JPH01108620A - Automatic adjusting controller for power factor - Google Patents

Abstract

PURPOSE:To control plural capacitors different in capacity by one controller by setting control orders on the plural capacitors different in capacity, and operating an application level or a cut-off level newly for the capacitor to be controlled at the next stage according to the control order. CONSTITUTION:When a reactive power exceeds the cut-off level, a CPU102 functions as a cut-off means, and a cut-off signal outputted from the CPU102 which outputs the cut-off signal is transmitted to a capacitor control part 50 via a relay control part 107. The capacitor control part 50 drives either electromagnetic contactors 60a-60c so as to cut off the capacitor ranked at a first place in the capacitors 62a-62c. In such a way, it is possible to control the plural capacitors different in capacity.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention detects reactive power, etc. and controls a power factor improvement capacitor connected to the electrical circuit in order to improve the power factor of the electrical circuit. The present invention relates to an automatic power factor adjustment control device.

[Prior Art] For example, in the conventional power factor automatic adjustment control device shown in Japanese Patent Publication No. 60-47823, shown in FIG. ), an amplifier circuit (5) that amplifies the detection signal from the reactive power detection section (4), and a signal amplified by the amplifier circuit (5) and the input level setting section (7) or the cutoff level setting section (9).
) Comparison circuit (6) that compares each setting value set by
) and (8), first and second sequential circuits (23) and (24) that drive the relay circuit (25) by the output of the comparison circuit (6) or (8), and the relay contact (26).
a)-(26n). Relay contact (26a
)--(26n) are connected to the magnetic contactors (60a)--(60c)-- through the control circuit (50), and the operation of these magnetic contactors (60a)--(6oc)- causes electricity. The capacitors (62a) to (62c) are turned on or off to the circuit (1).

A measuring transformer (2) and a d1 measuring current transformer (3) are connected to the electric circuit (1), the voltage and current of the electric circuit (1) are detected, and the reactive power detection section (4) is Reactive power is detected using the voltage and current, and power proportional to the detected reactive power is generated. The amplifier circuit (5) amplifies the output of the reactive power detector (4). The first comparison circuit (6) is an amplifier circuit (5
) and the output of the input level setting section (7),
If the output of the amplifier circuit (5) is higher than the output of the input level setting section (7), an output is generated.

The second comparison circuit (8) compares the output of the amplifier circuit (5) and the output of the cutoff level setting section (9), and if the output of the amplifier circuit is lower than the output of the cutoff level setting section (9), the output is changed. arise. The reset state of the timer circuit (20) is released upon input from the OR gate (19), and the timer circuit (20) is reset to the timer setting section (21).
), it generates an output after the set time has elapsed, and then 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 comparator circuit (6) and the output of the timer circuit (20).
The capacitors to be input into the capacitors are the first to nth capacitors (62
Select from a)-1 (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), and selects a capacitor to be cut off from the electric circuit (1). . The relay circuit (25) energizes the relay corresponding to the capacitor selected in the first sequential circuit (23) and deenergizes the relay corresponding to the capacitor selected in the second sequential circuit (24). Relay contact (26a)
~(26n) are the first to nth capacitors (62a) --
(62c) corresponds to -1 and is a relay contact that is energized or deenergized by the □ relay circuit (25).

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

This invention was made to solve the above-mentioned problems, and provides an automatic power factor adjustment control device that allows a single control device to control a plurality of capacitors with different capacities by assigning a control order to each one. It is intended to.

[Means for Solving the Problems] The automatic power factor adjustment control device according to the present invention includes a plurality of capacitors for improving the power factor of the electric circuit by being turned on and off in the electric circuit, and a plurality of capacitors. capacitor capacity setting means for converting each capacitance value into a regular capacitance value by inputting the most significant digit of the capacitance value; reactive power detection means for detecting reactive power of an electric circuit; Based on the capacitance values of a plurality of capacitors set by the setting means, the capacitors with different capacitance values are set to be controlled in descending order of capacitance or in descending order of capacitance value, and control is performed between capacitors with the same capacitance value. A control order setting means for setting the control order of the plurality of capacitors so that the control is performed in the set order among the comrades, and according to the control order set by the control order setting means,
The input level calculation means calculates the input level of the capacitor from the capacitance value of the capacitor to be controlled next and the composite transformation ratio of the reactive power detection means, and the control order is set by the control order setting means. cutoff level calculation means for calculating the cutoff level of the capacitor from the capacitance value of the capacitor and hunting prevention coefficient; and reactive power detected by the reactive power detection means, which exceeds the input level calculated by the input level calculation means. input determining means for determining whether or not the reactive power is present; A cutoff determination means for determining whether or not the reactive power detected by the detection means exceeds the cutoff level calculated by the cutoff level calculation means, and a case where the reactive power is slightly above the cutoff level in the cutoff determination means. The capacitor is further provided with a disconnection means for disconnecting the next controlled capacitor from the electric circuit.

[Function] A plurality of capacitors are connected to an electric circuit to advance a delayed phase, or are shut off to delay a leading phase.

