JPH08265973A - Compensation controller for power system - Google Patents

Abstract

PURPOSE: To prevent the transient characteristics or dynamic characteristics from deteriorating due to a series capacitor by detecting the electrical variables of a power system, generating a command value for a compensation voltage applying means based on the electrical variables thus detected and then applying a compensation voltage in series to a transmission line based on the command value. CONSTITUTION: Based on outputs delivered from a current detection means 8 and a voltage detection means 9, a power detection means 10 operates or detects power being transmitted on a transmission line 5. Based on the power thus detected, a command value generating means 11 delivers an insertion voltage command Vi* to a compensation voltage applying means 12 which applies a compensation voltage in series to the transmission line 5. Consequently, when a disturbance is generated due to resonance of a series capacitor 7 and a system reactance 6, an appropriate command value generating means 11 can deliver an insertion voltage for suppressing the disturbance to the compensation voltage applying means 12. With such constitution, the transient characteristics or dynamic characteristics can be prevented from deteriorating due to the series capacitor 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power system compensation control device for compensating a reactance voltage of a power system with a series capacitor.

[0002]

2. Description of the Related Art FIG. 11 is a diagram showing an example of a conventional AC power system compensation system using a series capacitor shown in "Measurement and Control Vol. 32, No. 9 (September, 1993) PP742-749". Is. In the figure, 1 is a power source on the power transmission side, 2 is a power transmission side bus, 3 is a power receiving side system, 4 is a power receiving side bus, 5 is a power transmission line, 6 is an inductance of the power system including the inductance of the power transmission line 5, and 7 is a series. Capacitors,
IL is the line current of the power transmission line 5.

In the above conventional compensation system in which the series capacitor 7 is provided on the line of the electric power system, when the electric power system inductance and thus the same reactance is large in long-distance high-power transmission, the reactance is canceled to improve the transmission limit. It is useful. In particular, there is an advantage over the compensation method using a power converter because the loss of the capacitor is extremely small and the cost is low.

[0004]

Since the conventional compensation control device for the electric power system is constructed as described above, when the power transmission line is turned on, at the time of a ground fault and at the time of recovery, at the time of switching the system, and other sudden voltage changes occur. At this time, the current of the resonance frequency component (transient component) due to the series capacitor 7 and the inductance 6 flows in addition to the current of the fundamental frequency component. Since this resonance frequency component is superimposed on the fundamental frequency component, a beat is generated and the amplitude and phase of the line current IL pulsate. Line current IL
12 is decomposed into the real axis component ILP and the imaginary axis component ILQ, the result is shown in FIG. That is, FIG. 7A shows a change with respect to time t, and FIG. 7B shows a locus. At this time, the pulsation frequency becomes a frequency that is the difference between the two frequencies. Of these, the actual shaft component ILP, that is, the pulsation of the active current, appears as the shaft torque pulsation of the generator and induces the shaft torsion vibration. In particular, there has been a problem that the shaft torsion vibration is further amplified when the frequency is close to the resonance frequency of the generator shaft. On the other hand, the imaginary axis component ILQ, that is, the pulsation of the reactive current, induces a voltage fluctuation. In addition to this, the series capacitor 7 generates a voltage obtained by integrating the current, whereas the inductance 6 generates a voltage proportional to the current differential, which causes a problem that transient characteristics and dynamic characteristics in control are deteriorated. In summary, in the series capacitor compensation method of the AC power system, there is a problem that the series capacitor 7 deteriorates transient characteristics and dynamic characteristics.

The present invention has been made in order to solve the above problems, and an object thereof is to obtain a compensation control device for a power system capable of preventing deterioration of transient characteristics and dynamic characteristics due to a series capacitor. To do.

Another object of the present invention is to obtain a compensation control device for a power system which can prevent transient line current pulsation.

Another object of the present invention is to obtain a compensation control device for a power system which can prevent transient pulsation of transmitted power.

Another object of the present invention is to obtain a compensation control device for a power system, which can realize more precise control of two components.

Another object of the present invention is to obtain a compensation control device for a power system, which can prevent transient pulsation of current or power by more economical compensation voltage applying means.

Another object of the present invention is to obtain a compensation control device for a power system, which can provide a simpler control method for the compensation voltage applying means.

Another object of the present invention is to obtain a power system compensation control device capable of improving the response characteristic of the compensation voltage applying means and hence the response characteristic of pulsation prevention.

The present invention also provides a compensation control device for a power system capable of improving the overcurrent withstanding capability or overload withstanding capability of the compensating voltage applying means or widening the variable control width required for system stabilization. To aim.

Another object of the present invention is to provide a power system compensation control device capable of preventing a local rise in line voltage and providing redundancy for a failure of the compensation voltage applying means. To do.

Another object of the present invention is to obtain a power system compensation control device capable of suppressing an overcurrent at the time of an accident.

A further object of the present invention is to obtain a compensation control device for a power system which can further improve the effect of suppressing overcurrent in the event of an accident.

[0016]

According to a first aspect of the present invention, there is provided a power system compensation control device, comprising: a power system including a series capacitor for compensating a reactance voltage of the power system.
Furthermore, a compensation voltage applying unit that is inserted in series in the line of the power system and that generates a voltage based on a command value, a compensation voltage applying unit, a unit for detecting an electrical variable of the power system, and an output of the detecting unit are received. And a command value generating means for generating a command value to the compensation voltage applying means.

According to a second aspect of the present invention, there is provided a power system compensation controller, comprising: a series capacitor for compensating the reactance voltage of the power system; and a current detecting means for detecting a line current flowing in the line of the power system or a proportional amount thereof. , A command value generating means for generating a command value for making the line current detected by the current detecting means a desired value, and a compensation voltage for the line of the power system based on the command value generated by the command value generating means. Compensation voltage applying means for applying.

