JPS6327933B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power factor adjustment device that detects reactive power, reactive current, or power factor in order to improve the power factor of a circuit, and outputs a signal to turn on or cut off a capacitor based on the detected reactive power, reactive current, or power factor. It is something. In particular, the present invention is effective in a power factor adjustment device of the type that cyclically controls turning on/off of a plurality of capacitors of equal capacitance.

Conventional power factor adjustment devices detect the reactive power, reactive current, or power factor of the circuit whose power factor is to be improved.
For this purpose, the capacitor's closing point and cutting point are set in advance, and when the detected value exceeds this value, a capacitor closing and shutting signal is output, and this signal turns on or shuts off the capacitor. ing.

However, in a conventional device, for example, if there are four punctures in the controlled capacitors (hereinafter referred to as C1 to C4), even if all C1 to C4 are turned on, the reactive power detection value will still exceed the point at which the capacitor is turned on. If it is, the capacitor input signal continues to be output. On the other hand, since all the capacitors are already closed, no matter how many closing signals are output, the power factor will not be improved any further, and this state will continue. Therefore, this signal inputs a signal to the capacitor control circuit that has already been turned on, and the control circuit relay is energized, causing unnecessary relay operation noise and undesirable conditions such as the relay coil generating heat. It is something that causes This phenomenon is the same in the case of shutoff; for example, if all of C1 to C4 are shut off and the reactive power detection value exceeds the capacitor cutoff point, the capacitor cutoff signal is repeatedly output.

In order to eliminate such drawbacks, interlock circuits have been installed. This can be done, for example, by installing a circuit that detects that a closing signal has been output to all of C1 to C4 and then stops outputting the closing signal, or by detecting that a shut-off signal is output to all of C1 to C4 and then This is done by providing a circuit that stops the output of the cutoff signal.

However, as a drawback of this, for example, when a manually operated changeover switch is used in the sequence of the capacitor control circuit, the following situation occurs. That is, in automatic operation, the power factor adjustment device automatically outputs a capacitor closing/cutting signal, thereby performing a capacitor closing/closing operation. On the other hand, in manual operation, the power factor adjustment device is separated from the control circuit, the capacitor is turned on or off by manual operation, and a capacitor of the capacity desired by the electrical manager is turned on. Therefore, when the power factor adjustment device is placed in the manual operation state, although it is disconnected from the capacitor control circuit, it does not turn off the power to the device itself. This has the disadvantage that the state becomes different from the state when switching to manual operation.

The present invention aims to eliminate all of the above-mentioned drawbacks of conventional devices and to provide a power factor adjusting device that operates extremely appropriately when used in a capacitor control circuit. Therefore, the present invention provides a power factor adjustment device that performs power factor adjustment by cyclically controlling on/off a plurality of capacitors of equal capacity according to detected reactive power. By using the auxiliary contacts of the switch, when all the capacitors are closed or closed, the closing and closing signals are not output to the sequential control circuit that excites the relays.
Further, even during manual operation, the closing signal and the shutoff signal are not output to the control circuit, so that when switching from automatic to manual mode, the state immediately before switching is maintained.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

That is, the figure is a block diagram showing one embodiment of the present invention. In the figure, 1 is a reactive power detection unit, which detects reactive power based on the voltage and current elements detected by the PT and CT connected to the circuit, and outputs an electrical signal proportional to this. be. 2 is an amplification circuit that amplifies the level of the signal;
3 is a comparison circuit A, and a capacitor input point setting section 4
is compared with the set value, and if it exceeds the input point, a comparison signal is output. Then, this signal is sent to gate circuit A1
1 to the timer circuit 9, and this timer circuit 9
outputs a closing signal when the timer time set by the timer setting section 10 has elapsed. Based on this signal, the control circuit A13 sequentially selects the corresponding capacitor circuit, excites the corresponding relay of the relay circuit 15, and then activates the relay. The contact 16 will be turned on, and the ON signal of this relay contact 16 will be input to the external capacitor control circuit to turn on the capacitor. By repeating the above operation, the capacitor will turn on from C1 to C4. They are introduced one after another in order. Reference numerals 31, 32, 33, and 34 are auxiliary contacts of the capacitor closing switch, which are turned on when the capacitor is closed and turned off when the capacitor is closed. Note that the contacts 31 to 34 are auxiliary contacts of the capacitors C1 to C4. Therefore, as the capacitors are turned on in the order of C1 to C4, the auxiliary contacts are turned on sequentially starting from 31.
When all of the capacitors C1 to C4 are turned on, the circuit consisting of the auxiliary contacts 31 to 34 is closed and the terminal 7 is grounded. Therefore, gate circuit A11 is closed. Therefore, since the comparison signal of the comparison circuit A3 cannot pass through the gate circuit A, the order control circuit A13 does not operate thereafter. That is, when all of the capacitors C1 to C4 are turned on, the turning operation of the power factor adjusting device of the present invention is stopped.

