JPH0974681A - Power flow controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To compensate the reactance state of a power system over a wide range by connecting a first winding having at least one Y-connection in series with a second winding which is combined with the first winding and providing a means which compensates the power transmitting state of the power system. SOLUTION: A power flow controller 10 is constituted of a serial compensator 11 which serially compensates a power system by causing a voltage of a leading phase to a line current, a main transformer 12, which adjusts phases, an adjusting transformer 13 which generates a voltage for adjusting the phase of the voltage generated by the transformer 12, and their control circuit 200. The compensator 11 is arranged between a terminal 14a and a neutral point 14 in each phase of Y-connection windings in the transformer 12. Therefore, the serial reactances of transmission lines, transformers, etc., can be compensated by means of the compensation capacitor of the compensator 11 and the transmission capacity of the power system can be increased and the system can be stabilized by the serial compensation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power flow controller connected to a power system and controlling a power flow condition of the power system, and more particularly to a power flow controlling a power flow condition by controlling a series reactance of the power system. Regarding the control device.

[0002]

2. Description of the Related Art As a method for controlling power flow in a power system, US Pat. No. 4,999,565 shown in FIG.
As described in P4,829,229, a method for adjusting the series reactance of the transmission line of the power system, for example, a Japanese patent,
There is a method of using a phase adjuster as disclosed in JP-A-63-15630.

In the method of adjusting the series reactance of the transmission line of the electric power system, the switching devices 314a, 314b, 314 are used.
There is a series compensator that inserts a capacitor in series with the transmission line by inserting the series capacitor 311 into the system at c or separating it from the system. With this configuration, a semiconductor switch 313 formed of a semiconductor element and a reactor 313a are connected in series to control the current flowing through the series capacitor 311 and are connected in parallel to the series capacitor. In order to protect the series capacitor from overvoltage, an overvoltage protection device 312 that bypasses both ends of the series capacitor when a certain voltage or more is applied is also connected in parallel to the series capacitor.

There is also a method of inserting a series compensator into a system through a series transformer, as in US Pat. No. 5,032,738 shown in FIG. The configuration of the series compensator 310 is similar to that of FIG. 30, in which the semiconductor switch 313 and the reactor 313a are connected in series, and the reactance capacitance inserted in the power transmission line is adjusted by turning the semiconductor switch on and off as appropriate.

The phase adjuster is a device for adjusting the phase of the phase voltage by, for example, matching voltages having a phase difference of 90 ° to the phase voltage of the system, and controlling the power flow by this phase adjustment. As the phase adjustment method, there are a method of using a transformer with a tap as a phase adjustment transformer, a method of generating a voltage of an arbitrary phase by a converter, and the like. Also, as a tap switch for a transformer with a tap,
There are a method using a mechanical contact and a method using a switch composed of a semiconductor element such as a thyristor.

Further, in the prior art, in order to compensate for the series reactance component of the power system, when a series capacitor is inserted in series with the power system to increase the transmission capacity of the power system and improve the transient stability, If the series capacitor is simply inserted in series with the power system, the reactance of the system and the series capacitor may cause series resonance. Therefore, as described in JP-A-54-22871, JP-A-54-154057, JP-A-55-92517, etc., a mechanical switch is connected to both ends of a series capacitor and a power system is connected. When there is a possibility that a resonance phenomenon will occur, there is proposed a method of closing a mechanical switch to short-circuit a series capacitor to prevent the resonance phenomenon from occurring in a power system.

However, in the structure in which the charging / discharging circuit of the series capacitor is formed by using the mechanical switch, the resonance phenomenon of the power system cannot be immediately dealt with, and in the worst case,
An abnormal phenomenon called low frequency shaft torsion resonance that resonates with the shaft system of the generator may occur. Therefore, in order to solve such a problem, for example, JP-A-6-261456, IEEE Transaction on Power Delivery, Vol.
As described in No. 3, p. 1460 to 1469 (July, 1993), by connecting a semiconductor switch composed of a thyristor in parallel with a series capacitor and controlling the firing phase of the thyristor, The occurrence of resonance phenomenon is suppressed.

[0008]

In the conventional power flow control device, the ground potential of the entire device is equal to the ground potential of the system in the operating state, and it is necessary to secure the ground insulation for the entire device. Therefore, the series capacitor 311
Heavy objects such as the semiconductor switch 313 and the semiconductor switch 313 must be supported by an insulator such as an insulator. For example, rated voltage 5
An insulation distance of 5 m or more is required for the 00 kV system.
As described above, the conventional technique has a problem in terms of earthquake resistance because the power flow control device, which is a heavy load, is located at a high place.

Further, since maintenance and inspection of the series compensator requires work at a high place, there is always a risk of dropping. Further, the semiconductor switch 313 located in the high voltage portion from the ground potential requires control and signal lines of the semiconductor switch, a power supply line, wiring such as a pipe for a semiconductor element cooling medium, and piping, and insulation is required for all of them. You have to secure it.

In the case of a power flow controller that controls a power flow using a phase adjuster, since the series reactance of the system increases because the series transformer is connected to the system, the transmission capacity decreases and the stability of the system decreases. It is accompanied by side effects such as decrease.
Particularly in a system with a relatively long total length or poor transient stability, the phase adjuster may be used to limit the transmission capacity. Further, there is a problem that the phase adjustment function alone has little effect of increasing the transmission capacity of the system and little effect of improving the transient stability.

Therefore, in the power flow controller of the present invention, the semiconductor switch 3 having a maintenance and inspection frequency higher than the maintenance and inspection frequency of the passive elements such as the series capacitor 311.
13 is to provide at least this semiconductor switch unit with a system potential lower than or equal to the ground potential of the system, and to provide a device configuration with which maintenance and inspection can be easily performed. Another object of the present invention is to provide a device configuration including a series capacitor, which has excellent earthquake resistance and is easy to maintain and inspect. Another object of the present invention is to provide a power flow control device that can control the power flow by solving the problem of increasing the reactance of the system even when performing the power flow control using the phase adjuster.

Further, in the conventional power flow controller, when the semiconductor switch is fired at an incorrect timing, the resonance phenomenon cannot be suppressed even if the resonance phenomenon occurs in the system. When the current and voltage waveforms of the power system are disturbed and the resonance phenomenon cannot be suppressed, an overvoltage may occur in the series capacitor and the power system, which may lead to an accident in the power system.

Therefore, the power flow controller of the present invention provides a series compensator capable of controlling a semiconductor switch at an accurate timing even if the waveform of an electric signal of the power system is disturbed due to the fluctuation of the power system. Especially.

Further, in the conventional power flow controller, the reactance amount of the controlled object required in the power system is compensated by controlling the reactance amount of the compensation capacitor connected to the power system. Since the amount of controllable reactance has been limited by the compensation capacitor, it has been difficult to compensate the reactance state of the power system in a wide range.

[0015]

In order to achieve the above object, in a power flow controller for controlling the power transmission state of a power system, a first winding having at least one Y connection, and the first winding. It is characterized in that it is provided with a power flow compensating means that is connected in series with the second winding that is combined with the wire and the Y connection of the first winding and that compensates the power transmission state of the power system.

Further, in order to achieve the above object, in a power flow controller including a compensating capacitor inserted in a power line, a semiconductor switch for controlling a compensation amount of the compensating capacitor is provided, and a potential applied to this semiconductor switch is applied to the power line. It is characterized in that the potential is less than or equal to the ground potential.

Further, in order to achieve the above object, the present invention is a power flow controller for a power system, comprising a compensating capacitor inserted in a transmission line and a protection device for bypassing both ends of this capacitor. A first winding of each of the transformers, one end of which is grounded, the other end of which is connected to both terminals of the compensation capacitor, and a second switch of each of the two transformers is connected via a semiconductor switch. The feature is that the windings are connected in parallel.

In order to achieve the above object, the present invention provides a power flow controller for a power system, which comprises a compensating capacitor inserted in a transmission line and a protective device for bypassing both ends of this capacitor. Has an autotransformer,
One end of each winding of this transformer is grounded, and the other end is connected to both terminals of the compensation capacitor.
It is characterized in that the midpoint of each winding of the autotransformer of the stand is connected via a semiconductor switch.

In order to achieve the above object, the present invention provides a power flow controller for a power system which includes a compensating capacitor inserted in a transmission line and a protective device for bypassing both ends of the capacitor. It has a transformer, one end of each primary winding and each secondary winding of this transformer is grounded, and
The other end of the secondary winding is connected to a power transmission line, and the other end of the secondary winding is connected via a compensation capacitor in which a semiconductor switch is connected in parallel.

In order to achieve the above-mentioned object, the present invention is a power flow controller including a compensation capacitor inserted in a power line, wherein a transformer is provided between the power line and ground.
Provide a semiconductor switch to control the compensation amount of the compensation capacitor, connect the semiconductor switch to the winding of the transformer, and connect the semiconductor switch in parallel to the compensation capacitor to protect between the semiconductor switch and the transformer. Is provided and the potential applied to this semiconductor switch is set to be equal to or lower than the ground potential of the power line.

Further, in order to achieve the above object, in a power flow controller provided with a compensation capacitor inserted in a power line, a semiconductor switch for controlling the amount of compensation of the compensation capacitor is provided, and the compensation capacitor is connected to the ground potential of the power line. And a transformer for setting the potential applied to the semiconductor switch to be less than or equal to the ground potential of the power line is placed between the compensation capacitor and the semiconductor switch.

In order to achieve the above object, according to the present invention, in a power flow control device equipped with a compensation capacitor inserted in a power line, a semiconductor is provided on the power line to control an amount of compensation of the compensation capacitor. It is characterized in that a switch is provided and a power line from a direction perpendicular to the arrangement direction of the insulating switch is provided to the semiconductor switch.

In order to achieve the above object, according to the present invention, in a power flow controller including a compensating capacitor connected to a power line, a semiconductor switch for controlling the charging / discharging state of the compensating capacitor and a compensating capacitor are provided. A current detecting means for detecting a flowing current, a voltage detecting means for detecting a voltage applied to the compensation capacitor, a current filter means for extracting only a specific frequency component of a current detected by the current detecting means, and a voltage detecting means. A voltage filter means for extracting only a specific frequency component of the detected voltage, a current direction determining means for determining the direction of the current to be passed through the semiconductor switch based on the output of the current filter means, and a voltage applied to the semiconductor switch. Voltage phase determining means for determining the phase based on the output of the voltage filter means,
The present invention is characterized by including a switching signal generating means for outputting a switching signal for controlling the semiconductor switch based on the judgment of the current direction judging means and the voltage phase judging means.

In order to achieve the above object, according to the present invention, in a power flow controller including a compensation capacitor connected to a power system and a phase adjuster, the reactance amount to be compensated in the power system is adjusted by the reactance capacitor. The amount and the reactance amount by the phase adjuster are controlled and combined.

[0025]

In the power flow controller of the present invention, the limitation of the transmission capacity caused by the reactance of the transmission line is eliminated. Further, by disposing the reactance compensation circuit section on the low-voltage side of the main transformer, the reactance compensation circuit section can be arranged on the ground potential side with respect to the phase voltage of the system, so that the problem of ground insulation is reduced. Furthermore, by providing a phase adjustment function and a reactance compensation function, it is possible to provide a power flow controller with a wider power flow control range than the conventional power flow controller.

In the power flow controller of the present invention, the semiconductor switch having a high frequency of maintenance and inspection in the device is set to be equal to or lower than the ground potential of the system, so that the maintenance and inspection can be facilitated and the semiconductor switch can be arranged with high earthquake resistance. It becomes possible to put it in.

Further, in the power flow controller of the present invention, since the semiconductor switch section can be set to a potential lower than the ground potential of the system,
Maintenance and inspection of semiconductor switches that are frequently performed for maintenance and inspection become easy, and wiring and piping for semiconductor switch control and signal lines, power supply lines, semiconductor element cooling medium pipes, etc. are required. It becomes easy to secure.