According to a third aspect of the present invention, there is provided a power system compensation controller, comprising: a series capacitor for compensating the reactance voltage of the power system; and a current detecting means for detecting a line current flowing in the line of the power system or a proportional amount thereof. , Voltage detection means for detecting the voltage of the power system or a proportional amount thereof, and line power detected by the current detection means and power transmitted through the line from the system voltage detected by the voltage detection means. Power calculation means for calculating, command value generation means for generating a command value for making the power calculated by the power calculation means a desired value, and a power value of the power system based on the command value generated by the command value generation means Compensation voltage applying means for applying a compensation voltage to the line.

According to a fourth aspect of the present invention, there is provided a power system compensation control device according to the first to third aspects, wherein the command value generating means outputs a vector command value including at least two axis vector components, The compensation voltage applying means outputs a voltage vector based on the vector command value.

According to a fifth aspect of the present invention, there is provided a power system compensation control apparatus according to the first to fourth aspects of the invention, wherein the command value generating means sets a phase for making the compensation voltage orthogonal to the current of the line. The command value is stored.

According to a sixth aspect of the invention, there is provided a power system compensation control device according to the first to fifth aspects of the invention, wherein the command value generating means includes means for correcting the phase of the command value,
The correction of the phase adjusts the electric power or the electric power present in the compensation voltage applying means.

According to a seventh aspect of the invention, there is provided a power system compensation control device according to the first to sixth aspects of the invention, wherein the compensation voltage applying means comprises a static power converter.

According to an eighth aspect of the present invention, there is provided a power system compensation control device according to the first to sixth aspects of the invention, wherein the compensation voltage applying means is constituted by a winding AC machine.

According to a ninth aspect of the invention, there is provided a power system compensation control apparatus according to the first to eighth aspects, wherein the compensation voltage applying means is dispersedly installed in the power system.

According to a tenth aspect of the present invention, there is provided the power system compensation control device according to the first to ninth aspects of the invention, wherein the overcurrent detection detects that the line current of the line of the power system exceeds an upper limit value. And means for short-circuiting the capacitor when the overcurrent is detected by the overcurrent detection means.

According to an eleventh aspect of the present invention, in the power system compensation control apparatus according to the tenth aspect of the present invention, when the overcurrent is detected by the overcurrent detecting means, the compensation voltage applying means changes the system reactance. It provides a voltage drop that resonates with the voltage.

[0027]

According to another aspect of the present invention, there is provided a power system compensation control device, wherein the power system includes a series capacitor for compensating the reactance voltage of the power system. Compensation voltage applying means composed of a dependent voltage source for generating a voltage, detection means for detecting an electric variable of the power system, and command value generating means for receiving an output of the detection means and generating a command value for the compensation voltage applying means. Since the voltage from the dependent voltage source that does not have a resonance relationship with the reactance is inserted, the resonance problem is alleviated. Further, since the electric variable of the electric power system is fed back to the compensation voltage, even if pulsation occurs, a voltage that suppresses the pulsation can be applied. Further, since the combined system reactance is reduced by the series capacitor, even if the voltage to be applied from the compensation voltage applying means is lower, the effective and reactive power amounts can be sufficiently adjusted.

According to a second aspect of the present invention, there is provided a power system compensation control device, wherein a series capacitor for compensating the reactance voltage of the power system, a line current flowing through a line of the power system, or a current detecting means for detecting a proportional amount thereof. Command value generating means for generating a command value for making the line current detected by the current detecting means a desired value, and applying a compensation voltage to the line of the power system based on the command value generated by the command value generating means. By including the compensating voltage applying means, the voltage from the dependent voltage source that does not have a resonance relationship with the reactance is inserted, so that the resonance problem is mitigated. Further, since the line current of the power system is fed back to the compensation voltage, even if a pulsation occurs in the line current, a voltage that suppresses the pulsation can be applied.

According to a third aspect of the present invention, there is provided a power system compensation control device, wherein a series capacitor for compensating the reactance voltage of the power system, a line current flowing through a line of the power system, or a current detecting means for detecting a proportional amount thereof. Voltage detection means for detecting the voltage of the power system or a proportional amount thereof,
A power calculation unit that calculates the power transmitted through the line from the line current detected by the current detection unit and the system voltage detected by the voltage detection unit, and the power calculated by the power calculation unit are desired. By including a command value generating means for generating a command value to be a value and a compensation voltage applying means for applying a compensation voltage to the line of the power system based on the command value generated by the command value generating means, the reactance is reduced. Since the voltage from the dependent voltage source that does not have a resonance relationship with is inserted, the resonance problem is mitigated. Further, since the transmission power of the power system is fed back to the compensation voltage, even if a pulsation occurs in the transmission power, a voltage that suppresses the pulsation can be applied.

According to a fourth aspect of the present invention, in the power system compensation control device according to the first to third aspects of the present invention, the command value generating means outputs a vector command value consisting of at least two axis vector components, and the vector Since the compensating voltage applying means outputs a voltage vector based on the command value, feedback control can be performed on both the real axis and the imaginary axis component, and thus both the effective and invalid components, so that the pulsation and sway of both components can be suppressed. Further, if the detecting means also detects the biaxial components, it is possible to obtain the action of distinguishing both components and controlling them independently.

According to a fifth aspect of the present invention, in the power system compensation control device according to the first to fourth aspects of the invention, the command value generating means has a phase for making the compensation voltage orthogonal to the current of the line. By generating the command value, the average power interposed in the compensation voltage applying means is controlled to be substantially zero, and the effect of reducing or suppressing the average power can be obtained.

According to a sixth aspect of the present invention, there is provided a power system compensation control device according to the first to fifth aspects, wherein the command value generating means includes means for correcting (adjusting) the phase of the command value. By adjusting the power or the amount of power that is present in the compensating voltage applying means by correcting the phase, the position of the voltage and current on the AC side of the compensating voltage applying means can be adjusted by a very simple means of correcting (adjusting) the phase. The intervening power can be adjusted by adjusting the phase difference.

According to a seventh aspect of the invention, there is provided a power system compensation control device according to the first to sixth aspects of the invention, wherein the compensation voltage applying means comprises a static power converter. The response speed to the control of (1) becomes faster, and thus the response speed of the above-mentioned pulsation suppression and control of the real axis / imaginary axis two components becomes faster.

