JP3322023B2 - Power receiving rate control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention controls a power factor at a power receiving point within a specified value, thereby improving a power factor at the power receiving point and reducing a power rate. It is about the method.

[0002]

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

[0003]

The above conventional control system basically controls the integrated reactive power by turning on or off a capacitor when the instantaneous reactive power exceeds a specified value. It was made.

However, in this conventional control method,
In the case of a customer-side power system in which a power factor improvement capacitor is installed only on the sub-substation side, multiple single-function automatic power factor correction devices using such capacitors are installed for each sub-substation. There was no other way but to install the table. In this way, the single-function automatic power factor improvement device contributes to the power factor improvement at each sub-substation, but has a direct effect on the power factor improvement at the receiving point in the receiving substation equipment that affects the power rate. It was difficult.

[0005] In other words, 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 factor can be effectively controlled by the above-mentioned conventional control method. In the case of a system distributed and installed in a substation, there is a problem that it is very difficult to control a power receiving rate.

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

[0007]

In order to achieve the above object, the present invention comprises a sub-station and a plurality of sub-stations connected to the sub-station, wherein only the sub-station is provided. In a power receiving factor control method in a power system in which a power factor improving capacitor is installed, a first reactive power converter is provided on the power receiving and transforming equipment side to capture a measurement value for power factor improvement control necessity determination, A second reactive power converter for taking in the measured value for control sub-transformation determination is provided on the sub-transformation facility side, and an arithmetic processing unit for arithmetically processing the measured values from the first and second reactive power converters is provided. the measured value arithmetic processing in parts, a control unit for controlling the charged and opening of the switch capacitor provided to determine the optimum capacitor combination for receiving power factor correction by the results of the processing, the control unit, Introduction of capacitor for rate improvement, open
When performing the release control, the
Control target for power factor improvement capacitors in substation facilities
Sub-station equipment that generates maximum reactive power after disconnecting
Are sequentially detected, and the optimal power factor in the
Determine the combination of capacitor control for improvement and invest in it.
After determining whether or not the capacitor can be turned on, insert the corresponding capacitor.
In the opening control, the substation equipment on the delay side
The power factor improvement capacitor in the control
Sub-stations that generate the least reactive power
The sub-station equipment for optimal power factor improvement.
Determine the combination of capacitor controls and allow or disengage them.
A power receiving rate control method characterized in that the applicable capacitor is opened after judging the possibility.

[0008]

[0009]

According to the present invention, the power factor improving capacitors provided in the sub-transformation facility as described above include the first and second capacitors.
The measured value from the reactive power converter is calculated and processed, and the power receiving rate is controlled by turning on and off according to the result of the processing. The power factor of the power receiving point in the power receiving and transforming equipment can be controlled also in the power system in which is installed.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, the power receiving and transforming equipment on the customer side is a power system composed of an extra high power receiving and transforming equipment and a plurality of sub-transformation equipments, and no power factor improving capacitor 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-transformation facility side, this is a control method for improving the power receiving rate.

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

The reactive power measured as described above is subjected to arithmetic processing in the arithmetic processing unit 13, and the processing result is input to the control unit 14 for controlling the opening and closing of the capacitor. The control unit 14 determines an optimum capacitor combination for improving the power factor at the power receiving point from the processing result, and sends out an output for controlling the opening / closing of the capacitor switch SW. The failure signals of the circuit breaker, the capacitor switch and the capacitor are monitored, and the control of the capacitor switch is not performed when there is a failure signal.

FIG. 2 shows the configuration of an apparatus to which the power receiving rate control method of the embodiment is applied. Here, a remote input / output device 2 for taking in signals for device status, failure or measurement, and performing on / off control output to the device is installed in the extra high voltage substation and each sub-station. Each is installed. Each of these remote input / output devices 2 is connected to a respective power facility (extra high substation facility, sub-station facility).
And a signal necessary for these controls, for example, an equipment status signal, an equipment failure signal, a measurement value signal, and an equipment control signal. Then, the central processing unit 1 performs an automatic control process for improving the power factor as described later,
Is arithmetically controlled by the central processing unit 1.

In the power receiving factor improving apparatus of the above-described embodiment, the reactive power is suppressed within an allowable range by turning on / off a plurality of power factor improving capacitors (advanced phase capacitors) installed on the sub-transformation facility side. The power factor of the load has been improved. Here, for example, due to a contract with a power company, if the monthly average power factor is lower than 85%, there is an obligation to pay a premium power basic fee, and conversely, if the average power factor is 85% or more, Since the basic fee is discounted, by improving such a power receiving rate, it is possible to further reduce the power fee by discounting, in addition to saving power by improving the power factor.

FIG. 3 is a flowchart for explaining the operation of this embodiment. In FIG. 3, Var (1) denotes secondary reactive power of the extra-high voltage transformer, and SC denotes a power factor improving capacitor. FIG. 4 shows that the reactive power advances and the limit H
5 illustrates an example of turning on / off (tripping) of a power factor improving capacitor in the embodiment when L or the delay limit LL is exceeded. Further, Table 1 shows an example of installation of a power factor improving capacitor in the sub-substation equipment to be controlled.

[0016]

[Table 1]

Here, the first to third substations are regarded as sub-station facilities, and the office building is regarded as one of the sub-station stations.
The reactive power (Var) value in each sub-station is
The signal is input to the central processing unit as described above for determining whether the capacitor is turned on or off.

