JPH0833783B2 - Automatic power factor adjustment controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention detects a reactive power or the like and controls a power factor improving capacitor connected to the electric circuit in order to improve the power factor of the electric circuit. The present invention relates to a power factor automatic adjustment control device.

[Prior Art] FIG. 3 shows a conventional automatic power factor adjustment control device disclosed in, for example, Japanese Patent Publication No. 60-47823. In the figure, the automatic power factor adjustment control device (30) is amplified by a reactive power detection unit (4), an amplification circuit (5) for amplifying a detection signal from the reactive power detection unit (4), and an amplification circuit (5). Signal and closing level setting section (7) or cutoff level setting section (9)
First and second comparing each set value set by
Comparing circuits (6) and (8), first comparing circuit (6)
Alternatively, the output of the second comparison circuit (8) causes the relay circuit (2
5) is provided with first and second sequential circuits (23) and (24), and relay contacts (26a) --- (26n). The relay contact (26a) --- (26n) is connected to the control circuit (5
0) is connected to the electromagnetic contactor (60a)-(60c)-, and the operation of these electromagnetic contactors (60a)-(60c)-causes the electric circuit (1) to have a capacitor (62a). −− (62
c) Turn on or shut off.

A measuring transformer (2) and a measuring current transformer (3) are connected to the electric circuit (1), and the voltage and current of the electric circuit (1) are detected. Reactive power is detected based on the voltage and the current, and power proportional to the detected reactive power is generated. The amplifier circuit (5) amplifies the output of the reactive power detection unit (4). The first comparison circuit (6) compares the output of the amplification circuit (5) with the output of the closing level setting unit (7), and the output of the amplification circuit (5) is higher than the output of the closing level setting unit (7). Higher output produces. The second comparison circuit (8) compares the output of the amplification circuit (5) with the output of the cutoff level setting section (9), and if the output of the amplification circuit is lower than the output of the cutoff level setting section (9), outputs the output. Occurs. The timer circuit (20) releases the reset state upon input from the OR gate (19), generates an output after the time set by the timer setting section (21) has elapsed, and thereafter returns to the reset state again. The first sequential circuit (23) is energized by the output of the first gate circuit (17), that is, the output of the first comparison circuit (6) and the output of the timer circuit (20), so that the electric circuit (1) is activated. The capacitors to be turned on are selected from the first to nth capacitors (62a)-(62c)-. The second sequential circuit (24) is energized by the output of the second gate circuit (18), that is, the output of the second comparison circuit (8) and the output of the timer circuit (20), Select the capacitor to cut off. The relay circuit (25) energizes the relay corresponding to the capacitor selected in the first sequential circuit (23) and deactivates the relay corresponding to the capacitor selected in the second sequential circuit (24). The relay contacts (26a) to (26n) correspond to the first to nth capacitors (62a)-(62c)-and are relay contacts that are energized or deenergized in the relay circuit (25).

[Problems to be Solved by the Invention] Since the conventional automatic power factor adjustment control device is configured as described above, only one closing level setting value and one cutting level setting value can be set, and it is easy to set. Since it cannot be changed, there is a problem that only capacitors of equal capacity can be controlled.

The present invention has been made to solve the above problems, and provides a power factor automatic adjustment control device capable of controlling a plurality of capacitors having different capacities by a control device by setting respective control orders. The purpose is to do.

[Means for Solving Problems] An automatic power factor adjustment control device according to the present invention includes a plurality of capacitors for improving the power factor of an electric circuit by being turned on and off in the electric circuit, and a plurality of capacitors. Capacitor capacitance value setting means for converting and setting the respective capacitance values of the respective capacitance values into the regular capacitance values by inputting the highest digit of the capacitance value, reactive power detection means for detecting reactive power of the electric circuit, and capacitor Based on the capacitance values of the plurality of capacitors set by the capacitance value setting means, the capacitors having different capacitance values are set to be controlled in ascending order of capacitance value or in descending order of capacitance value. The control order setting means for setting the control order of a plurality of capacitors so that control is performed between the capacitors having the same And a control order set by the control order setting means for calculating the making level of the capacitor from the capacitance value of the capacitor to be controlled next and the combined transformation ratio of the reactive power detecting means according to the control order. According to the following, the cutoff level calculation means for calculating the cutoff level of the capacitor from the capacitance value of the capacitor to be controlled next and the hunting prevention coefficient, and the reactive power detected by the reactive power detection means are calculated by the input level calculation means. A closing discriminating means for discriminating whether or not the closing level is exceeded, and a closing means for closing a capacitor to be controlled next to the electric circuit when the reactive power is below the closing level in the closing discrimination means. And the reactive power detected by the reactive power detection means was calculated by the cutoff level calculation means. And a cutoff judgment means for judging whether or not the cutoff level is exceeded, and a cutoff judgment means for cutting off the capacitor to be controlled next from the electric circuit when the reactive power is at the cutoff level. , Are provided.