According to an eighth aspect of the present invention, there is provided a power line compensation control device according to the first to sixth aspects, wherein the compensation voltage applying means is a winding type AC machine. When the secondary current is controlled in consideration of the given primary current with respect to the desired primary voltage and thus the number of primary magnetic flux linkages, the desired primary voltage can be controlled. That is, it can be utilized as a dependent voltage source. Therefore, by using the winding type AC machine having a large overcurrent withstanding capability, the overcurrent withstanding capability and the overload withstanding capability of the compensation voltage applying means are increased.

According to a ninth aspect of the present invention, there is provided the power system compensation control apparatus according to the first to eighth aspects, wherein the compensation voltage applying means is dispersedly installed in the power system.
Therefore, in the case of concentrated installation, the line voltage changes abruptly at the installation point of the compensation voltage applying means, whereas in the case of distributed installation, local rapid changes in the line voltage can be avoided. Further, even if one compensating voltage applying means fails, the semiconductor element will be in a short-circuit state at the time of failure, so that the operation can be continued by another sound compensating voltage applying means.

According to a tenth aspect of the present invention, there is provided an electric power system compensation control device according to the first to ninth aspects of the present invention, which is an overcurrent detecting means for detecting that the line current of the electric power system exceeds an upper limit value. By providing short-circuiting means for short-circuiting the capacitor when an overcurrent is detected by the overcurrent detecting means, the series capacitor compensates for the line reactance during normal operation and the combined reactance is reduced. Therefore, a larger current change can be obtained at a lower voltage, and it becomes easier to adjust the current and power by the compensation voltage applying means. On the other hand, in the event of a ground fault, compensation by the series capacitor is lost, so the ground current is suppressed to a small level.

According to an eleventh aspect of the present invention, in the power system compensation control apparatus according to the tenth aspect of the invention, when the overcurrent is detected by the overcurrent detecting means, the voltage of the system reactance is detected by the compensation voltage applying means. Gives a harmonious voltage drop. Thus, in the case of claim 10, the system reactance voltage originally suppresses the current, whereas the compensating voltage applying means applies a voltage that sums with the reactance voltage, so that the ground fault current is further suppressed. It

[0038]

【Example】

Example 1. FIG. 1 shows an embodiment of the present invention. In FIG. 1, 6 is a system consisting of line reactance, transformer leakage reactance, positively inserted transformer leakage reactance and positively inserted current limiting reactance. Reactance, 7 is a series capacitor, 8 is current detection means, 9 is voltage detection means, 10 is power detection means, 11 is command value generation means, 12 is compensation voltage application means (dependent voltage source), and Vi ^* is voltage command value. (Vector or scalar),
IL is the line current (vector or scalar). As the compensation voltage applying means 12, a DC / AC power converter,
A static or rotating subordinate variable voltage source such as a high frequency link type cycloconverter or a winding type AC machine may be used. The same reference numerals indicate the same means or equivalent means.

In the above embodiment, for simplification, the power detection means 10 can be omitted and the compensation voltage application means 12 can be controlled in response to the current detection means 8 representing the line current. At this time, various controls can be performed by giving the insertion voltage Vi corresponding to the detected current IL, but details will be described in the embodiment below, and here, the case of controlling in response to electric power will be described. .

Here, the series capacitor 7 cancels the system reactance 6 to reduce the combined reactance, and the line current changes more sensitively to the change of the insertion voltage Vi. That is, a lower insertion voltage is required, and the required capacity of the compensation voltage applying means 12 can be reduced.

Now, receiving the outputs from the current detection means 8 and the voltage detection means 9, the power detection means 10 calculates or detects the power transmitted through the power transmission line 5. Then
According to this electric power, the command value generating means 11 causes the insertion voltage command V
i ^* is output, and the compensation voltage applying means 1 receives this command value.
2 applies a compensation voltage Vi in series with the line. At this time, the command value generating means 11 is provided with a transfer characteristic for suppressing fluctuation of the power (at least with a differential transfer characteristic), feedback control is performed according to a deviation with respect to desired power, and variation power is used. It is possible to adopt a method of providing a transfer characteristic that suppresses fluctuation of electric power. Furthermore, if a voltage orthogonal to the line current and having a polarity opposite to the voltage of the system reactance 6 is inserted, the transmission power increases, and if a voltage having the same polarity is inserted, the transmission power decreases, so this mechanism is used. be able to. Furthermore, when receiving a desired value of transmitted power as a command from the outside, a command can be given from a higher-order system stabilization control means (for example, power system stabilizer PSS).

As a result, the series capacitor 7 produces a voltage proportional to the time integral value of the current and the system reactance 6 produces a voltage proportional to the time derivative of the current only with the series capacitor compensation, thus causing the resonance problem. On the other hand, the compensation voltage applying means 12 can insert a free voltage which is neither of them. Therefore, when a fluctuation due to resonance between the series capacitor 7 and the system reactance 6 is about to be generated, the compensation voltage applying means 12 can give an insertion voltage for suppressing the fluctuation by the appropriate command value generating means 11. Therefore, it is possible to reduce or suppress the LC resonance phenomenon in the compensation system based on the compensation by the series capacitor 7 which is low in loss and economical and the adverse effects caused by the ripple. That is, transient characteristics and dynamic characteristics in the series capacitor compensation method can be improved.

In summary, of the steady compensation of the reluctance voltage, the basic portion is compensated by the low-loss and economical series capacitor 7, and the compensation voltage applying means 12 is provided as a supplementary part where dynamic characteristics are involved. The LC resonance phenomenon and its adverse effects can be reduced or suppressed. In particular, in the case of a power line having a generator on the power transmission end side, it is also noted that it has an effect of preventing shaft torsion resonance due to torque pulsation of the generator. Further, the required voltage of the compensation voltage applying means 12 is lowered by using the compensation voltage applying means 12 and the series capacitor 7 together, and the required capacity is reduced.

