JPH0898406A - Power factor control system for receiving power - Google Patents

Abstract

PURPOSE: To obtain a system for controlling the power factor at a power receiving point even in such facility as power capacitors are installed only on the sub-transforming facility side by controlling a capacitor switch based on the operation results of measurements. CONSTITUTION: In case of a system comprising an extra-high-tension transforming facility SS and a plurality of sub-transforming facilities SU1-SUn, lines A and B are configured similarly and two main transformers are operated while being switched in the extra-high-tension transforming facility SS. A first reactive power converter 11 for measuring the reactive power through a total CT is provided on the secondary of a transformer TF. In each sub-transforming facility SU1-SUn, a second reactive power converter 12 measures the reactive power. A measured reactive power is processed at a processing section 13 and the results are fed to a control section 14 where a combination of capacitors optimal for improving the power factor at a power receiving point is determined before an output for controlling the opening/closing of a capacitor switch SW is delivered. This constitution realizes direct improvement of power factor at the power receiving point.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention controls the power factor at the power receiving point within a specified value to improve the power factor at the power receiving point and reduce power charges. It is related to the method.

[0002]

2. Description of the Related Art An example of a conventional general power receiving rate control system is shown in FIG. In this control method, the instantaneous reactive power (Var) is detected, and when the detected value exceeds a predetermined specified value, the power factor improving capacitor is turned on or off at regular intervals to receive power. Methods are known to improve the power factor. In the example of FIG. 5, when the instantaneous reactive power exceeds the delay specified value, the capacitors C1 and C2 are turned on, and when the advance reactive power exceeds the specified value, the capacitor C2 is opened. In this case, the power factor is, for example, according to the electricity supply regulation of the electric power company, the average power factor during the time from 8:00 am to 10:00 pm, and the instantaneous power factor is the advanced power factor. Is an instantaneous power factor of 100%
Is regarded as

[0003]

By the way, the above-mentioned conventional control method basically controls the integrated reactive power amount by turning on or off the capacitor when the value of the instantaneous reactive power exceeds the specified value. It is the one.

However, in this conventional control method,
In the case of a power system on the customer side where capacitors for power factor improvement are installed only on the sub-substation side, multiple single-function automatic power factor correction devices using such capacitors are provided for each sub-substation. The only option was to set up a stand. In this way, although the single-function automatic power factor correction device contributes to the power factor improvement for each sub-substation, it has a direct effect on the power factor improvement at the power receiving point in the power receiving and transforming equipment that affects the electricity rate. It was difficult.

That is, in the case of a system in which a power factor improving capacitor integrated in a power receiving and transforming facility is installed, the power receiving ratio can be effectively controlled by the above conventional control method, but such a capacitor has a plurality of sub-units. In the case of a system that is distributed and installed in a substation, there is a problem that it is very difficult to control the power reception rate.

The present invention has been made in view of the above circumstances, and directly controls the power factor of the power receiving point in the power receiving and transforming facility even in the facility in which the power factor improving capacitor is installed only on the sub-transformer facility side. It is an object of the present invention to provide a power reception rate control method that can be achieved.

[0007]

In order to achieve the above object, the present invention comprises a power receiving and transforming facility and a plurality of sub transforming facilities connected to the power receiving and transforming facility. In a power receiving factor control method in a power system in which a power factor improving capacitor is installed only on the facility side, a first reactive power converter for fetching a measurement value for determining whether power factor improving control is required on the power receiving and transforming facility side And a second reactive power converter for fetching a measured value for control sub-transformation determination on the side of the sub-transformer, and an arithmetic processing unit for arithmetically processing the measured values from the first and second reactive power converters. A control unit that controls the opening and closing of the capacitor switch by calculating the measured value with this processing unit, determining the optimum capacitor combination for improving the power reception rate based on the result of the processing, It is an feature.

A second aspect of the present invention is characterized in that the opening and closing of the switch of the capacitor for improving each power factor is performed by determining whether or not there is a failure of the breaker, the switch for capacitor and the capacitor. Is.

[0009]

According to the present invention, the power factor improving capacitors provided in the sub-transformation equipment as described above have the first and second capacitors.
Since the power reception rate is controlled by calculating the measured value from the reactive power converter and then opening and closing according to the result of the processing, the power factor improving capacitor can be controlled only on the sub-transformer side. Power factor control of the power receiving point in the power receiving and transforming facility can be performed even in the electric power system in which the is installed.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. In this example, in the power system in which the power receiving and transforming equipment on the customer side is composed of the extra-high voltage power receiving and transforming equipment and a plurality of sub-transforming equipment, no capacitor for power factor improvement is installed on the extra-high power receiving and transforming equipment side. In a power system in which a power-factor-improving capacitor is installed only on the sub-transformer side, this is a control method for improving the power-receiving ratio.