[Operation] A plurality of capacitors advance the delayed phase by being inserted into an electric circuit, or delay the advanced phase by being cut off.

When the capacitance value of each capacitor is 30KVA, 50KVA, 80KVA ... etc., The capacitor capacitance value setting means can input the highest digit 3,5,8 ... etc. It is set by converting into a predetermined signal indicating that each is 30KVA, 50KVA, 80KVA ....

The control order setting means is based on the capacitance value of each capacitor set by the capacitance value setting means, and between capacitors having different capacitance values, for example, when the capacitors are turned on, the capacitors having the highest capacitance value are sequentially turned on and cut off. At times, the control order is set such that the capacitors with smaller capacity are cut off in order. Further, capacitors having the same capacitance value are turned on in the order of setting so that the capacitors are used at the same frequency of use, and the control order is set so that the capacitors are cut off in the order in which they are turned on.

The reactive power detection means is composed of, for example, a current transformer, a transformer, a reactive power meter, etc., detects the reactive power of the electric circuit, converts the value into a predetermined signal, and outputs the signal.

The closing level calculating means obtains, for example, the product thereof from the capacitance value of the capacitor to be turned on next and the combined transformation ratio of the current transformer and the transformer of the reactive power detecting means according to the control order set by the control order setting means. , This value is the input level.

The cutoff level calculation means obtains, for example, the product of the capacitance value of the capacitor to be cut off next and the hunting prevention coefficient according to the control order set by the control order setting means, and sets this value as the cutoff level.

The input determination means determines whether or not the reactive power is below the input level.

The throwing means throws the capacitor to be turned on next into the electric circuit when the reactive power is kept at the turn-on level.

The interruption determination means determines whether or not the reactive power is known as the interruption level.

The interrupting means interrupts the next capacitor to be interrupted from the electric circuit when the reactive power is at a known interrupting level.

[Embodiment] An automatic power factor adjustment control device according to the present invention will be described with reference to Fig. 1 showing an embodiment and Fig. 2 showing a flow chart of a control system.

In FIG. 1, an electric circuit (1) is provided with a transformer (2) and a current transformer (3) for measurement, and these outputs are reactive power detection of a power factor automatic adjustment control device (100). It is input to the department (101). The reactive power detection means is composed of a transformer (2), a current transformer (3), a reactive power detection unit (101) and the like. The composite transformation ratio is obtained as the product of the voltage ratio and the current ratio of the primary side / secondary side of the transformer (2) and the current transformer (3). An automatic power factor adjustment control device (100) includes an arithmetic processing unit (hereinafter abbreviated as CPU) (102) including a microcomputer and a first storage unit that stores an arithmetic program executed by the CPU (102). (Hereinafter abbreviated as ROM) (103) and reactive power detector (10
A second storage unit (hereinafter abbreviated as RAM) (104) that temporarily stores the reactive power value detected by 1) and various input data input from the setting unit (105), and various control data. For example, it is calculated by the CPU (102) and the setting unit (105) for inputting the respective capacitance values of the capacitors (62a), (62b), (62c) ..., the composite transformation ratio and the hunting prevention coefficient. Display section (10
6) and a relay control unit (107) for outputting a closing signal and a cutoff signal to the capacitor control unit (50).

