss, there are many other merits such as reduction of electricity costs.

  The reactive power detection means includes a calculation means for detecting a voltage fluctuating with respect to the load and calculating a fluctuation value of the reactive power based on the detected voltage. Therefore, the reactive power fluctuation value applied to the load can be easily and reliably obtained. Therefore, the subsequent automatic power factor adjustment can be performed quickly and efficiently.

  Since the power factor automatic adjustment means can automatically adjust the power factor in accordance with the variable reactive voltage calculated by the calculation means, a phase advance capacitor is attached to each individual load device such as a light or an electric motor as in the past. Even if it is not, the loss of electric power energy can be intensively and efficiently improved by the high voltage power receiving equipment which is the electric power source.

  The power factor automatic adjustment means is connected to the secondary side of the transformer via the first switching element, and connected to the secondary side of the transformer via the second switching element, Since it includes a reactor connected in parallel with the capacitor and a control unit for controlling the first switching element and the second switching element in accordance with the output on the primary side of the transformer, the power factor can be reduced with a simple configuration. Can be adjusted easily.

  The power factor automatic adjustment means is wirelessly connected to a personal computer via a serial communication standard wireless unit so that bidirectional communication is possible, and the reactive power value detected by the reactive power detection means and the fluctuation invalid calculated by the calculation means The power factor automatically adjusted by the power and power factor automatic adjustment means can be constantly monitored in real time, so if there is an abnormality in the operation by the above means, the power factor adjustment can be finely adjusted manually, for example In such a case, it is possible to appropriately deal with the command from the personal computer.

It is a configuration block diagram of a cubicle type high voltage power receiving equipment provided with an automatic power factor adjusting device in one embodiment for carrying out the present invention.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. An automatic power factor adjustment apparatus according to the present invention is a transformer in a cubicle that takes out power from a low-voltage side breaker in a cubicle type high-voltage power receiving facility. It is installed for a single unit.

  That is, as shown in FIG. 1, the high-voltage power receiving facility P in this embodiment is a high-voltage power meter for measuring the power used by a segment switch (not shown) and a power meter from a utility pole high-voltage cable as a power supply source. To the high voltage load switch 1 (LBS) with a power fuse that receives high voltage via a voltage transformer (VCT) (not shown) that converts the voltage and current of the circuit to low voltage and inputs to the watt hour meter, A power-side capacitor 2 for power storage is connected in series, and a single-phase transformer 3 and a three-phase transformer 4 are connected in parallel via the power-side capacitor 2. Since the power-side capacitor 2 is overcharged when a current exceeding the rating flows, a method of automatically opening the high-voltage load switch 1 is employed. The transformers (transformers) 3 and 4 used in the cubicle type high-voltage power receiving facility have a role of converting the voltage received by the high voltage (6,600V) into low voltages of 100V and 200V. The low-voltage side of the single-phase transformer 3 is connected to an electric lamp (load-side equipment) via the circuit breaker 6 for electric circuit wiring of the low-voltage switchboard 5, while the low-voltage side of the three-phase transformer 4 is the power of the low-voltage switchboard 5. It is connected to an electric motor (load side equipment) through a circuit wiring breaker 7.

  In this embodiment, the power is taken out from the secondary (low voltage) side breaker 8 of the circuit breakers 6, 7, and the reactive power detection means A is connected to the low voltage side of the transformers 3, 4 in the high voltage power receiving equipment P. (Reactive power detection unit) and power factor automatic adjustment means B (power factor automatic adjustment unit) are installed, the reactive power of the transformers 3 and 4 is automatically detected by the reactive power detection means A, and power factor automatic adjustment means The power factor is automatically adjusted by B.

  Specifically, as shown in FIG. 1, the reactive power detection means A and the power factor are provided between the low voltage side of the transformers 3 and 4 and the empty breaker 8 on the secondary (low voltage) side of the circuit breakers 6 and 7. The automatic adjustment means B is connected to the vehicle. The reactive power detection means A includes a calculation means C (calculation unit) that detects a voltage that constantly fluctuates with respect to the load-side equipment and calculates a fluctuation value of the reactive power based on the detected voltage. The power factor can be automatically adjusted by the power factor automatic adjustment means B in accordance with the fluctuation reactive power (fluctuation value) by the calculation means C.

  The power factor automatic adjusting means B is wirelessly connected to a personal computer (PC) via a serial communication standard RS485 wireless unit 9 so that bidirectional communication is possible. The reactive power detecting means is connected to the personal computer (PC). The reactive power value detected by A, the variable reactive power (variation value) calculated by the calculation means C, and the power factor automatically adjusted by the power factor automatic adjustment means B can be constantly monitored in real time. The power factor automatic adjustment means B is preferably realized by wireless communication using a wireless unit, but may be realized by wired connection such as a LAN cable.

  As a specific configuration of the power factor automatic adjusting means B, a power factor adjusting circuit based on a thyristor gate angle command disclosed in Japanese Patent Application Laid-Open No. 2006-246552 is applied. That is, this circuit includes a phase advance capacitor connected to the secondary side of the transformers 3 and 4 via the first switching element (first thyristor), and the secondary side of the transformers 3 and 4. A reactor (coil) connected through two switching elements (second thyristors) and connected in parallel with the phase advance capacitor, and an open circuit breaker 8 on the secondary (low pressure) side of the circuit breakers 6 and 7. It is comprised from the control part (CPU) which controls a 1st switching element and a 2nd switching element according to the output of the fluctuation | variation reactive power calculated by the calculating means C, respectively.

