JP3142715B2 - Power factor adjustment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power factor adjusting device provided with a protective relay, and more particularly, to a power relay capable of automatically resetting a protective relay which has been cut off by detecting a harmonic and automatically re-inputting a capacitor circuit. The present invention relates to a power factor automatic adjustment device that can perform the power factor adjustment function and can suppress a decrease in the operation rate.

[0002]

2. Description of the Related Art In recent years, the number of cases where harmonics generated from semiconductor applied equipment inside and outside buildings and factories cause various obstacles to various equipments of electric power facilities has been rapidly increasing. Wave measures are considered important.

The high-voltage capacitor circuit for adjusting the power factor of the system is not an exception. At present, the power factor adjusting device is provided with a harmonic protection relay so that the capacitor circuit at the time of the inflow of the harmonic current can be obtained. The protection by automatic shut-off is provided for practical use.

[0004] A practical harmonic protection relay detects an overload due to harmonics flowing from the system and shuts off the circuit breaker. Further, after the breaking operation of the circuit breaker, the closing of the circuit breaker is prohibited until the administrator of the power equipment goes to the site and resets the harmonic protection relay.

[0005]

The harmonic protection measures in such a conventional power factor adjusting apparatus are applied to a case where the manager of the electric equipment is resident in the electric room or when the breaker is shut off. On the other hand, if this was reported, it was practically sufficient.

[0006] However, when the manager is absent, when the manager cannot rush to the site, or when the manager does not notice the switching operation of the relay, the capacitor circuit is released for a long time. In the meantime, there is a drawback that the power factor adjustment function that should be performed by the capacitor circuit does not work. In other words, for the purpose of a capacitor circuit that expects a discount on the electricity used by power factor adjustment, this drawback is always a major obstacle in performing fine power factor adjustment of power.

As a result, the capacitor circuit is protected by the automatic shutoff of the capacitor circuit when the harmonic current flows in, and the harmonic current is reduced and the power factor of the power needs to be adjusted despite the need to adjust the power factor. Did not work.

The present invention solves the above problems,
The purpose is to automatically reset the protection relay that has detected and cut off the harmonics, and to automatically turn on the capacitor circuit again. It is to provide.

Another object of the present invention is to equalize the number of times the circuit is opened and closed, and to suppress frequent opening and closing operations of the circuit by re-shutting off and on again when the inflow of harmonic currents occurs continuously. Another object of the present invention is to provide an automatic power factor adjusting device capable of preventing simultaneous injection of capacitors when the capacitor circuit is turned on again.

[0010]

In order to solve the above-mentioned problems, a power factor adjusting apparatus according to a first aspect of the present invention comprises a capacitor circuit 7 and a system 1 of the capacitor circuit 7 as shown in FIG. Power factor adjusting means 5 for adjusting connection, and protection for shutting off the capacitor circuit 7 and the power factor adjusting means 5 from the system 1 when a harmonic current flows from the system 1 and an overload is detected. A relay 3 and the protection relay 3
And a control means 9 for controlling the protection relay 3 so that the capacitor circuit 7 is reconnected to the system 1 after a predetermined time (T (1)) from the shut-off operation.

[0011] The first aspect of the power factor correction apparatus of the present invention, the power factor adjustment before SL during interrupting operation of the protective relay 3
The control means 9 further comprises a storage means 13 for storing the open / closed state of the capacitor circuit 7 by the regulating means 5, and the control means 9 sets a predetermined time (T
(1)) Thereafter, the capacitor circuit 7 is stored in the storage means 13
The protection relay 3 and the power factor adjusting means 5 are controlled so as to be reconnected to the system 1 in the open / closed state stored in.

A power factor adjusting apparatus according to a second aspect of the present invention is the power factor adjusting apparatus according to claim 1 , wherein the protective relay 3 is provided within a predetermined time (α) after reconnection of the capacitor circuit 7. Is turned off again, the control means 9
Controls the protection relay 3 and / or the power factor adjusting means 5 so as to reconnect the capacitor circuit 7 to the system 1 after a second predetermined time (T (2)) from the shutoff operation of the protection relay 3. The second predetermined time (T (2)) is longer than the predetermined time (T (1)).

Further, a power factor adjusting device according to a third aspect of the present invention is the power factor adjusting device according to claim 1 or 2 ,
The power factor adjusting means 5 sets the reconnection of the capacitor circuit 7 at a different timing (τ (1)
~ Τ (6)).