Furthermore, in the power flow controller of the present invention, the entire compensator can be installed at the ground potential, so that seismic resistance can be easily ensured in areas where many earthquakes occur, and at the time of construction and maintenance inspection of the compensator. Eliminates work in high places. In addition, part or all of the compensator can be stored in a grounded structure or in a closed container, reducing the probability of failure caused by lightning strikes or flying objects to the compensator, and increasing the reliability and operating rate of the device. Can be raised.

Further, in the power flow controller of the present invention, maintenance and inspection of the semiconductor switch is facilitated, and since a protector is provided between the semiconductor switch and the transformer, lightning on the power line or transients due to system size may occur. Even if a specific voltage or current flows, the influence does not propagate to the semiconductor switch, so that the semiconductor switch can be protected safely.

Further, in the power flow controller of the present invention, the compensating capacitor is arranged at the position of the ground potential of the power line, and the transformer for setting the potential applied to the semiconductor switch to the ground potential of the power line or less and the semiconductor switch. Since it is arranged between the first and second parts, there is an effect that the entire compensator can be made compact while facilitating maintenance and inspection.

Further, in the power flow controller of the present invention, an insulating switch is provided on the power line path, and the power line from the vertical direction to the semiconductor switch is provided with respect to the disposing direction of this insulating switch. There is an effect that the entire device can be configured compactly while improving the property.

Further, according to the power flow controller of the present invention, the current of the compensation capacitor and the voltage across the compensation capacitor are respectively detected, only a specific frequency component of the detected current and the detected voltage is extracted, and the extracted current is extracted. In accordance with, to determine the direction of the current to be passed through the semiconductor switch, and determine the phase of the voltage applied to the semiconductor switch according to the extracted voltage,
A switching signal is generated based on each judgment result, and conduction / non-conduction of the semiconductor switch is controlled according to the switching signal. Therefore, the voltage and current waveforms of the system are disturbed due to power system fluctuations such as system failure. Or
In order to restart the operation of the system after the failure recovery, even if the voltage and current of the system transiently change when the disconnector etc. is turned on and power transmission is started, the conduction / non-conduction of the semiconductor switch can be accurately measured. It can be controlled at any timing. Therefore, even if the series capacitor is shaken due to the introduction of the series capacitor, the resonance phenomenon occurring in the power system can be quickly suppressed and the system can be stabilized.

Particularly, when the semiconductor switch is composed of a semiconductor element in which a pair of at least one element is connected in series,
During the period in which the forward current should flow in one semiconductor element, one semiconductor element is turned on and the other semiconductor element is turned on when the phase of the reverse voltage applied to one semiconductor element is close to the zero point. When the other semiconductor element is turned on while the phase of the forward voltage applied to the other semiconductor element is close to the zero point during the period when the directional current should flow, the waveforms of the voltage and current in the power system are disturbed. However, it is possible to make each semiconductor element conductive at an accurate timing.

Further, according to the power flow controller of the present invention, the reactance state of the power system can be compensated in a wide range by controlling the reactance amount of the phase adjuster in addition to the compensation capacitor. It was

[0035]

EXAMPLES Examples of the present invention will be shown below. The same functions as those of the conventional one are designated by the same reference numerals.

FIG. 1 shows an example of the configuration of a power flow controller according to the present invention. The power flow controller 10 includes a series compensator 11 for generating a voltage in a lead phase with respect to a line current and compensating the system in series, a main transformer 12 and a main transformer 12 of a phase adjuster for adjusting the phase. The adjustment transformer 13 that generates a voltage that adjusts the voltage phase that is generated in the control circuit 200 and the control transformer 200. The series compensator 11 is connected between the neutral point 14 and the terminal 14 a connected to the neutral point in each phase of the Y-connection winding of the main transformer 12. With this configuration, the series reactance of the power transmission line and the transformer of the system and the series compensation capacitor of the series compensator 11 are connected in series, and the series reactance of the system can be compensated. In addition, the series compensator 11
Can be arranged on the ground potential side by connecting between the low voltage side terminal of the winding of the main transformer 12 and the ground point. In the conventional series compensation technique, as shown in FIG. 29, the series compensation device 110 is inserted in the middle of the power transmission line. Therefore, it is necessary to support the series compensator 110, which is a heavy object, at a high place with an insulator or the like in order to secure the ground compensation and the interphase insulation of the series compensator 110. However, the present invention solves this problem by enabling the configuration in which the series compensator is arranged on the ground potential side. Further, the series compensation by the series compensator 11 reduces the series reactance in the system and the main transformer 12, thereby increasing the transmission capacity and improving the stability of the system. By changing the compensation amount (degree of compensation) of the series reactance, the power flow of the system can be controlled. Main transformer 12
Can adjust the phase on the primary side and the secondary side of the main transformer 12 by the voltage generated by the adjusting transformer 13 to control the power flow passing therethrough. In addition, the secondary side of the main transformer 12 and 1
By changing the turns ratio on the secondary side, it is possible to connect systems with different rated voltages (for example, 550 kV system and 275 kV system). The adjusting transformer 13 generates an arbitrary voltage vector from the voltage vector generated in the main transformer 12 by a combination of the transformer and the tap switch, and combines this voltage vector with the voltage vector of the main transformer 12, The primary and secondary sides of the main transformer generate voltages whose phase angles differ by an arbitrary amount. The adjustment of the generated voltage vector in the adjusting transformer 13 is performed by changing the turns ratio of the adjusting transformer as follows.
This is performed by switching a plurality of taps with a tap switch configured by using a mechanical contact or a semiconductor element such as a thyristor. Alternatively, the adjusting transformer 13 may be replaced with a converter capable of generating a three-phase voltage vector having an arbitrary phase angle.

In FIG. 2, a portion for generating a phase control voltage of the power flow controller according to the present invention is constructed by using a converter 15 so as to generate a three-phase voltage vector having an arbitrary phase angle. Is. When the converter 15 fulfills the function of the adjusting transformer 13 shown in FIG. 1, the control of the amplitude and phase of the voltage generated in the adjusting transformer becomes continuous and high speed.
It becomes easy to perform control to suppress system sway.

FIG. 3 shows a main transformer 12, a series compensator 11 and its control circuit 1 in the power flow controller of the present invention.
4 shows an example configured by 4. This configuration does not have a phase adjusting function as in the case of the configuration shown in FIG. 1 or FIG. 2, but the series compensator 11 can compensate for the series reactance of the system and increase the transmission capacity. Further, by controlling the compensation amount of the series compensation, it is possible to adjust the reactance of the system and control the flowing power flow. Here, the main transformer 12 has a tertiary winding,
If this winding is Δ-connected, the triple harmonic component of the commercial frequency of the system voltage and current can be removed.

FIG. 4 shows an example constituted by the main transformer 12, the series compensator 11 and the control circuit 14 thereof, as in the example shown in FIG. As for the operation, as in the embodiment of FIG. 3, the series compensator 11 can compensate for the series reactance of the system and increase the transmission capacity. Further, by controlling the compensation amount of the series compensation, it is possible to adjust the reactance of the system and control the flowing power flow.
Here, the main transformer 12 is composed of a primary winding and a secondary winding. When the winding to which the series compensator is connected is the primary winding, the secondary winding is Δ-connected. In this case, the triple harmonic component of the commercial frequency of the system voltage and current can be removed.

FIG. 5 shows the main transformer 12 and the adjusting transformer 13 in the phase adjuster section of the power flow controller according to the present invention.
An example of the winding structure of is shown. The main transformer 12 is mainly composed of a primary side winding 12a and a secondary side winding 12b that pass a power flow, and a tertiary winding 12c that generates a voltage for phase adjustment. The adjustment transformer 13 is composed of a primary winding 13a connected to the tertiary winding of the main transformer and a secondary winding 13b that matches a voltage for phase adjustment to the main transformer. The direction of each winding shown in the figure matches the direction of the voltage vector generated by each winding, and the voltage vectors of the winding 12a and the winding 13b are deviated by 90 degrees. The voltage phase generated on the line 12a can be changed. The secondary winding 13b of the adjusting transformer 13 has a voltage adjusting tap 13c, which adjusts the voltage generated by switching the taps and controls the phase angle. If the voltage adjusting tap 13c is configured by using a semiconductor element such as a thyristor, high-speed and high-frequency switching can be performed, and thus phase control can be performed finely and flexibly. The series compensator 11 is connected to the ground potential side of the secondary winding 12b of the main transformer 12. By doing so, it is possible to install the series compensating device 11 composed of a heavy object such as a capacitor bank for series compensation directly on the ground or at a position of low ground insulation, and there is no problem such as earthquake resistance.

FIG. 6 shows an example of the configuration including the converter section when the part for generating the phase control voltage of the power flow controller according to the present invention is composed of the converter 15.
The converter 15 is a transformer for receiving an AC voltage from the tertiary winding of the main transformer, a forward converter for converting the AC voltage obtained through the transformer into a direct current, and a voltage converted by the forward converter. It is composed of an inverse converter for generating an AC waveform and a transformer for applying the voltage generated by the inverse converter to the main transformer. By interposing a transformer between the main transformer and the converter, the converter can be electrically insulated from the power system, and the influence of a failure that has occurred on the power system side on the converter side can be reduced.

FIG. 7 shows a circuit configuration of a series compensator used in the power flow controller according to the present invention. It is an example in which the entire series compensation device shown in FIG. 30 is installed on the ground side of the transformer 316a. Of the components of the series compensator,
Since the heaviest series capacitor 311 and the semiconductor switch 313 that has the highest frequency of maintenance and inspection can be installed on the ground, there is no need to lift it to a high place with an insulator, etc. And maintainability are both improved. In addition, the transformers 316a and 316b have the same series compensation effect whether they are in the same substation or in different substations located at distant places.

FIG. 8 shows an embodiment of the present invention, which has an apparatus configuration based on FIG. In this embodiment, the first terminal of the first winding of the transformer 316a is connected to the grid and the second terminal of the first winding is grounded. The first terminal of the second winding is connected to the power transmission system, and the second terminal of the second winding is connected to the series capacitor 31.
1, and is further grounded via the semiconductor switch 313. (Paired transformer 316b is not shown,
It is installed in a remote place. ) Also, the capacitor 31
1 and a winding of the transformer, as an electric power system protector, an overvoltage protection device 312, and switching devices 314b and 314a.
(Normally open) is provided. Further, in this embodiment, all the constituent elements including the series capacitor 311 and the semiconductor switch 313 can be ground-mounted with respect to the system potential, so that it can be easily housed in the closed container 318 such as a building or a ground tank. . Further, a part or all of the compensating device can be constituted by a gas insulated switchgear, or can be easily connected to another gas insulated switchgear. Furthermore, according to this embodiment, the semiconductor switch 313 can be configured to have a device grounded to a portion away from the transformer. Therefore, for example, when a lightning strike or an abnormality occurs in the power transmission system,
The transient voltage and current 424 are propagated to the capacitor 311, the semiconductor switch 313, and the overvoltage protection device 312 of the protector 312, the switchgear 314a, 31
Since 4b is present, it is possible to block those abnormalities without propagating them. As a result, it is possible to enhance the safety of the semiconductor switch portion of the compensator, which is most concerned about security. Furthermore, when an abnormality occurs in the series capacitor 311, the protection device 312 and the switchgear devices 314a and 314b can be shut off so that their adverse effects do not propagate to the power transmission system.

FIG. 9 shows an example in which the series compensator of the present invention is applied to a three-phase circuit. Series compensator 310
Is inserted between the low voltage side terminal of the Y winding of the three-phase transformer 316c and the grounding point. By doing so, the series reactance of each phase of the transmission line 400 can be compensated even when the series compensation device of the present invention is applied to a three-phase AC transmission system.

