JP2994596B2 - Power factor adjustment system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology of a power factor adjusting system having a function of preventing so-called harmonic interference in a phase advance capacitor equipment.

[0002]

2. Description of the Related Art FIG. 4 illustrates a conventional power factor adjusting system having a function of preventing a so-called harmonic interference, which is configured by combining a harmonic monitoring monitor for monitoring distortion of a harmonic voltage and a power factor adjusting device. FIG.

In FIG. 4, reference numeral 1 denotes a high-voltage trunk line of, for example, 6.6 kv, 2 denotes a high-voltage feeder, 31 and 32 denote transformers for power or electric light loads, and 61 denotes a reactor composed of a phase-advancing capacitor 41a and a reactor 41b. A switch for opening and closing the conduction of the capacitor unit 41, for example, a high-voltage electromagnetic contactor.

Further, a reactor / condenser unit 4
Reference numerals 2 and 43 denote a phase-advancing capacitor 42a and a series reactor 42b and a phase-advancing capacitor 43a and a series reactor 43b, respectively, and switches 62 and 63 are provided corresponding to the reactor-capacitor units 42 and 43, respectively. The parallel body composed of the reactor / condenser units 41 to 43 constitutes a phase advance capacitor facility.

[0005] Further, the power factor adjusting device 7 is driven by inputting the secondary voltage of the transformer 8 and the secondary current of the current transformer 9 in the power receiving unit.

In such a power factor adjusting system, at the time of startup, the power is sequentially turned on for each reactor / capacitor unit in accordance with a predetermined startup sequence (sequence) of the ordinary power factor adjusting device 7, and the system is started.

The power factor adjusting device 7 includes switches 61 to 6
(3) A command to turn on or open switches 61 to 63 necessary to compensate for reactive power due to a load delay so that a predetermined power factor (normally 100%) is obtained by appropriately opening and closing each of the switches. The output is output to the switching control circuit 10.

On the other hand, if the distortion rate of the harmonic voltage of the high-voltage main line 1 becomes high after the start-up (for example, if the distortion rate of the harmonic voltage becomes 3.5% or more), particularly, the capacity of the series reactor increases the capacity of the phase-advancing capacitor. In the case of 6% of the capacity, excessive harmonic current due to series resonance flows into the reactor / capacitor units 41 to 43, respectively, so that the phase-advancing capacitor and the series reactor are overheated, burnt out, abnormally vibrated and noise, etc. The so-called harmonic interference may frequently occur.

Therefore, as shown in FIG. 4, the harmonic monitoring monitor 11 and, for example, the reactor / capacitor unit 41
A current transformer 12 for measuring the magnitude of the current flowing through the entire phase-advancing capacitor equipment composed of the parallel bodies of .about.43 is provided. The output of the current transformer 12 is input to the harmonic monitoring monitor 11, and When the magnitude and duration of the harmonic distortion rate of the current flowing through the filter exceeds a predetermined value,
The harmonic monitoring monitor 11 outputs an alarm signal to the power factor adjusting device 7.

The alarm signal is, for example, an open command (open command) for opening the contacts of the switches 61 to 63,
Based on this opening command, the power factor adjusting device 7 and the opening / closing control circuit 10 perform a so-called sequence function so that the switches 61 to 61 are opened.
All 63 are forcibly opened (blocked), and as a result, the phase-advancing capacitor equipment can avoid so-called harmonic interference such as overheating, burning, or abnormal vibration or noise of the phase-advancing capacitor or the series reactor. ing.

When the return time of the harmonic monitoring monitor 11 exceeds a predetermined set time (for example, 30 minutes), the output of the alarm signal from the harmonic monitoring monitor 11 is released, and the forcibly opened and closed switch is opened. The units 61 to 63 are closed again, and the phase-advancing capacitor equipment returns to the original state before the forcible opening.

[0012]

In the conventional power factor adjusting system configured as described above, the capacitor unit 41
Since the magnitude of the current flowing through the entire phase-advancing capacitor facility consisting of the parallel bodies of the 43 to ４３43 is measured by the current transformer 12 and the measured current value is always input to the harmonic monitoring monitor 11, the power factor When the switches 61 to 63 are turned on based on the input command from the adjusting device 7 to the switching control circuit 10, the transient current flowing through the entire phase-advancing capacitor equipment is also measured and input by the current transformer 12 at the same time.

As shown in FIG. 5, for example, the transient current has a peak value several times as large as the steady value, and its frequency is mainly based on the resonance frequency of the entire phase-advancing capacitor equipment.