Next, the operation of the embodiment will be described with reference to FIGS. Every minute, the secondary reactive power of the extra-high voltage transformer is read (S1), and it is determined whether SC control including determination of the ON / OFF condition is necessary (S2). If the condition continues for 5 minutes (S3), the power factor
Injection control (S11 to S14) or release control (S2
1 to S24). This control cycle is, for example, 5 minutes in consideration of the discharging time of the capacitor. Here, Table 1 above
In the above, the sub-transformation facility in which the main CB is off, or a failed power factor improving capacitor is excluded from the above-mentioned controlled objects. If there are a plurality of power factor improving capacitors in the sub-station, the plurality of capacitors are simultaneously controlled as necessary.

The above-described control of the input of the power factor improving capacitor is performed as follows. First, the control cycle is 5 minutes,
This control cycle is set in advance on the memory of the CPU of the central processing unit. In this input control, the power factor control capacitor in the sub-station on the leading side is excluded from the control target, and the control is not performed. Then, the sub-transformation facilities that generate the maximum Var are sequentially detected (S1).
1) The optimum SC control combination in the corresponding sub-station is determined (S12), and it is determined whether or not the SC can be turned on (S13). Then, the corresponding SC is turned on (S14).

Here, the above-mentioned processes S11 to S14 are specifically performed by inputting a power factor improving capacitor (SC) of the sub-transformer where the result of the following equation is minimized. Further, in this case, in the process S13, the already-input capacitors are excluded from the input targets. In the following formula, the optimal SC capacity that can be input is appropriately selected from the combination of the sub-substation facilities.

| − (Optimum SC capacity that can be input) + reactive power value (+) | of the corresponding sub-transformation facility | On the other hand, the opening control of the capacitor for improving the power factor is performed as follows. First, the control cycle is set to 30 minutes, and this control cycle is set in advance in the memory of the CPU of the central processing unit. In this opening control, the capacitor for power factor control in the sub-station on the delay side is excluded from the control target, and the control is not performed. And the minimum Va
r are sequentially detected (S21), the optimal SC control combination in the relevant sub-station is determined (S22), and it is determined whether opening is possible or not (S2).
3), release the corresponding SC (S24).

Here, the above-mentioned processes S21 to S24 are specifically performed by inputting a power factor improving capacitor (SC) of the sub-transformation facility in which the result of the following equation is minimized. Further, in this case, in the process S23, the capacitors that have already been opened are excluded from the targets of cutoff.

| (Optimum SC capacity that can be input) + reactive power value of the sub-substation (−) | In the above-described control processing, the set value (q
Settings such as 1) and the setting value (q2) on the delay side are performed by keyboard input or the like on a CRT screen provided in the central processing unit. In this case, the adjustment width between the set value q1 and the set value q2 is, for example, about 1.5 times as large as the capacitance of the capacitor in order to prevent the fluctuation (hatching) of the reactive power when the capacitor is turned on and off. To be. The set value q2 is set to about 程度 to ５ of the set value q1.

[0024]

As described above, according to the present invention,
Calculate the reactive power measurement value on the power receiving equipment side and the reactive power measurement value on each sub-transformation equipment side to determine whether to turn on and off the capacitor. Because it is configured to control the opening and closing of the capacitor,
There is no need to install a plurality of single-function automatic power factor correction devices even in a customer-side power system in which power factor correction capacitors are installed only on the sub-transformation facility side. Although the above-described conventional single-function automatic power factor improving apparatus contributes to improving the power factor of each sub-transformation facility, it is not possible to directly improve the power factor of a power receiving point which affects the power rate. According to the present invention, the power factor at the power receiving point in the power receiving and transforming facility can be directly improved, so that the power rate can be effectively reduced.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram of a configuration example of a device to which a power reception rate control method according to an embodiment is applied.

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

FIG. 4 is a graph showing a change in reactive power in the example.

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

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 central processing unit 2 remote input / output device 11 and 12 first and second reactive power converters 13 arithmetic processing unit 14 control unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02J 3/00-5/00 G05F 1/70

Claims (1)

(57) [Claims] An electric power system comprising a power receiving and transforming facility and a plurality of sub-transformation facilities connected to the power receiving and transforming facility, wherein a power factor improving capacitor is installed only on the sub-transformer facility side. In the rate control method, a first reactive power converter that captures a measurement value for determining whether power factor improvement control is necessary is provided on the side of the substation equipment, and a control sub-transformation determination measurement value that captures a control substation determination value is provided on the sub-substation facility side. (2) a reactive power converter is 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 performs the arithmetic processing on the measured value, and receives the power based on the result of the processing. to determine the optimum capacitor combination for rate improvement provided a control unit for controlling the charged and opening of the switch capacitor, the control unit, the capacitor for power factor improvement is turned, the open system
Control, the sub-transformation on the leading side
From the control target to the power factor improvement capacitor in power equipment
Remove the sub-return equipment that generates the maximum reactive power
Detects the next and improves the optimal power factor in the corresponding sub-station
The combination of capacitor control for
After determining whether it is possible or not, turn on the corresponding capacitor, and in the open control,
After removing the power factor improving capacitor from the control target,
The sub-transformation facilities that generate the minimum reactive power are sequentially detected, and
Condensate for improving the optimal power factor in the corresponding sub-station
Control combination and determine whether it can be released.
A power receiving rate control method characterized by opening a corresponding capacitor after separating.