Next, 5 is a comparison circuit B, which compares the set value of the capacitor cutoff point setting section 6 and the output of the amplification circuit 2,
If the cutoff point is exceeded, a comparison signal is output. Then, this signal reaches the timer circuit 9 via the gate circuit B12, and this timer circuit 9 is connected to the timer setting section 1.
When the timer time set at 0 has elapsed, a cutoff signal is output. Based on this signal, the control circuit B14 sequentially selects the corresponding capacitor circuit, and the corresponding relay in the relay circuit 15 is de-energized and the relay contact 16 is turned off, and the on signal of this relay contact 16 is input to the external capacitor control circuit to cut off the capacitor.
By repeating the above operations, the capacitors are sequentially cut off in the order of C1 to C4. Reference numerals 41, 42, 43, and 42 are auxiliary contacts of the capacitor closing switch, which are turned on when the capacitor is in the cutoff state and turned off when the capacitor is in the cutoff state.

Note that the contacts 41 to 44 are connected to capacitors C1 to C1.
These are each auxiliary contact of C4. Therefore, as the capacitors are cut off in the order of C1 to C4, the auxiliary contacts are also turned on sequentially from 41 to 44. When all of the capacitors C1 to C4 are cut off, the circuit consisting of the auxiliary contacts 41 to 44 is closed and the terminal 8 is grounded. Therefore, gate circuit B12 is closed. Therefore, the comparison signal of comparison circuit B5 does not operate thereafter. That is, when all of the capacitors C1 to C4 are cut off, the closing operation of the power factor adjusting device of the present invention is stopped.

Next, the case of switching to manual operation will be explained. That is, 51 and 52 are switches for switching between manual operation and automatic operation, and when this switch is turned to the manual side, terminals 7 and 8 are grounded in the same manner as described above, and gate A11 and gate B12 are closed. , the shutoff operation and the closing operation of the power factor adjustment device of the present invention are stopped.

As described above, according to the present invention, in a power factor adjustment device that performs power factor adjustment by cyclically turning on/off a plurality of capacitors of equal capacity according to detected reactive power, each of the external When all capacitors are closed or closed using the auxiliary contact of the capacitor closing switch,
In addition, during manual operation, the sequential control circuit that excites the relays does not output the ON signal and the OFF signal, so that the effect of uniform control of the capacitor, which is a characteristic of cyclic control, is maintained under any conditions. Furthermore, when switching between automatic and manual mode, the effect can be obtained that the state immediately before switching can be reliably maintained.

[Brief explanation of drawings]

The figure is a block diagram showing one embodiment of the present invention. In the figure, 1 is a reactive power detection section, 3 is a comparison circuit A, 4 is a closing setting section, 5 is a comparison circuit, 6 is a cutoff point setting section, 7 is a terminal for prohibiting closing, 8 is a terminal for prohibiting cutting, 11 is a gate circuit A, 12 is a gate circuit B, 15 is a relay circuit, and 16 is a relay contact.

Claims (1)

[Scope of Claims] 1. A power factor adjustment device that detects a reactive component with respect to an active power component of a circuit and outputs a turning on and off signal that cyclically turns on and off a plurality of capacitors in order to adjust the reactive component. a reactive component detecting means for detecting a reactive component with respect to the active power component of the circuit; and a first means for comparing the output of the reactive component detecting means with the output of the capacitor closing point setting means and generating an output corresponding to the output of the reactive component detecting means. a comparison means; a second comparison means for comparing the output of the reactive component detection means and the output of the capacitor cutoff point setting means and generating an output corresponding to the comparison; and a corresponding capacitor provided for each of the capacitors. a first sequential control means for generating a closing signal to sequentially close selected relay contacts in the group of relay contacts for closing or disconnecting the relay contacts to or from the electric circuit; a second sequential control means that generates a cutoff signal that sequentially opens the capacitors; and a second sequential control means that is provided for each of the capacitors and is closed when the corresponding capacitor is in the closed state, and that is connected in series and has one end grounded. a closing auxiliary contact group; a breaking auxiliary contact group provided for each of the capacitors and closed when the corresponding capacitor is in the cut-off state, connected in series and one end of which is grounded; A timer circuit that receives the output of the second comparison means and outputs a closing command signal to the first sequential control means or a cutoff command signal to the second sequential control means, respectively, when the output continues for a predetermined period of time. means, a first comparator configured to prevent the output of the first comparing means from being generated when the other end of the auxiliary closing contact group is connected to one input and all of the auxiliary closing contacts are closed; gate circuit means, and the other end of the auxiliary breaking contact group is connected to one input so that the output of the second comparing means is not generated when all the auxiliary breaking contacts are closed. a second gate circuit means for switching between manual and automatic switching, which is connected in parallel to each of the auxiliary closing contact group and the auxiliary breaking contact group, and shorts both ends of each when in manual operation; A power factor adjustment device characterized by comprising the following. 2. The power factor adjustment device according to claim 1, wherein the reactive component is reactive power. 3. The power factor adjustment device according to claim 1, wherein the reactive component is a reactive current.