JP2611267B2 - Power factor automatic 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. 4 shows a conventional power factor automatic adjustment control device disclosed in Japanese Patent Publication No. 60-82323, for example. In the figure, a power factor automatic adjustment control device (30) is amplified by a reactive power detector (4), an amplifier circuit (5) for amplifying a detection signal from the reactive power detector (4), and an amplifier circuit (5). Signal and closing level setting section (7) or cutoff level setting section (9)
(6) and (8) for comparing with each level set value set by (1), and first and second sequential circuits for driving the relay circuit (25) by the output of the comparison circuit (6) or (8) (23) and (24), and relay contact (26a)
(26n). Relay contact (26a) ...
(26n) is an electromagnetic contactor (60a) via a control circuit (50) ...
… (60c) …… These magnetic contactors (60a)
By the operation of (60c), the capacitor (62a) (62c) is turned on or cut off in the electric circuit (1).

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 detector (4). The first comparison circuit (6) compares the output of the amplifier circuit (5) with the output of the input level setting section (7), and the output of the amplifier circuit (5) is higher than the output of the input level setting section (7). If it is high, it produces an output. 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), and is supplied to the electric circuit (1). The capacitor to be supplied is selected from the first to n-th 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 shut 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 n-th capacitors (62a) (62c) and are relay contacts that are 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, only one closing level and one shutoff level can be set, and once set, it is easy to set. There was a problem that it could not be changed.

The present invention has been made to solve the above problems, and when the power factor adjustment area is in the advanced reactive power area (leading mode), both the advanced reactive power and the delayed reactive power are used. A power factor automatic adjustment control device capable of changing a closing level and a cutoff level of a power factor adjusting capacitor in a case where the power factor adjustment capacitor is switched over in a range (standard mode) and in a case where the reactive power is in a delayed reactive power range (slow mode). It is intended to provide.

[Means for Solving the Problems] The automatic power factor adjusting apparatus according to the present invention is characterized in that a plurality of capacitors that are turned on and off to an electric circuit and a power factor adjusting area is advanced and is only in a reactive power area. Control mode setting means for setting a control mode to a leading mode, a standard mode, and a lagging mode, respectively, when both the leading reactive power region and the lag reactive power region are covered and only when the lag reactive power region is present. And, for any of the leading phase mode, the standard mode and the retarding mode set by the control mode setting means,
Level setting means for setting the closing level and cutoff level of the capacitor applied to the set control mode; reactive power detecting means for detecting reactive power of the electric circuit; and reactive power detected by the reactive power detecting means. A level discriminating means for discriminating whether or not the value for the input level set by the setting means is lower than a value for the shutoff level; and when the reactive power is lower than the input level of the capacitor in the level discriminating means. And control means for supplying any one of the plurality of capacitors to the electric circuit and cutting off any of the plurality of capacitors from the electric circuit when the reactive power exceeds the cutoff level.

[Operation] The capacitor advances the phase that is delayed by being input to the electric circuit, and delays the phase that is advanced by being cut off.

The control mode selection means is controlled automatically or manually.
If the power factor adjustment area is only in the leading reactive power area, it will be in the leading phase mode.If it covers both the leading reactive power area and the lagging power area, it will be in the standard mode. In such a case, the control mode is selected and set for the delay mode.

The level setting means calculates the closing level and the cutoff level to be applied to the selected control mode for any of the fast mode, standard mode, and slow mode set by the control mode setting means, or The setting is made by selecting from data stored in advance.

 The reactive power detecting means detects the reactive power of the electric circuit.

The level determining means determines whether the reactive power is lower than the input level set by the level setting means and whether the reactive power exceeds the shutoff level.

When the reactive power is lower than the input level, the control unit inputs the next capacitor to be supplied to the electric circuit among the capacitors which have not been supplied yet. When the reactive power exceeds the cutoff level, a capacitor to be cut off next among the capacitors supplied from the electric circuit is cut off from the electric circuit.

[Embodiment] A power factor automatic adjustment control device according to the present invention will be described with reference to Fig. 1 showing an embodiment, Fig. 2 showing a flowchart, and Fig. 3 showing a control mode.

In FIG. 1, an electric circuit (1) is provided with a transformer for measurement (2) and a current transformer for measurement (3).
These outputs are input to the reactive power detection unit (101) of the power factor automatic adjustment control device (100). The voltage and current actually applied to the electric circuit (1) are, for example, 6,
Due to the high voltage of 600V and 200A, it cannot be measured directly. So the electric circuit (1) and the transformer (2)
And a current transformer (3), reduce the output of each secondary side to, for example, about 110 V and 5 A, and measure the output by a reactive power detector (101) composed of a reactive power meter or the like. Current transformer (2), transformer (3) and reactive power detector (101)
Constitute the reactive power detecting means. Further, the power factor automatic adjustment control device (100) includes an arithmetic processing unit (hereinafter abbreviated as CPU) (102) including a microcomputer or the like,
A first storage unit (hereinafter abbreviated as ROM) (103) for storing an arithmetic program executed by (102), a reactive power value detected by the reactive power detection unit (101), and a setting unit (105) A second storage unit (hereinafter abbreviated as RAM) (104) for temporarily storing various input data input from the
Various control data, such as the input level value and cutoff level value, or a setting unit (105) for inputting calculation data for calculating these values, etc., and various calculation data calculated by the CPU (102) are displayed. Display section (106)
And the closing signal and the cutoff signal to the capacitor controller (5
0), and has a relay control section (107) for outputting the signal. Further, the automatic power factor adjustment control device (100) has a control mode setting section (108) that functions as control mode setting means. Each capacitor (62a), (62b), (62c) ...
... are the series reactors (61a), (61b), (61
c) ... and magnetic contactors (60a), (60b), (60c) ...
… Are connected and the electromagnetic contactors (60a), (60b), (60
c) The electric circuit (1) is turned on or off by the operation of. These capacitors (62a), (62b),
(62c) ... is the transformer (70a), (70b) and load (71
a) and (71b) are connected in parallel.

