JPH0797300B2 - Automatic power factor adjustment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention detects a reactive power, a reactive current or a power factor in order to improve the power factor of an automatic power factor adjusting device, particularly an electric circuit. The present invention relates to an automatic power factor adjustment device that can automatically control a capacitor for improving the power factor of an electric circuit based on the value and can also control the capacitor by manual operation.

[Prior Art] FIG. 5 is a block diagram showing a conventional power factor automatic adjusting device disclosed in, for example, Japanese Patent Publication No. 60-47823. In the figure, (1) is an electric circuit, (2) is a transformer for an instrument which is connected to the electric circuit (1) and measures the voltage of the electric circuit (1),
(3) is a current transformer for an instrument which is connected to the electric circuit (1) and measures the current of the electric circuit (1), and (4) is a reactive power detection device, the input side of which is an instrument transformer (2). ) And an instrument current transformer (3). (5) is an amplifier circuit, the input side of which is connected to the reactive power detection device (4) and amplifies this detection signal. (6) is a first comparison circuit, one input side of which is connected to an amplifier circuit (5) and the other input side thereof is connected to a closing point setting device (7). And the output signal from the input point setting device is compared. (8) is a second comparison circuit, one input side of which is an amplifier circuit (5),
The other input side is connected to the breaking point setting device (9), and the amplified signal from the amplifier circuit (5) and the output signal from the breaking point setting device (9) are compared. Reference numeral (10) is a first test switch for switching between the operating state signal generator (11) side and the test state signal generator (12) side. (13) is a test signal generator, and (14) is a second test switch connected to the test signal generator (13), and switches between the closing terminal (15) side and the breaking terminal (16) side. (17) is a first gate circuit, the input side of which is a first comparison circuit (6), an operating state signal generator (11), a closing terminal (15) and a test state signal generator (12), And a timer circuit (20) described later. (18) is a second gate circuit, the input side of which is the second comparator circuit (8), the operating state signal generator (11), the shutoff terminal (16) and the test state signal generator (12), And a timer circuit (20) described later
And are connected respectively. (19) is an OR gate, the input side of which is connected to the first gate circuit (17) and the second gate circuit (18). Timer circuit (20)
Is an automatic control timer, the input side of which is an OR gate (19)
And the output side is connected to the timer setting device (21). (23) is a first sequential circuit, the input side of which is connected to the first gate circuit (17).
(24) is a second sequential circuit, the input side of which is connected to the second gate circuit (18). (25) is a relay circuit, the input side of which is connected to the first and second sequential circuits (23) and (24), and the output thereof selectively drives the relay contacts (26a) to (26n). . Of the above components, all components except the electric circuit (1), the instrument transformer (2), and the instrument current transformer (3) constitute the automatic power factor adjuster (100). Further, (50) is a control circuit section including a manual control timer (not shown), the input side of which is connected to the output side of the automatic power factor adjusting device (100). (60a) to (60n) are electromagnetic contactors, each input side of which is connected to the electric circuit (1) and the control circuit (50), and the series reactors (61a) to (61n) and the capacitors (62a) to (62n) are connected in series. (70a) and (70b) are transformers, each input side of which is connected to the electric circuit (1) and a load (71a),
(71b) and each are connected in series.

The conventional automatic power factor adjustment device is configured as described above, and the electric circuit (1) is connected to the instrument transformer (2) and the instrument current transformer (3), and the voltage of the electric circuit (1) is changed. Is detected, the reactive power detection device (4) detects the reactive power by the voltage and the current, and produces an output proportional to the detected reactive power. The amplifier circuit (5) amplifies the output of the reactive power detection device (4). The first comparison circuit (6) compares the output of the amplifier circuit (5) with the output of the input point setting device (7), and the output of the amplifier circuit (5) is higher than the output of the input point setting device (7). Higher output produces. The second comparison circuit (8) is the output of the amplification circuit (5) and the breaking point setting device (9).
The output of the amplifier circuit (5) is lower than the output of the breaking point setting device (9), and an output is generated. The timer circuit (20) is released from the reset state at the time of input from the OR gate (19), generates an output after the time set by the timer setting device (21) elapses, 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 comparison circuit (6) and the output of the timer circuit (20), and the electric circuit (1). The capacitor connected with the capacitor (62a)
Select from (62n). The second sequential circuit (24) has a second
Of the gate circuit (18), that is, the output of the second comparison circuit (8) and the output of the timer circuit (20) to disconnect the capacitors from the electric circuit (1) from the capacitors (62a) to (62n). ) To choose from. Relay circuit (25)
Is energizing the relay corresponding to the capacitor selected in the first sequential circuit (23) and deactivating the relay corresponding to the capacitor selected in the second sequential circuit (24), and the relay of the corresponding relay. The capacitors (62a) to (62n) are turned on by the magnetic contactors (60a) to (60n) to which the capacitors to be selected are connected via the control circuit section (50) by selecting the contacts (26a) to (26n). Turn off. In addition, the relay contact (26
a) to (26n) are first to nth capacitors (62a) to (62n).
Corresponding to n), the relay circuit (25) is energized or deenergized.