FIG. 10 shows an arrangement configuration example of a series compensator using the circuit configuration of FIG. Here, the transformer 316c
Is connected to the gas insulated switchgear 401. The series compensator 310 is provided on the side surface of the transformer 316c where there is no connection with the gas-insulated switchgear 401.
6c is connected. The overvoltage protection device 312 is connected between the connection part of the series capacitor 311 and the transformer 316c. By doing so, it is possible to prevent both an overvoltage from entering the series capacitor 311 from the system side through the transformer 316c or an overvoltage which is generated in the series capacitor 311 and enters into the transformer 316c. As shown in FIG. 10, the series capacitor 311 and the semiconductor switch 313 are arranged such that their installation locations are in contact with an open space sufficient for maintenance and inspection work of the series capacitor 311 and the semiconductor switch 313. By doing so, it is particularly easy to carry in and install the heavy series capacitor 311 and to easily perform the maintenance work of the semiconductor switch 313. Also,
In this embodiment, since the power line to the semiconductor switch 313 is taken out from the vertical direction with respect to the arrangement direction of the gas-insulated switch provided on the path of the transmission line of each phase, the compensator for three phases is used. It is possible to configure the whole with the minimum space.

FIG. 11 shows an example of the configuration of a series compensator used in the power flow controller of the present invention. An overvoltage protection device is connected in parallel with a capacitor for series compensation, and is inserted or separated in a system. The series compensating device 11a is configured by using three phases of the series compensating device 11a configured by using a switchgear. Although not shown, it is possible to adjust the compensation degree of the series compensation by configuring the capacitor with a plurality of capacitors and changing the amount of the capacitor to be introduced into the system.

FIG. 12 shows a series compensator 11b of FIG. 11 in which a semiconductor switch composed of a semiconductor element such as a thyristor is connected in parallel with a capacitor for three phases. It is composed.
The compensation degree of series compensation can be adjusted by adjusting the input amount of the capacitor, and the compensation degree can be changed at high speed by controlling the semiconductor switch.

FIG. 13 shows a series compensator 11c in which a series capacitor and a semiconductor switch unit are connected to a power flow controller via a transformer, in contrast to the series compensator 11b of FIG.
Is used for three phases. Since the series capacitor and the semiconductor switch section can be electrically separated by the transformer, insulation from the system side becomes possible.

FIG. 14 is an example of a series compensator 11d using a converter to generate a voltage similar to the voltage generated when a series capacitor is inserted. At this time, the series compensator 11d is connected to the grid through the transformer 111, and the switchgear 112 connects and disconnects from the grid. Since the series compensator 11d configured by the converter can quickly and easily adjust the voltage waveform to be generated, it is easy to operate by sufficiently following the system fluctuation (for example, a fluctuation period of about 2 to 3 Hz). .

FIG. 15 shows an embodiment of the series compensator used in the power flow controller according to the present invention. This embodiment is different from the conventional series compensator shown in FIG. 29 or 30 in that the series capacitor 311 has a system voltage, but the potential of the semiconductor switch 313 is on the low voltage side. is there. In the embodiment, the series capacitor 311 in which the overvoltage protection device 312 is connected in parallel as a protector composed of a discharge gap or a non-linear resistance element is a switching device 314a, 314b, 31 which also operates as a protector.
4c inserts into or separates from the line.
The semiconductor switch 313 is configured to be able to control the forward and reverse currents using a semiconductor element such as a thyristor or a gate turn-off thyristor having an operating frequency characteristic higher than the power supply frequency. This semiconductor switch 313
And two transformers 31 whose primary side is connected to the earth of the system
Connect to the secondary side of 6a, 316b. Transformer 316a,
316b has a reactance equivalent to that of the reactor 313a as a leak reactance, which is shared by each, and has the same transformation ratio and winding direction. Also, the switchgear 31
Switching devices 4d and 314e connect the transformers 316a and 316b to both ends of the series capacitor 311, and have a function of simultaneously connecting the semiconductor switch 313 and the series capacitor 311. Through the transformers 316a and 316b, the ground voltage of the semiconductor switch 313 of the compensating device of the present invention becomes lower than the system voltage, so that the insulation distance between the semiconductor switch 313 and the ground can be shortened, and it is necessary to arrange the semiconductor switch 313 at a high place. Disappear. Therefore, it is possible to easily secure the earthquake resistance and reduce the risk associated with work at a high place during maintenance and inspection. Furthermore, wiring from the ground potential to the semiconductor switch,
Control and signal lines for semiconductor switches that need to be piped,
Installation of power lines, insulating pipes for semiconductor element cooling media, etc. becomes easy. Further, since the semiconductor switch 313 can be housed in a ground-standing building or tank, the maintainability and operability of the semiconductor switch 313 can be improved. Also, when performing maintenance inspection of the semiconductor switch 313,
If the switching devices 314d and 314e are opened, the maintenance and inspection work of the semiconductor switch 313 can be performed without stopping the series compensation by the series capacitor 311. Even if the system is stopped, the series capacitor 311 has a transformer 31
Since it is grounded via 6a and 316b, the electric charge remaining in the series capacitor 311 is naturally discharged, which is safe.

Next, using FIG. 16, the voltage vector 311v across the series capacitor 311 shown in FIG. 15, the voltage vector 313v across the semiconductor switch, and the transformer 316 are shown.
a, 316b primary side voltage vector 316av
1 shows the relationship between 316bv1 and secondary side voltage vectors 316av2 and 316bv2.

Assuming that the system ground voltage is V, the line current is I, and the reactance of the series capacitor 311 is jX _C , the voltage across the series capacitor 311 is V311v.
Is

[0053]

[Equation 1]

It is expressed as If the transformation ratio of the transformers 316a and 316b is n: 1, the respective primary side voltage V316a
v1, V316bv, secondary voltage V316av2, V316bv2 are expressed as follows. However, here, for the sake of simplicity, the transformer 31
6a and 316b are handled as ideal transformers.

[0055]

[Equation 2]

[0056]

(Equation 3)

Voltage V311 across the series capacitor 311
The relationship between v and the primary side voltages V316av1 and V316bv1 of the transformers 316a and 316b is

[0058]

(Equation 4)

It is Further, the voltage V313v across the semiconductor switch is calculated from the secondary side voltages V316av2 and V316bv2 of the transformers 316a and 316b, respectively.

[0060]

(Equation 5)

It becomes By substituting equations (2), (3) and (5) into equation (4), the relationship between the voltage V311v across the series capacitor 311 and the voltage V313v across the semiconductor switch becomes

[0062]

(Equation 6)

It becomes When the winding directions between the primary and secondary windings of the transformers 316a and 316b are opposite, the equations (2) and (3) are

[0064]

(Equation 7)

[0065]

(Equation 8)

Therefore, the voltage V311v across the series capacitor 311 and the voltage V313v across the semiconductor switch are
The relationship of

[0067]

[Equation 9]

It becomes In this way, the transformers 316a, 3
Since the transformation ratio of 16b is the same, the vector 311
v and vector 313v have the same phase or 180 °
The opposite phase and vector magnitude ratio is
It becomes equal to the transformation ratio of a, 316b. Since the series compensator according to the present invention includes the series capacitor, the semiconductor switch, and the transformer that maintain such a phase relationship, even if the semiconductor switch is arranged on the low voltage side with respect to the system potential, The phase relationship of voltage and current, which is important for on / off control, is the same as that of the conventional series compensator.

The current I313 flowing through the semiconductor switch is
Since the transformation ratio of the transformers 316a and 316b is n: 1, a specific multiple of the line current I will flow. I mean

[0070]

(Equation 10)

It becomes Therefore, by adjusting the transformation ratio of the transformers 316a and 316b from the equations (9) and (10), the voltage across the semiconductor switch 313 and the flowing current are controlled to a current state suitable for the rating of the semiconductor switch 313. be able to.

In other words, it is possible to construct the power flow controller of the present invention by using the semiconductor switch having the capacity that allows the current flow of several times the line current I to flow.

FIG. 17 is the same as the apparatus configuration of FIG. 15 except that it is particularly specified in another embodiment of the present invention. In this embodiment, the secondary sides of the transformers 316a and 316b are not grounded. Even with such a circuit configuration, the phase relationship shown in FIG. 16 is established, so that the semiconductor switch can be controlled as in the circuit of FIG. The characteristic of this circuit is that since the semiconductor switch 313 is electrically insulated from the system, it has an effect of preventing malfunction of the semiconductor switch due to noise or the like that enters from a ground point or the like.

FIG. 18 is the same as the apparatus configuration of FIG. 15 except that it is particularly specified in another embodiment of the present invention. In another embodiment in which the semiconductor switch 313 is arranged on the secondary side of the transformer 316a to the ground side, one terminal of the semiconductor switch 313 can be set to the ground potential, and the semiconductor can be changed by setting the transformation ratio of the transformers 316a and 316b. The voltage across the switch 313 can be adjusted. In particular, if the ground voltage is set to a fraction or less of that when it is directly inserted into the system, the semiconductor switch 313 can be easily housed in a ground-based building or tank.

FIG. 19 is the same as the apparatus configuration of FIG. 15 except that it is particularly specified in another embodiment of the present invention. FIG.
In the above circuit configuration, an example in which an autotransformer is used for the transformers 316a and 316b is shown. Figure 1 shows the phase relationship of each part.
Since it is the same as 6, the effect similar to that of FIG. 15 can be obtained, and the winding structure of the transformer can be simplified by using the autotransformer so that the ground insulation can be easily secured when the system voltage is high. become.

FIG. 20 shows another embodiment of the present invention. This embodiment has a circuit configuration in which transformers 316a and 316b are interposed in the system, and the ground potential of the entire series compensator can be arbitrarily selected, and the system voltages connected to the transformers 316a and 316b are different. However, it can be used by setting the transformation ratio. However, since the transformers 316a and 316b must pass the transmission power of the grid, the transformer capacity must be the same as that of a normal step-up / step-down transformer.
However, the series capacitor 311 and the semiconductor switch 313
Since the voltage vector of is not affected by the winding configuration of the transformer, the degree of freedom in designing the transformers 316a and 316b is wide.

FIG. 21 shows still another embodiment of the present invention, which is constituted by opening / closing devices 314a, 314b and 314c.
It has a circuit configuration that bypasses the entire compensator including the transformers 316a and 316b shown in FIG. At this time, the voltage class and the transformation ratio connected to the transformers 316a and 316b are the same. This has the advantage that the system operation can be continued even if the series compensator including the transformers 316a and 316b must be stopped for maintenance or the like.

22 and 23 show another embodiment of the present invention, which is the transformer 316 shown in FIGS. 20 and 21, respectively.
In this embodiment, an autotransformer is used for a and 316b. Especially when it is necessary to secure high-voltage insulation to ground, it is easy to manufacture a high-voltage transformer by using an autotransformer, which facilitates design and manufacture.

FIG. 24 shows an arrangement configuration example of the apparatus shown in FIG. Since the ground potential of the series capacitor 311 is the same as that of the system, the series capacitor 311 is arranged on the insulating frame supported by the insulator 317a, while the semiconductor switch 313 is connected to the transformer 316a,
Since it can be installed on the lower voltage side than the system voltage via 316b, the height of the insulator 317b required for ground insulation can be reduced. Further, the semiconductor switch 313 can be easily housed in a closed container 318 such as a ground-standing building or a ground tank such as a gas-insulated switchgear, so that maintainability, reliability, and safety can be easily improved. Further, it becomes possible to easily connect to another gas insulated switchgear.