FIG. 1 shows an outline of the extra-high voltage substation equipment SS and a plurality of sub substation equipment SU1 to SUn. In FIG.
The A and B lines are configured the same, ES is a ground switch, TRF is a switching switch, CB is a circuit breaker, TF is a transformer, SW is a capacitor switch for power factor improvement, and SC is power factor improvement. For capacitors. Extra-high voltage substation equipment S shown in Fig. 1
In S, switching operation is performed with two main transformers. Therefore, on the secondary side of the transformer TF, the first reactive power converter 11 that measures the reactive power by the total CT (not shown) is provided. In addition, the sub-transformation equipment SU1 to SUn of FIG.
Then, in the method as shown in FIG. 5, the reactive power is measured by the second reactive power converter 12 for each sub-transformation facility.

The reactive power measured as described above is arithmetically processed by the arithmetic processing unit 13, and the processing result is input to the control unit 14 which controls the opening and closing of the capacitor. The control unit 14 determines an optimal capacitor combination for improving the power factor at the power receiving point from the processing result, and sends an output for controlling the opening / closing of the capacitor switch SW. It should be noted that the circuit breaker, the capacitor switch, and the capacitor failure signal of each line are monitored, and the capacitor switch is not controlled when there is a failure signal.

FIG. 2 shows the configuration of an apparatus to which the power receiving rate control system of the embodiment is applied. Here, a remote I / O device 2 for taking in a signal for the state of the equipment, a failure, a measurement, etc., and performing on / off control output to the equipment is provided in the extra-high voltage substation equipment and each sub-substation equipment. Each is installed. Each of these remote input / output devices 2 has its own power equipment (special high-voltage substation equipment, sub-substation equipment).
And signals necessary for controlling these, such as a device status signal, a device failure signal, a measurement value signal, and a device control signal, are exchanged. Then, the central processing unit 1 performs an automatic control process for improving the power factor as described later, and the remote input / output unit 2
Are controlled by the central processing unit 1.

In the power receiving rate improving device of the above embodiment, the reactive power is suppressed within the allowable range by turning on / off a plurality of power factor improving capacitors (phase advancing capacitors) installed on the sub-transformer side. The load power factor is improved. Here, for example, due to a contract with an electric power company, if the monthly average power factor is less than 85%, there is an obligation to pay the premium power basic charge, and conversely, if the average power factor is 85% or more, Since the basic charge is discounted, by improving the power reception rate as described above, it is possible to save power by improving the power factor and further reduce the power charge by discounting.

FIG. 3 is a flow chart for explaining the operation of this embodiment. In FIG. 3, Var (1) means the secondary reactive power of the extra high voltage transformer, and SC means the capacitor for power factor improvement. In addition, in Fig. 4, the reactive power advances and the limit H
This is an example of turning on / off (tripping) a capacitor for power factor improvement in the embodiment when L or the delay limit LL is exceeded. Further, Table 1 shows an example of installation of capacitors for power factor improvement in sub-transformation equipment to be controlled.

[0016]

[Table 1]

Here, it is assumed that the first to third substations are sub-transformation facilities and the office building is also one of the sub-transformation facilities.
In addition, the reactive power (Var) value in each sub-transformer is
It is input to the central processing unit as described above to determine whether to open or close the capacitor.

Next, the operation of the embodiment will be described with reference to FIGS. Every 1 minute, the secondary reactive power of the extra-high voltage transformer is read (S1), and it is determined whether or not the control of the SC including the determination of the opening / closing condition is necessary (S2). When the condition continues for 5 minutes (S3), the opening control of the power factor improving capacitor (S11 to S14) or the closing control (S2).
1 to S24) are performed. This control cycle is, for example, 5 minutes in consideration of the discharge time of the capacitor. Here, Table 1 above
In (2), the sub-transformation equipment with the main CB turned off or the failed capacitor for power factor improvement is excluded from the above control targets. If the sub-transformer has a plurality of power factor improving capacitors, the plurality of capacitors are controlled simultaneously if necessary.