[0014]

In the power factor adjusting apparatus according to the first aspect of the present invention, FIG.
As shown in (1), the connection of the capacitor circuit 7 to the system 1 is automatically adjusted by the power factor adjusting means 5 to adjust the power factor of the power. However, in the protection relay 3, a harmonic current flows from the system 1 to prevent an overload. If detected, the capacitor circuit 7
And a signal (operation signal) indicating that the shutoff operation has been performed to the control means 9 while the power factor adjusting means 5 is cut off from the system 1.
Notify by BD.

The control means 9 receives the operation signal BD,
For example, the timing operation of the timer 11 is started, and after a lapse of a predetermined time T (1), the protection relay 3 is reset by the reset signal RS, and the capacitor circuit 7 is reconnected to the system 1.

As described above, the protection relay 3 which has once been cut off due to the overload at the time of the inflow of the harmonic current is automatically reset after a predetermined time T (1) has elapsed.
The capacitor circuit 7 can be automatically re-input to the system 1, and the power-factor adjustment function is operated by automatically re-inputting the capacitor circuit 7 without the need for the administrator to perform a reset operation as in the conventional case. The rate reduction can be suppressed.

In the power factor adjusting apparatus according to the first aspect of the present invention, when the control means 9 receives the notification of the operation signal BD from the protection relay 3, the control means 9 starts the time counting operation of the timer 11, for example. storing the opening and closing state of the capacitor circuit 7 by the power factor adjustment means 5 is connected adjusted in the storage unit 13. Further, after a lapse of a predetermined time T (1), the protection relay 3 is reset by the reset signal RS,
By controlling the power factor adjusting means 5, the capacitor circuit 7 is reconnected to the system 1 in the open / close state stored in the storage means 13.

As described above, when the capacitor is restarted, the capacitor circuit 7 is restarted so as to return to the state of the capacitor circuit 7 immediately before the shut-off operation. Therefore, the opening and closing frequency of the capacitor can be made uniform.

In the power factor adjusting apparatus according to the second feature of the present invention, when the protection relay 3 is turned off again within a predetermined time α after the capacitor circuit 7 is reconnected, the control means 9 is activated.
The protection relay 3 and / or the power factor adjusting means are configured to reconnect the capacitor circuit 7 to the system 1 after a lapse of a second predetermined time T (2) longer than the predetermined time T (1) from the shut-off operation of the protection relay 3. 5 is controlled.

This makes it possible to suppress the frequent opening and closing operations of the capacitor circuit 7 due to the automatic reset of the harmonic protection relay 3 when the high distortion state is continuously occurring.

Further, in the power factor adjusting device according to the third feature of the present invention, the control means 9 controls the power factor adjusting means 5 after a lapse of a predetermined time T (1) from the cutoff operation of the protection relay 3, When the capacitor circuit 7 is reconnected to the system 1, it is reconnected at different timings τ (1) to τ (6) for each of the capacitors C1 to C6.

Thus, when the capacitor circuit 7 is turned on again, it is possible to prevent an abnormal current from flowing into the system 1 due to simultaneous turning on.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a configuration diagram of a power factor adjusting apparatus according to one embodiment of the present invention.

In the figure, the power factor adjusting apparatus of this embodiment is connected to a system 1 and has a power factor adjusting capacitor circuit 7,
The power factor adjusting means 5 for adjusting the connection of the capacitor circuit 7 to the system 1. When a harmonic current flows from the system 1 and an overload is detected, the capacitor circuit 7 and the power factor adjusting means 5 are disconnected from the system 1. After a predetermined period of time after the protection relay 3 and the protection relay 3 are turned off, the capacitor circuit 7 is connected to the system 1
Control means 9 for controlling the protective relay 3 to reconnect to
The configuration includes a timer 11 and storage means 13 for storing the open / closed state of the capacitor circuit 7 by the power factor adjusting means 5 when the protection relay 3 is turned off.

As the protection relay 3 for harmonics, for example, a relay with an SHS type harmonic sensor manufactured by Shigetsu Seisakusho is used, and outputs an operation signal BD at the time of cutoff operation to reset to the original connection state. Signal terminal for resetting.

As the power factor adjusting means 5, for example, MI
The CAM-VAR3 is used, and the operation of the means is stopped by closing the terminals CS + and S- and between the terminals TS + and S-.

Further, the control means 9 is realized by a programmable controller, and the timer 11 is realized by a hardware timer or a software timer in the programmable controller.

