JP2001045663A - Series compensating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance tidal current control and system stability of a power system by compensating for line reactance voltage, regardless of the behavior of other phases. SOLUTION: This compensating device is provided with a transformer 6, formed by serial-connecting a primary winding to an AC system so as to apply the output voltage to the AC system, where a capacitor 7 is connected to the AC system in series, and the capacitor 7 and a secondary winding of the series transformer 6 are connected in parallel via a tap switching transformer 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a series compensator provided with a series transformer having a primary winding connected in series to an AC system so as to apply an output voltage to the AC system. The present invention relates to a series compensator capable of compensating a line reactance voltage irrespective of the movement of another phase.

[0002]

2. Description of the Related Art FIG. 28 is a circuit diagram showing a configuration example of a phase transformer as a conventional series compensator of this kind.

In FIG. 28, reference numeral 1 denotes a power transmission side voltage Vs;
Is the receiving side voltage Vr, 3 is the AC transmission line, 4 is the AC transmission line 3
, And constitute an AC system (three-phase AC system in the figure).

Further, a primary winding of a series transformer 6 is connected in series to the AC system so that an output voltage is applied to the AC system, and a secondary winding of the series transformer 6 is connected to a tap switching transformer. It is connected to an AC system via a vessel 5.

FIG. 29 shows a voltage vector of the phase transformer.

In FIG. 29, Va is a power transmitting side voltage of the series transformer 6, Vb is a power receiving side voltage of the series transformer 6, and Vo is a compensation voltage applied to the AC system by the series transformer 6.

[0007] The tap switching transformer 5 applies two other inter-phase voltages (a voltage having a phase difference of about 90 degrees) to the primary winding and switches the taps of the transformer. Adjust the magnitude of the voltage generated in the next winding. Then, the voltage adjusted by the tap switching is output from the secondary winding of the series transformer 6 to the primary winding, and the voltage is applied in series to the AC system.

FIG. 30 shows a voltage vector at the time of the line reactance 4 compensation operation.

In FIG. 30, VL is a line reactance voltage. By adjusting the tap of the tap switching transformer 5 and outputting the output voltage Vo from the series transformer 6 to the AC system, the line reactance voltage is compensated, and the same effect as when the system impedance X changes is obtained. can get.

Here, since the transmission power P can be expressed by P = (Vs.Vr.sin .theta.) / X, the system impedance X
Can be adjusted, the power flow of the power system can be controlled, and the power system can be operated stably.

[0011]

However, in the conventional series compensator, in the three-phase AC system, the connection of the tap switching transformer 5 causes the compensation voltage phase (the voltage having a phase difference of approximately 90 degrees) to the compensation target phase. ) Is obtained from the other two-phase voltages.

From this, when one of the three phases loses its voltage due to, for example, a system fault, the series compensation operation is performed even if the remaining two phases are sound. It becomes impossible to compensate the reactance voltage.

An object of the present invention is to provide a series compensator capable of compensating for a line reactance voltage irrespective of the movement of other phases, thereby controlling the power flow of an AC system and improving the system stability. .

[0014]

In order to achieve the above object, according to the first aspect of the present invention, a primary winding is connected in series to an AC system so as to apply an output voltage to the AC system. In a series compensator including a transformer, a capacitor is connected in series to an AC system, and the capacitor and a secondary winding of the transformer are connected in parallel via a tap switching transformer.

Therefore, in the series compensator according to the first aspect of the present invention, the capacitor connected in series to the AC system and the secondary winding of the transformer are connected in parallel via the tap switching transformer. The compensation voltage can be changed by switching the taps of the tap switching transformer.
As a result, even when the voltage of the other phase is missing, a compensation voltage can be obtained in the phase to be compensated, that is, the line reactance voltage can be compensated regardless of the movement of the other phase. In addition, it is possible to improve the power flow control and the power fluctuation suppression (system stability) of the AC system, and to improve the power transmission capacity.

According to a second aspect of the present invention, there is provided a series compensator including a transformer having a primary winding connected in series to an AC system so as to apply an output voltage to the AC system. , Connect a capacitor in series with the AC system,
The capacitor and the secondary winding of the transformer are connected in parallel, and the transformer is used as a tap switching transformer.

Therefore, in the series compensator according to the second aspect of the present invention, the capacitor connected in series to the AC system and the secondary winding of the transformer are connected in parallel, and the transformer is connected to the tap switching transformer. By doing so, it is possible to make the compensation voltage variable by switching the tap of the transformer.
As a result, in addition to having the same effect as that of the first aspect of the present invention, the tap switching transformer in the first aspect of the present invention can be omitted. This is particularly advantageous when it is not necessary or when the output voltage of the transformer is small and the voltage burden on the tap is small.

According to a third aspect of the present invention, in the series compensator of the first aspect, a polarity switching circuit is inserted between the secondary winding of the transformer and the secondary winding of the tap switching transformer. The current direction and the voltage direction of the secondary winding of the transformer and the secondary winding of the tap switching transformer are reversed.

Therefore, in the series compensator according to the third aspect of the present invention, a polarity switching circuit is inserted between the secondary winding of the transformer and the secondary winding of the tap switching transformer, and the secondary winding of the transformer is formed. By reversing the direction of the current and the direction of the voltage of the line and the secondary winding of the tap switching transformer, the selection range of the output voltage is widened, and the output voltage can be adjusted over a wider range.

On the other hand, according to a fourth aspect of the present invention, there is provided a series compensator including a transformer having a primary winding connected in series to an AC system so as to apply an output voltage to the AC system. A series of capacitors each having a switch connected in parallel are connected in series with the AC system, and a group of capacitors and the secondary winding of the transformer are connected in parallel.

