JPH0746763A - Reactive power regulator - Google Patents

Abstract

PURPOSE:To realize space savings and accurate control. CONSTITUTION:A receiving circuit is connected to a main bus B through a circuit breaker CB1 and a generator AG circuit is also connected to the main bus B through a circuit beaker CB2. Current transformers CT11 and CT12 are provided in both the circuits individually and the secondary windings of the respective current transformers CT11 and CT12 are individually connected to the primary winding of a total current transformer CT13. The secondary winding of the total current transformer CT13 is connected to an automatic power factor regulator 55 or a reactive power relay 91Q. The number of closing power capacitors is selected by the outputs of the automatic power factor regulator 55 and the reactive power relay 91Q.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, when a power receiving circuit and a private power generator are operated in parallel, adjusts the power factor of a power receiving point by supplying reactive power to a load by a reactive power adjusting device for continuous control. The present invention relates to a reactive power adjustment device.

[0002]

2. Description of the Related Art Normally, a circuit shown in FIG. 8 is used as a circuit for clearly separating the sharing of power factor control between a power capacitor and a generator. In FIG. 8, the power receiving circuit is a circuit breaker C.
It is connected to the main bus B via B1. Also, the generator AG
The circuit is connected in the middle of the power receiving circuit via the circuit breaker CB2, and the power receiving circuit and the generator circuit are operated in parallel. CT1 is a current transformer that detects the current of the power receiving circuit, and CT2 is a current transformer that detects the current of the generator circuit. CT3 is a current transformer that detects a current during parallel operation of the power receiving circuit and the generator circuit.

The current transformers CT1 and CT2 are connected to a power factor controller APFR or a reactive power controller AQR,
As a result, is controlled via the generators AG and AVR.
The current transformer CT3 is connected to the automatic power factor adjuster 55 or the reactive power relay 91Q. The secondary side of the transformer PT connected to the main bus B is connected to the automatic power factor adjuster 55 or the reactive power relay 91Q and the power factor controller APFR or the reactive power controller AQR.

Loads L1 and L2 are connected to the main bus B via circuit breakers CB3 and CB4, and a switchgear SW is provided.
The power capacitor C is connected via. Switchgear SW
Is controlled by the output of the automatic power factor adjuster 55 or the reactive power relay 91Q.

In the device constructed as described above, first, the power factors of the loads L1 and L2 operate the automatic power factor regulator 55 by the current detected by the current transformer CT3, and the regulator 55 is operated.
The switchgear SW is appropriately selected according to the output of the above-mentioned formula (1) to control the number of power capacitors C to be closed. Separately from this, the current transformer CT1 is used to finely control the reactive power of the power receiving point by the power generator AG by AQR or the power factor control by APFR. In addition, the reactive power or power factor control at the power generation point is controlled by the
Perform using 2. In this way, the power factor or reactive power control by the power capacitor and the control similar to the above by the generator are realized without interfering with each other.

FIG. 9 shows a circuit which uses a power capacitor only for receiving power. In FIG. 9, the power receiving circuit is connected to the main bus B through a circuit breaker CB1. The generator AG circuit is connected in the middle of the power receiving circuit via the circuit breaker CB2, and the power receiving circuit and the generator circuit are operated in parallel. CT1 is a current transformer that detects the current of the power receiving circuit, and CT2 is a current transformer that detects the current of the generator circuit. CT3 is a current transformer that detects the current during parallel operation of the power receiving circuit and the generator circuit.

An automatic reactive power adjusting device 55R is connected to the current transformer CT1, and the current transformers CT2 and CT3 are APFR.
Alternatively, two transformers PT connected to the main bus B are connected to AQR and APFR or AQR.
The secondary side and the output side of 55R are connected.

A load L1 is connected to the main bus B via a circuit breaker CB3, and a switchgear SW and a power capacitor C are connected in series. The opening / closing device SW controls the number of inputs by the output of 55R.

In the circuit of FIG. 9, the performance of 55R is such that when reactive power for a single power capacitor flows in, one power capacitor is automatically turned on and the power capacitor is disconnected with some hysteresis. Note that the power factor adjustment by the AG detects the reactive component of the load or the power factor and compensates it by the AG.