A series reactor (61a), (61b), (61c) ... and a magnetic contactor (60a), (60b), (60c) for each capacitor (62a), (62b), (62c) ... Are connected to each other, and the electromagnetic contactors (60a), (60b), (60c) ... Are turned on or off by the operation of the electric circuit (1). These capacitors (62a), (62b), (62c) ...
Are transformers (70a), (70b) and loads (71a), (71b)
Are connected in parallel to. Each electromagnetic contactor (60a), (60
b), (60c) ... Are controlled by a capacitor control unit (50), and the capacitor control unit (50) is a relay control unit (107).
Each electromagnetic contactor (60a), (60b), (60c) ... is operated based on the closing signal and the cut-off signal from.

In order to simplify the input procedure in the setting unit (105), the CPU (102) uses, for example, capacitors (62a), (62b),
When the capacity value of (62c) ... is 30KVA, 50KVA, 80KVA ..., 3,5,8 ... which are the most significant digits of each capacity value are set in the setting section (10
It is programmed so that you can enter it according to 5). That is, the CPU (102) has a common predetermined coefficient, for example,
It is programmed to uniformly multiply all input values by 10 KVA.

In general, a capacitor bank composed of a plurality of capacitors can be categorized into two types: a capacitor bank composed entirely of capacitors having the same capacitance, and a capacitor bank composed of capacitors having different capacitances. When the capacitor banks are all composed of capacitors of equal capacity, the capacitors are cut off in the order in which they are arranged, and the capacitors are turned on in the cut-off order. be able to. However, in the power factor automatic adjustment control, when finely-tuned control, that is, when the difference between the cutoff level setting value and the closing level setting value is set to be small, the capacitor always turned on preferentially and the power factor fine adjustment It is more effective to control the capacitors separately.

Therefore, the CPU (102) as the control order setting means determines the control order as follows based on the capacitance value of each capacitor input by the setting unit (105).

For example, a capacitor bank consists of 6 capacitors, C ₁ to C ₆ , and C _{1 to} C ₃ have different capacities.
It is also assumed that C _{4 to} C ₆ have the same capacity. The amount of capacity is
It is assumed that the order is C ₁ , C ₂ , C ₃ , C ₄ . Order in which turning on the capacitor, for example _{C 1, C 2, C 3} , C 4, C 5, and in the order of C _6, when the cut off conversely _{C 4, C 5, C 6} , C 3, The order is C ₂ , C ₁ .

Next, the power factor automatic adjustment control will be described with reference to the flowchart shown in FIG.

In the automatic power factor adjustment control, the value of the highest digit of the capacitance value of each capacitor is input to the CPU (102) by the setting unit (105) (1001).

The CPU (102) acts as a capacitor capacity value setting means and multiplies the most significant digit of the capacity value of each capacitor input from the setting section (105) by a predetermined coefficient to calculate and set the capacity value of the regular capacitor. (1002).

Next, the CPU (102) acts as a control order setting means, and sets the control order of each capacitor based on the calculated capacitance value of each capacitor (1003).

Further, the CPU (102) acts as a cutoff level calculation means and a closing level calculation means, and the capacitance value of the capacitor which is first controlled according to the control order of the capacitor and the hunting prevention coefficient and the composite value which are stored in advance in the RAM (104) and the like. The cutoff level and the input level are calculated based on the transformation ratio.

The composite transformation ratio is the product of the transformation ratio and the transformation ratio on the primary side / secondary side of the transformer (2) and the current transformer (3) as described above. What is actually measured is the secondary output of the transformer (2) and the current transformer (3), and the combined transformation ratio is used to convert the reactive power and the like of the actual electric circuit from these measured values. . The hunting prevention coefficient is a constant value to prevent the malfunction of turning on or off the capacitor again as soon as the capacitor is turned on or off due to a measurement error, etc. This is a safety factor for setting the time and target adjustment width to be relatively wide. In this embodiment, for simplification, [input level] = [capacitor capacity] × [composite transformation ratio]
... (1) [cutoff level] = [capacitor capacity] x [hunting prevention coefficient] ... (2) (1004, 1005).

Next, the reactive power detection means measures the reactive power (1006),
The CPU (102) determines whether the phase of the measured reactive power is advanced (1007).