The above-mentioned control of closing the power factor improving capacitor is performed as follows. First, the control cycle is 5 minutes,
This control cycle is preset in the memory of the CPU of the central processing unit. Further, in this closing control, the capacitor for power factor control in the sub-transformer on the leading side is removed from the control target and is not controlled. Then, the sub-transformation equipment that generates the maximum Var is sequentially detected (S1
1) After determining the optimum SC control combination in the corresponding sub-transformation equipment (S12) and determining that it is impossible to input (S12).
13) The corresponding SC is input (S14).

Here, the above-mentioned steps S11 to S14 are specifically carried out by inserting a power factor improving capacitor (SC) of the sub-transformation equipment which minimizes the result of the following equation. Further, in this case, in step S13, the capacitors that have already been turned on are excluded from being turned on. In the formula below, the optimum SC capacity that can be input is appropriately selected from the combination of the relevant sub-transformation facilities.

│- (optimum inputtable SC capacity) + reactive power value (+) │ of the corresponding sub-transformer On the other hand, the opening control of the power factor improving capacitor is performed as follows. First, the control cycle is 30 minutes, and this control cycle is set in advance in the memory of the CPU of the central processing unit. Further, in this opening control, the capacitor for power factor control in the sub-transformer on the delay side is excluded from the control target, and the control is not performed. And the minimum Va
After sequentially detecting sub-transformation facilities that generate r (S21), determining the optimum SC control combination in the corresponding sub-transformation facility (S22), and determining whether or not opening is possible (S23),
The corresponding SC is released (S24).

Here, the above-mentioned steps S21 to S24 are specifically carried out by inserting a power factor improving capacitor (SC) of the sub-transformation equipment which minimizes the result of the following equation. Further, in this case, in step S23, the capacitor that has already been opened is excluded from the target of interruption.

| (Optimum inputtable SC capacity) + reactive power value of the relevant sub-transformer (-) | Here, in the above control process, the set value (q
The setting of 1) or the set value (q2) on the delay side is performed by keyboard input or the like on the CRT screen provided in the central processing unit. Further, in this case, the adjustment width between the set value q1 and the set value q2 is, for example, about 1.5 times the capacitor capacity in order to prevent fluctuation (hatching) of the reactive power when the capacitor is turned on and off. To be The set value q2 is set to about 1/4 to 1/5 of the set value q1.

[0024]

As described above, according to the present invention,
The reactive power measurement value on the power receiving equipment side and the reactive power measurement value on each sub-transformation equipment side are calculated to determine the control of opening and closing of the capacitor, and the power factor improvement Since it is configured to control the opening and closing of the capacitor,
Even in the power system on the customer side where the power factor improving capacitors are installed only on the sub-transformer side, it is not necessary to install a plurality of single-function automatic power factor improving devices. And although the above-mentioned conventional single-function automatic power factor correction device contributes to the power factor improvement for each sub-transformer, it cannot directly improve the power factor of the power receiving point that affects the electricity rate. According to the invention, as a result of directly improving the power factor at the power receiving point in the power receiving and transforming facility, it is possible to effectively reduce the power charge.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an example in which an embodiment of the present invention is applied to a power receiving and transforming facility.

FIG. 2 is an explanatory diagram of a configuration example of an apparatus to which the power receiving rate control method of the embodiment is applied.

FIG. 3 is a flowchart illustrating the operation of the embodiment.

FIG. 4 is a graph showing fluctuations in reactive power in an example.

FIG. 5 is an explanatory diagram of a conventional power receiving rate control method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Central processing unit 2 ... Remote input / output device 11, 12 ... 1st and 2nd reactive power converter 13 ... Arithmetic processing part 14 ... Control part

Claims (2)

[Claims] 1. Power reception in an electric power system, which comprises a power receiving and transforming facility and a plurality of sub transforming facilities connected to the power receiving and transforming facility, and in which a power factor improving capacitor is installed only on the sub transforming facility side. In the rate control method, a first reactive power converter is provided on the side of the power receiving and transforming equipment for taking a measurement value for determining whether power factor improvement control is necessary, and a measurement value for controlling sub transformation is provided on the side of the sub transformation equipment. 2 Reactive power converters are provided, and an arithmetic processing unit for arithmetically processing the measured values from the first and second reactive power converters is provided. The arithmetic processing unit arithmetically processes the measured values and receives the power depending on the result of the processing. A power receiving rate control method characterized by having a control unit that determines the optimum combination of capacitors for improving the rate and controls the opening and closing of the switch for capacitors. 2. The switching on / off of each power factor improving capacitor switch is performed by determining whether or not there is a failure in the circuit breaker, the capacitor switch, and the capacitor. Power reception rate control method.