In FIG. 10, the power receiving circuit is a circuit breaker CB1.
Is connected to the main bus B via. The generator AG circuit is also connected to the main bus B via the circuit breaker CB2. CT1
Is a current transformer that detects the current of the power receiving circuit, and CT2 is a current transformer that detects the current of the generator circuit. Current transformer CT1
And CT2 are connected to a reactive power control device AQR or power factor control devices APFR1 and APFR2, respectively. The secondary side of the transformer PT connected to the setters S1 and S2 and the main bus B is connected to the AQR or APFR1 and 2. AQ
The output of R or APFR1,2 is the automatic voltage regulator A
Supplied to VR. The main bus B has a circuit breaker CB3,
In the circuit of FIG. 10 configured as described above in which the loads L1 and L2 are connected via the CB4, when power is received, AQR or APFR is set by the CT1 installed in the power receiving circuit.
1 is driven to control AG, and in the case of reverse power flow, CT2 installed in the power generation circuit drives AQR or APFR2 to control AG. In this circuit, whether the power is received (when the sum of the received power and the generated power flows to the load side) or the reverse power flow (in this case, the generated power flows to both the power receiving side and the load side), a power relay or power detector ( (Not shown), the control device is switched.

[0011]

The device shown in FIG. 8 is good in electrical characteristics and has no problem. However, after connecting the main circuit of the power receiving circuit and the main circuit of the generator together, the current transformer C
Since T3 is provided, the connection means of the main circuit is complicated, and in the worst case, there is a problem that one switchboard is required to house the current transformer CT3.

On the other hand, in the circuit of FIG. 9, in addition to the problem of FIG. 8, there is no problem in performing automatic reactive power control or automatic power factor control by the generator if the reactive power required by the load is less than the capacity of the generator. There is no. However, when such control is performed, there is a problem that the generator is in a low power factor operation, and when reactive power required by the load exceeds the capacity of the generator, there is a problem that control cannot be performed.

Further, in the circuit of FIG. 10, when the amount of power generation and the amount of power of the load are substantially equal, the current at the power receiving point becomes the difference between the generator current and the load current. Power factor) changes from receiving power to reverse power flow. That is, since a large generator is controlled to control a small current, it is difficult to control with high accuracy. Further, since the direction of the electric power changes from the power reception to the reverse flow, the directional control device (AQR, APFR) can detect only one direction. Furthermore, when trying to control power reception and reverse power flow with two control devices, it is necessary to detect the power flow and switch the device. However, in order to prevent hunting, if switching is provided with hysteresis, different control is performed for the same current. There is a problem that the system part is created and it becomes difficult to control accurately.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a reactive power adjusting device which saves space and achieves accurate control.

[0015]

In order to achieve the above object, the present invention provides a device for controlling a load power factor and reactive power by operating a power receiving circuit and a generator circuit in parallel. , The current transformer secondary side of the power receiving circuit and the current transformer secondary side of the generator circuit are connected to a total current transformer to generate a combined current from both current transformers, and this current causes the power factor of the load to It is characterized in that the reactive power is adjusted.

According to a second aspect of the present invention, the power receiving circuit and the generator circuit are connected in parallel and then connected to the main circuit, the power receiving circuit and the generator circuit are provided with the first and second current transformers, and the third circuit is provided in the main circuit.
Current transformer is provided, an automatic reactive power adjusting device is provided on the secondary side of the first and second current transformers, and its output and the output of the third current transformer are supplied to the reactive power or the power factor control device. In addition, the secondary output voltage of the transformer connected to the main circuit is given to the reactive power or power factor control device, and the automatic voltage regulator of the generator is controlled by the output of the reactive power or power factor control device. It is characterized in that the output of the automatic reactive power adjusting device controls the number of power capacitors for power factor improvement.

According to a third aspect of the invention, a power receiving circuit and a generator circuit are connected to a main circuit for parallel operation, and a current transformer is provided in each of the power receiving circuit and the generator circuit, and an automatic transformer is provided on the secondary side of the current transformer. Providing a reactive power adjusting device, supplying the output of the adjusting device to the total current transformer to generate a combined current, supplying the combined current to the reactive power or power factor control device and connecting it to the main circuit The secondary output voltage of the transformer and the current detected by a current transformer different from the current transformer provided in the generator circuit are supplied, and the generator is automatically controlled by the reactive power or the output of the power factor controller. The present invention is characterized in that the voltage regulator is controlled, and the number of power factor correction power capacitors to be controlled is controlled by the output of the automatic reactive power regulator.