The capacitor capacity value setting means is 30KVA, 50KVA, 80KVA, etc.
, etc., the most significant digit is 3, 5, 8, . , , etc., the input becomes 30KVA and 5KVA respectively.
0KVA.

It is converted into a predetermined signal indicating that it is 80KVA, and is set.

The control order setting means is based on the capacitance value of each capacitor set by the capacitor capacity setting means, and among capacitors with different capacitance values, for example, when turning on, the one with the largest capacitance value is turned on first, and when turning off, the control order setting means The control order is set such that the capacitance is cut off in order of decreasing capacitance value.

In addition, the control order is set so that capacitors having the same capacitance value are turned on in the set order so that the frequencies of use are the same, and are turned off in the order in which they are turned on.

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

The input level calculation means calculates, for example, the product of the capacitance value of the capacitor to be input next and the combined transformation ratio of the current transformer and the transformer of the reactive power detection means, according to the control order set by the control order setting means. , this value is the input level.

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

The input determining means determines whether the reactive power is below the input level.

The input means inputs the next capacitor to be input into the electric circuit when the reactive power is below the input level.

The cutoff determination means determines whether the reactive power exceeds the cutoff level.

The cutoff means cuts off the next capacitor to be cut off from the electrical circuit when the reactive power exceeds the cutoff level.

[Embodiment] An automatic power factor adjustment control device according to the present invention will be explained using FIG. 1 showing an embodiment and FIG. 2 showing a flowchart of a control system.

In Figure 1, the electrical circuit (1) includes a measuring transformer (
2) and a current transformer (3), the outputs of which are input to the reactive power detection section (101) of the automatic power factor adjustment control device (100). The reactive power detection means is a voltage transformer @
(2), current transformer (3) and reactive power detection unit (101
) etc. The 0 composite transformation ratio is the voltage ratio of the primary side / secondary side of each of the transformer (2) and current transformer (3),
and current ratio.

The automatic power factor adjustment control device (100) includes an arithmetic processing unit (hereinafter abbreviated as CPU) consisting of a microcomputer, etc.
(102), a first storage unit (hereinafter abbreviated as ROM) that stores calculation programs etc. executed by the CPU (102) (103), and a reactive power value detected by the reactive power detection unit (101). and a second storage section (hereinafter referred to as RAM) (104) that temporarily stores various input data inputted from the controller and setting section (105), and a second storage section (hereinafter referred to as RAM) (104) that temporarily stores various input data inputted from the setting section (105), and various control data such as the capacitors (62a) and (62b).
), (62c), .

, a setting section (105) for inputting the capacitance value, composite metamorphic ratio, hunting prevention coefficient, etc. of each of the CPUs.
(102) and displays various calculated data; and a relay control unit (106) for outputting the input signal and cutoff signal to the capacitor control unit (50).
107).

Each capacitor (62a), (62b), (62
c) , , , are each equipped with a series reactor (61a
), (61b), (61c), , and magnetic contactor (
60a), (60b), (60c), , are connected, and this electromagnetic contactor (60a), (60b)
, (60c) The electric circuit (
1) is turned on or cut off. These "77 capacitors (62a), (62b), (62c),
, are connected in parallel to transformers (70a), (70b) and loads (71a), (71b). Each electromagnetic contactor (60a), (60b), (6
0c), , , are controlled by a capacitor control section (50), and the capacitor control section (50) is controlled by a relay control section (
107), each electromagnetic contactor (60a), (60b), (60c), -0
make it work.

In order to simplify the input procedure in the setting section (105), the GPU (102) has, for example, each capacitor (62a),
(62b).

(62C),,,(7) Capacity value power 30KVA, 50KV
A, 80KVA, , te, the most significant digit of each capacity value is 3, 5, 8... , , are programmed so that they can be input using the setting section (105). That is, C
PU (102) has a common predetermined coefficient, for example l0KV
It is programmed to uniformly multiply A for all input values.

A capacitor bank consisting of a plurality of capacitors can generally be of two types: one consisting of all capacitors of the same capacity, and one consisting of a plurality of capacitors of different capacities. When a capacitor bank is made up of all capacitors of equal capacity, performing cyclic control in which the capacitors are cut off in the order in which they are arranged and the capacitors are turned on in the order in which they are cut off will equalize the frequency of use of each capacitor. be able to. However, when performing fine-grained control in automatic power factor adjustment control, that is, when setting the difference between the cutoff level setting value and the closing level setting value to a small value,
It is more effective to distinguish and control the capacitor that is always turned on with priority and the capacitor for fine power factor adjustment.

Therefore, as a control order setting means, the CPU (102)
The control order is determined as follows based on the capacitance value of each capacitor input by the setting section (105).

For example, assume that a capacitor bank is composed of six capacitors C, to C6, C1 to C3 have different capacities, and C4 to CO have the same capacity. It is assumed that the capacitances are in the order of C+r C2, C3, and C4. For example, the order in which capacitors are inserted is C1.
* The order is C2+ C3r C4r C5* CB. Conversely, when cutting off, C41G 5+ Ce r C
The order is a*C2+ C+.

