JPH0769751B2 - Automatic power factor adjustment controller - Google Patents

Description

Description: TECHNICAL FIELD The present invention detects a reactive power in order to improve the power factor of an electric circuit, and based on the detected value, a capacitor for improving the power factor of the electric circuit. The present invention relates to a power factor automatic adjustment control device for controlling the.

[Prior Art] FIG. 3 is a circuit diagram showing a partial block diagram of a conventional automatic power factor adjustment control device disclosed in, for example, Japanese Patent Publication No. 60-47823. In this figure, (1) is an electric circuit to be subjected to power factor control, (70a) and (70b) are transformers connected to this electric circuit (1), and (71a) and (71b) are respective transformers. Load connected to the electric circuit (1) via (60a), (60b)
(60n) are a plurality of electromagnetic contactors that are also connected to the electric circuit (1), and are provided for turning on and off a capacitor described later. (61a), (61b) ...
(61n) is a series reactor connected to each electromagnetic contactor,
(62a), (62b) ... (62n) are a plurality of capacitors provided for improving the power factor of the electric circuit (1).
Further, (100) is an automatic power factor adjustment control device, which includes a reactive power detection device (4), a widening circuit (5) for widening an output signal of the reactive power detection device (4), and a widened signal. A first comparison circuit (6) for comparing the output of the input point setting device (6),
It responds to any output of the second comparison circuit (9) for comparing the output signal of the amplification circuit (5) and the output of the breaking point setting device (8), both comparison circuits (7) and (9). An OR gate (10), a timer (20) reset by the output of this OR gate (10) and starting operation, a timer setting device (21) for setting the operation time of this timer (20),
A first AND gate (11) operating with the output of the first comparison circuit (7) and the output of the timer (20), and an output of the second comparison circuit (9) and the timer (20) Second
Of the AND gate (12) and the first AND gate (11), which selects a capacitor (62a) to (62n) to be connected to the electric circuit (1) from the first sequence control circuit ( 23), operates when the output of the second AND gate (12),
The second to select a capacitor to disconnect from the electrical circuit (1)
Of the sequence control circuit (24) and the capacitor selected by the first sequence control circuit (23) are activated to activate the relay (not shown) corresponding to the capacitor selected by the second sequence control circuit (24). Is composed of a relay circuit (25) for deactivating a relay (not shown) corresponding to. (26a), (26b) ...
(26n) is a contact of a relay controlled by the relay circuit (25), (50) is a relay contact (26a), (26b) ...
A control device that operates according to the open / closed state of (26n). For example, when the relay contact (26a) is closed, it operates to close the electromagnetic contactor (60a). Even when the contact is opened, the corresponding electromagnetic contactor operates so as to be opened.

The conventional automatic power factor adjustment control device is configured as described above, and the electric circuit (1) is connected via the instrument transformer (2) and the instrument AC (3) connected to the electric circuit (1). Is detected and the reactive power detection device (4) detects the reactive power by these voltages and currents, and produces an output proportional to the detected reactive power. The amplification circuit (5) amplifies the output of the reactive power detection device (4).
The first comparison circuit (7) compares the output of the widening circuit (5) with the output of the closing point setting device (6), and the output of the widening circuit (5) is the output of the closing point setting device (6). Higher than that produces an output. The second comparison (9) compares the output of the widening circuit (5) with the output of the breaking point setting device (8) to obtain the widening circuit (5).
Output is lower than the output of the breaking point setting device (8), an output is generated. The OR gate (10) is both comparison circuits (7),
An output is generated when there is an output in any of (9). The timer (20) is released from the reset state at the time of input from the OR gate (10), and after the time set by the timer setting device (21) has elapsed, an output is generated at the output terminal (22) and then returns to the reset state again. It is a thing. The first AND gate (11) generates an output when the output of the first comparison circuit (7) is still continuing at the time of output of the timer (20), and activates the first sequence control circuit (23). Then, the capacitors connected to the electric circuit (1) are selected from (62a) to (62n). For example, if the first and second capacitors are connected now, the third capacitor is selected. The second AND gate (12) produces an output when the output of the second comparison circuit (9) is still continuing when the timer (20) outputs, and activates the second sequence control circuit (24). Then, a capacitor to be separated from the electric circuit (1) is selected. For example, when the first and second capacitors are now connected, the second capacitor is selected. The relay circuit (25) energizes the relay corresponding to the capacitor selected by the first sequence control circuit (23), and the corresponding relay contacts (26a) to (26
n) is closed, or the second sequential control circuit (2
4) Deactivate the relay corresponding to the capacitor selected in 4) and open any of the relay contacts (26a) to (26n) corresponding to it. The control device (50) operates in response to the closing or opening of the relay contacts (26a) to (26n), and the electromagnetic contactors (60a) to (6) corresponding to the closing or opening of the relay contacts.
Since 0n) is closed or opened, the capacitors (62a) to (62n) connected to each are connected or disconnected.