FIG. 25 shows a configuration example in which the power flow controller of the present invention is arranged for three phases. Three-phase power line 400
Power flow controller 310 for three phases with respect to the installation direction of the
It is one example which arranged side by side. The configuration of the device for one phase is as follows: from the part close to the transmission line, which is the high voltage part, to the series capacitor part (series capacitor 311, overvoltage protection device 312, switchgear 314a, 314b, 314c,
(Including 314d and 314e) 319, transformer 316a,
316b and the semiconductor switch 313 are arranged.

FIG. 26 shows this arrangement as shown in FIG.
It is seen from the A ′ cross section. The terminal output from the series capacitor is connected to the semiconductor switch through a grounded transformer, which makes it easy to store these devices in a ground-based building or tank that is an insulating container.
In addition, since the semiconductor switch 313 that has become the low voltage portion can be arranged at a location away from the power transmission line 100 that is the high voltage portion, it becomes easy to install a switch control device, and the high voltage portion can be installed during maintenance and inspection. There is no need for maintenance personnel to come close to it, making it safe.

Further, in FIG. 25, for the three-phase transmission line,
Compensation capacitors are inserted in series for each individual phase wire, and a transformer is arranged at the symmetry position of the central axis AA 'of the capacitors corresponding to the connection terminal portions of the individual capacitors, and on this axis as well. By placing a semiconductor switch, the power line connecting each device terminal is configured to have the minimum distance.

Then, FIG. 27 shows a case where the series compensating devices 310 for three phases are arranged side by side in the installation direction of the power transmission line 400, as in FIG. 25. Here, the compensating device for each phase is arranged in parallel with the series capacitor unit 319 so that the transformer 316a, the semiconductor switch 313, and the transformer 316b are arranged in a straight line. With such an arrangement,
The width of the site required to install the power transmission line 400 and the series compensation device 310 can be narrowed.

FIG. 28 shows a series compensator 310 for three phases.
Is an example in which are arranged side by side in a direction perpendicular to the installation direction of the power transmission line 400. Here, in particular, the series capacitor unit 319, which is the high-voltage side of the series compensator 310 for the three phases, is connected to the semiconductor switch 313 and the transformer 3 which are the low-voltage side.
It is arranged so that the 16a and 316b sides face each other. With such an arrangement, the series compensator 31 for three phases
Since the potential difference between the phases of 0 can be reduced, the distance between the phases can be reduced and the installation area can be reduced.

In the conventional power flow control method shown in FIG. 29,
Although the phase adjuster 120 is used, as described above, the series reactance of the system increases due to the reactance of the phase adjuster itself, so it is not always suitable from the aspect of system stability. Therefore, in order to prevent a decrease in the stability of the system, it is necessary to devise a method such as reducing the series reactance of the system in combination with the series compensator 110. With respect to this problem, the present invention can provide a device that enables power flow control without increasing the reactance of the system.

FIG. 32 shows a configuration example of a line power flow control amount calculation circuit used in the control of the power flow control device according to the present invention. The line power flow control amount calculation circuit uses the system voltage signal 20
1 and the system current signal 202 are input, and the line power flow control amount 208 is output. The power flow calculation circuit 203 obtains the power flow of the system from the system voltage signal 201 and the system current signal 202,
The amount of change is obtained by the reset filter 204a, the phase compensating circuit 205a compensates for the phase shift due to the calculation, the low-pass filter 206a removes the noise component, and the amplifier 207a amplifies to a signal level required for control. In this way, the control signal for line power flow control of the power flow control device according to the present invention can be obtained.

FIG. 33 shows an example of the configuration of a system frequency control amount calculation circuit used in the control of the power flow controller according to the present invention. The system frequency control amount calculation circuit receives the system voltage signal or the system current signal 209 and outputs the system frequency control amount 211. The frequency meter 210b obtains the frequency of the system from the system voltage signal or the system current signal 209, obtains the amount of change by the reset filter 204b, removes the noise component by the low pass filter 206b, and the signal required for control by the amplifier 207b. Amplify to level.
In this way, the control signal for controlling the system frequency of the power flow controller according to the present invention can be obtained.

FIG. 34 shows an example of the construction of a generator speed control amount calculation circuit used in the control of the power flow controller according to the present invention. The generator speed control amount calculation circuit inputs the generator speed signal 212 and outputs a generator speed control amount 213. The frequency meter 210c obtains the frequency of the system from the generator speed signal 212 and resets the amount of change to the reset filter 2
The noise component is removed by the low-pass filter 206c, and amplified by the amplifier 207c to a signal level required for control. In this way, the control signal for controlling the system frequency of the power flow controller according to the present invention can be obtained.

FIG. 35 shows an example of the configuration of a series compensator control amount calculation circuit used for control in the series compensator of the power flow controller according to the present invention. In this series compensator control amount calculation circuit, the control input is switched depending on the control target. As a control input, the line flow control amount 20
8, system frequency control amount 211, generator speed control amount 213. Any of these may be used depending on the control target. The control input amount is selected by the switching circuit 214, the phase compensation circuit 205b corrects the phase shift, the differential operation unit 215 synthesizes it with the series compensation control command value 216, and the signal necessary for control by the amplifier 207d. It is amplified to a level and a series compensation control amount 216a is output.

FIG. 36 shows an example of the configuration of the phase adjustment device control amount calculation circuit used in the control of the phase adjuster of the power flow controller according to the present invention. In this phase adjustment device control amount calculation circuit, the control input is switched depending on the control target. As a control input, the line flow control amount 20
8, system frequency control amount 211, generator speed control amount 213
There is. Any of these may be used depending on the control target. The control input amount is selected in the switching circuit 214, the phase shift is corrected by the phase compensation circuit 205c, the phase adjustment control command value 217 is combined by the differential calculator 215, and the signal required for control by the amplifier 207e. It is amplified to a level and the phase adjustment control amount 217a is output.

FIG. 37 shows a configuration example of a control circuit for performing combined series compensation control and phase adjustment control of the power flow controller according to the present invention. In this composite control circuit, the control input is switched depending on the control target.
As control inputs, there are a line power flow control amount 208, a system frequency control amount 211, and a generator speed control amount 213. Any of these may be used depending on the control target. The control input amount is selected by the switching circuit 214, and the phase compensation circuit 205 is selected.
After correcting the phase shift at d, the control amount is distributed to the series compensation control and the phase adjustment control.
15 and the series compensation control command value 216 is combined, and the amplifier 2
In 07f, the signal is amplified to a signal level required for control, the series compensation control amount 216b is output, and in the phase adjustment control, the differential calculator 215 combines it with the phase adjustment control command value 217 and the amplifier 207g requires the control. Then, the signal is amplified to a signal level that becomes and the phase adjustment control amount 217b is output.

FIG. 38 shows an impedance control amount calculation circuit for obtaining a control amount by each impedance in the power flow controller of the present invention. The impedance of the power flow controller is calculated from the voltage signal 224 and the current signal 225 of the power flow controller by the impedance calculation circuit, and the deviation from the impedance control command value 230 is calculated by the differential calculator 215 and controlled by the amplifier 207j. It is amplified to a signal level required for the impedance control command 231. This impedance control command 231
Is the input of the series compensation control amount calculation circuit shown in FIG.
It can be used as an input of the phase adjustment device control amount calculation circuit shown in FIG.

FIG. 39 shows a tap control circuit used when the phase adjuster controls the taps of the adjustment winding as shown in FIG. 5 when performing the phase adjustment control in the power flow controller according to the present invention. . Phase adjustment commands 217a, 217
b, 217c and the like are input, the tap selection circuit 220 selects a tap to be switched, and the tap switching circuit 232 outputs a control signal to each tap.

FIG. 40 shows a converter voltage control circuit used when the phase adjuster controls the generated voltage by the converter as shown in FIG. 6 when the phase adjustment control is performed in the power flow controller according to the present invention. Is. Phase adjustment command 217
A, 217b, 217c and the like are input, and a phase control command is output by a firing control circuit for controlling a firing phase of a semiconductor element such as a thyristor which constitutes a converter.

FIG. 41 is a structural example of a control circuit for cooperatively performing series compensation control and phase adjustment control of the power flow controller according to the present invention. In this cooperative control circuit, the control input is switched depending on the control target.
As control inputs, there are a line power flow control amount 208, a system frequency control amount 211, and a generator speed control amount 213. Any of these may be used depending on the control target. The control input amount is selected by the switching circuit 214, and the phase compensation circuit 205 is selected.
After correcting the phase shift at e, the control amount dividing circuit 229 divides the control amount into the series compensation control and the phase adjustment control, and in the series compensation control, the differential calculator 215 synthesizes the series compensation control command value 216. Then, the amplifier 207h amplifies to a signal level required for control and outputs the series compensation control amount 216c, and in the phase adjustment control, the differential calculator 215 combines the phase adjustment control command value 217 and the amplifier 207i. Amplified to the signal level required for control, phase adjustment control amount 217c
Is output.

FIG. 42 shows a characteristic example of the control range of the series compensator used in the power flow controller of the present invention. This shows a change in reactance of the series fault device when the ignition phase of the semiconductor switch is controlled by the series compensation device as shown in FIG. 7 or FIG. In this figure, the ignition phase is 0 ° when the semiconductor switch is constantly off, and 180 ° when it is constantly on. The reactance of the series fault device is capacitive when it is off, and the capacitive reactance increases as the firing phase increases.
Since the resonance point 241 is at 0, it changes to an inductive reactance. At this time, the reactance in the range indicated by the range 240 has a characteristic that it does not change. Therefore, since the reactance control is discontinuous in the series compensator alone, the control in the power flow control is discontinuous. Therefore, the cooperative control circuit shown in FIG. 41 may be used to control the series compensator and the phase adjuster together.

43 to 50 show the sharing characteristics of the control reactance amount between the series compensator and the phase adjuster of the power flow controller according to the present invention. In these figures, the horizontal axis shows the reactance controlled by the power flow controller, and the vertical axis shows the individual reactances of the series compensator and the phase adjuster. With respect to the characteristic line 242 to be controlled, a control characteristic line 243 of the series compensator and a control characteristic line 244 of the phase adjusting device form a power flow controller.

FIG. 43 shows the control sharing between the series compensator and the phase adjuster of the power flow controller according to the present invention.
When the control reactance is inductive, the series compensator is bypassed by the bypass switch 321, and the phase adjuster is an example of inductive control only. Since the minimum value of the capacitive reactance of the series compensation device is X1, the phase adjuster may be controlled by the inductive reactance when the capacitive reactance is X1 or less.

FIG. 44 shows the control sharing between the series compensator and the phase adjuster of the power flow controller according to the present invention.
The series compensator is bypassed by the bypass switch 321 when the control reactance becomes the inductive reactance X2, and the phase adjuster is an example of inductive control only. Since the minimum value of the capacitive reactance of the series compensation device is X1 until the inductive reactance X2 is reached, the phase adjuster may be controlled by the inductive reactance when the capacitive reactance is X1 or less.

FIG. 45 shows control sharing between the series compensator and the phase adjuster of the power flow controller according to the present invention.
In the series compensator, the series capacitor is inserted in the system even if the control reactance becomes less than or equal to the capacitive reactance X1 or becomes inductive, and the phase adjuster is an example of inductive control only. The phase adjuster may be controlled by the inductive reactance after the control reactance reaches the capacitive reactance X1.

FIG. 46 shows the control sharing between the series compensator and the phase adjuster of the power flow controller according to the present invention.
The series compensator is bypassed by the bypass switch 321 when the control reactance becomes the capacitive reactance X1, and the phase adjuster is an example of controlling the capacitive and inductive reactances. The phase adjusting device may be controlled by the inductive reactance from the capacitive reactance X1.