Example 2. FIG. 2A is a diagram showing an embodiment relating to the compensation voltage applying means 12, and in FIG.
Is an insulating transformer having a primary winding 311 and a secondary winding 312 connected in series to the transmission line 5, and 33 is a secondary winding 312.
A static DC / AC power converter whose AC side terminal is connected to the power converter 35, and a DC capacitor 35 connected to the DC terminal of the static power converter 33. The static power converter 33 may be a voltage control type that controls an output voltage in a current source type,
In this case, a DC reactor can be used instead of the DC capacitor 35. Further, a high frequency link type cycloconverter having a high frequency circuit (high frequency capacitor) on the anti-power system side may be used. In any case, some kind of voltage command V
Anything that receives the i ^* and controls the output voltage may be used.

By configuring the compensating voltage applying means 12 by the static power converter 33, the response speed to the control of the compensating voltage applying means 12 becomes faster, and eventually the pulsation is suppressed and the actual voltage, current, power, etc. are suppressed. The response speed of control of the axis imaginary axis two components becomes faster. As a result, the effect of improving the response speed of system stabilization control can be obtained. The details will be described later in Examples.

Example 3. FIG. 2B is a diagram showing another embodiment of the compensation voltage applying means, in which 50 is a winding type AC machine having a primary winding 50a and a secondary winding 50b.
Reference numeral 00 is an excitation control device for the secondary winding 50b. The wound-type AC machine 50 generates a primary voltage according to the number of primary magnetic flux linkages determined by the primary current and the secondary current. That is, the required secondary current can be determined if the required primary voltage and the actual primary current are given. Further, since the power transmission line 5 is coupled to the primary winding 50a via the insulating transformer 31, a current representative of the line current iL also flows in the primary winding 50a, and this current detection means 8
Can be made to exist internally and can be replaced with the current detection means of the transmission line 5.

As described above, the required secondary excitation current i2 can be determined from the insertion voltage Vi ^* to be generated and the primary current i1∝IL, and the secondary current i2 and the insertion voltage Vi can be controlled by operating the excitation voltage. it can. The details will also be described in a detailed example below. The wound-type AC machine 50 can be controlled to have the desired primary voltage by controlling the secondary current in consideration of the given primary current with respect to the desired primary voltage and thus the primary magnetic flux linkage number. . That is, it can be utilized as a dependent voltage source. Therefore, by using the winding type AC machine 50 having a large overcurrent withstand capability, the compensation voltage applying means 12 is
The overcurrent withstand and overload withstand levels of are increased. further,
There is also an effect that a large variable current range for control necessary for system stabilization can be obtained. In other words, a large stabilization effect can be obtained by utilizing the fact that the overload tolerance is large. The details will be described later in Examples.

Example 4. 3A and 3B show the insertion voltage V
In the text, the dot mark "." representing an AC vector is omitted for convenience sake. In the figure, Vs and Vr are the power transmission side voltage vector and the power reception side voltage vector, IL is the line current vector, and Vx and Vc are the system reactance voltage vector and the series capacitor voltage vector, respectively. Considering the power reception side voltage as a reference, the power transmission side voltage V at the point where the system reactance voltage Vx is canceled by the series capacitor voltage Vc
If the insertion voltage Vi is controlled over the positive and negative polarities while maintaining the orthogonal relationship to the current centering on s (displayed by a solid line), the variation width of the voltage vector on the power transmission side indicated by the dotted line can be dealt with.

FIG. 9A shows a typical embodiment in which the voltage vector on the power transmission side is maintained so that the voltage on the power receiving side and the line current are in phase, and FIG. 7 illustrates an exemplary embodiment maintained to be in phase between and. These maintenance relationships are realized by the coordinated control with the equipment on both sides including the generator on the power transmitting side or the power receiving side, or the range of the phase of the line current vector with respect to the voltage vector on both sides of power transmission / reception. Can be decided.

Variables which are local and easily detected at the node where the compensation voltage applying means 12 is installed are used as vector references.
In order to minimize the integrated value of the active power present in the compensation voltage applying means 12 and thus the energy storage, it is preferable to use the line current vector itself as a reference. As a result, the insertion voltage vector is made orthogonal to the line current vector, and some in-phase (coaxial) voltage components or transient in-phase (coaxial) voltage components can be supplementarily inserted. . This detailed embodiment will also be described later.

What is important in obtaining the above-mentioned vector relation is to compensate a part or most of the steady system reactance voltage Vx with the steady series capacitor voltage Vc to obtain transient characteristics and dynamic characteristics (for example, change of variables). The stability due to the eigenvalue and the frequency characteristic against variation) discussed with respect to the component are improved by the auxiliary insertion voltage Vi. In addition, during transients such as fault current limiting during a ground fault, an inductive voltage in the same direction as the inductive system reactance is applied. Such an action can be realized by providing the command value generation means 11 with a line current control system.

In summary, by applying a voltage vector orthogonal to the line current vector in series to the line from the compensating voltage applying means 12, line current control and voltage fluctuation between the power transmitting and receiving ends can be dealt with, and compensation can be performed. Voltage applying means 12
It is possible to obtain the effect of minimizing the electric power intervening in. Therefore, the compensating voltage applying means 12 can be simplified and the economy can be improved.

Example 5. FIG. 4 is a diagram showing a detailed partial embodiment relating to the power detection means 10 and the command value generation means 11. In the power detection means 10 of the figure, 13 and 14 are three-phase / two-phase conversion means or the same operation means for performing the operation of the following equation. The three-phase / two-phase conversion means 14 relating to the electric current is also
The same calculation may be performed only by changing the voltage to the current, and conversion can be performed using the same conversion matrix.

[0054]

[Equation 1]

Further, 15 is a power detection means or power calculation means for receiving or outputting the current detection means 8 and the voltage detection means 9 to detect or calculate the transmitted power. These detection outputs are given to the command value generating means 11.