Therefore, in the series compensator according to the fourth aspect of the present invention, a series of a plurality of capacitors each having a switch connected in parallel is connected in series with the AC system. By connecting and closing the switch in parallel with the secondary winding of the transformer, the capacitance of the capacitor group changes, and the voltage across the capacitor group and the voltage of the transformer connected in parallel to the capacitor group The output voltage of the compensator changes to achieve compensation voltage adjustment.

According to the fifth aspect of the present invention, the fourth aspect is provided.
In the series compensator of the invention, the capacitor group is connected via a second transformer having a primary winding connected in series to the AC system.

Therefore, in the series compensator according to the fifth aspect of the present invention, by connecting the capacitor group via the second transformer whose primary winding is connected in series to the AC system, the capacitor and the switch are connected. This is particularly advantageous in terms of withstand voltage and insulation.

According to a sixth aspect of the present invention, there is provided a series compensator including a transformer having a primary winding connected in series to an AC system so as to apply an output voltage to the AC system. , Connect a capacitor in series with the AC system,
The capacitor and the secondary winding of the transformer are connected in parallel, and the compensation voltage generator is connected to the secondary side of the transformer.

Therefore, in the series compensator of the invention, the capacitor connected in series to the AC system and the secondary winding of the transformer are connected in parallel, and a compensation voltage is generated on the secondary side of the transformer. By connecting the device, variable voltage adjustment becomes possible, and a wide range of compensation can be performed continuously. Further, since a high-speed compensation voltage can be realized, the control performance is improved to several stages.

According to the seventh aspect of the present invention, in the sixth aspect,
In the series compensator of the invention, the capacitor is connected via a second transformer whose primary winding is connected in series to the AC system.

Therefore, in the series compensator according to the seventh aspect of the present invention, the capacitor is connected through the second transformer whose primary winding is connected in series to the AC system.
Capacitors and tap-changing transformers can be isolated from the AC system. Further, since the voltage applied to the capacitor and the tap switching transformer can be reduced by the turns ratio of the transformer and the second transformer, it is particularly advantageous when introducing the transformer into a high-voltage system.

On the other hand, according to the invention of claim 8, there is provided a series compensator comprising a transformer having a primary winding connected in series to an AC system so as to apply an output voltage to the AC system. , Connect a capacitor in series with the AC system,
This capacitor and the secondary winding of the transformer are connected in parallel, and a compensation current generator is connected to the secondary side of the transformer.

Therefore, in the series compensator according to the present invention, the capacitor connected in series to the AC system and the secondary winding of the transformer are connected in parallel, and the compensation current is connected to the secondary side of the transformer. By connecting the generator, the current is output to the capacitor by the compensation current generator, so that the capacitor voltage can output a voltage of any magnitude and phase. And since this capacitor voltage is output as a voltage from the primary winding of the transformer via the secondary winding of the transformer, any magnitude can be used as the compensation voltage of the series compensator,
The phase voltage can be output.

[0030] According to the ninth aspect of the present invention, the above-mentioned eighth aspect is provided.
In the series compensator of the invention, the capacitor is connected via a second transformer whose primary winding is connected in series to the AC system.

Therefore, in the series compensator according to the ninth aspect of the present invention, the capacitor is connected through the second transformer having the primary winding connected in series to the AC system.
Capacitors and tap-changing transformers can be isolated from the AC system.

Further, since the voltage applied to the capacitor and the tap switching transformer can be reduced by the turns ratio of the transformer and the second transformer, it is particularly advantageous when the transformer is introduced into a high voltage system.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 is a basic circuit diagram showing a configuration example of a series compensator according to the present embodiment, and the same elements as those in FIG. Is shown.

In FIG. 1, reference numeral 1 denotes a power transmitting side voltage Vs, 2 denotes a power receiving side voltage Vr, 3 denotes an AC power transmission line, and 4 denotes a line reactance L of the AC power transmission line 3, and these constitute an AC system.

On the other hand, a transformer 6 having a primary winding connected in series to the AC system is provided so as to apply the output voltage to the AC system.

A capacitor 7 is connected in series with the AC system.

Further, the capacitor 7 is connected to the primary winding of the tap switching transformer 5, and the secondary winding of the tap switching transformer 5 is connected to the secondary winding of the transformer 6.

That is, the capacitor 7 and the secondary winding of the transformer 6 are connected in parallel via the tap switching transformer 5 and the taps of the tap switching transformer 5 are switched so that the output voltage of the transformer 6 is changed. It is configured to adjust Vo.

In FIG. 1, for the sake of simplicity, the case where the capacitor 7 is constituted by one capacitor has been described. However, the present invention is not limited to this. A capacitor in which two capacitors are connected in series and parallel may be used.

Next, the operation of the series compensator according to the present embodiment configured as described above will be described with reference to FIGS.

FIG. 2 is a diagram showing the movement of the voltage and current when the turns ratio of the tap switching transformer 5 is 1: 1.

In FIG. 2, if the system current is Is,
Is flows through the path of Vs → capacitor 7 → transformer 6 → Vr.

Here, the capacitance of the capacitor 7 is C, the turns ratio of the tap switching transformer 5 is 1: 1 and the transformer 6 is
Is 1: 1, the system current Is flows through the primary winding of the transformer 6, so that the secondary winding of the transformer 6 and the secondary winding of the tap switching transformer 5 also have a current. Is flows.

Since the turns ratio of the tap switching transformer 5 is 1: 1, the current Is also flows through the primary winding of the tap switching transformer 5, and as a result, twice the current Is flows through the capacitor 7.

Assuming that the capacitor voltage when the current Is flows through the capacitor 7 having the capacitance C is VIs, a compensation voltage of 2 VIs is generated in the capacitor voltage Vc at this time. Since the compensation voltage of the capacitor voltage is output from the primary winding of the transformer 6 via the tap switching transformer 5, the output voltage VL of the transformer 6 becomes 2
VIs, and the compensation voltage Vo output from the series compensator.
Is 4 VIs.