FIG. 47 shows control sharing between the series compensator and the phase adjuster of the power flow controller according to the present invention.
The series compensator is an inductive reactance X2 bypassed by the semiconductor switch 313 when the control reactance becomes the capacitive reactance X1, and the phase adjuster is an example of controlling the capacitive and inductive reactances. The phase adjusting device may be controlled by the inductive reactance from the capacitive reactance X1-X2.

FIG. 48 shows the control sharing between the series compensator and the phase adjuster of the power flow controller according to the present invention.
In the series compensator, the control reactance is the capacitive reactance X1 from the capacitive reactance X1 to the inductive reactance X2, and when the inductive reactance X2 is controlled by the inductive reactance, the phase adjuster controls the capacitive reactance from the inductive reactance. This is an example of controlling. The phase adjusting device controls so as to correct the reactance of the series compensating device from the capacitive reactance X1 to the inductive reactance X2, and in other reactances, the series compensating device and the phase adjusting device share the control amounts.

FIG. 49 shows control sharing between the series compensator and the phase adjuster of the power flow controller according to the present invention.
In the series compensator, when the control reactance is bypassed by the bypass switch 321 from the capacitive reactance X1 to the inductive reactance X2 and controlled by the inductive reactance X2 from the inductive reactance X2, the phase adjuster controls the capacitive reactance from the inductive reactance. This is an example of controlling. The phase adjuster has a capacitive reactance X
From 1 to inductive reactance X2, control is performed so as to correct the reactance of the series compensator, and in other reactances, the series compensator and the phase adjuster share control amounts.

FIG. 50 shows the control sharing between the series compensator and the phase adjuster of the power flow controller according to the present invention.
In the series compensator, the control reactance is changed from the capacitive reactance X1 to the inductive reactance X2 by the semiconductor switch 313 to become the inductive reactance X2, and when the inductive reactance X2 is controlled by the inductive reactance, the phase adjuster is capacitive. This is an example of controlling the inductive reactance from the reactance. The phase adjusting device controls so as to correct the reactance of the series compensating device from the capacitive reactance X1 to the inductive reactance X2, and in other reactances, the series compensating device and the phase adjusting device share the control amounts.

In FIG. 51, a series capacitor 311 is inserted in series with the power transmission line 400, a bypass switch 321 and an overvoltage protection element 312 are connected to both ends of the series capacitor 311, and the reactor 31 is connected.
The semiconductor switch 313 is connected via 3a.
The semiconductor switch 313 is a semiconductor element in which a pair of at least one element is connected in series, for example, a thyristor 320.
a and 320b, and each thyristor 3
20a and 320b are connected in anti-parallel with each other. Each of the thyristors 320a and 320b constitutes a charging / discharging circuit for the series capacitor 311 and becomes a conducting or non-conducting state in response to a switching signal from the control device 326 to open / close the charging / discharging circuit. The controller 326
As a voltage detection means for inputting a current signal 325 detected by a current detector 324 as a current detection means for detecting a current flowing through the electric power system 400, that is, a current flowing through the series capacitor 311 and for detecting a voltage across the series capacitor 311. The voltage signal 323 detected by the voltage detector 322 is input, and the current signal 325 and the voltage signal 32 are input.
The switching signal 327 is generated on the basis of 3.

Specifically, as shown in FIG. 52, the controller 326 controls the filter section 332 and the current direction determining section 33.
3, a voltage phase determination unit 336 and a pulse generation unit 353 are provided. The filter unit 332 includes a current filter 328 and a voltage filter 329. As shown in FIGS. 53A and 53B, the current filter 328 extracts a specific frequency component of the current signal 325, for example, a commercial frequency component, and outputs a current signal 331. Is configured as. The voltage filter 329 is configured as a voltage filter unit that extracts only a specific frequency component of the voltage signal 323, for example, a commercial frequency component, and outputs the voltage signal 330. That is, the current filter 328 and the voltage filter 32
Reference numeral 9 is a filter having characteristics as expressed by the following equation, for example, a second-order bandpass filter having a commercial frequency f as a center frequency.

[0108]

[Equation 11]

The current direction determination section 333 is provided with a forward direction comparator 334 and a reverse direction comparator 335 as current direction determination means. Each of the comparators 334 and 335 has a set value (ground potential) as shown in (c) and (d) of FIG.
And a current signal 331 are compared with each other, and a signal corresponding to the comparison result is output. The comparator 334 outputs the forward current phase signal 343 and the comparator 335.
Outputs a reverse current phase signal 344.

Here, the current flowing from the generator side of the power system 400 to the load side via the series capacitor 311 is referred to as the forward current I, and the current flowing in the direction opposite to the forward current I via the series capacitor 311 is defined as The thyristor 320a has a reverse current, the forward voltage V is the voltage when the voltage on the generator side is high, and the reverse voltage is the reverse voltage with respect to the load side of the series capacitor 311.
Is defined as one semiconductor element and the thyristor 320b is defined as the other semiconductor element, the comparator 334 constitutes a forward direction comparison means and the comparator 335 constitutes a reverse direction comparison means.

When the directions of the voltage and the current are defined as described above, the forward current phase signal 343 becomes the thyristor 320b.
This indicates the period in which the reverse current should flow through (the other semiconductor element). The reverse current phase signal 344 also indicates a period in which the forward current I should flow through the thyristor 320a (one semiconductor element). For example, when the thyristor 320b becomes conductive during the period indicated by the forward phase signal 343, a current flows from the electrode 311a of the series capacitor 311 to the electrode 311b side via the reactor 313a and the thyristor 320b. At this time, a forward current flows in the thyristor 320b with respect to the thyristor 320b, but this current is a current in the direction opposite to the forward current I of the power system. On the other hand, when the thyristor 320a becomes conductive during the period indicated by the reverse phase signal 344, the thyristor 320a and the reactor 313a move from the electrode 311b of the series capacitor 311.
A current flows to the electrode 311a side via the. This current is
It becomes a forward current to the thyristor 320a and a forward current I of the current system 10.

The voltage phase determination section 336 is provided with an absolute value circuit 337 and a comparator 339 as voltage phase determination means. The voltage signal 330 is input to the absolute value circuit 337 and the ignition phase control signal is input to the comparator 339. The ignition phase control signal 340 of a DC voltage with a fixed voltage level is input from the source 341. The absolute value circuit 337 is configured as a voltage absolute value signal generating means for generating a voltage absolute value signal 338 indicating the absolute value of the voltage signal 330, as shown in FIG. The comparator 339 compares the voltage absolute value signal 338 and the firing phase control signal 340, and generates a firing phase signal 342 as a pulse signal at the timing when the phases of both signals match. Is configured as. This firing phase signal 342 is a voltage signal 330.
Is input to the pulse generation unit 353 as a signal indicating that is near the zero point.

The pulse generator 353 is constituted by including AND calculators 345, 346 and gate pulse circuits 349, 350 as switching signal generating means. The logical product operator 345, as shown in (c), (f), and (g) of FIG. 53, the forward current phase signal 343 and the firing phase signal 342.
The forward firing phase signal generating means for generating the forward firing phase signal 347 according to the logical product of On the other hand, the logical product operator 346 is (d) of FIG.
As shown in (f) and (h), the reverse current phase signal 344
And a firing phase signal 342 according to a logical product of the firing phase signal 342 and the firing phase signal 342. The gate pulse circuit 349 uses the forward firing phase signal 347 as shown in (g) and (i) of FIG.
In response to the rising edge of, the forward gate pulse 351 is generated and the forward gate pulse 351 is output as a switching signal to the thyristor 320b. Gate pulse circuit 3
As shown in (h) and (j) of FIG. 53, 50 generates a backward gate pulse 352 in response to the rising of the backward firing phase signal 348, and uses this backward gate pulse 352 as a switching signal. It is configured as a reverse gate pulse generating means for outputting to the thyristor 320a.

In the above structure, when the system is operated with the series capacitor 311 inserted in the power system 400, the thyristors 320a and 320b are ignited even when the system is shaken due to a system failure or the like. If the phase control is not executed, the resonance current generated by the series capacitor 311 and the series reactance of the power system 400 flows in the power system 400. Therefore, the waveforms of the voltage and the current of the power system 400 are shown in FIGS. The waveform becomes as shown in). That is, when the resonance current flows through the power system 400, if the ignition phase control for the thyristors 320a and 320b is not performed at all, both the voltage and the current of the power system 400 are distorted, and an overvoltage occurs across the series capacitor 311. If such a state continues, overvoltage may occur in the series capacitor 311 and the power system 400, or the iron core of the transformer of the power system 400 may be saturated, and the power system 4
00 becomes unstable. Then, the increase of the voltage of the series capacitor 311 causes the overvoltage protection operation of the overvoltage protection element 312 to be continued, and the duty of the overvoltage protection element 312 becomes strict.

On the other hand, as in the present embodiment, the current and the voltage across the series capacitor 311 are detected, only the commercial frequency components of the detected current and voltage are extracted, and the sequence is based on the extracted current and voltage. When the direction gate pulse 351 and the reverse direction gate pulse 352 are generated, each gate pulse 351 and 3 is generated.
By 52, the thyristors 320a and 320b can be fired at accurate timing. That is, the current signal 3 of the power system 400 due to a failure of the power system 400 or the like.
25, even if the waveform of the voltage signal 323 is disturbed, the filter 32
Since the current signal 331 and the voltage signal 330 are extracted via 9, 328, the phase of the fundamental frequency component of the power system 400 can be accurately grasped. And current signal 3
31. Based on 31 and the voltage signal 330, a reverse voltage (a voltage in the forward direction for the thyristor 320a) is applied to the thyristor 320a, and the thyristor 320a is made conductive when the level of this voltage is near the zero point. On the other hand, when the forward voltage V is applied to the thyristor 320b,
Since the thyristor 320b is made conductive when the level of the forward voltage V becomes close to the zero point,
Each thyristor 320a, 320b can be fired at an accurate timing.

When such control is performed, (a) in FIG.
As shown in (b), when the current and voltage waveforms are disturbed due to the fluctuation of the power system 400, the thyristor 320a
Alternatively, the current waveform is slightly disturbed or the voltage across the series capacitor 311 jumps up at the beginning of the current flowing through 320b, but after 150 ms, the current distortion disappears and the overvoltage of the series capacitor 311 disappears. Recognize.

As described above, according to this embodiment, only the reference frequency component is extracted from the electric signals (current signal, voltage signal) of the power system, and the semiconductor switch 313 is turned on based on the extracted frequency component. Since the non-conduction is controlled, even if the power system 400 is shaken due to the introduction of the series capacitor 311 into the power system 400, the series resonance phenomenon occurring in the power system 400 is suppressed and the power system is controlled. Can be stabilized. Moreover, in this embodiment, since the control system has no integral element, the series resonance phenomenon can be promptly suppressed.

Further, in the above-mentioned embodiment, the case where the thyristor is used as the semiconductor element has been described, but an element such as a gate turn-off thyristor can be used as the semiconductor element.

56 and 57 show an example in which the power flow controller of the present invention is applied to a system. When power is transmitted from the bus bar 31a to the bus bar 31c shown in FIG. 56, the transmitted power P13 has a power level V1 of the bus line 31a, a phase of φ1, a voltage level of the bus line 31c of V3, and a phase of φ3. If the series reactance of the power transmission line is X13,
It is expressed by equation (1).

[0120]

(Equation 12)

Here, the phase difference angle is φ1-φ3, and it is understood that the transmitted power P13 is naturally determined by the voltage of the bus bar, the phase difference angle, and the series reactance between the bus lines.

On the other hand, when the power flow controller 10 of the present invention is applied, the transmission power P12 from the bus bar 31a to the bus bar 31b has a voltage magnitude of the bus bar 31b of V2,
When the phase is φ2 and the series reactance of the transmission line or the like is X12, it is expressed by the equation (2).