However, the harmonic monitoring monitor 11 monitors the harmonics of the phase-advancing capacitor equipment in which the switches 61 to 63 are normally turned on to prevent harmonic interference. Abnormally large harmonic current content is recorded due to the influence of the transient current accompanying the injection of 61 to 63, and the steady-state harmonic current content to be monitored for the harmonic failure of the advanced capacitor equipment. Cannot be recorded, and as a result, there is a problem that the harmonic monitoring monitor 11 performs an operation that does not match the actual situation.

Further, for example, when the phase-advancing capacitor equipment is composed of only a parallel body of capacitors having no reactor component, even a slight change in the harmonic voltage related to the phase-advancing capacitor equipment has an excessively large harmonic number times. Since the current flows through the current transformer 12, the harmonic monitoring monitor 11 performs an operation affected by the excessive current, and thus has a problem that it does not perform a normal operation.

The present invention has been made to solve the above problems, and eliminates the disadvantage that the harmonic monitoring monitor performs an abnormal operation under the influence of an excessive current flowing through the entire phase-advancing capacitor equipment. Accordingly, it is an object of the present invention to obtain a power factor adjustment system capable of performing an operation that matches the actual situation.

[0017]

A power factor adjusting system according to the present invention comprises a series combination of a phase-advancing capacitor and a series reactor connected to high-voltage feeders to which power is supplied from a high-voltage main line via switches. Several reactors
For a high-voltage feeder that detects a parallel body of capacitor units, a transformer and current transformer for the high-voltage main line provided on the high-voltage main line, and a current flowing from the high-voltage main line to the parallel body of the reactor and capacitor units provided for the high-voltage feeder Current transformer and the magnitude and duration of the harmonic distortion rate of the current flowing in the parallel body of the reactor and the capacitor unit based on the detected values of the current transformer for the high voltage feeder exceed a predetermined value. In the case, a harmonic monitoring monitor that outputs an alarm signal, and a control signal for adjusting a power factor so as to have a specified power factor based on a detection value of a transformer and a current transformer for a high-voltage main line, and a harmonic wave. A power factor adjusting device for transmitting a forcible opening control signal for forcibly opening all switches of the plurality of reactor / condenser units when an alarm signal is received from the monitoring monitor; A switching control circuit for controlling the switching of a plurality of reactor / condenser units in response to a control signal sent from the regulating device. An input blocking means for temporarily blocking input to the monitoring monitor is provided. The harmonic monitoring monitor operates the input blocking means when the alarm signal is released to temporarily block the input of the detected value to the harmonic monitoring monitor. The blocking means cancels the input blocking operation after a lapse of a predetermined time from the execution of the input blocking operation.

Also, a parallel body of a plurality of reactor / capacitor units, each of which is a series body of a phase-advancing capacitor and a series reactor connected to a high-voltage feeder to which power is supplied from the high-voltage main line via a switch, A high-voltage mains transformer and a current transformer, and a high-voltage feeder current transformer for detecting a current flowing from the high-voltage mains to a parallel body of reactor condenser units provided in the high-voltage feeder, and a high-voltage feeder A harmonic that outputs an alarm signal when the magnitude and duration of the harmonic distortion rate of the current flowing through the parallel-connected reactor-capacitor units based on the detection values of the current transformers exceed a predetermined value. The monitor sends a power factor adjustment control signal so that the specified power factor is obtained based on the detection values of the monitoring monitor and the transformer and current transformer for the high voltage mains, and When an alarm signal is received from the wave monitoring monitor, a power factor adjusting device that sends out a forcible opening control signal for forcibly opening all the switches of the plurality of reactor / condenser units and a power factor adjusting device that sends out the signal. In a power factor adjustment system comprising a switching control circuit for controlling switching of a plurality of reactor / condenser units in response to a control signal, a high-voltage feeder is provided between a current transformer for a high-voltage feeder and a harmonic monitoring monitor. Is provided with a filter for removing a signal component in a predetermined band from the detection value of the current transformer.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is an explanatory diagram of the power factor adjustment system according to the first embodiment. In FIG. 1, as a new configuration with respect to the conventional example, reference numeral 21 denotes a harmonic monitoring monitor 11 and a current transformer 1.
2 between the switching control circuit 10 and the switch 61.
63 is a current conversion circuit as input blocking means for temporarily blocking current input to the harmonic monitoring monitor 11 for a predetermined period of time based on the input command to the control signals 63 to 63.

Here, the current conversion circuit 21 is constituted by, for example, a timed relay so that a current signal is input from the current transformer 12 to the harmonic monitoring monitor 11 via a normally closed contact (not shown). Is also good.