FIG. 3 is a diagram showing the movement of the voltage and current when the turns ratio of the tap switching transformer 5 is 1: 0.5.

In FIG. 3, the compensation voltage Vo output from the series compensator becomes 2.25 VIs, and the compensation voltage can be made variable by switching the taps of the tap switching transformer 5.

As a result, even when the voltage of the other phase is lost, a compensation voltage can be obtained in the phase to be compensated. By controlling this compensation voltage, power flow control and power fluctuation suppression of the AC system (system stability) Can be improved, and the power transmission capacity can be improved.

As described above, in the series compensator of the present embodiment, the capacitor 7 connected in series to the AC system and the secondary winding of the transformer 6 are connected in parallel via the tap switching transformer 5. The compensation voltage can be made variable by switching the taps of the tap switching transformer 5.

As a result, even when the voltage of another phase is lost, a compensation voltage can be obtained in the phase to be compensated, that is, the line reactance voltage can be compensated regardless of the movement of the other phase. By doing so, it is possible to improve the power flow control and the power fluctuation suppression (system stability) of the AC system, and it is possible to realize the improvement of the power transmission capacity.

(Second Embodiment) FIG. 4 is a circuit diagram showing a configuration example of a series compensator according to the present embodiment. The same elements as those in FIG. And
Here, only different parts will be described.

In FIG. 4, a capacitor 7 is connected in series to an AC system, this capacitor and a secondary winding of a transformer 6 are connected in parallel, and the transformer 6 is used as a tap-switching transformer. The tap switching transformer 5 is omitted by providing the tap switching function to the unit 6.

In the series compensator of the present embodiment configured as described above, the capacitor 7 connected in series to the AC system and the secondary winding of the transformer 6 are connected in parallel, and the transformer 6 is connected By using the tap switching transformer, it is possible to change the compensation voltage by switching the taps of the transformer 6.

Thus, the same operation and effect as in the first embodiment can be obtained, and in addition, since the tap switching transformer 5 can be omitted, the system voltage can be reduced in a low-voltage system. This method is particularly advantageous when no measures regarding electrical insulation are required or when the output voltage of the transformer 6 is small and the voltage load on the tap is small.

(Third Embodiment) FIG. 5 is a circuit diagram showing a configuration example of a series compensator according to the present embodiment. The same elements as those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted. And
Here, only different parts will be described.

That is, as shown in FIG. 5, the series compensator of this embodiment has a configuration in which the capacitor 7 in FIG. 1 is connected via the second transformer 8.

In the series compensator of this embodiment configured as described above, the capacitor 7 is connected to the second transformer 8
, It is possible to insulate the capacitor 7 and the tap switching transformer 5 from the AC system.

Further, since the voltage applied to the capacitor 7 and the tap switching transformer 5 can be reduced by the turns ratio of the transformer 6 and the second transformer 8, particularly when the transformer is introduced into a high-voltage system. This method is advantageous.

(Fourth Embodiment) FIG. 6 is a circuit diagram showing a configuration example of a series compensator according to the present embodiment. The same elements as those in FIGS. 1 to 5 are denoted by the same reference numerals. The description will be omitted, and only different portions will be described here.

That is, as shown in FIG. 6, the series compensator of the present embodiment comprises a secondary winding of the transformer 6 and a secondary winding of the tap switching transformer 5 in any of FIGS. Between the secondary winding of the transformer 6 and the secondary winding of the tap switching transformer 5, the current direction and the voltage direction are reversed (reversed).

FIG. 7 is a circuit diagram showing a configuration example of the polarity switching circuit 9.

As shown in FIG. 7, the polarity switching circuit 9
It is configured as shown using two changeover switches SW1 and SW2.

The polarity switching circuit 9 may be constituted by using a semiconductor switch made of a semiconductor instead of the changeover switches SW1 and SW2.

In the series compensator of the present embodiment configured as described above, the polarity switching circuit 9 is inserted between the secondary winding of the transformer 6 and the secondary winding of the tap switching transformer 5, By inverting the current direction and the voltage direction of the secondary winding of the transformer 6 and the secondary winding of the tap switching transformer 5, the selection range of the output voltage is widened, and the output voltage is wider. Output voltage adjustment can be realized.

FIG. 8 is the same as the transformer turns ratio and tap set values shown in FIG. 3 above, the turns ratio of the tap switching transformer 5 is 1: 0.5, and the polarity is inverted by the polarity switching circuit 9. FIG. 7 is a diagram showing the movement of voltage and current at the time.

In FIG. 8, when the polarity is inverted by the polarity inverting circuit 9, a current of 0.5Is flows through the primary winding of the tap switching transformer 5 in a direction to decrease the voltage Vc of the capacitor 7.

As a result, the current flowing through the capacitor 7 becomes smaller than the system current, and the capacitor voltage Vc is set to 0.1.
5 VIs. Then, this voltage is reduced to 0.25 VIs by the tap switching transformer 5 and output in the opposite phase from the primary winding of the transformer 6 by the polarity inverting circuit 9, so that the compensation voltage Vo of the present series compensator becomes 0. .25V
becomes c.

As described above, by using the polarity inversion circuit 9, the selection range of the output voltage is widened, and the output voltage can be adjusted over a wider range.

(Fifth Embodiment) FIG. 9 is a circuit diagram showing a configuration example of a series compensator according to the present embodiment. The same elements as those in FIG. Here, only the different parts will be described.

In FIG. 9, a plurality of (three in the figure) capacitors each having a switch 11 connected in parallel are connected in series to form a capacitor group 10. The capacitor group 10 is connected in series to an AC system. Further, the capacitor group 10 and the secondary winding of the transformer 6 are connected in parallel, and the switch 11 is closed or opened to change the capacitance of the capacitor group 10.