Next, the basic operation of the power factor adjusting apparatus according to the present embodiment will be described with reference to the timing chart shown in FIG. FIG. 2 shows a timing chart of the period from the first overload detection by the harmonic current, to the prohibition of turning on of the capacitor circuit 7 and to the turning on of the capacitor circuit 7 possible.

The power factor adjusting device of this embodiment adjusts the power factor of the power by automatically adjusting the connection of the capacitor circuit 7 to the system 1 by the power factor adjusting means 5, but the harmonic current enters the overload region. (Refer to FIG. 2 (a)), the protection relay 3 uses its own operation characteristics to connect the device to the system 1 with the operation time t.
(See FIG. 2 (b)) and notifies the control means 7 of the fact that the shut-off operation has been performed by the operation signal BD.

The control means 9 recognizes that the capacitor circuit 7 cannot be turned on by the notification of the operation signal BD (see FIG. 2C), and counts the time of the timer 11 (FIG. 2C).
(Refer to (d)), and after a lapse of a predetermined time T (1),
The protection relay 3 is automatically reset by a reset signal RS (see FIG. 2E), and the capacitor circuit 7 is connected to the system 1
To reconnect.

Note that the predetermined time T (1) from the shut-off operation to the automatic reset must be longer than the discharge time of the capacitors C1 to C6. Although the discharge time of the capacitors C1 to C6 is long and is about 5 minutes, in the case of the present embodiment, from the viewpoint of suppressing the number of times of opening and closing of the capacitor circuit 7, the predetermined time T
(1) is expected to take about one hour, and there is almost no problem.

As described above, in the power factor adjusting apparatus of the present embodiment, the automatic reset of the harmonic protection relay 3 can be realized as its basic operation. Therefore, even if the administrator does not perform the sequential reset operation when the protection relay 3 operates, The capacitor circuit 7 can be automatically turned on again, and it is possible to prevent the operation rate of the power factor adjustment function of the device from decreasing. In addition, since the administrator does not need to go to the electric room, there is an effect of reducing daily management work.

The following functions can be added as a first modification of the power factor adjusting apparatus of the present embodiment that performs the above basic operation.

That is, in the control means (programmable controller) 9, the open / close state of the capacitor circuit 7, which is connected and adjusted by the power factor adjusting means 5, is stored in the storage means 13 by the control sequence when the protection relay 3 is turned off. After the predetermined time T (1) has elapsed, the protection relay 3 is reset by the reset signal RS, and the power factor adjusting means 5 is controlled so that the capacitor circuit 7 is operated in the open / closed state stored in the storage means 13. 1 to be reconnected.

FIG. 3 shows each capacitor C of the capacitor circuit 7.
It is explanatory drawing explaining the connection control operation of Nos. 1 to C6. In the figure, a black circle "●" indicates that the capacitor is turned on, and a white circle "○" indicates that the capacitor is opened.

Conventionally, when the administrator resets the protection relay 3 at the time of restarting, the power factor automatic adjustment device is also reset, and therefore, as shown in FIG.
, The capacitors are sequentially supplied from the first capacitor C1, and the frequency of the capacitors that are supplied in the shortest order inevitably tends to increase extremely.

On the other hand, when the capacitor circuit 7 is turned on again, by returning to the state of the capacitor circuit 7 immediately before the shut-off operation, the capacitor switching frequency of the capacitor circuit 7 can be made uniform. In FIG. 3B, the capacitors C3 and C4 are turned on immediately before the shut-off operation, and the capacitors C3 and C4 are also turned on when restarting.

As described above, in the power factor adjusting apparatus according to the first modification, upon restarting, the capacitor circuit 7 immediately before the cutoff operation is activated.
Is re-input so as to return to the state described above, so that the opening and closing frequency of the capacitor can be made uniform.

Further, as a second modification of the power factor adjusting device of the present embodiment, the following functions can be added.

That is, when the protection relay 3 is turned off again within a certain time α after the reconnection of the capacitor circuit 7,
The control means 9 sets the second
After a predetermined time T (2), the protection relay 3 and / or the power factor adjusting means 5 are controlled so that the capacitor circuit 7 is reconnected to the system 1. Here, the second predetermined time T (2) is the predetermined time T
(1) Set longer.

The specific operation of the power factor adjusting apparatus according to the second modification will be described with reference to the timing chart shown in FIG. 4 and the flowchart shown in FIG.