In a fourth aspect of the present invention, a power receiving circuit and a generator circuit are connected to a main circuit for parallel operation, and a current transformer is provided in each of the power receiving circuit and the generator circuit, and the output of the current transformer is a total current transformer. To generate a combined current, supply the combined current to the reactive power or the power factor control device, and to provide the secondary output voltage of the transformer connected to the main circuit to the control device and the generator circuit. A current detected by a current transformer other than the current transformer is supplied, and the reactive power or the output of the power factor controller controls the automatic voltage regulator of the generator.

[0019]

[Function] The current flowing in the main circuit and the generator circuit and the voltage from the transformer are controlled by the reactive power or the power factor control device, and this control output is supplied to the automatic voltage regulator to determine the reactive component or the power factor of the load. Compensate with the generator. Thereby, the reactive component or the power factor control can be performed regardless of the magnitude of the current of the power receiving unit and the direction of the power flow of the power receiving unit. Further, since the detection point is the load current, as long as the load does not change, there is no large change and the current does not become extremely small unlike the power receiving point, so that accurate detection can be performed. Further, since the direction of the tidal current does not change, a directional control device can be used. In addition to this, when controlling the number of power factor correction power capacitors to be supplied by the output of the automatic reactive power regulator, the reactive current is equal to or more than a single component of the power capacitor. If this is set to be relatively small, the load power factor itself is improved by the power capacitor before the operating power factor of the generator deteriorates.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION In the following description of the first embodiment of the present invention with reference to the drawings, the same parts as those in FIG. In Fig. 1, the power receiving circuit and the generator circuit are directly
Each is connected to the main bus B. CT11 is a current transformer that detects the current flowing through the power receiving circuit, CT12 is a current transformer that detects the current flowing through the generator circuit, and both current transformers CT11, C
The secondary side of T12 is connected to the primary side ends of the two windings of the total current transformer CT13. Total current transformer C
The other end of the primary side of T13 is connected to the power factor control device APFR or the reactive power control device AQR. The secondary side of the total current transformer CT13 is connected to the automatic power factor adjuster 55 or the reactive power relay 91Q.

The current transformer C is constructed as in the above embodiment.
The combined current of T11 and CT12 is the total current transformer CT13.
Occurs on the secondary side of. At this time, the current transformers CT11 and CT
If the current ratio of 11 is different, the turns ratio of the total current transformer CT13 is changed so that CT11 and C are correctly placed on the secondary side of CT13.
The combined current of T12 is generated. This allows
Since the same current as the secondary side of the current transformer CT3 shown in FIG. 8 flows through the secondary side of the total current transformer CT13, this current causes the switchgear SW to be opened and closed to control the number of power capacitors C to be turned on. If so, the same control as in the case of FIG. 8 can be performed.

The power factor or reactive power control at the power receiving point or the generator terminal by the generator AG is performed by the current transformers CT11 and C.
It is performed by APFR or AQR according to the detection current of T12. Further, when the current transformer for detecting the current of the power receiving circuit and the current transformer for detecting the generator circuit current have the same current ratio, the secondary side of each current transformer is directly connected in parallel as shown in FIG. However, even if connected to the automatic power factor adjuster 55 or the reactive power relay 91Q, the same control as in the case of the total current transformer CT13 can be performed. Further, when the current transformers have different current ratios, auxiliary current transformers CT14 and CT15 are provided on the secondary side of one or both current transformers, as shown in FIG.
Equivalent control is obtained even if the current ratio is substantially adapted.

