JPH10174292A - Transforming device fitted with the capacitor for improvement of power factor contributing to countermeasure against higher harmonic waves - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform power factor control at low cost by outputting an opening/closing command for the low-voltage switch of a capacitor unit for improvement of power factor, on the basis of the command of a power factor control circuit and the secondary voltage of a transformer detected with a voltage detecting circuit. SOLUTION: In case the power factor measured by a power factor measuring circuit 4 is, for example, 98% or under in lagging power factor, a power factor control circuit 5 outputs an ON command to a capacitor unit for improvement of power factor. At this point, a voltage detecting circuit 6a detects the secondary voltage of a low-voltage transformer 31. When the secondary voltage is 218V or over, there is no output from the terminal of the voltage detector 6a, and the AND condition of an AND circuit does not materialize, and an ON command is not outputted to the power factor adjusting circuit 61. When the secondary voltage of the low-voltage transformer 31 is 216V or over, it is outputted from the terminal of the voltage detector 6a, and the AND condition of the AND circuit materializes, and a Tb timer outputs it after set time, and 10 seconds later, a T4 timer outputs an ON command. As a result, the low-voltage switch SW1 of the capacitor unit for power factor improvement of the power factor adjusting circuit 61 is turned on to make and connect a phase-advanced capacitor C1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substation with a power factor improving capacitor which contributes to harmonic countermeasures.

[0002]

2. Description of the Related Art Heretofore, there has been widely used a device in which a capacitor facility for improving a power factor is provided on a high-voltage bus and the on / off of the capacitor is controlled so that the power factor at a power receiving point approaches 1 as much as possible. In such a device with a power factor improving capacitor, a method of installing a reactor in series with the power factor improving capacitor to suppress harmonics flowing out of the load on the premises has been adopted. When it is high, a method of increasing the capacity of the series reactor to 6%, 8%, or 13% of the capacity of the power factor improving capacitor or increasing the withstand capacity is adopted. If the increase in the number of series reactors is not sufficient, a method of separately installing a harmonic absorption filter (passive type of LC resonance or active type of inverter application) may be used. However, this type of filter is expensive.

[0003]

On the other hand, guidelines for measures to suppress harmonics have also been issued. According to the guidelines, power factor improving capacitor equipment is subdivided into small capacities and installed on the low voltage side of each load transformer. Although a method has been proposed, this method increases the cost, and the third harmonic, which is canceled on the high voltage side by the delta winding of the transformer (high voltage / low voltage) in the premises, appears on the low voltage side, so that it is usually used. The 6% series reactor has a problem that the third harmonic increases. Also, from the viewpoint of power factor improvement, this method requires a separate power factor control device on the secondary side of each transformer, and has a problem that it is difficult to perform power factor control collectively.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a substation apparatus which performs power factor control at a low cost with a simple circuit configuration while taking measures against harmonics flowing in from a power supply system side and harmonics flowing out of an in-house load. I do.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a substation apparatus which receives power from an external power supply system via a transformer, each of which has a phase advance with a series reactor through a low voltage switch. A power factor adjustment circuit configured by a plurality of power factor improvement capacitor units composed of capacitors, and a power factor measurement circuit that measures a power factor at a power receiving point;
When the power factor at the receiving point is equal to or less than a predetermined delay power factor, a command to turn on the power factor improving capacitor unit is output, and when the power factor is equal to or more than a predetermined leading power factor, a command to open the power factor improving capacitor is output. A power factor control circuit is provided, and for each load, a voltage detection circuit that detects a transformer secondary voltage supplied to the load, a command from the power factor control circuit, and a voltage detected by the voltage detection circuit. An open / close command circuit for outputting a command for opening / closing a low-voltage switch of the power factor improving capacitor unit based on the secondary voltage of the transformer.

Further, the switching command circuit provided for each load includes: (a) the secondary voltage of the transformer detected by the voltage detection circuit is equal to or lower than a predetermined value, and the power factor control circuit outputs a closing command. In the meantime, a plurality of improvement capacitor units constituting the power factor adjustment circuit are sequentially and sequentially delayed in a predetermined order, and when the output of the injection command is stopped, the on state of the power factor improvement capacitor unit is maintained. And
(B) While the voltage on the secondary side of the transformer detected by the voltage detection circuit is equal to or more than the predetermined value or while the open command is being output from the power factor control circuit, the power factor improving capacitor unit is connected to the transformer 2 When the secondary voltage of the transformer decreases below the predetermined value or when the output of the release command stops, the power factor improving capacitor is opened as the secondary voltage increases or in a predetermined order. The unit is configured to keep the open state of the low-voltage switch as it is.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 shows a circuit configuration of a power receiving device according to the present invention. In the illustrated example, power is supplied to two local loads, but the number of loads may be more.