FIG. 4 shows a case where the overload detection due to the harmonic current occurs continuously and frequently, and shows a timing chart for the first and second overload detections. FIG. 5 is a flowchart for explaining a control sequence of the control means (programmable controller) 9.

In FIG. 5, the basic operation described above is performed for the first overload detection. Timer 11 at this time
Is T (1).

After the first automatic reset, if the second overload state is detected within the time period α (see FIG. 4A), the protection relay 3 turns off (FIG. 4B )reference)
And the operation signal BD is output to the control means 9 (step S1).

When the control means 9 recognizes that the capacitor circuit 7 cannot be turned on by the notification of the operation signal BD (see FIG. 4C), the connection is adjusted by the power factor adjusting means 5 in step S2. The open / closed state of the capacitor circuit 7 is stored in the storage unit 13. At the same time, in step S3, a second predetermined time T (2) is set in the timer 11, and the timer 11 starts counting (see FIG. 4D). At this time, the second predetermined time T (2)> time T (1).

Next, after a lapse of a second predetermined time T (2),
In step S4, the reset signal RS (FIG. 4 (e)
), The protection relay 3 is automatically reset. In step S5, the power factor adjusting means 5 is controlled to reconnect the capacitor circuit 7 to the system 1 in the open / closed state stored in the storage means 13.

As described above, in the present modification, the predetermined time T (2) until the second re-input is set to the time T until the previous re-input.
(1) By taking longer, frequent opening and closing operations of the capacitor circuit 7 are suppressed.

Further, when the overload detection due to the harmonic current continues and frequently occurs, the time T (2), T
(3) After the automatic reset by, T (i),…, if the protection relay restarts within the time limit α due to an overload condition, T (1) <T (2) <T ( 3) <… <T (i-1) <T
Attempt to automatically reset the protection relay 3 at the time (i).

Assuming that the time difference between T (i-1) and T (i) is 1 hour, even if the high strain state continues for 24 hours, the opening and closing operation can be performed six times a day in principle. Thus, the number of times of opening and closing per day can be suppressed to 10 times or less. Also,
Considering the case where the protection relay 3 restarts at the timing exceeding the time limit α even for one second, when the capacitor circuit is operated for 24 hours, 2 hours 24 minutes ≦ α + T (1) The number of times of opening and closing is suppressed to 10 times or less.

As described above, according to the present modification, the frequent opening / closing operation of the capacitor circuit 7 due to the automatic reset of the harmonic protection relay 3 can be suppressed when the high distortion state continuously occurs.

Further, as a third modification of the power factor adjusting device of the present embodiment, the following functions can be added.

In the power factor adjusting means 5, the reconnection of the capacitor circuit 7 is performed at different timings (.tau. (1) to .tau. (6)) for each of the capacitors C1 to C6. That is, when the capacitor circuit 7 is turned on again, an abnormal current flows through the system 1 due to the simultaneous turning on of the capacitor circuit 7.

FIG. 6 is a timing chart for explaining the time difference input of the capacitor circuit 7. Each capacitor C1
C6 are supplied at predetermined timings τ (1) to τ (6), respectively, so that they are not supplied at the same time. Here, each time has a time difference of about 5 seconds, and τ (6)> τ (5)> τ (4)> τ (3)> τ (2)>
τ (1).

The method of this modification utilizes a method generally used for automatic power recovery control of power receiving and distribution equipment and the like. This has the effect of shifting the peak of the inrush current flowing into the distribution system when the control device is turned on, and preventing an abnormally high current from flowing into the distribution system.

Summarizing the above, in the power factor adjusting apparatus of the present embodiment, the harmonic protection relay 3 that has been cut off by detecting the harmonic current is automatically turned off after a lapse of time corresponding to the past operation history of the protection relay 3. Since it can be reset, the capacitor circuit 7 can be automatically restored to the state before the shut-off operation, and the restoration work can be performed without the trouble of the administrator such as the power receiving and distribution equipment.
There is an advantage that management work of power receiving and distribution equipment and the like can be reduced.

Further, when the capacitor circuit 7 is turned on again, the capacitor circuit 7 is sequentially turned on before the protection relay 3 is turned off, so that the safe and highly reliable operation of the capacitor circuit 7 can be achieved.