[0123]

(Equation 13)

However, in the equation (2), the capacitive reactance by the series compensation function of the power flow controller of the present invention is XC, and the phase angle by the phase adjustment function is α. The transmitted power P12 can be controlled by controlling the reactance XC and the phase angle α of the power flow controller. For example, if the capacitive reactance XC is increased, the transmission power P12 is increased, and if the phase angle α is increased, the phase difference angle of the system is decreased and the system stability is increased. In addition, the magnitude of the power flow P12 can be controlled by controlling the capacitive reactance XC and the phase angle α of the power flow controller 10 without changing the magnitude or phase of the bus voltage, and the required power can be supplied to the power demand. It is possible to transmit power accordingly.

FIG. 57 shows a case where the power flow controller according to the present invention is used for interconnection of systems having different rated voltages. The bus bars 31b and 31c have the same rated voltage, but the bus bar 31a has a different rated voltage.
Buses 31a and 31c are connected via a transformer 34, and busses 31a and 31b are connected via a power flow controller 10. By providing the main transformer of the power flow control device 10 with a transforming capability, it becomes possible to connect such grids having different rated voltages. Figure 5 shows the flow control at this time.
6 is similar to the case shown in FIG. 6, for example, when controlling the power flow 32a and 32c from the bus 31a, the power flow 32
In order to increase a, the phase angle α of the power flow controller 10
Control to reduce the phase difference angle of the system or increase the compensation degree of series compensation. Conversely, in order to increase the power flow 32c, the phase difference angle of the system is increased by controlling the phase angle α of the power flow controller 10, or the compensation degree of series compensation is decreased. In this way, it is possible to create a power flow distribution that minimizes the loss in the power transmission line, or to create a power flow distribution that can supply the power required by the loads scattered in each part without being affected by the impedance of the power transmission line. It will be possible.

FIG. 58 shows the control range of the power flow by the power flow controller of the present invention. If there is no phase adjuster, P
When the electric power of 1 is sent, the operating point 24 of the system becomes the point on the electric power phase difference angle of θ1 which is the point on the electric power phase difference angle curve 21a of the system. The operating point 24 moves on the electric power phase difference angle curve 21a as the power flow increases and decreases, and is stable in the operating range 22 from point A to point B where the phase difference angle is 90 ° or less. The adjustment range of the phase angle is −δ1 (power phase difference angle curve 21b) to +.
When a phase adjuster having δ2 (power phase difference angle curve 21c) is used, the control range is point A, point F, point B, point C, point D which is the stability operation region on the power phase difference angle curves 21b and 21c. It becomes the range 23a surrounded by. On the other hand, when the power flow controller of the present invention is used, the phase adjustment range −δ1
In addition to + δ2, the power phase difference angle curves 21a, 21b, and 21c are 21
Since it changes to d, 21e, and 21f, the control range is expanded to a range including the range 23a which is the stability operation region and the range 23b surrounded by the points E, F, A and D. In particular, if the compensation degree of the system reactance by the series compensator 11 is made variable, the power flow can be controlled at any point within the control ranges 23a and 23b. As described above, it is understood that the power flow control device of the present invention has a wide power flow control range.

59 to 61 show transient changes in the operating point at the time of system failure. FIG. 59 shows the case of a conventional system without the power flow compensator of the present invention. Electric power P1
(= Generator output), operating point 24 of the system with phase difference angle θ1
Changes according to the operation locus 25 at the time of system failure. First, when the generator output decreases due to the occurrence of a system failure, the generator begins to accelerate and the phase difference angle opens. When the fault is removed at the phase difference angle θ2, the generator output recovers, but the phase difference angle continues to accelerate up to θ3 due to the inertial force. Here, the region 26 corresponds to the acceleration energy of the generator, and the region 27 corresponds to the deceleration energy of the generator. When the acceleration energy 26 exceeds the deceleration energy 27, the phase difference angle exceeds 90 °, and the generator goes out of step.

On the other hand, when the power flow controller of the present invention is used, it operates as shown in FIG.
When the system is operating at the same electric power P1 as in FIG. 59, the system causes the phase difference angle θ4 due to the series compensation function of the power flow controller.
It can be operated at the operating point 24a of the system (<θ1). The power phase difference angle curve 21d upon failure recovery is the power phase difference angle curve 21
Since it is larger than a, the acceleration energy of the generator 26a
On the other hand, the deceleration energy 27a becomes sufficiently large, which makes it difficult for the generator to step out. Further, the operation locus 25a at the time of system failure is an operation in which the phase difference angle increases to θ5 and then recovers to θ4. At this time, the phase difference angle θ5 is an angle sufficiently smaller than 90 °, and the generator loses step. The margin is increased and the system becomes stable. In addition, power P2 (> P
1) When the system is operating at the operating point 24b with the phase difference angle θ6, the acceleration energy 26b can be obtained by operating the operating point 24b on the operation locus 25b by the series compensation function and the phase control function of the power flow controller. On the other hand, sufficient deceleration energy 27b can be obtained at the phase difference angle θ7 within the phase control region so that the generator is not out of step and the out-of-step of the generator can be prevented.

Alternatively, as shown in FIG. 61, in the case of the transmission power P2, the operation on the power phase difference angle curve 21a without the power flow controller is performed by the phase adjusting function of the power flow controller of the present invention. Point 24b (phase difference angle θ6)
Can be set to the operating point 24c (phase difference angle θ8 <θ6) of the system on the power phase difference angle curve 21e. By doing so, the phase difference angle can be made small, so that the synchronizing power with the system of the generator becomes strong, and the operating point 24c of the system fluctuates like the operation locus 25c at the time of system failure. Since θ9 (<θ6), there is a sufficient phase difference angle until the generator goes out of step, and the system can be stabilized.

In this way, the power flow controller according to the present invention can stabilize the system in response to transient power fluctuations.

Further, in the power flow controller of the present invention described above, the compensation degree of series compensation and the control of the phase angle are as follows.
It is possible to use a semiconductor switch configured by using semiconductor elements such as thyristors or GTOs, and it is more effective to combine a plurality of these semiconductor elements in series and parallel to use as one semiconductor switch. It becomes possible to control.

[0132]

According to the present invention, the power flow control of the electric power system can be controlled over a wide range as compared with the conventional phase adjuster and the like. In other words, since the power flow distribution is determined by the impedance of the system and the phase difference angle of each power source, it may not be possible to send power to a place where a load that requires power exists. By controlling the power flow distribution by using the power flow controller,
An appropriate power flow distribution that can sufficiently supply the electric power required by the load can be obtained. Further, even for transient or long-cycle fluctuations of the power system, the fluctuations can be suppressed by controlling the phase difference angle and the degree of compensation, and the system can be stabilized.

Further, according to the present invention, the series capacitor 311 and the semiconductor switch 3 which are the constituent elements of the series compensation device.
13 and the like can be arranged at a lower position than before,
In areas where many earthquakes occur, the problem of seismic resistance can be easily solved, and work at high places during construction and maintenance inspection of series compensator is reduced. Further, since the semiconductor switch can be easily separated from the system while continuing series compensation, safe maintenance and inspection can be performed. In addition, part or all of the series compensator can be stored in a ground-based structure or a closed container, so by applying it to a gas-insulated switchgear, lightning strikes on the series compensator or equipment failure due to flying objects can occur. The probability can be reduced, and the reliability and operating rate of the device can be improved.

[Brief description of drawings]

FIG. 1 is a circuit configuration example of a power flow controller according to an embodiment of the present invention.

FIG. 2 is a circuit configuration example of a power flow controller according to an embodiment of the present invention.

FIG. 3 is a circuit configuration example of a power flow controller according to an embodiment of the present invention.

FIG. 4 is a circuit configuration example of a power flow controller according to an embodiment of the present invention.

FIG. 5 is a circuit configuration example of a phase adjustment device section according to an embodiment of the present invention.

FIG. 6 is a circuit configuration example of a phase adjustment device section in one embodiment of the present invention.

FIG. 7 is a circuit configuration example of a series compensation device section in one embodiment of the present invention.

FIG. 8 is a circuit configuration example of a series compensation device section according to an embodiment of the present invention.

FIG. 9 is a circuit configuration example of a power flow controller according to an embodiment of the present invention.

FIG. 10 is a circuit configuration example of a power flow controller according to an embodiment of the present invention.

FIG. 11 is a circuit configuration example of a series compensation device section according to an embodiment of the present invention.

FIG. 12 is a circuit configuration example of a series compensation device section in one embodiment of the present invention.

FIG. 13 is a circuit configuration example of a series compensation device section in one embodiment of the present invention.

FIG. 14 is a circuit configuration example of a series compensation device section in one embodiment of the present invention.

FIG. 15 is a circuit configuration example in which the semiconductor switch section is arranged on the low voltage side in the series compensation device section in the embodiment of the present invention.

FIG. 16 is a voltage vector when the semiconductor switch unit is arranged on the low voltage side in the series compensation device unit according to the embodiment of the present invention.

FIG. 17 is a diagram illustrating a series compensator section according to an embodiment of the present invention when the semiconductor switch section is arranged on the low voltage side,
One embodiment of the present invention in which the transformer connection is changed.

FIG. 18 is a circuit diagram of a series compensator section according to an embodiment of the present invention, in which a semiconductor switch section is arranged on a low voltage side,
An embodiment of the present invention in which the installation place of the semiconductor switch is changed.

FIG. 19 is a diagram illustrating a case where the semiconductor switch unit is arranged on the low voltage side in the series compensation device unit according to the embodiment of the present invention;
An example of the present invention using an autotransformer.

FIG. 20 is a diagram illustrating a case where the semiconductor switch unit is arranged on the low voltage side in the series compensation device unit according to the embodiment of the present invention.
An embodiment of the present invention in which the potential of the entire device is changed.

FIG. 21 is a diagram illustrating a case where the semiconductor switch unit is arranged on the low voltage side in the series compensation device unit according to the embodiment of the present invention;
One embodiment of the present invention having a bypass circuit.

FIG. 22 is a diagram illustrating a case where the semiconductor switch unit is arranged on the low voltage side in the series compensation device unit according to the embodiment of the present invention;
The modification of FIG. 20 using an autotransformer.

FIG. 23 is a diagram illustrating a series compensator section according to an embodiment of the present invention when the semiconductor switch section is arranged on the low voltage side.
The modification of FIG. 21 using an autotransformer.

FIG. 24 is a diagram illustrating a case where the semiconductor switch unit is arranged on the low voltage side in the series compensation device unit according to the embodiment of the present invention;
An example of installation of the device of FIG.

25 is an embodiment of the present invention in which the device of FIG. 15 is applied to a three-phase power transmission line.

FIG. 26 is a side view of FIG. 25.

FIG. 27 is a modification of FIG. 25.

FIG. 28 is a modification of FIG. 25.

FIG. 29 is an example of a conventional power flow control method for a power system.

FIG. 30 shows an example of a conventional series compensation device.

FIG. 31 shows an example of a conventional series compensation device.

FIG. 32 is a configuration example of a line power flow control amount calculation circuit used for controlling the power flow control device of the present invention.

FIG. 33 is a configuration example of a system frequency control amount calculation circuit used for control of the power flow controller of the present invention.

FIG. 34 is a configuration example of a generator speed control amount calculation circuit used for control of the power flow controller of the present invention.

FIG. 35 is a configuration example of a series compensator control amount arithmetic circuit used for controlling the power flow controller of the present invention.

FIG. 36 is a configuration example of a phase adjustment device control amount calculation circuit used for control of the power flow controller of the present invention.

FIG. 37 is a configuration example of a composite control amount calculation circuit used for control of the power flow controller of the present invention.

FIG. 38 is a configuration example of an impedance control circuit used for controlling the power flow controller of the present invention.

FIG. 39 is a configuration example of the converter voltage control circuit of the phase adjusting device used for controlling the power flow controller of the present invention.

