JPH0854945A - Power factor controller - Google Patents

Abstract

PURPOSE:To propose a power factor controller which is capable of preventing the degradation/explosion of a capacitor and a reactor, regarding a power factor controller improving the power factor of a power system or the power factor controller composed of the capacitor and the reactor, in particular. CONSTITUTION:Because higher harmonic generated from a load, a power system or the equipment, etc., affecting the power system is detected by a higher harmonic detection means 3, a capacitor 13 or a reactor 12 which is connected with the load, the power system or the equipment, etc., affecting the power system in parallel is disconnected by a separation means 11 when this higher harmonic is detected and an alarm is made to be outputted by a notification means 5, the flow-in of the higher harmonic generated by the load to the capacitor 13 or the reactor 12 can be prevented, and the degradation/explosion of the capacitor 13 or the reactor 12 is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power factor control device for improving the power factor of a power system, and more particularly to a power factor control device composed of a capacitor and a reactor.

[0002]

2. Description of the Related Art Conventionally, as a power factor control device of this type, FIG.
There was something shown in. This FIG. 3 (A), (B), (C)
Shows a connection mode diagram and an equivalent circuit diagram of the conventional device.

In FIG. 1A, a conventional power factor control device 3
00 is connected in parallel to the load 200 connected to the power system 100, and is formed by a series circuit of a capacitor 11C (or 12C) and a reactor 11L (or 12L),
This capacitor 11C (or 12C) compensates for the phase delay caused by the load 200, and the reactor 11L
(Or 12L) suppresses the effect of inrush current. Further, the power factor control device 300 absorbs a harmonic current generated in the load 200 by the series resonance circuit when the capacitor 11C (or 12C) and the reactor 11L (or 12L) are imitated as a series resonance circuit. As a result, the harmonic current flowing out to the power system 100 can be suppressed.

The power factor control device 30 shown in FIG. 3B.
0 is a capacitor 11C, a reactor 11L and a resistor 11
It is formed by connecting in series with R and acts as a tuning filter. That is, the values of the capacitor 11C and the reactor 11L are constants such that 2πfn = 1 / square root (LC) with respect to the harmonic frequency fn to be absorbed so as to obtain a low impedance by resonating with a single harmonic. Is the configuration selected.

In the power factor control device 300 shown in FIG. 3C, the reactor 12L and the resistor 12R are connected in parallel, and the capacitor 12C is connected in series to the parallel circuit, so that the secondary type height is increased. Acts as a secondary filter.
Since the resonance circuit as the second-order high-order filter has a low impedance even in the lowest frequency band at the resonance frequency, it can absorb the harmonic current in a wide frequency range.

Each of the reactors 11L and 12L acts so as to control the excessive current flowing through the capacitors 11C and 12C by the current generated by the counter electromotive force. FIG. 4 is a schematic configuration diagram of another conventional power factor control device.

In the figure, a conventional power factor control device is a switch 200 (S2, S3), a capacitor C1 (C2, C3) and a reactor L1 (L2, L3) for a load 200 connected to a power system 100. The series control circuits F1, F2, F3 are connected in parallel, and the switch control circuit 30 controls the switches S1, S2, S3 based on the load current IL from the current transformer CT5 and the load voltage VL from the voltage transformer PT5. Is configured to be selected and input.

The switch control circuit 30 calculates the reactive power QL flowing into the load 200 from the detected load current IL and load voltage VL, and any one of the series circuits F1 and F2 corresponding to the reactive power QL. , F3, and operates so as to turn on the switch S1 (or S2, S3) of any one of the selected series circuits F1 (or F2, F3).
By turning on the switch S1 (or S2, S3), one of the series circuits F1 (or F2, F3) is connected in parallel to the load 200 and the power factor on the side of the power system 100 can be improved.

[0009]

Since the conventional power factor control device is constructed as described above, polyvinyl chloride (PCB) is used as the insulating oil of the capacitor constituting the device.
When the capacitor is used, there is a problem that if an excessive current due to a resonance phenomenon flows in this capacitor, it is overheated, which causes characteristic deterioration, and eventually there is a risk of explosion.

A capacitor using this PCB is the Showa 47
The production was banned in 1965 and the use was banned in 1976,
The existing equipment is still in use because it is allowed to continue. When the explosion occurs in the capacitor using the PCB that is operating as the existing equipment, the toxicity of the PCB seriously affects the human body and poses a risk of environmental pollution. Further, the reactor also has a problem that it is overheated due to the energization of an excessive current due to the resonance phenomenon and causes characteristic deterioration, which may result in explosion.