When a signal is input to the timed relay, the normally closed contact is opened for a predetermined period of time (for example, one second), and a signal from the current transformer 12 to the harmonic monitor 11 is transmitted from the current transformer 12 to the harmonic monitor 11. The input of the current signal may be blocked.

In the power factor adjusting system according to Embodiment 1 configured as described above, the switch 6
The power factor adjusting device 7 is required to compensate for the reactive power due to the load delay so that a predetermined power factor (usually 100%) is obtained by appropriately opening and closing each of 1 to 63.
A switching ON / OFF command of the switch of the phase advance capacitor unit is output to the switching control circuit 10. And the opening / closing control circuit 1
0 based on the output of the control signal from the switches 61-63.
Or release.

In this case, a command to turn on or off the switch from the power factor adjusting device 7 to the switching control circuit 10 is also input to the current conversion circuit 21 at the same time, and the current conversion circuit 21
2 of the secondary side current a predetermined prescribed time (e.g., 1
(Seconds) so that a transient current flowing through the entire phase-advancing capacitor equipment with the closing of the electromagnetic contactor 6 is temporarily prevented from being input to the harmonic monitoring monitor 11 (for example, a current transformer ( not shown )). 12 to the ground on the secondary side ).

Therefore, according to the first embodiment, the phase advance capacitors 4 connected to the high voltage feeders 2 to which power is supplied from the high voltage main line 1 via the switches 61 to 63, respectively.
A plurality of reactor / condenser units 41 to 41 each formed of a series body of 1a to 43a and series reactors 41b to 43b
43, a high-voltage main line transformer 8 and a current transformer 9 provided in the high-voltage main line 1, and reactor-condenser units 41 to 41 provided in the high-voltage feeder 2 from the high-voltage main line 1.
A current transformer 12 for a high voltage feeder for detecting a current flowing in a parallel body of 43, and a harmonic of a current flowing in a parallel body of the reactor capacitor units 41 to 43 based on a detection value of the current transformer 12 for a high voltage feeder. A harmonic monitoring monitor 11 for outputting an alarm signal when the magnitude of the distortion rate and the duration thereof exceed a predetermined value; and a transformer 8 for a high-voltage main line.
And a control signal for adjusting the power factor so as to have a specified power factor based on the detection value of the current transformer 9, and a plurality of reactor / capacitor units when an alarm signal is received from the harmonic monitoring monitor 11. 41-43 switches 61-
And a switch 61 for a plurality of reactor / condenser units 41 to 43 in response to a control signal sent from the power factor adjusting device 7. And a switching control circuit 10 for controlling the opening and closing of the high-voltage feeder 12 in the power factor adjusting system.
A current conversion circuit 21 for temporarily blocking input to 1 is provided, and the harmonic monitor 11 operates the current conversion circuit 21 when the alarm signal is released to temporarily block the input of the detected value to the harmonic monitor 11. At the same time, the current conversion circuit 21 releases the input blocking operation after a lapse of a predetermined time after performing the input blocking operation.
Even if the current transformer 12 measures the transient current flowing through the entire phase-advancing capacitor equipment with the input of the power supply, the current value is not input to the harmonic monitoring monitor 11, and the current flowing through the entire phase-advancing capacitor facility becomes a steady state. When the current value measured by the current transformer 12 is input to the harmonic monitoring monitor 11,
The harmonic monitoring monitor 11 always targets the steady-state current of the entire phase-advancing capacitor equipment, and has an inconvenience of performing an abnormal operation under the influence of an excessive current flowing through the entire phase-advancing capacitor equipment, that is, the so-called harmonic disturbance. As a result, the harmonic current content can be correctly monitored and the operation corresponding to the actual situation can be performed.

Embodiment 2 FIG. 2 shows Embodiment 2 of the present invention.
It is explanatory drawing of the power factor adjustment system which concerns on. In FIG. 2, as a new configuration with respect to the conventional example, a filter 22 cuts a current signal component in a predetermined band (for example, a 14th-order higher-order component).

Here, for example, the filter 22 shown in Table 1 is employed.

[0027]

[Table 1]

The filter 22 has, for example, characteristics as shown in FIG. 3, and in the case of FIG.
It has the property of attenuating at z to 10 KHz.

In the power factor adjusting system according to Embodiment 2 configured as described above, the current transformer 1
Numeral 2 measures the magnitude of the current flowing through the entire phase-advancing capacitor facility consisting of the parallel-connected reactor-capacitor units 41 to 43. Then, the measured value is input from the current transformer 12 to the harmonic monitoring monitor 11 via the filter 22.