[0009] The power receiving device receives an extra high voltage (66
kV), the voltage is reduced to 6 kV by the extra high voltage receiving transformer 2, and further reduced to 105V or 210V by the low voltage transformers 31 and 32 in the premises, and the loads 101 and 102 in the premises, respectively.
Powering. Reference numeral 4 denotes a power factor measurement circuit that measures the power factor at the receiving point A from the voltage and current phases at the receiving point A.
Is the power receiving point A based on the power factor measured by the power factor measurement circuit 4.
Is a power factor control circuit that controls the power factor adjustment circuits 61 and 62 provided for each load so that the power factor in the load is as close to 1 as possible. If the power factor of the entire load in the premises is 98% or less of the delay power factor, It is set so as to output an "injection command" of the power factor improving capacitor, and to output an "opening command" of the power factor improving capacitor if the advance power factor is 99% or more. Next, the power factor adjustment circuit 61 of the load 101 and the power factor adjustment circuit 62 of the load 102 will be described. However, since the circuit configurations of both circuits are exactly the same, only the power factor adjustment circuit 61 of the load 101 will be described.

Now, assuming that the premises load 101 is a single-phase 105V or 210V illumination load, the low-voltage transformer 31
Adopts a three-phase delta winding on the high voltage primary side and a three-phase irregular star winding on the low voltage secondary side, as shown in FIG.
The power factor adjusting circuit 61 includes a voltage detector 6a for detecting a secondary voltage of the low-voltage transformer 31, and three power factor improving capacitors connected in parallel with the load 101 to each terminal of the secondary star winding. Unit, that is, (1) low-voltage switch SW1,
A first power factor improving capacitor unit formed by connecting a series reactor L1 and a phase advance capacitor C1 in series;
(2) low-voltage switch SW2, series reactor L2,
A second power factor improving capacitor unit formed by connecting a phase-advancing capacitor C2 in series, and (3) a low-voltage switch SW.
3, a series reactor L3 and a third phase-advancing capacitor C3 connected in series, a third power factor improving capacitor unit, and a command from the power factor control circuit 5 ("make command" or "open command"). And an open / close command circuit 6b for opening / closing the low-voltage switches SW1, SW2, SW3 based on the output from the voltage detection circuit 6a.

The voltage detector 6a detects the secondary voltage of the low-voltage transformer 31, that is, the supply voltage to the load, and as shown in FIG. 3 showing a detailed circuit configuration of the switching command circuit 6b, Is 222 V or more, for example,
When the voltage is 20 V or more, the signal is output from the terminal b. When the voltage is 218 V or more, the signal is output from the terminal c. When the voltage is 216 V or less, the signal is output from the terminal d. The capacity of the series reactors L1, L2, and L3 of the three power factor adjusting circuits is 13%, 8%, and 6%, respectively.
Each capacity of C1, C2 is approximately 1 capacity of the capacity of the low voltage transformer 31.
0%. If the capacity of the low-voltage transformer 31 is, for example, 1000
kVA, power factor improving capacitors C1, C
2. Each capacity of C3 is 100 kVA.

On the other hand, when the in-plant load 101 is a general power, the low-voltage transformer 31 has a three-phase delta winding on both the high-voltage primary side and the low-voltage secondary side, as shown in FIG. The capacity of the series reactors L1, L2, and L3 constituting the power factor improving capacitor unit of the power factor adjusting circuit 61 is 8%, 6%, and 6%, respectively.

FIG. 3 shows a circuit configuration of the open / close command circuit 6b.