[Problems to be Solved by the Invention] In the conventional automatic power factor adjustment control device, when changing the closing point setting value or the closing point setting value, the power factor adjusting operation is stopped,
Therefore, the output of the capacitor control signal must be stopped, which causes a problem that the capacitor control state until the setting value is changed is canceled.

The present invention has been made to solve the above-mentioned problems, and the demand level and delay in an electric circuit are set to a closing level for connecting the capacitor to the electric circuit and a cutoff level for disconnecting the capacitor from the electric circuit. It is decided based on the advanced power factor control mode, and the power can be controlled without changing the capacitor control state by changing the make-up level or the cutoff level during the power factor adjusting operation. The purpose is to obtain a rate automatic adjustment control device.

[Means for Solving the Problems] An automatic power factor adjustment control device according to the present invention is a power-on level for connecting the above-mentioned capacitor based on each element of a power factor control mode of a demand factor and delay and advance in an electric circuit. And each element of the above input level determination,
Means for determining a cutoff level for disconnecting the capacitor from the electric circuit based on the capacitance value of the capacitor to be controlled is provided, and the cutoff level value determined by this means is taken in by the interrupt processing to the control means. A setting change switch means is provided to change the setting of the demand factor and the power factor control mode, and then the setting change switch is pressed to generate an interrupt and perform interrupt processing. Update
The power factor adjustment operation is continued with the updated data.

[Operation] In the present invention, the setting switch operation is read when the setting change switch is pressed, and when the demand factor and power factor control mode are changed, the demand factor data and the power factor control mode are interrupted. Update the data,
By continuing the power factor adjusting operation using the updated data, the control by the closing level and the cutoff level after the setting change is performed without changing the capacitor control state.

[Embodiment] An embodiment of the present invention will be described below with reference to FIG. 1 which is a block diagram. FIG. 2 is a flow chart of the program written in the arithmetic processing unit shown in FIG. In FIG. 1, (100A) is an automatic power factor adjustment control device of the present invention, which is composed of the following parts. That is, (4) is an invalid circuit of the electric circuit (1) due to the voltage from the meter transformer (2) and the current from the meter AC (3) connected to the electric circuit (1) as in FIG. A reactive power detection device that detects electric power and produces an output proportional to the reactive power, (30) detects active power of the electric circuit (1) from the outputs of the instrument transformer (2) and the instrument alternator (3). Then
An active power detection device that produces an output proportional to active power,
Reference numeral (32) is an arithmetic processing unit which operates according to a program written in advance as shown in the flowchart of FIG. That is, the output of the active power detection device (30) is compared with the active power setting value set by the active power setting unit (31) (second step 4). ) Output is compared with the closing level (step 9) or interruption level (step 6) set by the setting section (31), and if the closing level is exceeded, the closing signal (step 1)
0), and when the cutoff level is exceeded, a cutoff signal (step 7) is generated. On the other hand, if the output of the active power detection device (30) is less than or equal to the active power set value (step 4), the cutoff signal (step 7) is generated. These control signals drive the relay circuit (25) and relay contacts (26a) to (26n)
The electromagnetic contactors (60a) to (6
0n) turns capacitors (62a) to (62n) on and off. Further, (33) is a display unit for displaying a calculation result, a closing signal, and a shutoff signal. (34) is a setting change push switch which is pushed when the closing level or the cutoff level is to be changed. By pushing this switch, an interrupt is generated and interrupt processing is performed. Other configurations are the same as the conventional ones, and thus the description thereof is omitted. Next, how to set the closing level calculated in step 1 and step 12 or the interruption level calculated in step 3 in FIG. 2 will be described. Active power W, delayed reactive power Q, power factor
between cos θ The relationship between Where cos θ = 0.995 or power factor 9
9.5% or more is rounded off to the nearest 100%, but when the power factor is 99.5%, the delayed reactive power Q is Q ≈ W × 0.1.