As described above, automatic power factor control is performed even when an overcurrent is flowing due to a resonance phenomenon due to harmonics. If the capacitor is turned on and off in this state, the life of the switch is significantly shortened. Alternatively, the capacitor or the reactor itself may explode.

Further, in order to prevent overheating and explosion accident due to the resonance phenomenon of the capacitor and the reactor forming the power factor control device, methods such as surface temperature measurement of equipment and monitoring of abnormal sound can be considered. There was a problem that it was dangerous because it could not be monitored and it was necessary to confirm it by approaching the equipment.

The present invention has been made to solve the above problems, and an object thereof is to propose a power factor control device capable of preventing deterioration and explosion of a capacitor and a reactor used for power factor improvement. To do.

[0014]

FIG. 1 shows the principle of the present invention. In the figure, the power factor control device according to the present invention is
In a power factor control device that is connected in parallel to a load connected to a power system and is formed by connecting a capacitor and a reactor in series, a predetermined value that occurs in the load, the power system, or a device that affects the power system. Harmonic detection means for detecting harmonics of the value, separation means for separating the capacitor or reactor from the power system when the harmonics are detected, and an alarm as an abnormality occurrence when the harmonics are detected An output notification unit is provided to protect the capacitor or the reactor from harmonics generated by the load, the power system, or devices that affect the power system.

Further, the power factor control device according to the present invention comprises detection set value means for setting the frequency value of the harmonic detected by the harmonic detection means to an arbitrary value, if necessary. Further, a power factor control device according to the present invention is a power factor control device which is connected in parallel to a load connected to a power system and is formed by connecting a capacitor and a reactor in series, wherein the load, the power system or Harmonic detection means for detecting harmonics of a predetermined value generated in devices that affect the power system, separation means for separating the capacitor or reactor from the power system when the harmonics are detected, and the harmonic And a warning unit that outputs an alarm as an abnormality when a wave is detected, and protects the capacitor or the reactor from harmonics generated by the load, the power system, or devices that affect the power system.

Further, the power factor control device according to the present invention comprises detection setting value means for setting the frequency value of the higher harmonic wave detected by the higher harmonic wave detecting means to an arbitrary value, if necessary.

[0017]

In the present invention, the harmonic detecting means detects the harmonic generated from the load, the electric power system or equipment affecting the electric power system, and when this harmonic is detected, it is connected in parallel to the load. Since the capacitor or reactor to be disconnected is separated by the separating means and the alarm is output by the notifying means, the inflow of harmonics generated by the load on the capacitor or the reactor, the power system or equipment that affects the power system, etc. This will prevent the deterioration or explosion of the capacitor or reactor.

Further, according to the present invention, the detection level of the harmonic is arbitrarily set by the detection value setting means.
The constants of the capacitors and the reactor with respect to the harmonic frequency can be adjusted, and the power factor on the load side can be adjusted by setting the optimum detection state for each device.

Further, in the present invention, the harmonic detecting means detects a harmonic generated from a load, a power system or a device affecting the power system, and in the case of an abnormality when the harmonic is detected. Since the harmonic filter is separated by the separating means and the alarm is output by the notifying means,
It is possible to prevent harmonics generated by a load, an electric power system or a device that affects the electric power system from flowing into a capacitor and a reactor forming a harmonic filter, and prevent deterioration or explosion of the capacitor or the reactor in advance.
Furthermore, during normal operation when harmonics generated by a load other than the load connected in parallel to the harmonic filter, the power system, or equipment that affects the power system are not detected, it is possible to absorb the harmonics generated by the load connected in parallel. , Block the output of harmonics to the outside.

Further, in the present invention, the detection level of the harmonic is arbitrarily set by the detection value setting means,
Since the constants for the harmonic frequencies of the capacitors and reactors that form the harmonic filter can be adjusted, the power factor on the load side can be adjusted by setting the optimum detection state for each device.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. FIG. 2 is a block diagram of the apparatus of this embodiment. In the figure, the power factor control device according to the present embodiment is a three-phase three
The load current IL of the power supply line 10 of the line to the current transformers CT1 and C
The load voltage VL of the power supply line 10 is detected at T2.
Is detected by the voltage transformer PT1, the control calculation unit 1 calculates the reactive power component based on the detected load current and IL and the load voltage VL, and outputs the control command signal S3. A capacitor switch which outputs an ON / OFF command signal S4 based on the time-over signal S2 and is connected to the power supply line 10 via the control circuit section 21 based on the control command signal S3 or the ON / OFF command signal S4. The configuration is such that the capacitor switch 11 of the series resonance circuit of 11, the reactor 12 and the capacitor 13 is controlled to be turned on and off.