The open / close command circuit 6b includes a power factor control circuit 5
Timer 71 that receives an “open command” from the
When the output from the timer 71 is received, for example, a T1 timer 72 that outputs 200 seconds later, a T2 timer 73 that also outputs 100 seconds later, a T3 timer 74 that also outputs 10 seconds later, and a power factor control circuit 5 An AND circuit 81 which takes the logical product of the [input command] of the above and the output from the terminal d of the voltage detector 6a, a Tb timer 82 receiving the output of the AND circuit 81, and an output from the Tb timer 82 For example, a T4 timer 83 that outputs after 10 seconds,
Similarly, for example, a T5 timer 84 that outputs after 100 seconds
And a T6 timer 85 that is also output after 200 seconds,
An OR circuit 91 for performing an OR operation on the output from the timer 72 and the output from the terminal a of the voltage detector 6a;
An OR circuit 92 for performing an OR operation on the output from the terminal 3 and the output from the terminal b of the voltage detector 6a, and an OR circuit for performing an OR operation on the output from the T3 timer 74 and the output from the terminal c of the voltage detector 6a And a circuit 93. In the present embodiment, the time from when the signal is received to when the signal is output to both the Ta timer 71 and the Tb timer 82 is set to a maximum of 100 seconds or less (for example, 10 seconds). Further, the Ta timer and the Tb timer provided in the opening / closing command circuit 6d (see FIG. 1) of the power factor improving capacitor unit 62 for the other local load 102 are provided with the opening / closing command circuit 6b of the power factor adjusting circuit 61 described above. The time is set, for example, 10 seconds longer than the set time of the Ta timer 71 and the Tb timer 82 provided in (see FIG. 3). Similarly, the setting times of the Ta timer and the Tb timer provided in the opening / closing command circuit of the power factor improving capacitor unit are set so as to be sequentially increased with a time difference of, for example, 10 seconds for other in-plant loads. I have.

Next, the operation of the power receiving apparatus for controlling the power factor and suppressing harmonics will be described.

When the power receiving device is receiving extraordinary power from the power supply system 1, the power factor measuring circuit 4 measures the power factor at the power receiving point A.

First, the case of a delayed power factor will be described.

When the power factor measured by the power factor measuring circuit 4 is equal to or less than 98% of the delayed power factor, the "input command" is output from the power factor control circuit 5 to the power factor improving capacitor unit. On the other hand, at this time, the low voltage transformer 3 is detected by the voltage detector 6a.
1 secondary-side voltage is detected. Secondary voltage is 218
When the voltage is equal to or higher than V, there is no output from the terminal d of the voltage detector 6a, and the AND condition of the AND circuit 81 is not satisfied.
Therefore, no closing command is output to the power factor adjusting circuit 61. However, when the secondary voltage of the low-voltage transformer 31 is 216 V or less, the voltage is output from the terminal d of the voltage detector 6a, so that the AND condition of the AND circuit 81 is satisfied, and the Tb timer 82 outputs after a set time. As a result, first, after 10 seconds, the T4 timer 83 outputs the "input command", so that the low-voltage switch SW1 of the first power factor improving capacitor unit of the power factor adjustment circuit 61 is turned on, and the phase advance capacitor C1 is turned on. Is done. If the power factor still does not improve to 98% or more of the delayed power factor, the voltage on the secondary side of the transformer of the power factor adjustment circuit 62 for the next load 102 is increased to 216 after 10 seconds.
V, the low voltage switch SW1 'of the first power factor improving capacitor unit is turned on, and the phase advance capacitor C
1 'is input. As a result, when the power factor is improved to exceed the delayed power factor of 98%, the "input command" is no longer output from the power factor control circuit 5;
The ND condition is not satisfied, the Tb timer 82 is reset, and the state calms down in this state.

However, if the power factor is still not improved, the first power factor adjusting circuit of the power factor adjusting circuit provided from the substation and provided to another load having a transformer secondary voltage of 216 V or less is provided. The low-voltage switches of the power factor improving capacitor unit are sequentially turned on with a delay of 10 seconds, and the phase-advancing capacitors are turned on. Such an operation is sequentially performed for all loads to which the voltage condition can be applied, and when the power factor does not become 98% or more of the delay power factor, 100 seconds have elapsed after the output of the Tb timer 82. Sometimes the first load 1
The T5 timer 84 of the open / close command circuit 6b of the power factor adjustment circuit 61 of FIG. As a result, the low-voltage switch SW2 of the second power factor improving capacitor unit is turned on,
The phase advance capacitor C2 is turned on. The series reactor L2 (8%) connected here has a smaller reactance value than the series reactor L1 (13%) connected earlier.