Next, the method of deriving the reference vector required for the internal control and calculation of the command value generating means 11 will be described first.
In the command value generating means 11, reference numerals 16 and 17 denote integrating means or integral calculating means, which rotate the phase in the direction delayed by 90 ° (the axes are interchanged and one polarity becomes negative), and the flux linkage number λα of the α-β axis. , Λβ are output. At this time, the sign is changed with respect to the β-axis integrating means 17 whose polarity changes, and the β-axis flux linkage number λβ is obtained. Reference numeral 18 is a vector absolute value calculating means, 1
9 and 20 are unit vectors [eα, e that are reference vectors.
β] ^T = [sin θe, cos θe] ^T is output as a dividing unit, and 21 is a unit (inverse trigonometric function calculating unit) for calculating the rotation angle θe of the reference vector from the unit vector [eα, eβ] ^T. The above 16 to 21 are coordinate standard calculation means for determining the reference coordinates (unit vector e or rotation angle θe of the reference vector) for observation and control. In the above-mentioned embodiment, since the magnetic flux linkage numbers λα and λβ obtained by integrating the voltage are used as a reference, it is less susceptible to the influence of the instantaneous voltage fluctuation, and the malfunction due to the surge is less likely to occur.

As another embodiment, the flux linkage numbers λα, λβ
Instead, the voltage vectors Vα, Vβ and the current vector iα,
iβ can be chosen as the reference vector. In this case, the voltage or current obtained from the output of the voltage detection means 9 or the current detection means 8 is converted into three-phase / two-phase by the three-phase / two-phase conversion means 13 and 14, and its output Vα, Vβ or iα, iβ is converted. It may be inserted in the absolute value calculating means 18 and the dividing means 19, 20. These have a feature that the derivation of the reference vector is easy. In addition, the current vector has a feature that it is easy to survive a ground fault and is not easily affected by a voltage surge. Further, these are combined with a PLL (Phase Locked Loop) to determine the rotation angle θe of the reference vector, and the unit vector [eα, eβ] ^T = [sin θe,
cos θe] ^T can be calculated.

Then, in order to control the transmitted power, the command value V of the insertion voltage vector to be applied by the compensation voltage applying means.
The part for calculating i ^* will be described. In the figure, 2
2, 23 is a power control means, 22 is a power comparison unit, 2
3 is a power control calculation unit. Further, reference numeral 24 is a coordinate conversion means for converting the current vectors iα, iβ into the quantities id, iq of the synchronous rotation coordinates by the unit vectors eα, eβ, and performs the calculation of the following equation.

[0059]

[Equation 2]

That is, it is a vector rotator which reverses the current vectors iα, iβ rotating at the electrical angle θe by θe by the above equation and converts them into a stationary vector. Furthermore, 2
Reference numerals 5 and 26 are multiplication means, 27 is orthogonal transformation means (orthogonal switching means), and 28 is vector rotation means.

Next, the operation will be described. First, the power comparison unit 22 compares the power command P ^* with the transmitted power P, and the deviation is given to the power control calculation unit 23 to output a proportional coefficient (insertion reactance) Xi. At this time, the power control calculation unit 23 may perform control calculation such as proportional calculation P, proportional integral calculation PI, and proportional integral differential calculation PID. Then, the multiplication means 25, 26 add the proportional coefficient Xi to each axis current id, iq.
To output voltage vectors Vid ^* and Viq ^* to be inserted. At this time, the phase of the reactance voltage to be inserted must be advanced by 90 ° (π / 2) from the current. That is,
It is necessary to perform the orthogonal transformation, and the orthogonal transformation means 27 is the means for giving the outputs of the multiplying means 25 and 26 to the other axes and inverting the sign given from the imaginary axis (q axis) to the real axis (d axis). . These calculations are applied to the stator coordinates (α-β axis, RS
It may be performed on the T axis.

By performing the transmission power control, the pulsation suppressing action of the transmission power by the feedback control action works. Therefore, even if the pulsation of active power due to the beat with the LC resonance is about to occur, the power control works, so that the effect of suppressing these pulsations is further ensured.
The insertion reactance Xi can also be used when the line current is controlled by the variable reactance control. Further, the variational rotation angle command Δθ from the compensation voltage applying means 12
A vector rotating means 28 for applying rotation is provided, and this output Vi ^* serves as a voltage vector command to the compensation voltage applying means 12. Here, the variation rotation angle command Δθ ^* has a function of adjusting the electric power intervening in the compensation voltage applying means 12 and is an amount corresponding to the integrated value (a voltage or speed of the compensating voltage applying means 12 opposite to the power supply side). Is responsible for controlling. The vector rotation can be obtained by multiplying the input vector by the matrix of the following equation from the left.

[0063]

(Equation 3)

This embodiment requires a simple coefficient multiplication,
Moreover, since the orthogonal voltage is applied, the average value and integrated value of the electric power intervening in the compensation voltage applying means 12 can be made almost zero. Therefore, there is an economical advantage.

Example 6. FIG. 5 is a diagram showing another detailed partial embodiment of the power detection means 10 and the command value generation means 11. In the figure, 51 and 53 are d-axis (real axis) current control means, 51 is the current comparison section, 53 is the current control calculation section, 52 and 54 are q-axis (imaginary axis) current control means, 52 Is the current comparison unit, and 54 is the current control calculation unit. Further, 55 and 58 are coefficient multiplying means (coefficient multiplier) for determining a voltage command value to be given to the same axis, and 56 and 57 are coefficient multiplying means (coefficient multiplier) for determining a voltage command value to be given to another axis (orthogonal axis). Reference numeral 60 is a command value combining means (addition / subtraction means).

The detection operation unit for the current, voltage, power and reference vector is the same as in FIG. next,
The operation of the voltage command value generator when the line current is controlled by the inner control loop will be described. The power comparison unit 22 compares the power command P ^* with the transmitted power P, and the deviation is given to the power control calculation unit 23 to output the actual axis current command value id ^* .
At this time, the power control calculation unit 23 may perform control calculation such as proportional calculation P, proportional integral calculation PI, and proportional integral differential calculation PID. Further, the actual axis current command value id ^* is calculated by the current comparison unit 5
In step 1, the current deviation is compared with the real axis current id, and this current deviation is given to the current control calculation unit 53 to output the current deviation response amount ied.
At this time, the current control calculator 53 may perform control calculations such as proportional calculation P and proportional integral calculation PI.