Current transformers CT3 and CT4 are connected to the lead-in line to the series resonance circuit, and the current IC is detected and output to the harmonic wave detector 3. This harmonic detection unit 3
Based on the current wave of the detected current IC, for example, the third,
Harmonic components such as the fifth and seventh harmonics are extracted, and compared with the set harmonics that have been set and input by the harmonic level setting unit 6 in advance, and the detection signal S1 of "H" or "L" is detected by the timer 4 And an output to the alarm output unit 5.

When the detection signal S1 (hereinafter, "H" detection signal) indicating that a higher harmonic than the set harmonic is extracted is input to the timer 4, the "H" detection signal S1 is input.
Of the input time, and when the integrated value exceeds a preset value, the time-over signal S2 is output to the control calculation unit 1.

When the "H" detection signal is input, the alarm output unit 5 outputs an alarm indicating that a current containing a harmonic component has flowed into the series resonance circuit. The control circuit unit 21 inputs the control command signal S3 and the on / off command signal S4 from the control arithmetic unit 1 to the capacitor switch 11 and
It is converted into a signal that controls opening.

Next, the operation of the apparatus of this embodiment based on the above configuration will be described. First, an upper limit value and a lower limit value of the reactive power are set in advance by the reactive power value setting unit 7, and normally, the load current IL and the load voltage VL are controlled by the current transformers CT1, CT2 and the voltage transformer PT1. Input to 1.
This control calculation unit 1 measures the reactive power and outputs a control command signal S3 when the upper limit value is exceeded, thereby outputting a cutoff signal to the capacitor switch 11 via the control circuit unit 21 and the reactor 12 , Capacitor 13 to power line 10
Disconnect from. When the calculated reactive power falls below the lower limit value, the control command signal S3 is output to output an input signal to the capacitor switch 11 via the control circuit unit 21, thereby allowing the reactor 12 and the capacitor 13 to be output. Connect and adjust to an appropriate power factor.

In parallel with this power factor adjustment, the current transformer CT
3, CT4 constantly detects the current IC, and the harmonic detection unit 3 extracts the harmonics of the detected current IC, and the harmonics having a value equal to or higher than the value set in advance by the harmonic level setting unit 6 are extracted. When the extraction time continues longer than the time set by the timer 4, a signal is output to the control calculation unit 1. Upon receipt of this signal, the control calculation unit 1 stops the automatic power factor control, and at the time of this stop, the capacitor switch 1
If 1 is turned on, a disconnection signal is immediately output to turn off the capacitor switch 11, and the reactor 12 and the capacitor 13
Is disconnected, and the alarm circuit section 5 outputs an alarm signal to notify the abnormality.

In the above, the embodiment in the case of detecting the reactive power is described, but it is also applicable to the power factor control device for turning on / off the capacitor and the reactor by the power factor control, the current control, the time control and the like. Also, in the case of detecting harmonics, not only the current transformers CT3 and CT4 but also the method using the current transformers CT1 and CT2 can be applied.

In the figure, the current transformers CT3 and CT4 are set above the capacitor switch 11, but the current transformer can be installed inside the capacitor switch 11. Although the timer 4 is configured to output the time-out signal based on the preset reference time in the above embodiment, the timer 4 may be configured to include the reference time setting unit for setting the reference time to an arbitrary value. You can also Since the reference time can be arbitrarily set in this way, it is possible to select the optimum time corresponding to each harmonic filter.

Further, in the above embodiment, the capacitor 13 of the power factor control device is used for advancing the phase, and the reactor 12 is also used.
Is configured to act to suppress the influence of the inrush current, but the reactor 12 and the capacitor 13 which are tuned to the characteristic harmonic current generated in the load 2 connected in parallel with the reactor 12 and the capacitor 13. Is formed as a harmonic filter of a series resonance circuit, and the closed state is maintained without opening the capacitor switch 11 even when the harmonic detection unit 3 detects a harmonic corresponding to this unique harmonic current. It can also be configured as follows.