Hereafter, the power factor at the receiving point A is delayed by a power factor of 98.
The same operation is repeated until the value reaches% or more. In addition, even if the power factor is not improved by the above operation, the low-voltage transformer 3
When the secondary side voltage of the first signal becomes 216 V or more, the voltage detector 6
Since there is no output from the terminal d of a, the AND circuit 81
Is not satisfied, and the operation of the power factor adjusting circuit stops here.

Next, the case of the advance power factor will be described.

As a result of the measurement by the power factor measuring circuit 4, when the power factor at the receiving point A is advanced and the power factor is 99% or more, the power factor control circuit 5 outputs an "open command" of the power factor improving capacitor unit. Is done. When "open command" is output, Ta
The timer 71 starts and outputs after a set time. As a result, T1 timer 72, T2 timer 73, T3 timer 74
Are started at the same time, but the T3 timer 74 outputs first after 10 seconds. As a result, the OR condition of the OR circuit 93 is satisfied, so that the low-voltage switch SW3 of the first power factor improving capacitor unit is turned off and the phase advance capacitor C3 is opened. If the leading power factor still does not become 99% or less, the first power factor improving capacitor unit phase leading capacitor connected in parallel to the next load 102 is opened 10 seconds after that.

In this way, the phase-advancing capacitor of the power factor improving condenser unit is sequentially opened for other loads. If the progressing power factor is still not improved, the Ta timer 71 is used. 100 seconds (set time of the T2 timer 73) after the start of the T2 timer 73, the T2 timer 73 outputs, the OR condition of the OR circuit 92 is satisfied, and the second power factor improving capacitor unit of the first load 101 is now provided. Is turned off, and the phase advance capacitor C2 is opened. This operation is performed for other loads until the advance power factor becomes 99% or less. During that time, if the advance power factor is improved, the state is settled down. Is output by the T1 timer 72 after 200 seconds (the set time of the T1 timer 72), whereby the OR condition of the OR circuit 91 is satisfied, and the first load 101 again returns to the first state.
Switch SW1 of the power factor improving capacitor unit
Is turned off, and the phase advance capacitor C1 is opened.

The "open command" from the power factor control circuit 5
Irrespective of the presence or absence of the condition, the OR condition of the OR circuits 91, 92, and 93 is satisfied according to the voltage value of the secondary voltage of the low-voltage transformer 31, that is, the output state from the terminals a, b, c, and d of the voltage detector 6a. , The low-voltage switch SW of the third, second, and first power factor improving capacitor units as the voltage value increases
3, SW2, and SW1 are turned off in this order, so that a voltage rise due to a leading power factor of the load is prevented, and the leading power factor is also improved.

As described above, in the present invention,
Connect a plurality of power factor improvement capacitor units connected in parallel with a phase-advancing capacitor and a series reactor to the secondary side of the receiving transformer, and make a difference in the reactor capacity of the power factor improvement capacitor unit. When the power factor is improved, the power factor adjustment circuit unit is turned on in order of the reactor capacity, and when the power factor is improved, the power factor adjustment circuit is controlled so that it is opened in order of the reactor capacity, which is smaller. In this case, the effect of suppressing harmonics in this circuit will be considered.

The third harmonic, which has been a particular problem in a single-phase circuit, can be absorbed by a power factor improving capacitor unit comprising a series reactor of about 13% and a phase-advancing capacitor which are preferentially supplied. Even when the fifth harmonic is large, it can be absorbed to some extent by the power factor improving capacitor unit including the series reactor of about 8%, and the fifth harmonic can be stably absorbed without abnormal heating of the series reactor.

Here, the present inventors have confirmed the effect of the present invention on suppressing harmonics generated in the premises for two models as shown in FIGS. 4 (a) and 4 (b).