FIG. 40 is a configuration example of an ignition phase control signal generation circuit of a series compensation device used for controlling the power flow controller of the present invention.

FIG. 41 is a configuration example of a coordinated control circuit for the phase adjustment device and the series compensation device used for controlling the power flow controller of the present invention.

FIG. 42 is a control range characteristic example of a series compensator used for controlling the power flow controller of the present invention.

FIG. 43 shows an example of control characteristics of the cooperative control circuit of FIG. 41.

44 shows an example of control characteristics of the cooperative control circuit of FIG. 41.

45 shows an example of control characteristics of the cooperative control circuit of FIG. 41.

FIG. 46 shows an example of control characteristics of the cooperative control circuit of FIG. 41.

FIG. 47 shows an example of control characteristics of the cooperative control circuit of FIG. 41.

48 shows an example of control characteristics of the cooperative control circuit of FIG. 41.

FIG. 49 shows an example of control characteristics of the cooperative control circuit of FIG. 41.

50 shows an example of control characteristics of the cooperative control circuit of FIG. 41.

FIG. 51 shows an example of the overall configuration of a series compensation device used in the power flow controller of the present invention.

52 is a configuration example of the control circuit shown in FIG. 51.

FIG. 53 is a waveform example of each part for showing the operation of FIGS. 51 and 52.

FIG. 54 is a waveform example showing the state of the power system when the ignition phase control is not performed on the semiconductor switch of the series compensation device used in the power flow controller of the present invention. An example of the overall configuration.

FIG. 55 is a waveform example showing the state of the power system when the ignition phase control is performed on the semiconductor switch of the series compensation device used in the power flow controller of the present invention. An example of the overall configuration.

FIG. 56 is an example of application of the power flow controller of the present invention to a system.

FIG. 57 shows an example of application of the power flow controller of the present invention to a system.

FIG. 58 is a control range of the power flow controller according to the present invention.

FIG. 59 shows a transitional change in the operating point of the system when the system fails without the power flow controller of the present invention.

FIG. 60 is a transitional change in the operating point of the system at the time of system failure when the power flow controller of the present invention is applied.

FIG. 61 is a transient change in the operating point of the system at the time of system failure when the power flow controller of the present invention is applied.

[Explanation of symbols]

10 ... Power flow controller, 11, 11a, 11b, 11
c, 11d, 110, 310 ... Series compensation device, 12 ... Main transformer, 12a, 12b, 12c ... Main transformer winding, 1
3, 13a, 13b ... Winding of adjusting transformer, 13c ... Voltage adjusting tap, 14 ... Neutral point, 14a ... Connection terminal with neutral point, 15 ... Voltage generating converter, 21a, 21b, 21
c, 21d, 21e, 21f ... Power phase difference angle curve, 22 ...
Operating range, 23a, 23b ... Control range, 24, 24a,
24b ... Operating point of system, 25, 25a, 25b, 25c
... motion locus, 26, 26a, 26b ... acceleration energy,
27, 27a, 27b ... deceleration energy, 31a, 31
b, 31c ... Bus, 32a, 32b, 32c ... Power flow, 33 ... Load, 34, 111, 316a, 316b ...
Transformer, 112, 314a, 314b, 314c, 31
4d, 314e ... Switchgear, 120 ... Phase adjuster, 20
0, 326 ... Control circuit, 201 ... System voltage signal, 202
... system current signal, 203 ... power flow calculation circuit, 204a, 2
04b, 204c ... Reset filter, 205a, 20
5b, 205c, 205d, 205e ... Phase compensation circuit,
206a ... Low-pass filter, 207a, 207b, 2
07c, 207d, 207e, 207f, 207g, 2
07h, 207i, 207j ... Amplifier, 208 ... Line power flow control amount, 209 ... System voltage signal or system current signal,
210b, 210c ... Frequency meter, 211 ... System frequency control amount, 212 ... Generator speed signal, 213 ... Generator speed control amount, 214 ... Switching circuit, 215 ... Differential calculator 216
... Series compensation control command value 216a, 216b, 216c
... Serial compensation control signal, 217 ... Phase control command value, 217
a, 217b, 217c ... Phase adjustment control amount, 218a ...
Phase adjusting device primary side voltage signal, 218b ... Phase adjusting device secondary side voltage signal, 219 ... Phase difference calculation circuit, 220 ... Tap switch selection circuit, 221 ... Tap switch control signal 222 ... Firing phase control circuit, 223 340 ... Ignition phase control signal, 224 ... Voltage signal across power flow controller, 225 ... Current signal in power flow controller, 226 ... Impedance calculation circuit, 227 ... Reference voltage generation circuit, 228
... Reference voltage signal, 229 ... Control amount dividing circuit, 230 ... Impedance control command value, 231, ... Impedance control signal, 232 ... Tap switch switching circuit, 240 ...
Uncontrollable region, 241 ... Resonance point, 242 ... Total value of control reactance amount, 243 ... Control reactance amount by series compensator, 244 ... Control reactance amount by phase adjusting device, 311, 311a, 311b ... Series capacitor, 311v ... Voltage vector across the series capacitor, 3
12 ... Overvoltage protection device, 313 ... Semiconductor switch, 31
3a ... Reactor, 313v ... Semiconductor switch end voltage vector, 315 ... Series transformer, 316c ... Three-phase transformer, 316av1, 316av2, 316bv1, 316bv2 ... Transformer end voltage vector, 317a, 317b ... Support insulator, 3
18 ... Ground standing building or closed container, 319 ... Series capacitor part, 320 ... Thyristor, 321 ... Bypass switch, 322 ... Voltage detector, 323 ... Voltage signal,
324 ... Current detector, 325 ... Current signal, 327 ... Control signal, 328, 329 ... Filter, 330 ... Voltage signal,
331 ... Current signal, 332 ... Filter section, 333 ... Current direction determination section, 334, 335, 339 ... Comparator, 336
... voltage phase determination unit, 337 ... absolute value circuit, 338 ... voltage absolute value signal, 341 ... firing phase control signal source, 342 ... firing phase signal, 343 ... forward current phase signal, 344 ... reverse current phase signal , 345, 346 ... AND operator, 3
47 ... Forward firing phase signal, 348 ... Reverse firing phase signal, 349, 350 ... Gate pulse circuit, 351 ... Forward gate pulse, 352 ... Reverse gate pulse, 353
... pulse generator, 400 ... transmission line, 401 ... gas insulated switchgear, 410 ... power system, 420 ... bushing, 42
4 ... Transient voltage and current.

Claims (76)