In FIG. 9, for the sake of simplicity, the case where the number of capacitors connected in series is three is described. However, the present invention is not limited to this. A configuration in which a number of capacitors are connected in series may be adopted.

In the series compensator of this embodiment configured as described above, a capacitor group 10 formed by connecting a plurality of capacitors each having a switch 11 connected in parallel is connected in series with the AC system. By connecting the capacitor group 10 and the secondary winding of the transformer 6 in parallel, by closing or opening the switch 11, the capacitance of the capacitor group 10 changes. The voltage Vc at both ends and the output voltage VL of the transformer 6 connected in parallel to the capacitor group 10 change, so that it is possible to realize the compensation voltage adjustment.

(Sixth Embodiment) FIG. 10 is a circuit diagram showing a configuration example of a series compensator according to the present embodiment.
The same elements as those in FIG. 9 are denoted by the same reference numerals, and description thereof will be omitted. Only different parts will be described here.

That is, as shown in FIG. 10, the series compensator of the present embodiment uses the switch 11 shown in FIG.
Are constituted by semiconductor switches 12 in which thyristors are connected in antiparallel.

In the series compensator of the present embodiment configured as described above, the switch 11 for changing the capacitance of the capacitor group 10 is constituted by a semiconductor switch in which thyristors are connected in antiparallel. As a result, the number of capacitors to be turned on can be switched at high speed by the thyristor, so that compensation control can be performed at higher speed.

(Seventh Embodiment) FIG. 11 is a circuit diagram showing a configuration example of a series compensator according to the present embodiment.
The same elements as those in FIGS. 9 and 10 are denoted by the same reference numerals, and description thereof will be omitted. Here, only different parts will be described.

That is, as shown in FIG. 6, the series compensator according to the present embodiment includes a capacitor group 10 shown in FIG. 9 or 10 and a second transformer having a primary winding connected in series to an AC system. 8.

In the series compensator of this embodiment configured as described above, the capacitor group 10 is connected via the second transformer 8 whose primary winding is connected in series to the AC system. This is particularly advantageous in terms of withstand voltage and insulation between the capacitor and the switch.

(Eighth Embodiment) FIG. 12 is a circuit diagram showing a configuration example of a series compensator according to the present embodiment.
The same elements as those in FIG. 28 are denoted by the same reference numerals, and the description thereof will be omitted. Only different parts will be described here.

In FIG. 12, a capacitor 7 connected in series to an AC system and a secondary winding of a transformer 6 are connected in parallel, and a compensation is made in parallel with this connection point, that is, on the secondary side of the transformer 6. The configuration is such that the voltage generation circuit 13 is connected.

In the series compensator of the present embodiment configured as described above, the capacitor 7 connected in series to the AC system and the secondary winding of the transformer 6 are connected in parallel, and the Since the compensation voltage generating circuit 13 is connected to the next side, variable voltage adjustment becomes possible, and wide-range compensation can be performed continuously. Further, since a high-speed compensation voltage can be realized, the control performance is improved to several stages.

That is, the compensation voltage Vo of the present series compensator can output a voltage of any magnitude and phase by the compensation voltage generating circuit 13, but the compensation voltage Vo is delayed by 90 degrees with respect to the system current Is. By using the phase voltage, a compensation voltage equivalent to the capacitor 7 can be output.

In the above-described system using the tap switching transformer and the system in which the number of connected capacitors is switched, a compensating voltage value that can be output is determined by the number of taps and the number of capacitors, and the compensation is performed stepwise. On the other hand, by using the compensation voltage generation circuit 13, variable voltage adjustment becomes possible, and a wide range of compensation amount can be continuously performed. In addition, a high-speed compensation voltage can be realized, and the control performance is improved several stages.

(Ninth Embodiment) FIG. 13 is a circuit diagram showing a configuration example of a series compensator according to the present embodiment.
The same elements as those in FIG. 12 are denoted by the same reference numerals, and description thereof will be omitted. Only different parts will be described here.

That is, as shown in FIG. 13, the series compensator of this embodiment
A switch 14 is connected between the switch and the compensation voltage generating circuit 13.

In the series compensator of the present embodiment configured as described above, since the switch 14 is connected between the capacitor 7 and the compensation voltage generating circuit 13,
When the switch 14 is opened, the capacitor 7 is separated from the transformer 6 and the compensation voltage generation circuit 13, so that when the capacitor 7 and the compensation voltage generation circuit 13 are stopped for maintenance or other reasons, they are operated as different devices. It is possible to do.

(Tenth Embodiment) FIG. 14 is a circuit diagram showing a configuration example of a series compensator according to the present embodiment. The same elements as those in FIGS. 12 and 13 are designated by the same reference numerals. The description will be omitted, and only different portions will be described here.

That is, as shown in FIG. 14, the series compensator of the present embodiment replaces the capacitor 7 shown in FIG. 12 or 13 with a second transformer 8 having a primary winding connected in series to an AC system. It is configured to be connected via a.

In the series compensator of the present embodiment configured as described above, the capacitor 7 is connected via the second transformer 8 whose primary winding is connected in series to the AC system. Thereby, the capacitor 7 and the tap switching transformer 5 can be insulated from the AC system.

Further, since the voltage applied to the capacitor 7 and the tap switching transformer 5 can be reduced by the turns ratio of the transformer 6 and the second transformer 8, the present system is particularly suitable for introduction into a high voltage system. Is advantageous.

(Eleventh Embodiment) FIG. 15 is a circuit diagram showing a configuration example of a series compensator according to the present embodiment. The same elements as those in FIG. 28 are denoted by the same reference numerals and description thereof is omitted. Here, only the different parts will be described.

In FIG. 15, the capacitor 7 connected in series to the AC system and the secondary winding of the transformer 6 are connected in parallel, and the compensation is made in parallel with this connection point, that is, on the secondary side of the transformer 6. The configuration is such that the current generation circuit 15 is connected.