As an example of the extra-high power reception, an extra-high voltage of 66 kV having a system-side short-circuit capacity of 2,857 MVA and a capacity of 10,000
6.6 kV for transformer 2 with 0 kVA and 7% impedance
In the model 1 shown in FIG. 4A, the series reactor L1 is connected to the secondary low-voltage side of the low-voltage transformer 2 by a low-voltage transformer 2 having a capacity of 1,000 kVA and an impedance of 7%. A first power factor improving capacitor unit including a phase capacitor C1, a second power factor improving capacitor unit including a series reactor L2 and a phase advance capacitor C2, and a series reactor L3 and a phase advance capacitor C3. A model in which a third power factor improving capacitor unit is connected and a harmonic current generation source 100 is connected, and a model 2 shown in FIG. The second and third power factor improving capacitor units are connected to the primary high voltage side of the low voltage transformer 31, and the harmonic current source 100 is connected to the secondary low voltage side. A. In model 1, the capacity of series reactor L1 is 13%, the capacity of L2 is 8%, and the capacity of L3 is 6%. In model 2, series reactors L1, L2, L3
Are 6%, and the capacities of the capacitors C1, C2 and C3 are 100 kVA, which is 10% of the capacity of the low-voltage transformer 31 in both the models 1 and 2.

Table 1 below shows the harmonic absorption (%) of the above two models.

[0030]

Table 1 Harmonic order 5th 7th 11th 13th order Model 1 40.0 28.4 24.3 23.7 Model 2 9.9 5.3 4.1 3.9 From Table 1, the model 1 It can be seen that the higher the harmonic component absorption.

Table 2 compares the effect of suppressing the outflow of the harmonic component generated from the in-plant load to the system side in the case of high-voltage power receiving with a receiving-point short-circuit capacity of 150 MVA, and is shown in%. The model in this case corresponds to the same model shown in FIGS. 4A and 4B without the extra high power receiving transformer 2.

[0032]

Table 2 Harmonic order 5th 7th 11th 13th order Model 1 39.8 28.2 24.1 23.5 Model 2 9.1 4.8 3.72 3.6 From Table 2, the model 1 It can be seen that the outflow suppression effect is greater.

Table 3 compares the effect of preventing the inflow of harmonic components flowing from the power supply system side for the same two models, and shows the distortion rate of the _n-th voltage Vn of the power supply system as 3
%, And the ratio of the current flowing into the capacitor on a 300 kVA basis is shown in%).

[0034]

Table 3 Harmonic order 5th 7th 11th 13th order Model 1 0.10 0.05 0.03 0.02 Model 2 0.27 0.10 0.05 0.04 Model 2 / Model 1 62 1.96 1.77 1.74 From Table 3, it can be seen that Model 1 has less inflow of harmonic components from the power supply system side to the power factor improving capacitor unit.

In the above embodiment, it is important that the plurality of power factor improving capacitor units constituting the power factor adjusting circuit for one load have different series reactor capacities. Preferentially put in the capacitor unit with large capacity of series reactor,
In order to improve the lead power factor, the capacitor units with the smaller capacity of the series reactor are opened preferentially in order.

In the above-described embodiment, the power receiving device that receives extra-high power from the power supply system has been described. However, the present invention is not limited to extra-high power receiving, and can be similarly applied to high-voltage power receiving. For example, the present invention can also be realized as a power receiving device such as a cogeneration system that is provided with in-house power generation and performs an interconnected operation with a system power supply.

[0037]

According to the present invention, the unit capacity of the power factor improving capacitor unit composed of the series reactor and the phase advance capacitor is reduced to about 1/10 of the capacity of the low-voltage transformer for the load. Since the power factor is divided, the power factor can be controlled precisely and finely within a range of about 99% from 98% behind. In addition, one power factor measurement device may be used to perform power factor control for a plurality of loads, and the power factor measurement device may apply a power at one power receiving point to a substation that supplies power to a plurality of loads. The circuit configuration can be simplified because it is only necessary to measure the power factor and output the "input command" or "open command" to the power factor improving capacitor units of all the loads supplied by the power receiving device collectively. In addition to being advantageous in terms of cost, it is also possible to prevent an increase in voltage due to the advance power factor. Further, according to the power factor control method of the present invention, a control sequence circuit standardized for all loads can be used.

In addition to the above effects, in the power receiving device according to the present invention, the third harmonic which is particularly problematic in the single-phase circuit has a relatively large capacity of 13% which is preferentially supplied when the delay power factor is improved. It is absorbed by a power factor improving capacitor unit consisting of a large series reactor and a phase advance capacitor. This is advantageous when an irregular star winding is used for the secondary winding of the premises transformer as a single phase 105V or 210V lighting power supply. Even when the fifth harmonic is large, it is absorbed by a power factor improving capacitor unit including a series capacitor having a medium capacity of about 8% and a phase advance capacitor. The power factor improving capacitor unit stably absorbs the fifth harmonic without overheating abnormally.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an embodiment of a substation with a power factor improving capacitor which contributes to harmonic countermeasures according to the present invention.