  Further, as a modification of the power factor automatic adjusting means B, a power factor adjusting circuit by shift correction disclosed in Japanese Patent Laid-Open No. 6-22457 may be applied. This circuit detects reactive power by reactive power detection means A based on the output of the three-phase transformer 4, and sets the capacity and target power factor value of the phase advance capacitor set by the setting unit, the control reference line setting unit and the target Based on the control reference line set by the value shift amount setting unit and the shift amount, the control unit (CPU) calculates the capacitor insertion point and the cutoff point, and controls the phase advance capacitor so that it falls within this range. is there.

  Furthermore, power factor adjustment by a relay circuit disclosed in Japanese Patent Laid-Open No. 6-67743 may be applied as another modification of the power factor automatic adjustment means B. This is the input point calculated from the output of the reactive power detection means A, the target power factor set by the setting unit, the active power at that time, and the capacity of the phase advance capacitor in accordance with a program written in advance by the arithmetic processing unit. Compares the set value or breakpoint set value, and if the closing point set value is exceeded, a closing signal is supplied, and if the breaking point set value is exceeded, a blocking signal is supplied to drive the relay circuit section, and the control circuit section is driven by a relay contact. The phase advance capacitor is turned on and off by an electromagnetic contactor via

  As a specific configuration of the reactive power detection means A, the voltage and current that are actually applied are, for example, 6600 V and 200 A, respectively. A flow device (not shown) is provided, and each secondary output is decompressed to about 110 V and 5 A, for example, and measured by a reactive power detection circuit composed of a reactive energy meter or the like. The reactive power detection means A is composed of a current transformer, a transformer, and a reactive power detection circuit.

  In the above-described embodiment, various other modifications are possible as reactive power detection means (including calculation means) and power factor automatic adjustment means.

  Next, an example of the operation of the embodiment configured as described above will be described. First, from a utility pole high-voltage cable, which is a power supply source, through a section switch, a meter transformer (VCT) (not shown), and the like. Thus, the high voltage load switch 1 receives a high voltage, and the power side capacitor 2 is charged. At this time, if a current exceeding the rating flows, the power-side capacitor 2 is overcharged, so the high-voltage load switch 1 is automatically opened.

  Then, the electric power stored in the power-side capacitor 2 is sent to the single-phase transformer 3 and the three-phase transformer 4. From the low-voltage side of the single-phase transformer 3, an electric circuit wiring circuit breaker 6 of the low-voltage switchboard 5 is connected. To the electric lamp (load-side equipment) and from the low-voltage side of the three-phase transformer 4 to the electric motor (load-side equipment) via the power circuit wiring breaker 7 of the low-voltage switchboard 5.

  At this time, the power is taken out from the secondary (low voltage) side breaker 8 of the circuit breakers 6 and 7, and the reactive power detection means A automatically detects the reactive power on the low voltage side of the transformers 3 and 4 in the high voltage power receiving equipment P. Is done. Based on this detected voltage, the calculation means C (calculation unit) calculates the amount of fluctuation of the reactive power, and the power factor is automatically adjusted by the power factor automatic adjustment means B according to this fluctuation value.

  The reactive power value detected by the reactive power detection means A, the variable reactive power (fluctuation value) calculated by the calculation means C, and the power factor automatically adjusted by the power factor automatic adjustment means B are each a personal computer (PC). This personal computer (PC) is used when the operation by each of the above means A, B, and C is abnormal or when the power factor adjustment is set manually, for example. It can be dealt with accurately.

  Thus, since the power factor can be automatically adjusted from the power source in the cubicle type high-voltage power receiving facility P, the loss of power energy can be greatly improved, and the burden on the power consumer side can be minimized.

A ... Reactive power detection means (reactive power detection unit)
B ... Power factor automatic adjustment means (Power factor automatic adjustment unit)
C: Calculation means (calculation unit)
P ... High-voltage power receiving equipment (cubicle)
DESCRIPTION OF SYMBOLS 1 ... High voltage load switch 2 ... Electric power side capacitor | condenser 3 ... Single phase transformer 4 ... Three phase transformer 5 ... Low voltage switchboard 6 ... Circuit breaker for electric circuit wiring 7 ... Circuit breaker for power circuit wiring 8 ... Empty breaker 9 ... RS485 Wireless unit

Claims (5)

  High-voltage load switchgear that receives high-voltage from the power supply source, power-side capacitor for power storage, single-phase transformer and three-phase transformer connected in parallel to the power-side capacitor, low-voltage distribution board connected to the single-phase transformer Reactive power detection for the low-voltage side of at least one transformer in a cubicle type high-voltage power receiving facility comprising a circuit breaker for lighting circuit wiring and a circuit breaker for power circuit wiring of a low-voltage switchboard connected to a three-phase transformer And an automatic power factor adjusting device. A power factor automatic adjusting device characterized by comprising:   2. The automatic power factor adjustment according to claim 1, wherein the reactive power detecting means includes a calculating means for detecting a voltage fluctuating with respect to the load and calculating a fluctuation value of the reactive power based on the detected voltage. apparatus.   3. The power factor automatic adjusting device according to claim 1, wherein the power factor automatic adjusting means is capable of automatically adjusting the power factor in accordance with the variable reactive voltage calculated by the calculating means.   The power factor automatic adjustment means is connected to the secondary side of the transformer via the first switching element, and connected to the secondary side of the transformer via the second switching element, The reactor connected in parallel with a capacitor | condenser and the control part which respectively controls a 1st switching element and a 2nd switching element according to the output of the primary side of a transformer are provided. The power factor automatic adjustment device according to any one of Items 1 to 3.   The power factor automatic adjustment means is connected to a personal computer through a serial communication standard unit so as to be capable of bidirectional communication. The reactive power value detected by the reactive power detection means, the variable reactive power calculated by the calculation means, the power 5. The power factor automatic adjusting device according to claim 2, wherein each of the power factors automatically adjusted by the rate automatic adjusting means can be constantly monitored in real time.