Even if a specific harmonic is generated from the load 2 connected in parallel to the reactor 12 and the capacitor 13 as described above, the specific harmonic is transmitted to another power factor control device connected to the same power line 10. The output of can be blocked. Further, when a harmonic current other than the specific harmonic is generated and output from another load connected to the same power supply line 10, the detection by the harmonic detecting unit 3 is performed as in the case of the above embodiment. Based on the above, the control circuit unit 21 controls the capacitor switch 11 to open, and the reactor 12 and the capacitor 13 are separated from the power supply line 10 to prevent deterioration, explosion, and the like.

[0031]

As described above, in the present invention, the harmonic detecting means detects the harmonic generated from the load, the electric power system or the equipment affecting the electric power system, and detects the higher harmonic. In this case, the capacitor or reactor that is connected in parallel to the load is separated by the separating means and the alarm is output by the notifying means, so that the load on the capacitor or reactor, the power system, or equipment that affects the power system, etc. It is possible to prevent the inflow of generated harmonics, and it is possible to prevent deterioration or explosion of the capacitor or the reactor. Further, in the present invention, the constant for the harmonic frequency of the capacitor and the reactor can be adjusted by arbitrarily setting the detection level of the harmonic by the detection value setting means, and by setting the optimum detection state for each device. This has the effect that the power factor on the load side can be adjusted. In the present invention, the harmonic detection means detects a harmonic generated from the load, the power system, or a device that affects the power system, and the harmonic is detected in the case of an abnormality. Since the filter is separated by the separating means and the alarm is output by the notifying means, the harmonics generated by the load, the power system, or devices that affect the power system flow into the capacitors and reactors that form the harmonic filter. Can be prevented, and deterioration or explosion of the capacitor or reactor can be prevented. Furthermore, during normal operation when harmonics generated by loads other than the load connected in parallel to the harmonic filter, the power system, or devices that affect the power system are not detected,
The harmonics generated from the loads connected in parallel can be absorbed, which has the effect of blocking the output of the harmonics to the outside. Further, in the present invention, by setting the detection level of the harmonics by the detection value setting means, the constants for the harmonic frequencies of the capacitors and the reactor forming the harmonic filter can be adjusted, and the optimum value for each device can be adjusted. It has an effect that it can be in a detection state.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of a power factor control device according to the present invention.

FIG. 2 is a block configuration diagram of a power factor control device according to an embodiment of the present invention.

FIG. 3 is a connection mode diagram and an equivalent circuit diagram of a conventional power factor control device.

FIG. 4 is a schematic configuration diagram of another conventional power factor control device.

[Explanation of symbols]

 1 Control Calculation Unit 2,200 Load 3 Harmonic Wave Detection Unit 4 Timer 5 Alarm Output Unit 6 Harmonic Level Setting Unit 7 Reactive Power Value Setting Unit 10 Power Line 11 Capacitor Switch 12 Reactor 13 Capacitor 21 Control Circuit Unit 100 Power System 300 Power factor controller

Claims (4)

[Claims] 1. A power factor control device which is connected in parallel to a load connected to an electric power system and is formed by connecting a capacitor and a reactor in series, which affects the load, the electric power system or the electric power system. Harmonic detection means for detecting harmonics of a predetermined value generated in equipment, etc., separation means for separating the capacitor or reactor from the power system when the harmonics are detected, and when the harmonics are detected A power factor control device comprising: a notification unit that outputs an alarm when an abnormality occurs, and that protects a capacitor or a reactor from harmonics generated by the load, the power system, or devices that affect the power system. 2. The power factor control device according to claim 1, further comprising detection value setting means for setting a frequency value of a harmonic detected by the harmonic detection means to an arbitrary value. Rate control device. 3. A power factor control device comprising a harmonic filter which is connected in parallel to a load connected to a power system and is formed by connecting a capacitor and a reactor in series, wherein the load, the power system or the power Harmonic detection means for detecting a harmonic of a predetermined value that occurs in a device or the like that affects the system, separation means for separating the harmonic filter from the power system when the harmonic is detected, and the harmonic A force for protecting a harmonic filter from harmonics generated by the load, the electric power system, or a device affecting the electric power system, etc. Rate control device. 4. The power factor control apparatus according to claim 3, further comprising detection value setting means for setting the frequency of the harmonic detected by the harmonic detection means to an arbitrary value. Control device.