Here, the high-order (14th or higher) current component is cut off by the filter 22, and the
, A current measurement value from which the higher-order component has been cut is input.

Therefore, according to the second embodiment, the phase-advancing capacitors 4 connected to the high-voltage feeders 2 to which power is supplied from the high-voltage mains 1 via the switches 61 to 63, respectively.
A plurality of reactor / condenser units 41 to 41 each formed of a series body of 1a to 43a and series reactors 41b to 43b
43, a high-voltage main line transformer 8 and a current transformer 9 provided in the high-voltage main line 1, and reactor-condenser units 41 to 41 provided in the high-voltage feeder 2 from the high-voltage main line 1.
A current transformer 12 for a high voltage feeder for detecting a current flowing in a parallel body of 43, and a harmonic of a current flowing in a parallel body of the reactor capacitor units 41 to 43 based on a detection value of the current transformer 12 for a high voltage feeder. A harmonic monitoring monitor 11 for outputting an alarm signal when the magnitude of the distortion rate and the duration thereof exceed a predetermined value; and a transformer 8 for a high-voltage main line.
And a control signal for adjusting the power factor so as to have a specified power factor based on the detection value of the current transformer 9, and a plurality of reactor / capacitor units when an alarm signal is received from the harmonic monitoring monitor 11. 41-43 switches 61-
And a switch 61 for a plurality of reactor / condenser units 41 to 43 in response to a control signal sent from the power factor adjusting device 7. And a switching control circuit 10 that controls the opening and closing of the high-voltage feeder 12 between the high-voltage feeder current transformer 12 and the harmonic monitoring monitor 11. Since the filter 22 for removing a signal component in a predetermined band is provided, even if an excessive current flows through the entire phase-advancing capacitor equipment and is measured by the current transformer 12, the measured value is not changed by the filter 22.
As a result, the higher-order current component is cut and input to the harmonic monitoring monitor 11, and the apparent higher-order component caused by the sampling of the harmonic monitoring monitor 11 disappears. Therefore, the harmonic monitoring monitor 11 records an excessive current. As a result, it is possible to perform an operation that matches the actual situation.

[0032]

According to the present invention, there are provided a plurality of reactor / capacitor units which are connected in series to a high voltage feeder to which power is supplied from a high voltage main line via a switch, and which are formed of a series body of a phase advance capacitor and a series reactor. Parallel bodies,
A high-voltage mains transformer and a current transformer provided on the high-voltage mains, and a high-voltage feeder current transformer for detecting a current flowing from the high-voltage mains to a parallel body of reactor and capacitor units provided on the high-voltage feeder; An alarm signal is output when the magnitude and duration of the harmonic distortion rate of the current flowing through the parallel-connected reactor / capacitor unit exceed a predetermined value based on the detection value of the current transformer for the feeder. Transmits a control signal for power factor adjustment so that the specified power factor is obtained based on the detected values of the harmonic monitor monitor and the transformer and current transformer for the high-voltage mains, and receives an alarm signal from the harmonic monitor monitor In this case, a power factor adjusting device that sends a control signal for forced opening that forcibly opens all switches of a plurality of reactor / condenser units, and a control signal that is sent from the power factor adjusting device In a power factor adjustment system with a switching control circuit that controls the switching of multiple reactor / condenser units according to the conditions, the detection value of the current transformer for the high-voltage feeder is temporarily blocked from being input to the harmonic monitoring monitor The harmonic monitoring monitor operates the input blocking means when the alarm signal is released to temporarily block the input of the detected value to the harmonic monitoring monitor, and the input blocking means performs the input blocking operation. Since the input blocking operation is released after a predetermined time has elapsed since the current was conducted, even if the current transformer measures the transient current flowing in the parallel Is not input to the harmonic monitoring monitor, and the current value measured by the current transformer when the current flowing through the parallel By input to the Monitor, harmonic surveillance monitor, always directed to the constant current of the parallel body of the reactor-condenser unit,
The inconvenience of abnormal operation due to the effect of excessive current flowing through the parallel combination of reactor and capacitor units, the so-called harmonic disturbance, has been eliminated, and the harmonic current content has been correctly monitored to match the original actual situation. Actions can be taken.