On the other hand, q-axis current control side (imaginary axis current control side)
Is used to control the electric power or the integral response amount of the electric power interposed in the compensation voltage applying means, which will be described later. The q-axis current command value iq ^* is given from the compensation voltage applying means 12. The operation and characterization of the q-axis current control means 52 and 54 are described in the above d.
It may be similar to the case of the shaft. By performing the line current control, the line current pulsation is suppressed by the feedback control, and the LC resonance is suppressed more reliably. Here, an example of fine control for controlling the biaxial component of the line current, that is, the current vector is shown, but the actual axis current control system (line active current control section) is mainly used. Therefore, the effect of improving the pulsation suppressing effect due to LC resonance can be obtained only by the scalar control such as the absolute value or the effective value of the current.

Example 7. Next, the detailed operation of the part that determines the voltage command value from the biaxial line current control means will be described. Coefficient multiplication means 55 to 58 and synthesis means 5 are applied to the outputs from the control calculation means 53 and 54 for each axis.
9 and 60 perform the matrix calculation of the following equation.

[0069]

[Equation 4]

Here, k2 is a coefficient for giving a quadrature reactance voltage for flowing the self-axis current, and k3 is a coefficient for adding a resistance drop voltage and damping for giving the self-axis current. In this manner, not only the reactance voltage to the orthogonal other axis but also the voltage component of the same axis (self axis) is applied to improve the control characteristic of the line current.
Further, instead of the real axis current command id ^* in active current command ip ^*, can be utilized instead of the imaginary axis current command iq ^* in reactive current command i _Q ^*. Further, the imaginary axis current command iq ^* is set to zero, and its variation influences the electric power intervening in the compensation voltage applying means 12. Therefore, the variation imaginary axis current command Δiq ^* from the compensation voltage applying means 12 is received. As a result, the electric power present in the compensation voltage applying means 12 and its integrated response amount can be controlled. The voltage command value vector Vi ^* obtained as described above
Is given as the insertion voltage command to the compensation voltage applying means 12.

Further, instead of the command inputs id ^* and iq ^* of the command value generating means 11, the line current command (absolute value) i
_L ^* , active current command i _P ^* , reactive current command i _Q ^* , active power command Pr, reactive current command Qr, etc. are given, and the system current is controlled by giving these commands from a host control means (not shown). ， Active current or reactive current control or active power or reactive power control, which in turn controls power flow, system stabilization control (voltage, current, power stabilization, step out suppression, control theoretical dynamic characteristic stabilization, etc.) ) And the phase differential swing of the system
Power fluctuations can be suppressed and transient and dynamic characteristics can be further improved.

Example 8. FIG. 6 is a diagram showing a partial embodiment relating to the static compensation voltage applying means, in which primary windings 311a and 311b are respectively connected in series to the transmission line 5 and secondary windings 312a and 312b are respectively connected. Typical two-level or three-level three-phase inverters 33a, 33
It comprises phase transformers 31a, 31b connected to b. A high frequency link type cycloconverter may be used instead of the inverter. Further, 35 is a smoothing capacitor for DC link,
In the case of a cycloconverter, it is an AC capacitor for high frequency links. The number of phases of this high-frequency link is 3 other than single phase
It can be a polyphase such as a phase.

In the main circuit section as described above, the secondary winding 312
An example in which a phase difference of 30 ° (π / 6) in electrical angle is provided between a and 312b, and by adding this phase difference, harmonics of the combined voltage in the primary windings 311a and 311b are reduced and The harmonic currents of the secondary windings 312a and 312b are also reduced. Naturally, the static power converters (three-phase inverters) 33a and 33b are also operated with a phase difference of 30 ° (π / 6) in electrical angle. Prior to the activation of the main circuit section, an initial charging circuit and an initial charging operation mode can be provided.

Next, in the figure, the voltage of the AC capacitor 35 for link changes depending on the integrated value of the input and output of the electric power intervening in the converter, that is, the energy balance. Therefore, it is necessary to adjust this voltage to a predetermined range. Become. Therefore, the following control unit is further provided. In the figure, 36 is a voltage detecting means, 37 and 38 are voltage controlling means (regulator AV
R), 37 is a comparison part with the command voltage Vdc ^* , 38
Is the voltage control calculator. Here, the voltage control calculation unit 38 may perform control calculation such as proportional calculation P, proportional integral calculation PI, and proportional integral differential calculation PID. This output is fed back to the command value generating means 11 and fed back as the insertion voltage command Vi ^* . At this time, the command value generating means 11
In an amount related to the power interposed compensation voltage application means ^{12 (iq *, △ θ *} ) is controlled, the voltage component of the line current and phase are included in the inserted voltage command Vi ^*, the control is performed. As a result, the DC current of each power converter unit and thus the DC voltage are adjusted, and the voltage control system is completed.

Next, a portion for controlling each power converter unit upon receiving the insertion voltage command Vi ^* will be described. In the figure, 39 is a coordinate conversion means, 41 is a vector rotation means, and 40 and 42 are 2-phase / 3-phase conversion means. Now,
The coordinate conversion means 39 uses the voltage vector command Vi ^* common to the plurality of power converters 33a and 33b as a fixed coordinate (stationary reference frame) by using a “reference vector (unit vector) having a rotation angle θe” represented by the following equation. ).

[0076]

(Equation 5)

That is, the following equation is calculated. The reference vector required for this calculation is given by the command value generating means 11.

[0078]

(Equation 6)

The voltage vector command Vi ^* is a dq2 axis component of an arbitrary synchronous rotation coordinate (synchronous reference frame) corresponding to the real axis component and the imaginary axis component of Re-Im display well known in AC theory. Is converted into a quantity (alternating current) on the α-β axis of fixed coordinates by the above coordinate conversion. The phase number conversion means 40 and 42 are phase number conversion means or phase number conversion calculation means for converting a two-phase command on the α-β axis into a three-phase command. This phase number conversion is expressed by the following equation.