FIG. 2 is a connection diagram showing an embodiment of the second invention.
In the current transformer CT2 shown in FIG.
G is provided and the output of this 55G is AQR or APFR.
In addition, the number of power capacitors C is controlled via the output of 55R and the OR circuit OR. 55G when constructed as in the embodiment of the second invention
However, since the power capacitor C is controlled, the power capacitor C is controlled by the command of 55G by detecting the generator output current before the power generator operates in a low power factor or cannot be controlled due to the reactive power required by the load side. The reactive power can be controlled with. The setting of 55G is to set the power capacitor C to 1 when the reactive current of more than one power capacitor unit flows out.
Although the power capacitor C is automatically turned on for the number of cars or with some hysteresis, the supply current from the generator AG is delayed at the disconnection point of the power capacitor C in order to avoid the supply of the advance current from the generator AG. Can be performed in the range of. Regarding the control of the generator AG, CT
3 is for detection, and CT2 is for control.

FIG. 3 is a connection diagram showing an embodiment of the third invention.
The same parts as those in FIG. 2 are described with the same reference numerals. In FIG. 3, the power receiving circuit and the generator circuit are directly connected to the main bus B, respectively. The secondary sides of CT1 and CT2 are connected to 55R and 55G, respectively, and at the same time, they are connected to the primary side ends of the two windings of the total current transformer CT13. Secondary side of total current transformer CT13 is AQR or APF
It is connected to R and the output of this AQR or APFR
Control the generator via AVR. With this configuration, control can be performed in the same manner as in the second embodiment.

In the embodiment of FIG. 3, the current transformer CT
When the current ratio of CT1 and CT2 are different, total current transformer C
The winding ratio of T13 may be changed to generate a synthetic current. If the current transformers CT1 and CT2 have the same current transformer ratio instead of the total current transformer CT13, secondary circuits of these current transformers CT1 and CT2 may be directly connected in parallel as shown in FIG. Further, when the current transformer ratio is different, one or both of the auxiliary current transformers CT14 and CT as shown in FIG.
Even if 15 is used, this operation control can be made the same.

FIG. 4 is a connection diagram showing an embodiment of the fourth invention.
In FIG. 4, the power receiving circuit and the generator circuit are circuit breakers CB1,
Each is directly connected to the main bus B via CB2. C
T1 and CT2 are respectively connected to the primary side of a so-called total current transformer CT13, and the secondary side of CT13 is connected to AQR or APFR. AQR or APFR has a current transformer CT5 provided in the secondary side of the transformer PT and the generator circuit.
The secondary side of is also connected. AQR or APFR
Output controls the generator via AVR. In addition, loads L1 and L2 are applied to the main bus B through circuit breakers CB3 and CB4.
Are connected.

When constructed as in the fourth embodiment of the invention, C
The combined current of T1 and CT2 is 2 of the total current transformer CT13.
It occurs in the next circuit. The combined current obtained in the secondary circuit is AQ
Since it is input to R or APFR, even if the magnitude relationship between the load and the generated power changes, the detected amount is a combined power of the received power and the generated power, so the change is continuous and the magnitude of the current changes. However, it is unidirectional only on the load side, and can be controlled by one controller (AQR or APFR).

FIG. 5 is a wiring diagram showing another embodiment of the fourth aspect of the invention. In FIG. 4, the power receiving circuit has a main bus B through CB1.
The generator circuit is connected to the middle of the power receiving circuit via CB2, and the power receiving circuit and the generator circuit are connected in parallel to form a main circuit. The current transformer CT3 is installed in the main circuit,
CT3 is connected to AQR or APFR. The generator circuit is provided with CT4, and the output of this CT4 is supplied to AQR or APFR. When configured as shown in FIG.
Since the reactive component of the loads L1 and L2 or the power factor of the load is detected by CT3 and supplied to AQR or APFR, the same control as that of the fourth embodiment can be performed.

[0029]

As described above, according to the present invention,
Since the current transformer is provided in the power receiving circuit and the generator circuit to detect and compensate the power factor or reactive component of the load, the following effects can be obtained.

(1) Adjusting the power factor of the load and the overcurrent by using the current detected by the current transformer in the power receiving circuit and the generator circuit as a combined current, simplifying the circuit, and configuring the switchboard. Can be simplified.

(2) Since the automatic control of the power capacitor is added to the generator circuit, the operating efficiency of the generator can be improved.
This is done by using a reactive current equal to or more than that of a single power capacitor, but if this is set relatively small, the load power factor itself can be improved by the power capacitor before the operating power factor of the generator deteriorates.