Generally, there are coefficients called demand rate and load rate, which are respectively expressed as follows.

， By transforming the formula Here, the installed capacity can be equivalently set to the composite transformation ratio set by the setting unit (31). Therefore, set the power factor to 100.
% Of the active power W when it is desired to be set (i) maximum demand power (delay control) (ii) average power for a certain period (intermediate control) (iii) power of advance power factor higher than average power (advance control) 3 A power factor control mode setting switch is provided so that the power factor control mode can be selected from among various types of power factor control modes, that is, delay control, intermediate control, and advance control. If the demand rate x 1/100 is α, the load rate x 1/100 is β, and the value that determines the degree of advancement when performing advance control is γ, then W is calculated from the following equation. You can

In the mode of (i), W = synthetic metamorphic ratio × α ... In the mode of (ii), W = synthetic metamorphic ratio × α × β ... In the mode of (iii), W = synthetic metamorphic ratio × α × β × γ ...
... β and γ have fixed values as internal data, and α is set by providing a demand rate setting switch. Therefore, if the power factor control mode and the demand factor are determined, the formula W
The input level can be determined by substituting the value obtained by the formula. The power factor control mode and the demand factor are set by the setting section (31), the setting switch is read only once in step 1 of FIG. 2, and is set in the internal data like other setting switches. Next, the cutoff level can be obtained by the sum of the value obtained by multiplying the capacitance value to be controlled next among the capacitor capacitance values set by the setting unit (31) by the hunting prevention coefficient and the closing level obtained by the formula. I can.

If the power factor control mode and demand factor switch settings are changed and the setting change push switch (34) is pressed during the power factor adjustment operation, an interrupt occurs, and an interrupt occurs during interrupt processing. Set flags (step 13)
Only, and does not affect the control processing at all.
When it is detected that the interrupt flag is set in the control process (step 8), the switch is read (step 11) to update and input the internal data of the power factor control mode and the demand factor. Calculate the level (step 12). The shutoff level is determined based on the data of this make level (step 3), and the make and shutoff control is performed using the new make level and shutoff level. Therefore, the control can be continued by changing the making level and the cutoff level without changing the control state of the capacitor.

[Effects of the Invention] The present invention is configured as described above, and determines the closing level for connecting a capacitor to an electric circuit based on the power factor control mode of the demand ratio and the delay or advance in the electric circuit. In addition, the cutoff level for disconnecting the capacitor from the electric circuit is determined based on the above-mentioned elements and the capacitance value of the capacitor to be controlled, and the change of each level causes interrupt processing. It is possible to change the capacitor input level and the capacitor cutoff level without changing the capacitor control state up to.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a flow chart for explaining the operation of the above embodiment, and FIG. 3 is a partial block diagram of a conventional automatic power factor adjustment control device. It is a circuit diagram shown. In the figure, (100A) is an automatic power factor adjustment control device, (30) is an active power detection device, (31) is a setting unit, (32) is an arithmetic processing unit, (33) is a display unit, and (34) is a setting change. It is a push switch. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A control for detecting reactive power of an electric circuit and connecting a capacitor to the electric circuit or disconnecting a capacitor connected to the electric circuit when the reactive power reaches a predetermined level. In the automatic power factor adjustment control device for adjusting the power factor of the electric circuit by means, a closing level for connecting the capacitor based on the demand factor and each element of the power factor control mode of delay and advance in the electric circuit. And a means for determining a cutoff level for disconnecting the capacitor from the electric circuit on the basis of each element for determining the closing level and the capacitance value of the capacitor to be controlled, and the cutoff determined by this means. The power factor control mode updated by the interruption processing is provided with the setting change switch means for taking in the level value by the interruption processing to the control means. Power factor automatic adjustment control apparatus characterized by adjusting the power factor automatic continued at de.