2A and 2B show connections of a low-voltage transformer in a premises, wherein FIG. 2A shows connections when used as a power source for lighting, and FIG. 2B shows connections when used as a power source for general power.

FIG. 3 is a block diagram illustrating a circuit configuration of an opening / closing command circuit.

FIG. 4 shows two models for confirming the harmonic suppression effect of the substation according to the present invention, wherein (a) shows a model in which a power factor improving capacitor unit is connected to the low voltage side of a low voltage transformer,
(B) shows a model in which this unit is connected to the high voltage side of a low voltage transformer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 External power supply system 2 Extra high voltage receiving transformer 31, 32 Low-voltage transformer in premises 4 Power factor measuring circuit 5 Power factor controlling circuit 61, 62 Power factor adjusting circuit 6a, 6c Voltage detecting circuit 6b, 6d Opening / closing command circuit 71, 72 , 73, 74, 82, 83, 84, 85 Timer 100 Harmonic current source 101, 102 Premise load

Claims (7)

[Claims] 1. A substation apparatus that receives power from an external power supply system via a transformer, supplies power to a plurality of loads, and has a power factor adjustment circuit for each load, wherein each of the power factor adjustment circuits includes a series reactor. And a phase-advancing capacitor connected in series, comprising multiple power factor improving capacitor units. Each power factor improving capacitor unit is installed on the transformer secondary side of the on-premise power distribution equipment via a low-voltage switch. A power factor measuring circuit for measuring the power factor at the point, and when the power factor at the power receiving point is equal to or less than a predetermined delay power factor, outputs a command to turn on the power factor improving capacitor unit, and when the power factor is equal to or greater than a predetermined lead power factor A power factor control circuit that outputs a release command of the power factor improving capacitor, a voltage detection circuit that detects a voltage of the transformer secondary supplied to the load for each load, rate The detected by the command and the voltage detection circuit from the control circuit transformer 2
And a switching command circuit for outputting a switching command for the low-voltage switch based on the secondary voltage. 2. The power transformer with a power factor improving capacitor according to claim 1, wherein the series reactors of the plurality of power factor improving capacitor units constituting the power factor adjusting circuit have different values. 3. The power factor improving device according to claim 1, wherein the capacity of the series reactor of the plurality of power factor improving capacitor units constituting the power factor adjusting circuit is set to several to ten and several ten percent of the capacity of the phase-advancing capacitor. Substation with condenser for 4. The power factor adjusting circuit according to claim 1, wherein the single phase capacitor of the plurality of power factor improving capacitor units constituting the power factor adjusting circuit is about 1/10 of the capacity of the transformer of the on-premise distribution equipment. Substation with a power factor improving capacitor. 5. The switching command circuit provided for each load, wherein: (a) a supply command to the load detected by the voltage detection circuit is equal to or less than a predetermined value and a power-on command is output from the power factor control circuit; During the power factor adjustment circuit, a plurality of power factor improving capacitor units constituting the power factor adjusting circuit are sequentially turned on in a predetermined order, and when the output of the turn-on command is stopped, the power factor improving capacitor unit is turned off. And (b) a power factor improving capacitor unit while the supply voltage to the load detected by the voltage detection circuit is equal to or greater than the predetermined value or while the power factor control circuit outputs an open command. As the transformer secondary-side voltage increases or sequentially delayed in a predetermined order to release the voltage, and the transformer 2-side voltage drops below the predetermined value or the output of the release command is stopped. Can the claim 1 configured to maintain the open state of the capacitor unit power factor correction
6. The substation with a power factor improving capacitor according to any one of items 5 to 5. 6. An opening / closing command circuit provided for each of a plurality of loads, receives a closing command or an opening command from the power factor control circuit, and first turns on or off a power factor improving capacitor unit of the power factor adjusting circuit. 6. The substation with a power factor improving capacitor according to claim 1, wherein a time until opening is set to be sequentially delayed for each load. 7. The substation with a power factor improving capacitor according to claim 5, wherein a time interval for opening and closing the low voltage switch connected to the power factor improving capacitor unit is set by a timer.