In the series compensator of the present embodiment configured as described above, the capacitor 7 connected in series to the AC system and the secondary winding of the transformer 6 are connected in parallel, and the Since the compensating current generating circuit 15 is connected to the next side, the current is output to the capacitor 7 by the compensating current generating circuit 15, so that the capacitor voltage Vc can output a voltage of any magnitude and phase. Since the capacitor voltage Vc is output as a voltage from the primary winding of the transformer 6 via the secondary winding of the transformer 6, the compensation voltage Vo of the present series compensator has an arbitrary magnitude and phase. It is possible to output a voltage.

That is, by making the output current of the compensation current generating circuit 15 the same phase as the system current Is, it is possible to output the compensation voltage Vo as a variable capacitor.

(Twelfth Embodiment) FIG. 16 is a circuit diagram showing a configuration example of a series compensator according to the present embodiment. The same elements as those in FIG. Here, only the different parts will be described.

That is, as shown in FIG. 16, the series compensator of this embodiment
Are connected via a second transformer 8 whose primary winding is connected in series to the AC system.

In the series compensator of the present embodiment configured as described above, the capacitor 7 is connected via the second transformer 8 whose primary winding is connected in series to the AC system. Thereby, the capacitor 7 and the tap switching transformer 5 can be insulated from the AC system.

Further, the voltage applied to the capacitor 7 and the tap-changing transformer 5 can be reduced by the turns ratio of the transformer 6 and the second transformer 8, so that this system is particularly suitable for the case where the transformer is introduced into a high-voltage system. Is advantageous.

(Thirteenth Embodiment) FIG. 17 is a circuit diagram showing a configuration example of a series compensator according to the present embodiment. The same elements as those in FIGS. The description will be omitted, and only different portions will be described here.

That is, in the series compensator of the present embodiment, as shown in FIG. 17, the compensation voltage generating circuit 13 in any of FIGS. 12 to 14 is replaced with a self-extinguishing element (for example, using a GTO) 16. A reverse conducting diode 17 connected in parallel with the self-extinguishing element 16;
8 and an interconnection reactor 19 for interconnection, and is constituted by a voltage source converter in which the self-extinguishing element 16 is bridge-connected.

The self-extinguishing element (GT) of the voltage source converter
O) A PWM control circuit 20 for generating a 16 switching pattern is provided, and a PWM pattern corresponding to the voltage command value Vinv ^* is generated to drive the self-extinguishing element (GTO) 16.

The interconnection reactor 19 may be installed as an independent reactor, or may be substituted by designing the transformer to have a large leakage reactance.

In the series compensator of the present embodiment configured as described above, the compensation voltage generating circuit 13 is constituted by a voltage source converter using the self-extinguishing element 16, so that a high-speed response is achieved. In addition to this, it is possible to simplify the configuration and reduce the cost.

(Fourteenth Embodiment) FIG. 18 is a circuit diagram showing a configuration example of a series compensator according to the present embodiment. The same elements as those in FIGS. 15 and 16 are designated by the same reference numerals. The description will be omitted, and only different portions will be described here.

That is, as shown in FIG. 18, the series compensator of the present embodiment replaces the compensation current generating circuit 15 in FIG. 15 or FIG.
) And a DC current source 21, and is constituted by a current source converter in which the self-extinguishing element 16 is bridge-connected.

The self-extinguishing element (GT) of the current source converter
O) A PWM control circuit 20 for generating a switching pattern of 16 is provided, and a PWM pattern corresponding to the current command value Iinv ^* is generated to drive the self-extinguishing element (GTO) 16.

In the series compensator according to the present embodiment configured as described above, the compensation current generating circuit 15 is constituted by a current source converter using the self-extinguishing element 16, so that a high-speed response is achieved. In addition to this, it is possible to simplify the configuration and reduce the cost.

(Fifteenth Embodiment) FIG. 19 is a circuit diagram showing a configuration example of a series compensator according to the present embodiment. In FIG. 19, the same elements as those in FIGS. The description will be omitted, and only different portions will be described here.

That is, as shown in FIG. 19, the series compensator of the present embodiment replaces the compensation current generating circuit 15 shown in FIG. 15 or 16 with a self-extinguishing element (for example, GTO).
), A reverse conducting diode 17 connected in parallel with the self-extinguishing element, a DC voltage source 18, and an interconnection reactor 19 for interconnection.
Is a bridge-connected voltage source converter.

The self-extinguishing element (GT) of the voltage source converter
O) A PWM control circuit 20 for generating the 16 switching patterns and a current control circuit 22 for controlling the output current Iinv of the compensation current generation circuit 15 are provided to detect the output current Iinv and to respond to the current command value Iinv ^* . Output current.

The interconnection reactor 19 may be installed as an independent reactor, or may be substituted by designing the leakage reactance of the transformer to be large. In the series compensator of the present embodiment configured as described above, the compensation voltage generating circuit 15
6 and a current control circuit 22 for controlling the output current of the voltage source converter, thereby enabling a high-speed response, simplification of the configuration and low cost. Can be achieved.

(Sixteenth Embodiment) FIG. 20 is a circuit diagram showing a configuration example in which any one of the series compensators shown in FIGS. 1 to 19 is applied to a single-phase AC system as an AC system.

In FIG. 20, the electric power generated by the generator 23 is transferred from the three-phase AC system 24 through the single-phase AC system 25,
It is sent to the customer 26.

In the present embodiment configured as described above, the present series compensator is applied to a single-phase AC transmission line, that is, by using an AC system as a single-phase AC system, the stability of the single-phase AC transmission line is improved. Can be improved.

Further, when the present invention is applied to a single-phase loop system as shown in the figure, it becomes possible to control the power flow. For example, when a strong system and a weak system are connected in parallel, the current is controlled by the strong system. And it is possible to improve the operation efficiency of transmission lines,
This method is particularly advantageous when the distribution system is a target.