When the phase of the reactive power is advanced, the CPU (102) acts as a disconnection determining means and determines whether the reactive power exceeds the previously calculated interrupting level (1008).

If the reactive power exceeds the cutoff level here, CP
The U (102) acts as a blocking means and outputs a blocking signal (1009). The cutoff signal output from the CPU (102) is passed through the relay control unit (107) to the capacitor control unit (50).
Be transmitted to. The capacitor controller (50) has a control priority of 1
The electromagnetic contactor ((60a), (60) to shut off the second capacitor ((62a), (62b), (62c) ...)
Drive either b), (60c) ...).

If the reactive power is delayed in step (1007), the CPU (102) functions as a closing determination means, and determines whether the reactive power exceeds the previously calculated closing level (1010).

Then, when the reactive power is around the input level, the CPU (102) acts as an input means and outputs an input signal (1011). The closing signal output from the CPU (102) is passed through the relay control unit (107) to the capacitor control unit (50).
Be transmitted to. The capacitor controller (50) has a control priority of 1
Magnetic contactor (60a), (60b), to turn on the second capacitor ((62a), (62b), (62c) ...)
Drive any of (60c) ...).

When the capacitor with the first control order is cut off or turned on in step (1009) or step (1011), the process returns to step (1003) and the above steps are repeated for the capacitor with the second control order.

It should be noted that, in the above-mentioned embodiment, the control order of the capacitors was from the one having the largest capacity at the time of turning on, and from the one having the smallest capacity at the time of shutting off, but it is not necessarily limited to this, and the capacitors are put in order from the smallest capacity. Needless to say, they may be cut off in descending order of capacity.

As described above, according to the present invention, a control order is assigned to a plurality of capacitors having different capacities, and a closing level and a cutoff level are newly calculated for a capacitor to be controlled next according to the control order. Therefore, it is possible to control a plurality of capacitors having different capacities with a single control device. Furthermore, the CPU can convert the regular capacitance values of multiple capacitors by inputting only the highest digit of each capacitance value of multiple capacitors with different capacitances into the setting section. The input work to the CPU at the setting unit by the switch becomes easy, and the time required for the input is greatly shortened.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of an automatic power factor adjustment control device according to the present invention, FIG. 2 is a flow chart showing automatic power factor adjustment control, and FIG. 3 is a diagram showing a conventional automatic power factor adjustment control device. Is. In the figure, (101) is a reactive power detector, (102) is a CPU, and (10)
5) is a setting unit, and (50) is a capacitor control unit.

Claims (1)

[Claims] 1. A plurality of capacitors for improving the power factor of the electric circuit by being turned on and off in the electric circuit, and only one numerical value of the most significant digit of the capacitance value of each of the plurality of capacitors. By inputting, the capacitor capacitance value setting means for converting and setting the normal capacitance values of the plurality of capacitors respectively, the reactive power detecting means for detecting the reactive power of the electric circuit, and the capacitor capacitance value setting means. Based on the capacitance values of the plurality of capacitors that have been set, it is set so that control is performed between capacitors with different capacitance values in ascending order of capacitance value or in order of increasing capacitance value, and capacitors with the same capacitance value are set. Between the control order setting means for setting the control order of the plurality of capacitors so as to perform control in the set order, and the control order setting means According to the control order set by, the closing level calculation means for calculating the closing level of the capacitor from the capacitance value of the capacitor to be controlled next and the combined transformation ratio of the reactive power detection means, and the setting order by the control order setting means. According to the control order, a cutoff level calculation means for calculating the cutoff level of the capacitor from the capacitance value of the next capacitor to be controlled and the hunting prevention coefficient, and the reactive power detected by the reactive power detection means is calculated as the input level calculation. A closing determination means for determining whether or not the closing level calculated by the means has been exceeded, and in the closing determination means, when the reactive power is above the closing level, the next And a reactive means detected by the reactive power detecting means. In the case where the electric power exceeds the cutoff level calculated by the cutoff level calculation means, the cutoff judgment means, and in the cutoff judgment means, when the reactive power is known as the cutoff level, A power factor automatic adjustment control device comprising: a cutting means for cutting off the capacitor to be controlled next from an electric circuit.