[Problems to be Solved by the Invention] In the conventional automatic power factor adjusting device as described above, a manual control switch and a timer must be externally attached in order to perform a manual operation. And there was a problem that the timer for manual control operates asynchronously.

The present invention has been made in order to solve such a problem, and it is possible to perform a manual operation even during an automatic adjustment of a power factor and to collectively manage an automatic control timer and a manual control timer. The purpose is to obtain an automatic power factor adjustment device capable of

[Means for Solving Problems] An automatic power factor adjusting device according to the present invention detects an ineffective component of an electric circuit and produces an output proportional to the ineffective component, a manual operation switch, A setting unit for setting a closing level or a cutoff level, and a timer function for manual control is started when the manual operation switch is turned on, and a control signal for connecting a capacitor to the electric circuit is output after a lapse of a designated timer time. Immediately when the operation switch is turned off, a capacitor cutoff signal for disconnecting the capacitor from the electric circuit is output, the invalid component detection unit and the setting unit are compared, and the output of the invalid component detection unit exceeds the input level. If the timer function for automatic control is started and a predetermined timer time has elapsed, a control signal for connecting a capacitor to the electric circuit is output. If the output of the invalid component detection unit exceeds the cutoff level, the arithmetic processing unit that starts the automatic control timer function and outputs a control signal for disconnecting the capacitor from the electric circuit after a predetermined timer time elapses. A display unit that displays an output signal from the arithmetic processing unit, the manual operation switch is provided for each capacitor, and when the manual operation switch is turned on, the arithmetic processing unit causes the automatic control timer function. When the manual operation switch starts to operate during the timekeeping operation, the count value of the automatic control timer function is reset, and the automatic control timer function does not operate when the manual control timer function operates.

[Operation] In the present invention, when the manual operation switch is turned on, the corresponding manual control timer is started, and the capacitor closing signal is output after the designated timer time has elapsed. When the manual control timer starts, the automatic control timer is reset, and the automatic control timer does not operate while the manual control timer is operating. When the manual operation switch is turned off, a capacitor cutoff signal is output and the automatic control timer is reset.

[Embodiment] FIG. 1 is a block diagram showing a configuration of an automatic power factor adjusting device according to an embodiment of the present invention. In the figure, (30) is a manually operated switch group, and a switch is provided for each capacitor. (31) is a setting unit, and (32) is an arithmetic processing unit, the input side of which is connected to the reactive power detection unit (4), the manual operation switch (30) and the setting unit (31), and the output side of which is a relay. It is connected to the circuit (25) and the display section (33). The other components are the same as those in FIG.

The automatic power factor adjuster (100A) includes a reactive power detector (4), a relay circuit (25), and a manual operation switch (3).
0), a setting section (31), an arithmetic processing section (32), a display section (33), and relay contacts (26a) to (26n).

FIG. 2 is a view showing a flowchart of the program written in the arithmetic processing section (32) in FIG.

FIG. 3 is a diagram showing a detailed flowchart of step S2 in FIG.

FIG. 4 is a diagram showing a detailed flowchart of step S4 in FIG.

In the automatic power factor adjusting device configured as described above, the automatic power factor adjusting device (100A) uses an electric circuit based on the voltage from the instrument transformer (2) and the current from the instrument current transformer (3). It has a reactive power detection unit (4) which detects the reactive power of (1) and produces an output proportional to the reactive power. The arithmetic processing section (32) performs the manual control processing of step S2 and the automatic control processing of step S4 shown in FIG. 2 in accordance with a program written in advance.

In the manual control process shown in FIG. 3, it is checked whether or not there is a manual operation (step S5), and if there is a manual operation, the automatic control timer is reset (step S7) to check whether it is a manual ON operation ( In step S8), the manual control timer is started in the case of the manual on operation (step S11), and the interruption signal is output in the case of the manual off operation (step S9), and the manual control timer is reset (step S10).

Also, check whether the timer for manual control is on (step
S6), if the timer for manual control is operating, it is checked whether or not the designated timer time has elapsed (step S12). If the timer has elapsed, a closing signal is output (step S13) and the output control timer is reset (step S13). Step S14). This process is performed for each capacitor.

In the automatic control process shown in FIG. 4, the output of the reactive power detection unit (4) is compared with the closing level (step S23) or interruption level (step S16) set by the setting unit (31), and the closing level is set. If the level is exceeded, the automatic control timer is operating, and the specified timer time has elapsed, a cutoff signal is output (step S21).

The automatic control timer is started when the reactive power exceeds the closing level and the cutoff level (step S26), but the automatic control timer is not started while the manual control timer is operating. If a manual operation occurs while the automatic control timer is operating, the automatic control timer is reset (step S7). In this way, manual operations are processed with priority over automatic operations.

Here, the timer for manual control and the timer for automatic control are
This is realized by a timer interrupt, the counter value is incremented by 1 only when the timer is on, and it is determined whether the designated timer time has elapsed by referring to this counter value.

The closing signal and the breaking signal drive the relay circuit (25),
The relay contacts (26a) to (26n) connect the magnetic contactors (60a) to (60n) through the control circuit (50) to the capacitor (62
This is a device that turns on and off a) to (62n). Further, the calculation result and the closing signal / interruption signal are displayed on the display unit (33).