(3) The operation of the generator can be stopped within the possible curve of the generator. It can be set so that the capacity of making and disconnecting the capacitor is performed within the possible curve.

(4) All the above adjustments are automatically performed by using the automatic reactive power adjusting device 55G.

(5) Since the detection point is a load current, unless the load is applied, there is no great change and the current does not become extremely small unlike the power receiving point, so that accurate detection can be performed.

(6) Regardless of the magnitude of the current in the power receiving unit and the direction of the power flow in the power receiving unit, the reactive component or power factor control can be continuously performed by using one controller.

(7) Since the direction of the tidal current does not change, a unidirectional control device can be used.

(8) The reactive power adjustment capability of the entire system is improved.

[Brief description of drawings]

FIG. 1 is a single wire connection diagram showing an embodiment of the first invention.

FIG. 2 is a single wire connection diagram showing an embodiment of the second invention.

FIG. 3 is a single wire connection diagram showing an embodiment of the third invention.

FIG. 4 is a single wire connection diagram showing an embodiment of the fourth invention.

FIG. 5 is a single wire connection diagram showing another embodiment of the fourth invention.

FIG. 6 is a connection diagram in which current transformers are directly connected in parallel.

FIG. 7 is a connection diagram when an auxiliary current transformer is used.

FIG. 8 is a single-line connection diagram showing a conventional example.

FIG. 9 is a single line connection diagram showing a conventional example.

FIG. 10 is a single line connection diagram showing a conventional example.

[Explanation of symbols]

 CT1-CT5, CT11, CT12 ... Current transformer CT13 ... Total current transformer CT14, CT15 ... Auxiliary current transformer B ... Main bus SW ... Switchgear C ... Power capacitor 55 ... Automatic power factor regulator 91Q ... Reactive power relay APFR … Power factor control device AQR… Reactive power control device

Claims (4)

[Claims] 1. A device for adjusting reactive power by operating a power receiving circuit and a generator circuit in parallel, wherein a current transformer secondary side of the power receiving circuit and a current transformer secondary side of the generator circuit are connected in parallel, A reactive power adjusting device characterized in that a combined current is generated from both current transformers, and the power factor and reactive power of a load are adjusted by this current. 2. A power receiving circuit and a generator circuit are connected in parallel and then connected to a main circuit, first and second current transformers are provided in the power receiving circuit and the generator circuit, and a third current transformer is provided in the main circuit. And an automatic reactive power adjusting device is provided on the secondary side of the first and second current transformers to supply its output and the output of the third current transformer to the reactive power or the power factor control device, The secondary output voltage of the transformer connected to the main circuit is given to the reactive power or the power factor control device, and the automatic power regulator of the generator is controlled by the reactive power or the output of the power factor control device and the automatic reactive power is controlled. A reactive power adjusting device characterized in that the number of thrown power factor improving power capacitors is controlled by the output of the power adjusting device. 3. A power receiving circuit and a generator circuit are connected to a main circuit for parallel operation, and a current transformer is provided in each of the power receiving circuit and the generator circuit, and automatic reactive power adjustment is provided on the secondary side of the current transformer. A device is provided and the output of the adjusting device is supplied to the total current transformer to generate a combined current, and the combined current is supplied to the reactive power or the power factor control device and the transformer connected to the main circuit to the control device. A secondary output voltage of the generator and a current detected by a current transformer different from the current transformer provided in the generator circuit are supplied, and an automatic voltage regulator for the generator is generated by the reactive power or the output of the power factor controller. And controlling the number of power factor correction power capacitors to be turned on by the output of the automatic reactive power adjustment device. 4. A power receiving circuit and a generator circuit are connected to a main circuit for parallel operation, and a current transformer is provided in each of the power receiving circuit and the generator circuit to supply the output of the current transformer to the total current transformer. Generating a combined current, supplying the combined current to the reactive power or the power factor control device, and the secondary output voltage of the transformer connected to the main circuit to the control device and the current transformer provided in the generator circuit. A reactive power adjusting device characterized in that a current detected by a current transformer different from the above is supplied to control the automatic voltage adjusting device of the generator by the reactive power or the output of the power factor control device.