[0080]

(Equation 7)

Further, in the figure, reference numeral 41 is a vector rotation means (VR) or a vector rotation calculation means, and the calculation is represented by the following equation, where θ is a general rotation angle input.

[0082]

(Equation 8)

In the vector rotation means 41 shown in FIG.
Means -30 ° (-π / 6). As a result, the operation command with the phase difference of the main circuit is obtained. As a result, the power flow and the line current can be controlled by the major loop in combination with the command value generating means shown in FIGS. Furthermore, even if pulsations due to LC resonance are generated, those pulsations can be suppressed. As a result, shaft torsional vibration of the generator is also suppressed. Further, by giving these command values from the host control means, various stabilization controls as well as power fluctuation prevention are realized.

Example 9. FIG. 7 is a diagram showing a partial embodiment of compensating voltage applying means using a winding type AC machine.
Reference numeral 70 designates an auxiliary transformer, 151R, 151S, 151T designate primary winding current detecting means capable of also detecting line current, 16
9 is a power supply for secondary excitation (AC / AC power converter, AC-D
C-AC converter / inverter or cycloconverter), 160a, 160b, 160c are current detecting means capable of detecting both direct current and alternating current, 152, 161
Is a three-phase / two-phase conversion means (can be converted by using the same conversion matrix as in the case of voltage also in the case of current), 162 and 167 are vector rotation means, 163 and 164 are comparison parts of secondary excitation current control means, and 165. , 166 are current control calculation units of the secondary excitation current control means, and 168 is a 2-phase / 3-phase conversion means.

Further, 155 is a detecting means for the mechanical rotation angle θm, and 156 is a means for multiplying the output of the rotation angle θm by the number of pole pairs np to convert it into a rotating electrical angle θr. further,
Reference numeral 157 is a speed detection means for detecting (calculating) the rotation speed ωr from the rotation electrical angle θr, 158 is a speed control means, 159.
Is a slip angle detecting means for detecting the slip angle θs by subtracting the rotating electrical angle θr from the electrical angle θe, and 153 is a coordinate converting means for converting the amount of the αβ axis into the amount of the dq axes of the synchronous rotation coordinate, 154
Is a secondary excitation command calculation means for generating secondary excitation current commands i2d ^* , i2q ^* from the insertion voltage command Vi ^* and the primary currents i1d, i1q.

Next, the operation will be described. In the figure, the output of the speed control means 158 is fed back to the command value generation means 11 and fed back as an insertion voltage command Vi ^* .
At this time, the command value generating means 11 causes the compensation voltage applying means 1
2 is controlled, that is, the amount (iq ^* , Δθ ^* ) related to the active power and torque of the wound-type AC machine 50 is controlled, and the voltage component in phase with the line current is included in the insertion voltage command Vi ^*. , This control is performed. As a result, the torque and thus the speed of the wound-type AC machine 50 are adjusted, and the speed control system is completed. With these, it is possible to control the speed of the wire-wound AC machine 50 by adjusting the compensating voltage applying means, that is, the electric power and the torque present in the wire-wound AC machine 50. If the command ωr ^* of this speed control system is commanded within the upper and lower limits, the rotational energy can be converted into active power and taken in and out within the upper and lower limits of speed.

On the other hand, the vector rotating means 162 causes the secondary excitation current vector i2 of the slip frequency by the slip angle θs.
Is reversely rotated (the input current vector is multiplied from the left by a conversion matrix of θ = −θs in Expression 8) to convert into the amount of synchronous rotation coordinates. As a result, the secondary excitation current vectors i2d and i2q in synchronous rotation coordinates are obtained, and the same command values i2d ^* and i2q ^* are obtained ^.
Compared to. The command values i2d ^* , i2q ^* are obtained by the secondary excitation command calculation means 154 performing the calculation of the following equation.

[0088]

[Equation 9]

Here, ωe is the angular frequency of the system, M is the primary secondary mutual inductance of the winding AC machine, L1 is the primary inductance of the winding AC machine, and Lt is the leakage inductance of the transformer. That is, the primary current vector [i
1d, i1q] ^T and insertion voltage command vector [Vid
^* ', Viq ^* '] ^T and the secondary current command vector [i
2d ^* , i2q ^* ] ^T can be determined. Prior to this, the primary winding current i1 of the winding type AC machine 50 proportional to the line current
(R, S, T) is 3 phase / 2 by the 3 phase / 2 phase conversion means 152.
After the phase transformation, the coordinate transformation means 153 further transforms the fixed coordinate quantities i1α and i1β into the synchronous rotation coordinate quantities i1d and i1q.

Further, in the figure, after comparison is made by the comparison units 163, 164 of the secondary excitation current control means, calculation is made by the current control calculation sections 165, 166 of the secondary excitation current control means to obtain the secondary voltage command V2d. ^* , V2q ^* are output. This output is rotated by the sliding angle θs by the vector rotating means 167 and converted into rotor coordinate amounts V2α ^* and V2β ^* . Further, this output is subjected to a two-phase / three-phase conversion and given to the secondary excitation power source 169, a three-phase voltage command V2 ^* = [v
_2u ^* , _v2v ^* , _v2w ^* ] ^T can be obtained. As a result of desired secondary excitation being obtained by these secondary excitation current control systems, the desired insertion voltage, that is, the primary winding voltage is obtained.

Example 10. FIG. 8 is a diagram showing another embodiment of the compensation voltage applying means using a winding AC machine, in which a primary voltage control system is provided as a method of determining the secondary current command.
In the figure, 71 is a primary voltage detection means, 72 is a collective coordinate conversion means, and 73 is a voltage control means.

The collective coordinate conversion means 72 may be executed separately for the two-phase / three-phase conversion means 152 and the coordinate conversion means 153, but they can be collectively calculated by the following equation. In this respect, the same applies to the above-described embodiment, and the inverse conversion can be collectively performed in the same manner. The same applies to current conversion.