Next, automatic power factor adjustment control will be explained using the flowchart shown in FIG.

During automatic power factor adjustment control, the most significant digit value of the capacitance value of each capacitor is input to the CPU (102) by the setting section (105) (10θ1).

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

Next, the GPLI (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).

Furthermore, the CPU (102) acts as a cutoff level calculation means and a closing level calculation means, and the capacitor =14
- According to the ff1l cape order, the cutoff level and the input level are calculated respectively based on the capacitance value of the capacitor #i controlled first and the anti-hunting coefficient and composite transformation ratio stored in advance in the RAM (104), etc. .

As described above, the composite transformation ratio is the product of the primary/secondary side transformation ratio and current transformation ratio of the transformer (2) and current transformer (3). Actual measurements will be made on the transformer (2) and current transformer (3).
), and the composite transformation ratio is used to convert the reactive power of the actual electric circuit from these actually measured values. The anti-hunting coefficient is a constant value used to prevent malfunctions (this is called hunting) where the power factor deviates from the target adjustment range as soon as the capacitor is turned on or cut off due to a measurement error, etc., and the capacitor is turned on or cut off again. This is a safety factor for setting a wide range of time and target adjustment. In this example, for the sake of simplicity, [Input level I = [Capacitor capacity JilX [Synthetic transformation ratio I...(1)] (1004,
1005).

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

If the phase of the reactive power is leading, the CPU (102) acts as a cutoff determination means and determines whether the reactive power exceeds the previously calculated cutoff level (1008).

Here, if the reactive power exceeds the cutoff level, CP
U (102) acts as a cutoff means and outputs a cutoff signal (1009). The cutoff signal output from the CPU (102) is transmitted to the capacitor control section (50) via the relay control section (107). Capacitor control section (
50) is the capacitor with the first control order ((62a)
, (62b), (52c), etc.).
c), , noise deviation drives ).

If the reactive power is delayed in step (1001), the CPU (102) acts as an input determining means and determines whether the reactive power is below the previously calculated input level (1010).

And if the reactive power is below the input level,
The CPU (102) acts as a closing means and outputs a closing signal (1011). The input signal output from the CPU (102) is transmitted to the capacitor control section (50) via the relay control section (107). Capacitor control section (5
0) is the capacitor with the first control order ((62a),
(62b).

(60a), (60b), (60c),
, , ).

Step (1009) or Step (1 (111)
When the capacitor ranked first in the control order is cut off or turned on, the process returns to step (1003) and the above steps are repeated for the capacitor ranked second in the control order.

In the above example, the control order of the capacitors was in order from the largest capacitance when turning on, and in order from the smallest capacitance at the time of crossing and cutting off, but it is not necessarily limited to this, and the capacitors are turned on in order from the smallest capacitance to the smallest capacitance. However, it goes without saying that it is also possible to shut off the devices in descending order of capacity.

[Effects of the Invention] As described above, according to the present invention, a plurality of capacitors with different capacitances are ranked in control order, and the closing level and cut-off level are newly calculated for the capacitor to be controlled next according to the control order. This has the effect that a single control device can control a plurality of capacitors with different capacities.

[Brief explanation of the drawing]

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 flowchart showing automatic power factor adjustment control, and FIG. 3 is a diagram showing a conventional automatic power factor adjustment control device. It is. In the figure, (101) is a reactive power detection unit, and (102) is a cp
u, (105) is a setting section, and (50) is a capacitor control section.

Claims (1)

[Claims] (1) Enter a plurality of capacitors to improve the power factor of the electric circuit by being connected to and disconnected from the electric circuit, and enter the capacitance value of each of the plurality of capacitors by entering the most significant digit of the capacitance value. capacitor capacity setting means for converting to a regular capacitance value and setting the capacitance value; reactive power detection means for detecting reactive power of the electric circuit; and capacitance values of the plurality of capacitors set by the capacitor capacity setting means. Based on this, the capacitors with different capacitance values are set to be controlled in the order of the smallest capacitance or the largest capacitance value, and the control is set to be performed in the order of setting between capacitors with the same capacitance value. control order setting means for setting the control order of the plurality of capacitors; and a combined transformation ratio of the capacitance value of the capacitor to be controlled next and the reactive power detection means according to the control order set by the control order setting means. a closing level calculation means for calculating the closing level of the capacitor from the above, and a cutting level of the capacitor calculated from the capacitance value of the capacitor to be controlled next and the hunting prevention coefficient according to the control order set by the control order setting means. a power-off level calculating means; a power-on determining means for determining whether the reactive power detected by the reactive power detecting means is below a power-on level calculated by the power-on level calculating means; and a power-on determining means. wherein, when the reactive power is below the input level, input means for inputting the next controlled capacitor to the electric circuit; and the reactive power detected by the reactive power detection means is a cutoff determination means for determining whether or not the cutoff level calculated by the cutoff level calculation means is exceeded; and in the cutoff determination means, the reactive power exceeds the cutoff level. an automatic power factor adjustment control device comprising: a cutoff means for cutting off the next controlled capacitor from the electric circuit;