(Seventeenth Embodiment) FIG. 21 is a circuit diagram showing a configuration example in which any one of the series compensators shown in FIGS. 1 to 19 is applied to a single-phase AC system as an AC system.

In FIG. 21, electric power generated by the generator 23 is transferred from the three-phase AC system 24 through the single-phase AC system 25,
It is sent to the customer 26.

In the present embodiment configured as described above, the present series compensator is applied to the three-phase AC transmission line, that is, since the AC system is a three-phase AC system, the stability of the three-phase AC transmission line is improved. Can be improved.

In the case of a long-distance AC system in which the distance from the generator 22 to the bus 27 is relatively long, the electrical distance can be shortened by compensating for the line reactance, and large electric power can be supplied over a long distance. It is possible to expect the effect of improving the power transmission capacity, such as sending power to

Further, when the present invention is applied to a three-phase loop system, it is possible to control the power flow. For example, when a strong system and a weak system are connected in parallel, the current is shared by the strong system. This makes it possible to improve the operation efficiency of the transmission line, and this method is particularly advantageous when the power system is a target.

(Eighteenth Embodiment) FIG. 22 is a circuit diagram showing a configuration example of a series compensator according to the present embodiment. The same elements as those in FIGS. The description will be omitted, and only different portions will be described here.

That is, in the series compensator of the present embodiment, as shown in FIG. 22, the compensation voltage generating circuit 13 in any of FIGS. 12 to 14 is replaced with a self-extinguishing element (for example, using GTO) 16. A reverse conducting diode 17 connected in parallel with the self-extinguishing element 16;
8 and a connection reactor 19 for connection, and is constituted by a voltage-source converter in which the self-extinguishing element 16 is connected in a three-phase bridge.

The output side of the compensation voltage generating circuit 13 is
It is connected to the secondary winding of the transformer 6 and the capacitor 7 via the transformer 28.

Further, the self-extinguishing element (G
TO) 16 is provided with a PWM control circuit 20 for generating a switching pattern, and a PWM corresponding to a voltage command value Vinv ^* is provided.
A pattern is generated to drive the self-extinguishing element (GTO) 16.

The interconnection reactor 19 may be installed as an independent reactor, or may be substituted by designing the transformer 28 with a relatively large leakage reactance.

In the series compensator of this embodiment configured as described above, the voltage-source converter is connected to the self-extinguishing element 1.
6 is connected to a secondary winding of the transformer 6 and a capacitor 7 via a transformer 28, so that the self-extinguishing element 16 constituting the voltage source converter is connected.
(The number of self-extinguishing elements 16 is 4 × 3 phases = 12, half of which is sufficient), and the capacity of the voltage-source converter can be reduced. Becomes possible (1 × 3 times 1 × √ as the capacity of the voltage source converter)
Three times the capacity is sufficient).

(Nineteenth Embodiment) FIG. 23 is a circuit diagram showing a configuration example of a series compensator according to the present embodiment. In FIG. 23, the same elements as those in FIGS. The description will be omitted, and only different portions will be described here.

That is, in the series compensator of this embodiment, as shown in FIG. 23, the compensation voltage generating circuit 13 in any of FIGS. 12 to 14 is replaced with a self-extinguishing element (for example, using GTO) 16. A reverse conducting diode 17 connected in parallel with the self-extinguishing element 16;
8 and an interconnection reactor 19 for interconnection, and is constituted by a voltage-source converter in which the self-extinguishing element 16 is connected in a single-phase bridge for each phase.

The output side of the compensation voltage generating circuit 13 is
It is connected to the secondary winding of the transformer 6 and the capacitor 7 via the transformer 28.

Further, the self-extinguishing element (G
TO) 16 is provided with a PWM control circuit 20 for generating a switching pattern, and a PWM corresponding to a voltage command value Vinv ^* is provided.
A pattern is generated to drive the self-extinguishing element (GTO) 16.

The interconnection reactor 19 may be installed as an independent reactor, or may be substituted by designing the transformer 28 with a relatively large leakage reactance.

In the series compensator of the present embodiment configured as described above, the voltage-source converter is connected to the self-extinguishing element 1.
6 are connected by a single-phase bridge for each phase, and
Is connected to the secondary winding of the transformer 6 and the capacitor 7 through the capacitor, the capacity of the voltage source converter can be reduced (the capacity of the voltage source converter is 1 × 3 times). In addition, since the output voltage of each phase can be controlled independently, the phase to be compensated can be controlled without being affected by the state of the other phase.

(Twentieth Embodiment) FIG. 24 is a circuit diagram showing a configuration example of a series compensator according to the present embodiment. The same elements as those in FIGS. 15 and 16 are designated by the same reference numerals. The description will be omitted, and only different portions will be described here.

That is, as shown in FIG. 24, the series compensator of the present embodiment is configured such that the compensation current generating circuit 15 shown in FIG. 15 or FIG.
) And a DC current source 21, and is constituted by a current-source converter in which the self-extinguishing element 16 is connected in a three-phase bridge.

The output side of the compensation current generating circuit 15 is
It is connected to the secondary winding of the transformer 6 and the capacitor 7 via the transformer 28.

Further, the self-extinguishing element (G
TO) 16 is provided with a PWM control circuit 20 for generating a switching pattern, and a PWM corresponding to a current command value Iinv ^*.
A pattern is generated to drive the self-extinguishing element (GTO) 16.

In the series compensator of the present embodiment configured as described above, the current source converter is connected to the self-extinguishing element 1.
6 is connected to the secondary winding of the transformer 6 and the capacitor 7 via the transformer 28, thereby forming the self-arc-extinguishing element 16 constituting the current source converter.
(The number of self-extinguishing elements 16 is 4 × 3 phases = 12, half of which is sufficient for 6), and the capacity of the current source converter can be reduced. Becomes possible (1 × 3 times 1 × √ as the capacity of the current source converter)
Three times the capacity is sufficient).