[0058]

As described above, according to the present invention, when a harmonic current flows from a system in a protective relay and an overload is detected, the capacitor circuit and the power factor adjusting means are cut off from the system, Notifying the control means that the shut-off operation has been performed, the control means resets the protection relay after a lapse of a predetermined time and reconnects the capacitor circuit to the system. Is to automatically reset the protection relay that has been cut off after a lapse of a predetermined time, so that the capacitor circuit can be automatically re-input to the system, and the administrator can reset every time as usual Even if it does not operate, it is possible to provide a power factor adjusting device capable of suppressing the decrease in the operation rate of the power factor adjusting function by automatically re-entering the capacitor circuit.

Further, according to the present invention, the control means stores in the storage means the open / close state of the capacitor circuit which is connected and adjusted by the power factor adjusting means during the shut-off operation, and resets the protection relay after a predetermined time has elapsed. At the same time, controlling the power factor adjusting means, the capacitor circuit is reconnected to the system in the open / closed state stored in the storage means, and is re-input so as to return to the state of the capacitor circuit immediately before the shut-off operation upon restarting. Therefore, it is possible to provide a power factor adjusting device capable of equalizing the opening and closing frequency of the capacitor.

Further, according to the present invention, when the protection relay is turned off again within a predetermined time (α) from the reconnection of the capacitor circuit, the control means sets the predetermined time (T ( 1)) A second longer predetermined time (T (2)
) After the lapse of time, the capacitor circuit is reconnected to the system, so if the high distortion state is continuously occurring, the power factor that can suppress the frequent opening and closing operation of the capacitor circuit due to the automatic reset of the harmonic protection relay An adjustment device can be provided.

Further, according to the present invention, when the control means controls the power factor adjusting means to reconnect the capacitor circuit to the system after a predetermined time has elapsed from the shutoff operation of the protection relay,
Since the power is supplied again at a different timing for each capacitor, it is possible to provide a power factor adjusting device capable of preventing an abnormal current from flowing through the system due to simultaneous power supply.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a power factor adjusting device according to an embodiment of the present invention.

FIG. 2 is a timing chart illustrating a basic operation of the power factor adjusting device according to the present embodiment.

3A and 3B are explanatory diagrams illustrating a connection control operation of a capacitor circuit. FIG. 3A is a diagram illustrating a conventional connection control, and FIG. 3B is a diagram illustrating a connection control according to a first modification.

FIG. 4 is a timing chart illustrating an operation in a case where overload detection due to a harmonic current continues and frequently occurs in the power factor adjustment device according to a second modified example.

FIG. 5 is a flowchart illustrating a control sequence of a control unit (programmable controller) 9 in a power factor adjustment device according to a second modification.

FIG. 6 is a timing chart for explaining a time difference input of a capacitor circuit in a power factor adjusting device according to a third modified example.

[Explanation of symbols]

1 system 3 (harmonic) protection relay 5 power factor adjustment means 7 (for power factor adjustment) capacitor circuit 9 control means (programmable controller) 11 timer 13 storage means C1 to C6 capacitor t protection relay operation time T (1) ( Predetermined time from the first shut-off operation to automatic reset) T (2) Second predetermined time (from the second shut-off operation to automatic reset) α The shortest allowable time until the protection relay restarts ● Insertion of a capacitor State ○ Capacitor open state τ (1) to τ (6) Time from automatic reset to capacitor ready state

Claims (3)

(57) [Claims] 1. A capacitor circuit, a power factor adjusting means for adjusting connection of the capacitor circuit to a system, and when a harmonic current flows from the system and an overload is detected, the capacitor circuit and the power A protection relay for disconnecting the rate adjusting means from the system, a control means for controlling the protection relay so as to reconnect the capacitor circuit to the system after a predetermined time from the shutoff operation of the protection relay, and a disconnection of the protection relay The power factor adjusting means during operation
For storing the open / closed state of the capacitor circuit according to
And a control step , wherein the control means performs a predetermined time from a shutoff operation of the protection relay.
After a while, the capacitor circuit is stored in the storage means.
The protective relay to reconnect to the
Power factor control characterized by controlling a heater and power factor adjusting means
Adjusting device. 2. The control circuit according to claim 2, wherein said protection relay is turned off again within a predetermined time after reconnection of said capacitor circuit. The power factor adjusting device according to claim 1, wherein the protection relay and / or the power factor adjusting means is controlled to reconnect the power factor to the system, and the second predetermined time is longer than the predetermined time. Wherein the power factor adjusting means, the power factor controller according to claim 1 or 2, characterized in that the reconnection of the capacitor circuit at different timings for each capacitor.