[Claims] 1. A power flow controller for controlling a power transmission state of a power system, comprising: a first winding having at least one Y connection; a second winding that is combined with the first winding; A power flow controller, comprising a power flow compensating means connected in series with the Y connection of the first winding and compensating for a power flow state of the power system. 2. The power flow controller according to claim 1, wherein a capacitor as power flow compensating means and a control means by a semiconductor element in parallel with the capacitor are provided, and a power flow compensating means for compensating the power transmission state of the power system is provided. An electric power flow controller characterized by being provided. 3. The power flow controller according to claim 2, wherein the voltage applied to the capacitor is equal to or lower than the system voltage of the power system. 4. The power flow control device according to claim 1, wherein the power flow control is a transformer for stepping up or down the system voltage between the first winding and the second winding. apparatus. 5. The power flow controller according to claim 1, wherein the second winding is a Δ-connection winding. 6. The power flow controller according to claim 1, further comprising a third winding different from the first and second windings, and the third winding is a Δ-connection winding. A power flow control device characterized by the above. 7. The power flow controller according to claim 1, wherein the first winding or the second winding is provided with winding adjusting means for changing a winding state. 8. The electric power flow controller according to claim 7, wherein the winding adjusting means changes the winding state of the first winding or the second winding to apply the winding to the first winding. A power flow control device characterized by changing a phase difference between a primary voltage and a secondary voltage applied to the second winding. 9. The power flow controller according to claim 7, wherein the winding adjusting means is a switch for switching a plurality of taps drawn from the first winding or the second winding. Power flow control device. 10. A power flow controller according to claim 9, wherein the switch comprises a mechanical contact. 11. A power flow controller according to claim 9, wherein the switch is a switch formed by using a semiconductor element. 12. The power flow controller according to claim 1, wherein the voltage generated in the second winding is controlled by a converter. 13. The power flow controller according to claim 1, wherein the power flow compensator is connected between a low-voltage side terminal of a Y-connection winding of the first transformer and a neutral point of the first transformer. A power flow controller, wherein the neutral point is connected to a ground point or a ground impedance. 14. The power flow controller according to claim 1, further comprising a frequency converter that generates an AC voltage as the power flow compensating means, and the frequency converter is connected to the first winding. Power flow control device. 15. The power flow controller according to claim 1, wherein the first winding or the second winding is a transformer winding for phase adjustment. 16. The power flow controller according to claim 15, wherein a phase adjusting voltage generated by an AC voltage by a converter is used as the phase controlling means of the phase adjusting transformer. . 17. The power flow control device according to claim 16, wherein the power flow control device comprises a transformer that connects the converter to the phase adjustment transformer, and a switch device that connects or disconnects the phase adjustment transformer to a grid. And power flow controller. 18. The power flow controller according to claim 1, wherein the low-voltage side winding terminal of the first transformer including the first winding is connected to another transformer, and the first transformer is connected. Voltage generated by the second transformer by combining the voltage generated by the second transformer and the voltage generated by the second transformer, and the phase difference between the primary side voltage and the secondary side voltage of the first transformer An electric power flow control device characterized by being changed by. 19. The power flow controller according to claim 18, wherein the voltage generated in the second transformer is changed by means for controlling the transformation ratio of the second transformer. Control device. 20. A power flow controller including a compensating capacitor inserted in a power line, comprising a semiconductor switch for controlling a compensation amount of the compensating capacitor, wherein a potential applied to the semiconductor switch is equal to or lower than a ground potential of the power line. A power flow control device characterized by the above. 21. The power flow controller according to claim 20, wherein a transformer is provided between the power line and the ground, the semiconductor switch is connected to a winding of the transformer, and a potential applied to the semiconductor switch is applied to the power line. An electric power flow control device characterized in that the electric potential is set below ground potential. 22. The power flow controller according to claim 20, wherein a value of a current flowing through the semiconductor switch is equal to or larger than a value of a current flowing through the power line. 23. The power flow controller according to claim 21, wherein one end of a first winding of the transformer is connected to the power line, and the other end of the first winding is grounded. A power flow controller, wherein one end of two windings is connected to the semiconductor switch. 24. The power flow controller according to claim 21, wherein the transformer comprises an autotransformer, one end of the winding is connected to the power line, and the other end of the winding is grounded. A power flow control device, wherein the semiconductor switch is connected to a voltage-divided terminal of the autotransformer. 25. The power flow controller according to claim 20, wherein the compensation capacitor is inserted in series with the power line. 26. The power flow controller according to claim 20, wherein the semiconductor switch is connected in parallel to the compensation capacitor. 27. A power flow controller for a power system, comprising a series capacitor inserted in a transmission line and a protection device for bypassing both ends of the capacitor, the power flow controller having two transformers, each of the transformers being provided. One end of the first winding is grounded, the other end is connected to both terminals of the series capacitor, and the second winding of each of the two transformers is connected in parallel via a semiconductor switch. A characteristic power flow controller. 28. The power flow controller according to claim 27, wherein the other end of each of the two transformers is connected to both terminals of the series capacitor via a switchgear. 29. The power flow controller according to claim 27, wherein at least one terminal of the second windings of the two transformers is grounded. 30. A power flow controller for a power system, comprising a series capacitor inserted in a power transmission line and a protection device bypassing both ends of the capacitor, the power flow controller having two autotransformers. One end of each winding is grounded, the other end is connected to both terminals of the series capacitor, and the midpoint of each winding of the two autotransformers is connected via a semiconductor switch. A power flow control device characterized by the above. 31. The power flow controller according to claim 30, wherein the other end of each of the two transformers is connected to both terminals of the series capacitor via a switchgear. 32. The winding ratio and polarity of the two transformers or autotransformers are adjusted so that the ground potential of the semiconductor switch is equal to or lower than the ground potential of the power transmission line. A characteristic power flow controller. 33. A power flow controller for a power system, comprising a series capacitor inserted in a transmission line and a protection device bypassing both ends of the capacitor, the power flow controller having two transformers, each of the transformers One end of the primary winding and each secondary winding is grounded, each other end of the primary winding is connected to the power transmission line, and the secondary winding is connected via the series capacitor in which a semiconductor switch is connected in parallel. A power flow control device characterized in that the other ends of the lines are connected. 34. The power flow controller according to claim 33, further comprising a switchgear for separating the two transformers from the power transmission line. 35. The power flow controller according to claim 33, wherein a switchgear is connected between the switchgear for separating from the power transmission line and the two transformers. 36. The power flow according to claim 33, wherein a winding ratio and a polarity of the two transformers are adjusted so that a ground potential of the semiconductor switch is equal to or lower than a ground potential of the power transmission line. Control device. 37. A power flow controller including a compensating capacitor inserted in a power line, wherein a transformer is provided between the power line and ground, and a semiconductor switch is provided for controlling a compensation amount of the compensating capacitor. The semiconductor switch is connected to the winding of the semiconductor switch, the semiconductor switch is connected in parallel to the compensation capacitor, a protector is provided between the semiconductor switch and the transformer, and the potential applied to the semiconductor switch is An electric power flow controller characterized in that the electric potential of the electric power line is set to be lower than the ground potential. 38. The power flow controller according to claim 37, wherein an overvoltage protection device is provided as the protector. 39. The power flow controller according to claim 37, wherein a breaker is provided as the protector. 40. The power flow controller according to claim 37, wherein the compensation capacitor is connected to a winding of the transformer, and the protector is provided between the compensation capacitor and the transformer. Power flow control device. 41. The power flow controller according to claim 37, wherein one end of a first winding of the transformer is connected to the power line and the other end of the first winding is grounded. A power flow controller, wherein one end of two windings is connected to the semiconductor switch. 42. The power flow controller according to claim 37, wherein the compensation capacitor is connected between the semiconductor switch and the transformer. 43. The power flow controller according to claim 37, wherein the semiconductor switch is grounded. 44. The power flow controller according to claim 37, wherein the compensation capacitor is grounded. 45. A power flow controller including a compensating capacitor inserted in a power line, comprising a semiconductor switch for controlling a compensation amount of the compensating capacitor, wherein the compensating capacitor is disposed at a position of a ground potential of the power line. A power flow controller, wherein a transformer for setting the potential applied to the semiconductor switch to be less than or equal to the ground potential of the power line is arranged between the compensation capacitor and the semiconductor switch. 46. The power flow controller according to claim 45, wherein the transformer is grounded and is arranged between the compensation capacitor and the semiconductor switch. 47. The power flow controller according to claim 45, wherein the compensation capacitor is inserted in series with the power line, and a transformer is arranged in parallel with the compensation capacitor at both ends of the compensation capacitor. A power flow control device characterized by the above. 48. The power flow controller according to claim 45, wherein the transformer is arranged at symmetry positions on the central axes of both ends of the compensation capacitor. 49. The power flow controller according to claim 45, wherein the semiconductor switches are arranged on the central axes of both ends of the compensation capacitor. 50. The power flow controller according to claim 45, wherein the semiconductor switch is arranged between the transformers. 51. The power flow controller according to claim 45, wherein the compensation capacitors are inserted in series for each of the three-phase power lines and for each of the power lines of each phase. 52. The power flow controller according to claim 45, wherein the compensation capacitors for at least two phases of the three-phase power lines are arranged to face each other. 53. The power flow controller according to claim 45, wherein a transformer is arranged parallel to the compensation capacitor corresponding to both ends of the compensation capacitor for at least two phases of the three-phase power line, A power flow control device characterized in that transformers for each phase are arranged facing each other. 54. A power flow controller including a compensating capacitor inserted in a power line, comprising an insulating switch on the power line, and a semiconductor switch for controlling a compensation amount of the compensating capacitor. An electric power flow control device characterized in that a power line from the vertical direction to the semiconductor switch is provided with respect to the arrangement direction. 55. The power flow controller according to claim 54, wherein an insulating switch is provided on each of the power lines for every three phases, and the semiconductor is arranged in a direction perpendicular to a direction in which the insulating switch for each phase is arranged. A power flow control device characterized in that a power line to a switch is provided. 56. The power flow controller according to claim 54, wherein the compensation capacitor is arranged on a power line path from the insulating switch to the semiconductor switch. 57. The power flow controller according to claim 54, wherein a protector is provided on a power line path from the insulating switch to the semiconductor switch. 58. The power flow controller according to claim 54, wherein the protection device is arranged between the compensation capacitor and the insulating switch. 59. The power flow controller according to claim 54, wherein a semiconductor switch for each phase is arranged in parallel with the insulating switch for each phase. 60. The power flow controller according to claim 54, wherein the compensation capacitor is arranged on a power line path from the insulating switch to the semiconductor switch, and is parallel to the insulating switch for each phase. A power flow controller, wherein the compensation capacitors are arranged for each phase. 61. A power flow controller comprising a compensating capacitor connected to a power line, wherein a semiconductor switch for controlling a charging / discharging state of the compensating capacitor, and a current detecting means for detecting a current flowing through the compensating capacitor. A voltage detection means for detecting a voltage applied to the compensation capacitor; a current filter means for extracting only a specific frequency component of the detected current by the current detection means; and a specified voltage detected by the voltage detection means. A voltage filter means for extracting only the frequency component, a current direction determination means for determining the direction of the current to be passed through the semiconductor switch based on the output of the current filter means, and the phase of the voltage applied to the semiconductor switch A voltage phase determination means for determining based on the output of the voltage filter means, and the current direction determination means Serial voltage phase determining means determines the power flow controller is characterized in that a switching signal generating means for outputting a switching signal for controlling the semiconductor switch based on. 62. The power flow controller according to claim 61, further comprising voltage phase determining means for determining that the phase of the voltage applied to the semiconductor switch is near zero based on the output of the voltage filter means. A power flow control device characterized by the above. 63. The power flow controller according to claim 61, wherein a current flowing from the generator side of the power system to the load side via the compensation capacitor is forward current, and the current flowing through the compensation capacitor is forward direction. A reverse current is a current flowing in the opposite direction to the current, and a forward voltage is a voltage when the voltage on the generator side is high with reference to the load side of the compensation capacitor.
When a voltage in the reverse direction to the forward voltage is a reverse voltage, the semiconductor switch is composed of a pair of semiconductor elements connected in anti-parallel to each other, and the current direction determining means is one of the semiconductor elements. A period in which a forward current should flow and a period in which a reverse current should flow in the other semiconductor element are determined from the output of the current filter means, and the voltage phase determination means is the reverse phase applied to one semiconductor element. A power flow controller, wherein the phase of the directional voltage and the phase of the forward voltage applied to the other semiconductor element are determined based on the output of the voltage filter means. 64. The power flow controller according to claim 61, wherein a current flowing from a generator side of the power system to a load side through the compensation capacitor is a forward current, and a forward current is passed through the compensation capacitor. Is the reverse current flowing in the reverse direction, the forward voltage is the voltage when the generator side voltage is high with reference to the load side of the compensation capacitor,
When a voltage reverse to the forward voltage is a reverse voltage, the semiconductor switch includes a pair of semiconductor elements connected in antiparallel to each other, and one semiconductor element is applied with the reverse voltage. That is, the semiconductor element is turned on by the switching signal only on the condition that the other semiconductor element is turned on by the switching signal only on the condition that the forward voltage is applied. The period in which the forward current should flow and the period in which the reverse current should flow in the other semiconductor element are determined from the output of the current filter means, and the voltage phase determination means is the reverse direction applied to one semiconductor element. A power flow controller, wherein the voltage and the phase of the forward voltage applied to the other semiconductor element are determined based on the output of the voltage filter means. 65. A power flow controller according to claim 61, wherein said current filter means is a current filter for extracting a commercial frequency component from the detected current of said current detection means, and said voltage filter means is a voltage filter. A power flow controller comprising a voltage filter for extracting a commercial frequency component from the detection voltage of the detection means. 66. The power flow controller according to claim 65, wherein the current filter and the voltage filter are bandpass filters that pass only commercial frequency components of an electric power system. Power flow control device. 67. The power flow controller according to claim 61, wherein the voltage phase determination means generates a voltage absolute value signal generating means for generating a voltage absolute value signal indicating an absolute value of an output signal of the voltage filter means, It comprises an ignition phase signal generating means for comparing the absolute voltage signal and the ignition phase control signal indicating a predetermined voltage level and outputting an ignition phase signal when the phases of the two signals match. A power flow control device characterized by the above. 68. The power flow controller according to claim 61, wherein a current flowing from the generator side of the power system to the load side via a series capacitor is defined as a forward current, and the current is reverse to the forward current via the series capacitor. When the current flowing in the direction is the reverse current, the current direction determination means compares the output of the current filter means with the set value, and indicates the period in which the forward current should flow in one of the semiconductor elements. It is characterized by comprising reverse direction comparing means for generating a phase signal and forward direction comparing means for generating a forward current phase signal indicating a period in which a reverse current should flow in the other semiconductor element. Power flow controller. 69. A power flow controller according to claim 61, wherein said switching signal generation means generates a forward firing phase signal in accordance with the logic of the output of said current direction determination means and the output of said voltage phase determination means. Forward firing phase signal generating means, backward firing phase signal generating means for producing a backward firing phase signal according to the logic of the output of the current direction determining means and the output of the voltage phase determining means, and the forward Forward gate pulse generating means for generating a forward gate pulse as a switching signal for making the other semiconductor element conductive in response to the direction firing phase signal, and one semiconductor in response to the reverse firing phase signal. And a reverse gate pulse generating means for generating a reverse gate pulse as a switching signal for turning on the element. Power flow controller. 70. A power flow controller according to claim 61, wherein said switching signal generating means generates a forward firing phase signal according to a logical product of the output of said current direction determining means and the output of said voltage phase determining means. Forward firing phase signal generation means, reverse firing phase signal generation means for generating a reverse firing phase signal according to a logical product of the output of the current direction determination means and the output of the voltage phase determination means, and Forward gate pulse generating means for generating a forward gate pulse as a switching signal for making the other semiconductor element conductive in response to the forward firing phase signal, and one of the one in response to the backward firing phase signal. And a reverse gate pulse generating means for generating a reverse gate pulse as a switching signal for turning on the semiconductor element. Power flow controller. 71. The power flow controller according to claim 61, wherein the semiconductor switch is configured by connecting a plurality of semiconductor elements in series or in parallel. 72. A power flow controller including a compensation capacitor connected to a power system and a phase adjuster, wherein a reactance amount to be compensated in the power system is determined by the reactance amount by the compensation capacitor and the phase adjuster. An electric power flow controller characterized by controlling and combining reactance amounts. 73. The power flow controller according to claim 72, wherein an opening / closing switch is provided in parallel with the compensation capacitor. 74. The power flow controller according to claim 72, wherein a coil and a semiconductor switch are provided in parallel with the compensation capacitor. 75. The power flow controller according to claim 72, wherein a voltage applied to the compensation capacitor is equal to or lower than a system voltage of the power system. 76. The power flow controller according to claim 72, wherein a winding state of a winding connected to the power system as the phase adjuster is changed.