(Twenty-First Embodiment) FIG. 25 is a circuit diagram showing a configuration example of a series compensator according to the present embodiment. In FIG. 25, the same elements as those in FIGS. The description will be omitted, and only different portions will be described here.

That is, as shown in FIG. 25, the series compensator of the present embodiment replaces compensation current generating circuit 15 in FIG. 15 or FIG. 16 with a self-extinguishing element (for example, GTO).
) And a DC current source 21, and the current-source converter is configured such that the self-extinguishing element 16 is connected in a single-phase bridge for each phase.

The output side of the compensation current generating circuit 15 is
It is connected to the secondary winding of the transformer 6 and the capacitor 7 via the transformer 28.

Further, the self-extinguishing element (G
TO) 16 is provided with a PWM control circuit 20 for generating a switching pattern, and a PWM corresponding to a current command value Iinv ^*.
A pattern is generated to drive the self-extinguishing element (GTO) 16.

In the series compensator of the present embodiment configured as described above, the current source converter is connected to the self-extinguishing element 1.
6 are connected by a single-phase bridge for each phase, and
Is connected to the secondary winding of the transformer 6 and the capacitor 7 through the capacitor, the capacity of the current source converter can be reduced (the capacity of the current source converter is 1 × 3 times). In addition, the output current of each phase can be controlled independently, and the phase to be compensated can be controlled without being affected by the state of the other phase.

(Twenty-second Embodiment) FIG. 26 is a circuit diagram showing a configuration example of a series compensator according to the present embodiment. In FIG. 26, the same elements as those in FIGS. The description will be omitted, and only different portions will be described here.

That is, as shown in FIG. 26, the series compensator according to the present embodiment uses compensation current generating circuit 15 shown in FIG. 15 or FIG.
), A reverse conducting diode 17 connected in parallel with the self-extinguishing element, a DC voltage source 18, and an interconnection reactor 19 for interconnection.
Is constituted by a voltage source converter connected in a three-phase bridge.

The output side of the compensation current generating circuit 15 is
It is connected to the secondary winding of the transformer 6 and the capacitor 7 via the transformer 28.

Further, the self-extinguishing element (G
TO) 16, a PWM control circuit 20 for generating a switching pattern, and an output current Iinv of the compensation current generation circuit 15.
And a current control circuit 22 for controlling the output current Iinv
And outputs a current corresponding to the current command value Iinv ^* .

The interconnection reactor 19 may be installed as an independent reactor, or may be substituted by designing the transformer 28 with a relatively large leakage reactance.

In the series compensator of the present embodiment configured as described above, the voltage source converter is connected to the self-extinguishing element 1.
6 is connected to a secondary winding of the transformer 6 and a capacitor 7 via a transformer 28, so that the self-extinguishing element 16 constituting the voltage source converter is connected.
(The number of self-extinguishing elements 16 is 4 × 3 phases = 12, half of which is sufficient), and the capacity of the voltage-source converter can be reduced. Becomes possible (1 × 3 times 1 × √ as the capacity of the voltage source converter)
Three times the capacity is sufficient).

(Twenty-third Embodiment) FIG. 27 is a circuit diagram showing a configuration example of a series compensator according to the present embodiment. The same elements as those in FIGS. 15 and 16 are designated by the same reference numerals. The description will be omitted, and only different portions will be described here.

That is, in the series compensator of this embodiment, as shown in FIG. 27, the compensation current generating circuit 15 shown in FIG. 15 or FIG.
), A reverse conducting diode 17 connected in parallel to the self-extinguishing element 16, a DC voltage source 18, and an interconnection reactor 19 for interconnection. It is composed of a voltage type converter connected in a single-phase bridge for each phase.

The output side of the compensation voltage generating circuit 13 is
It is connected to the secondary winding of the transformer 6 and the capacitor 7 via the transformer 28.

Further, the self-extinguishing element (G
TO) 16, a PWM control circuit 20 for generating a switching pattern, and an output current Iinv of the compensation current generation circuit 15.
And a current control circuit 22 for controlling the output current Iinv
And outputs a current corresponding to the current command value Iinv ^* .

The interconnection reactor 19 may be installed as an independent reactor, or may be substituted by designing the transformer 28 with a relatively large leakage reactance.

In the series compensator of this embodiment configured as described above, the voltage-source converter is connected to the self-extinguishing element 1.
6 are connected by a single-phase bridge for each phase, and
Is connected to the secondary winding of the transformer 6 and the capacitor 7 through the capacitor, the capacity of the voltage source converter can be reduced (the capacity of the voltage source converter is 1 × 3 times). In addition, the output current of each phase can be controlled independently, and the phase to be compensated can be controlled without being affected by the state of the other phase.

[0155]

As described above, according to the series compensator of the present invention, the capacitor connected in series to the AC system and the secondary winding of the transformer are connected in parallel via the tap switching transformer. Or the capacitor connected in series with the AC system and the secondary winding of the transformer are connected in parallel, and the transformer is a tap-switching transformer, so regardless of the movement of other phases By compensating for the line reactance voltage,
Power flow control of the power system and improvement of system stability can be achieved.

[Brief description of the drawings]

FIG. 1 is a basic circuit diagram showing a first embodiment of a series compensator according to the present invention.

FIG. 2 is a view for explaining voltage and current when the turns ratio of the tap switching transformer is 1: 1 in the series compensator of the first embodiment.

FIG. 3 is a diagram for explaining voltage and current when the turns ratio of the tap switching transformer is 1: 0.5 in the series compensator of the first embodiment.

FIG. 4 is a circuit diagram showing a second embodiment of the series compensator according to the present invention.