The control mode will be described with reference to FIG. As is well known, the active power is the cosine component of the apparent power actually flowing in the electric circuit (its phase is denoted by ψ), and the reactive power is the sine component of the apparent power. Generally, in the power factor automatic adjustment control, one half of the total capacitor capacity is set as a control region in the early phase region and the control region in the late phase region so that the power factor is 1, that is, ψ = 0. In this embodiment, this control area is a standard mode area. On the other hand, when all the capacitors are turned on, a delay still remains in the apparent power phase ψ, or conversely, even when all the capacitors are cut off, the apparent power phase が still remains advanced. In such a case, the leading reactive power or the lag reactive power is assumed to be present to some extent, and the capacitors are turned on and off in the leading reactive power region and the lag reactive power region so as to converge to a certain target value. Control is more effective. In other words, when the phase の of the apparent power is advanced, the advanced reactive power region is set to the advanced mode, and when the phase ψ is delayed, the phase is classified as the lag mode. Set the phase mode target value. The fast-mode region and the slow-mode region are set so that the power factor adjustment converges to this target value, and the target value is used as a center, and the half of the capacity of all capacitors is used separately for closing and blocking. I do.

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

Control mode setting unit (108) which is a control mode setting means
Sets one control mode among three control modes of a leading phase mode, a standard mode, and a lagging mode (10
01).

Next, the CPU (102) operates as a level setting means, calculates a target value in the set control mode and a closing level and a cutoff level indicating a limit of an adjustment area with respect to the target value, or stores it in the RAM (104) in advance. And select from the existing data (1002).

Here, the leading mode is a light load state in which the inductive load is not operating much, and the standard mode is a state in which the inductive load is operating on average, and the lag mode is Is a heavy load state in which many inductive loads are operating. Therefore, a value smaller than the average power called minimum power is used as the target value in each control mode, for example, in the phase advance mode. In the standard mode, the average power is set as the target value. In the delay mode, the maximum demand power is set as the target value. For example, a value smaller than the target value by one half of the total capacitor capacity and a value larger by one half of the total capacitor capacity are used as the closing level and the cutoff level in each of these control modes (safety factors such as a hunting prevention coefficient). Multiplied by a factor).

Next, the reactive power detecting means detects the reactive power of the electric circuit (1) and measures the value (1003).

The CPU (102) acts as level determination means, and first determines whether the measured reactive power exceeds a target value (1004). And if it exceeds, step (1002)
It is determined whether or not the interruption level set in (1) is exceeded (1005). If it exceeds, the CPU (102) acts as a control means and outputs a shutoff signal (1006).
The shutoff signal output from the CPU (102) is transmitted to the capacitor control unit via the relay control unit (107). The capacitor control unit (50) drives the electromagnetic contactor (60a),
For example, the capacitor (62a) is disconnected from the electric circuit (1). The control order of the capacitors is determined in advance based on the setting order when the capacities of the capacitors are equal, and based on the order of smaller capacities when the capacities are different.

If the reactive power does not exceed the target value of the reactive power in step (1004), the CPU (102) determines whether the reactive power is lower than the input level (1007). When the reactive power is below the input level, the CPU (102) acts as a control means and outputs an input signal (1008). The closing signal output from the CPU (102) is transmitted to the capacitor control unit (50) via the relay control unit (107). The capacitor control unit (50) drives, for example, the electromagnetic contact (60b) to feed the capacitor (62b) to the electric circuit (1). The control order of the capacitors to be supplied is determined based on the setting order when the capacities of the capacitors are equal, and based on the order of larger capacities when the capacities are different.

In the above embodiment, the target values in each control mode are the minimum power, the average power, and the maximum demand power, but the target values are not limited to these values. Needless to say, the input level and the cutoff level can be arbitrarily set for control purposes.

[Effects of the Invention] As described above, according to the present invention, the control mode can be set to the leading phase mode, the standard mode, and the retarding mode, so that the closing level and the cutoff level can be set to be suitable for each control mode. It has the effect that it can be changed.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a power factor automatic adjustment control device according to the present invention, FIG. 2 is a flowchart showing power factor automatic adjustment control, FIG. 3 is a diagram showing a control mode area, FIG. FIG. 1 is a diagram showing a conventional power factor automatic adjustment control device. In the figure, (101) is a reactive power detector, (102) is a CPU, (108)
Is a control mode setting unit.

Claims (1)

(57) [Claims] When a plurality of capacitors which are turned on and off to an electric circuit and a power factor adjustment area is advanced and is only in a reactive power area,
Control mode setting means for setting the control mode to the leading mode, the standard mode, and the lagging mode, respectively, when both the area of the leading reactive power and the area of the lagging reactive power and only in the area of the lagging reactive power; A phase advance mode set by the control mode setting means,
A level setting means for setting a closing level and a cutoff level of a capacitor to be applied to the set control mode for any of the standard mode and the slow mode; and a reactive power for detecting a reactive power of the electric circuit. Detecting means; and level determining means for determining whether the reactive power detected by the reactive power detecting means is lower than a value for the input level set by the level setting means and whether it exceeds a value for a shutoff level. When the reactive power is lower than the input level of the capacitor in the level determining means, one of the plurality of capacitors is input to the electric circuit, and when the reactive power exceeds the cutoff level, Control means for disconnecting any of the plurality of capacitors from a circuit; Dynamic adjustment control device.