Here, the closing setting value or the closing setting value determined in step S16 or step S23 will be described. The relationship of Q = W × ((1 / cos ² θ) −1) ^1/2 ...... holds between the active power W, the delayed reactive power Q, and the power factor cos θ. Where cos θ = 0.995, that is, the power factor
99.5% or more is rounded off and regarded as 100%. The delayed reactive power Q at that time is, from the formula, Q≈W × 0.1 ....

Generally, (demand rate) = ((maximum power demand) / (equipment capacity)) x 10
It is a coefficient called 0 ... (load factor) = ((average power for a certain period) / (maximum power demand)) x 100. , Transforming the formula, (maximum power demand) = (equipment capacity) x (demand rate) x (1/10
0) …… (average power during a certain period) = (maximum power demand) × (load factor) × (1/100) …… where the installed capacity is equivalently the composite transformation set by the setting unit (31) You can set it as a ratio. Also, the maximum power demand,
The average power for a certain period can be obtained from the values calculated from the demand rate and load rate set by the setting unit (31). Therefore, by substituting the equation or the value obtained by the equation for the value of the active power W in the equation, the injection point set value can be obtained. Which one to substitute is set by the setting section (31). Next, the cut-off point set value is set in the setting section (3
Obtain the value by multiplying the capacitance value to be controlled next with the capacitor capacitance value set in 1) by the hunting prevention coefficient and the closing point set value obtained by the formula.

[Effects of the Invention] As described above, the present invention sets an invalid component detection unit that detects an invalid component of an electric circuit and produces an output proportional to this invalid component, a manually operated switch, and a closing level or a cutoff level. When the setting unit and the manual operation switch are turned on, the timer function for manual control is started to output a control signal for connecting a capacitor to the electric circuit after a specified timer time has elapsed, and immediately when the manual operation switch is turned off, the control signal is output. A capacitor cutoff signal for disconnecting the capacitor from the electric circuit is output, the invalid component detection unit and the setting unit are compared, and when the output of the invalid component detection unit exceeds the input level, an automatic control timer function is activated. A control signal for connecting a capacitor to the electric circuit is output after a predetermined timer time has elapsed after the start, and the invalid component is also output. When the output of the detection unit exceeds the cutoff level, an arithmetic processing unit that starts a timer function for automatic control and outputs a control signal for disconnecting a capacitor from the electric circuit after a predetermined timer time has passed, and the arithmetic processing unit And a display unit for displaying an output signal of the capacitor, the manual operation switch is provided for each capacitor, and when the manual operation switch is turned on, the arithmetic processing unit is manually operated at the time of the timekeeping operation of the automatic control timer function. When the switch starts operating, the count value of the automatic control timer function is reset, and the manual control timer function does not operate when the switch is in operation, so that the manual control timer and the automatic control timer are Since it is realized by software, the device can be made inexpensive, and since two types of timers are comprehensively managed, manual operation is possible rather than automatic control. There is a large effect such as can be processed preferentially.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an automatic power factor adjusting device according to an embodiment of the present invention, FIGS. 2 to 4 are flowcharts of an embodiment of the present invention, and FIG. 5 is a conventional automatic power factor adjusting device. It is a configuration block diagram of. In the figure, (1) ... electric circuit, (2) ... instrument transformer, (3) ... instrument current transformer, (4) ... reactive power detector, (25) ... relay circuit, (26a) to (26n) …… Relay contacts, (30) …… Manual operation switch group, (31) ……
Setting section, (32) …… Calculation processing section, (33) …… Display section,
(50) …… Control unit, (60a) to (60n) …… Magnetic contactor,
(61a) to (61n) …… Series reactor, (62a) to (62
n) ... condenser, (100a) ... automatic power factor adjustment device. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. An invalid component detection unit for detecting an invalid component of an electric circuit and producing an output proportional to the invalid component, a manual operation switch, a setting unit for setting a closing level or a cutoff level, and the manual operation switch. When the manual operation switch is turned on, the timer function for manual control is started to output a control signal for connecting a capacitor to the electric circuit after a specified timer time has elapsed, and the capacitor which immediately disconnects the capacitor from the electric circuit when the manual operation switch is turned off. A cutoff signal is output, the invalid component detection unit and the setting unit are compared, and if the output of the invalid component detection unit exceeds the input level, the automatic control timer function is started and a predetermined timer time elapses. After that, a control signal for connecting a capacitor to the electric circuit is output, and the output of the reactive component detection unit exceeds the cutoff level. In this case, an arithmetic processing unit that starts the automatic control timer function and outputs a control signal for disconnecting the capacitor from the electric circuit after a predetermined timer time has elapsed, and a display unit that displays the output signal from the arithmetic processing unit. The manual operation switch is provided for each capacitor, and when the manual operation switch is turned on, the arithmetic processing unit causes the automatic operation control to be performed when the manual operation switch starts operating during the time counting operation of the timer function for automatic control. An automatic power factor adjusting device characterized in that the count value of the timer function is reset, and the automatic control timer function does not operate when the manual control timer function is in operation.