FIG. 5 is a circuit diagram showing a third embodiment of the series compensator according to the present invention.

FIG. 6 is a circuit diagram showing a fourth embodiment of the series compensator according to the present invention.

FIG. 7 is a configuration diagram showing an example of a polarity switching circuit in the series compensator of the fourth embodiment.

FIG. 8 is a diagram for explaining voltage / current when the polarity is reversed at a turns ratio of 1: 0.5 of the tap switching transformer in the series compensator of the fourth embodiment.

FIG. 9 is a circuit diagram showing a fifth embodiment of the series compensator according to the present invention.

FIG. 10 is a circuit diagram showing a sixth embodiment of the series compensator according to the present invention.

FIG. 11 is a circuit diagram showing a seventh embodiment of the series compensator according to the present invention.

FIG. 12 is a circuit diagram showing an eighth embodiment of a series compensator according to the present invention.

FIG. 13 is a circuit diagram showing a ninth embodiment of a series compensator according to the present invention.

FIG. 14 is a circuit diagram showing a tenth embodiment of the series compensator according to the present invention.

FIG. 15 is a circuit diagram showing an eleventh embodiment of the series compensator according to the present invention.

FIG. 16 is a circuit diagram showing a twelfth embodiment of the series compensator according to the present invention.

FIG. 17 is a circuit diagram showing a thirteenth embodiment of the series compensator according to the present invention.

FIG. 18 is a circuit diagram showing a fourteenth embodiment of a series compensator according to the present invention.

FIG. 19 is a circuit diagram showing a fifteenth embodiment of the series compensator according to the present invention.

FIG. 20 is a circuit diagram showing a sixteenth embodiment of the series compensator according to the present invention.

FIG. 21 is a circuit diagram showing a seventeenth embodiment of a series compensator according to the present invention.

FIG. 22 is a circuit diagram showing an eighteenth embodiment of the series compensator according to the present invention.

FIG. 23 is a circuit diagram showing a nineteenth embodiment of the series compensator according to the present invention.

FIG. 24 is a circuit diagram showing a twentieth embodiment of the series compensator according to the present invention.

FIG. 25 is a circuit diagram showing a twenty-first embodiment of the series compensator according to the present invention.

FIG. 26 is a circuit diagram showing a twenty-second embodiment of the series compensator according to the present invention.

FIG. 27 is a circuit diagram showing a twenty-third embodiment of the series compensator according to the present invention.

FIG. 28 is a circuit diagram showing a configuration example of a phase transformer which is a conventional series compensation device.

FIG. 29 is a view showing a voltage vector of a phase transformer which is a conventional series compensator.

FIG. 30 is a diagram showing voltage vectors at the time of line reactance compensation by a phase transformer which is a conventional series compensator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Transmission side voltage Vs, 2 ... Reception side voltage Vr, 3 ... AC transmission line, 4 ... Line reactance, 5 ... Tap switching transformer, 6 ... Transformer, 7 ... Capacitor, 8 ... Second transformer, 9 ... Polarity switching circuit, 10 ... Capacitor group, 11 ... Switch, 12 ... Semiconductor switch, 13 ... Compensation voltage generation circuit, 14 ... Switch, 15 ... Compensation current generation circuit, 16 ... Self-extinguishing element, 17 ... Diode, 18 ... DC voltage source, 19: interconnection reactor, 20: PWM control circuit, 21: DC current source, 22: current control circuit, 23: generator, 24: three-phase AC system, 25: single-phase AC system, 26: demand House, 27 ... busbar, 28 ... transformer.

Claims (9)

[Claims] 1. An apparatus for applying an output voltage to an AC system,
In a series compensator comprising a transformer having a primary winding connected in series to the AC system, a capacitor is connected in series to the AC system, and a secondary winding of the capacitor and the transformer is provided. A series compensator characterized in that the series compensator is connected in parallel with a line via a tap switching transformer. 2. Applying an output voltage to an AC system,
In a series compensator including a series transformer having a primary winding connected in series to the AC system, a capacitor is connected in series to the AC system, and a secondary of the capacitor and the transformer is connected. A series compensator wherein a winding is connected in parallel, and the series transformer is configured as a tap switching transformer. 3. The series compensator according to claim 1, wherein a polarity switching circuit is inserted between a secondary winding of the transformer and a secondary winding of the tap switching transformer. A series compensator wherein a current direction and a voltage direction of a secondary winding and a secondary winding of the tap switching transformer are reversed. 4. Applying an output voltage to an AC system,
A series compensator comprising a transformer having a primary winding connected in series to the AC system, wherein a plurality of capacitors each having a switch connected in parallel to the AC system are connected in series. A series compensator comprising: connecting a group of capacitors formed as described above; and connecting the group of capacitors and a secondary winding of the transformer in parallel. 5. The series compensator according to claim 4, wherein the group of capacitors is connected via a second transformer having a primary winding connected in series to the AC system. Series compensator. 6. An apparatus for applying an output voltage to an AC system,
In a series compensator comprising a transformer having a primary winding connected in series to the AC system, a capacitor is connected in series to the AC system, and a secondary winding of the capacitor and the transformer is provided. A series compensator connected to a secondary side of the transformer and a compensation voltage generator connected to a secondary side of the transformer. 7. The series compensator according to claim 6, wherein the capacitor is connected via a second transformer having a primary winding connected in series to the AC system. Compensator. 8. Applying an output voltage to an AC system,
In a series compensator including a transformer having a primary winding connected in series to the AC system, a capacitor is connected in series to the AC system, and a secondary of the capacitor and the series transformer is connected. A series compensator comprising: a winding connected in parallel; and a compensation current generator connected to a secondary side of the transformer. 9. The series compensator according to claim 8, wherein said capacitor is connected via a second transformer having a primary winding connected in series to said AC system. Compensator.