Also, a parallel body of a plurality of reactor / capacitor units, each of which is a series body of a phase-advancing capacitor and a series reactor connected via switches to a high-voltage feeder to which power is supplied from the high-voltage trunk, A high-voltage mains transformer and a current transformer, and a high-voltage feeder current transformer for detecting a current flowing from the high-voltage mains to a parallel body of reactor condenser units provided in the high-voltage feeder, and a high-voltage feeder A harmonic that outputs an alarm signal when the magnitude and duration of the harmonic distortion rate of the current flowing through the parallel-connected reactor-capacitor units based on the detection values of the current transformers exceed a predetermined value. The monitor sends a power factor adjustment control signal so that the specified power factor is obtained based on the detection values of the monitoring monitor and the transformer and current transformer for the high voltage mains, and When an alarm signal is received from the wave monitoring monitor, a power factor adjusting device that sends out a forcible opening control signal for forcibly opening all the switches of the plurality of reactor / condenser units and a power factor adjusting device that sends out the signal. In a power factor adjustment system comprising a switching control circuit for controlling switching of a plurality of reactor / condenser units in response to a control signal, a high-voltage feeder is provided between a current transformer for a high-voltage feeder and a harmonic monitoring monitor. A filter that removes signal components in a predetermined band from the detected value of the current transformer is provided, so even if an excessive current flows through the parallel body of the reactor and capacitor units and is measured by the current transformer, The measured value is filtered by the filter to remove higher-order current components and input to the harmonic monitor, and the apparent higher-order component resulting from sampling of the harmonic monitor is displayed. Because there is no,
The harmonic monitoring monitor does not record an excessive current, and can operate in accordance with the actual situation.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a power factor adjustment system according to a first embodiment.

FIG. 2 is an explanatory diagram of a power factor adjustment system according to a second embodiment.

FIG. 3 is a characteristic diagram of a filter 22 of the power factor adjustment system according to the second embodiment.

FIG. 4 is an explanatory diagram of a power factor adjustment system having a conventional harmonic interference prevention function.

FIG. 5 is a diagram showing a transient current flowing through the entire phase-advancing capacitor equipment when a switch is turned on in the conventional power factor adjusting system.

[Explanation of symbols]

 21 current conversion circuit, 22 filter.

Claims (2)

(57) [Claims] 1. A parallel body of a plurality of reactor / capacitor units each comprising a series body of a phase-advancing capacitor and a series reactor connected to a high-voltage feeder to which power is supplied from a high-voltage main line via a switch, respectively. A transformer and a current transformer for a high-voltage main line provided on the main line, and a current transformer for a high-voltage feeder that detects a current flowing from the high-voltage main line to a parallel body of the reactor capacitor units provided in the high-voltage feeder, An alarm signal when the magnitude and duration of the harmonic distortion rate of the current flowing in the parallel body of the reactor / capacitor units exceed a predetermined value based on the detected value of the current transformer for the high voltage feeder. And a power factor adjustment control signal such that the specified power factor is obtained based on the detection values of the transformer and the current transformer for the high-voltage main line. And a power factor adjusting device for transmitting a forcible opening control signal for forcibly opening all switches of the plurality of reactor / capacitor units when receiving an alarm signal from the harmonic monitoring monitor. A switching control circuit for controlling the switching of the plurality of reactor / condenser units according to a control signal sent from the power factor adjusting device. Input blocking means for temporarily blocking the input of the value to the harmonic monitoring monitor, wherein the harmonic monitoring monitor operates the input blocking means when the alarm signal is released to detect the detected value to the harmonic monitoring monitor. And the input blocking means cancels the input blocking operation after a lapse of a predetermined time after performing the input blocking operation. Power factor correction system comprising. 2. A parallel body of a plurality of reactor / capacitor units each comprising a series body of a phase-advancing capacitor and a series reactor connected to a high-voltage feeder to which power is supplied from a high-voltage main line via a switch, respectively. A transformer and a current transformer for a high-voltage main line provided on the main line, and a current transformer for a high-voltage feeder that detects a current flowing from the high-voltage main line to a parallel body of the reactor capacitor units provided in the high-voltage feeder, An alarm signal when the magnitude and duration of the harmonic distortion rate of the current flowing in the parallel body of the reactor / capacitor units exceed a predetermined value based on the detected value of the current transformer for the high voltage feeder. And a power factor adjustment control signal such that the specified power factor is obtained based on the detection values of the transformer and the current transformer for the high-voltage main line. And a power factor adjusting device for transmitting a forcible opening control signal for forcibly opening all switches of the plurality of reactor / capacitor units when receiving an alarm signal from the harmonic monitoring monitor. A power factor adjusting system comprising: an open / close control circuit that controls opening / closing of the switches of the plurality of reactor / condenser units according to a control signal transmitted from the power factor adjusting device; A power factor adjusting system, comprising: a filter for removing a signal component in a predetermined band from a detected value of the high-voltage feeder current transformer with a harmonic monitoring monitor.