[0093]

[Equation 10]

In the inverse transformation, the transformation matrix part is expressed by transposing the transformation matrix of the above equation. The voltage control unit 73 may have the same configuration as the current control units 163 to 166 shown in FIG.
The output is the secondary current command vector [i2d ^* , i2q
^* ] Can be used as ^T. However, since the d-axis voltage is obtained by the q-axis exciting current and the q-axis voltage is obtained by the d-axis exciting current, the sign of the output of the d-axis voltage control means is changed to q.
The axis exciting current command is used, and the output of the q-axis voltage control means is used as the d-axis exciting current command. As a result, it is possible to provide the secondary current control system capable of having the function of preventing the overcurrent of the secondary winding and the current limiting function in the minor loop, and the control system of the insertion voltage outside the minor loop. Further, together with the command value generating means 11 shown in FIGS. 4 and 5, the power flow and the line current can be controlled by a major loop. Furthermore, even if pulsations due to LC resonance are generated, those pulsations can be suppressed. As a result, shaft torsional vibration of the generator is also suppressed. Further, by giving these command values from the host control means, various stabilization controls as well as power fluctuation prevention are realized.

Example 11. FIG. 9 is a diagram showing another embodiment of the present invention, in which 81 is an overcurrent detecting means,
Reference numeral 82 is a capacitor short-circuit means, 83 and 84 are capacitor short-circuiting metallic switch means and semiconductor switch means, 85 is a capacitor discharge current suppressing reactor, 86 is a capacitor overvoltage suppressing arrester, 87 is an arrester current detecting means, and 88 is an arrester. Voltage detection means, 89 is absorbed energy (integrated power) of the arrester and temperature rise calculation means, and 90 is logic synthesis (OR) means.

In the figure, when a fault current due to a current ground fault or the like occurs, the short-circuiting means is activated in response to the output of the overcurrent detecting means 81 to short-circuit the series capacitor 7. As a result, the system reactance 6 (addition of a current limiting reactor and a transformer leakage reactance as necessary) acts to limit the accident current, and can switch to the role of producing the accident current limiting effect. Furthermore, at the time of this accident, if the output of the compensating voltage applying means 12 is not short-circuited and the above-mentioned current control system is operated, the compensating voltage applying means 12 will add to the inductive voltage for suppressing the line current, that is, the reactance voltage. To generate a voltage. Further, when the overcurrent is detected, the insertion voltage command can be switched to generate a voltage that adds to the reactance voltage. This further improves the current limiting effect. Of course, it is possible to properly compensate the combined reactance with the series capacitor 7 during normal times so that the maximum reactance can be accommodated.

Further, the present invention is used for the interconnection line as an interconnection system for interconnection between electric power systems, the system reactance 6 is positively adjusted as necessary, the series capacitor 7 is used for compensation, and By short-circuiting the series capacitor 7 in response to the current detecting means 81, it is possible to satisfy both the required interconnection (or power transmission) during normal operation and its control function and the current limiting function during an accident. That is,
A device useful as an AC interconnection control system between electric power systems is realized. The short-circuit means 82 can also be used as the parallel arrester protection short-circuit means that responds to the absorbed energy of the arrester 86 and the temperature rise. In this respect, the same applies when the semiconductor switch 84 is used.

Example 12 FIG. 10 is a diagram showing another embodiment according to the present invention. In the figure, reference numeral 100 is a transformer, 101 is a speed detecting means of the generator 1, 102 is a detecting or calculating means of the variation speed Δωr, 103 is a stabilizing control means, and 104 is a generating power or generator torque controlling means. ,
Reference numeral 105 is a speed control means, 106 is a speed governor of the turbine or turbine input adjustment means, 107 is a branch line current detection means, 108 is a branch line voltage detection means, and 109 is a branch load system. Note that ωr ^* is a speed command, ωe is a synchronous angular speed, and Vi ^* is an insertion voltage command.

By disposing the series capacitors in a distributed manner as shown in the figure, it is possible to suppress a local sudden change in the ground line voltage. That is, the change width of the line voltage distribution becomes narrow, and the duty of insulating the line and the device is reduced. By disposing the compensation voltage applying means connected in series in a distributed manner as shown in the figure, the transient fluctuation width due to the series insertion voltage of the ground line voltage is also narrowed and the duty of insulating the line and the equipment is reduced. Furthermore, not only that, but even if a part or one of the inserted power supplies fails, the static compensation voltage applying means is likely to be in a short-circuit state (otherwise, it can be short-circuited by gate control for short-circuiting). The function of can be maintained and the operation of system compensation and control can be continued. That is, redundancy is obtained.

Further, by dispersively installing on both sides of the branch node to the branch system, control suitable for the lines on both sides can be realized and the voltage at the branch point can be stably maintained. A command value generation system such as 8b, 9b, 10b may be installed on the branch line side. At this time, the control considering the branch line current may be executed by the devices of the same group b or both groups. Further, the voltage of the branch point voltage can be adjusted by the group b device upstream of the branch point, and for this reason, the power detecting means of the detecting means 10b can be replaced with the voltage detecting means. Furthermore, a voltage control means may be provided outside the power control means of the command value generation means 11b, and a command to the power control system or a command to the line current control system may be given by the output of the voltage control means.

Further, if only the quadrature voltage against the current in which the dynamic characteristics of differentiation and integration do not work is applied, the insertion voltage command can be determined by multiplying the line current by jk1X as in the group c in FIG. Thereby, the control means can be simplified.
However, in this case, it becomes a passive element with respect to the current. On the other hand, the control method of the above-described embodiment in which an independent voltage that is non-proportional to the line current is applied to control the current can more actively control the current. There is a feature that the improvement effect is great.

As shown in the figure, when this compensator is installed on the generator side before step-up, the insulation duty of the insulation transformer is reduced, and the originally required high-voltage insulation function of the power transmission step-up transformer can be shared. . In particular, when using a static power converter that required dual converter transformers and step-up (high voltage) transformers or a winding type AC machine for which high voltage insulation of winding voltage is difficult as compensation voltage applying means. The above effect is great. Furthermore, if the compensating voltage applying means is installed at a short distance from the viewpoint of information transmission speed (power station, generator, and a substation close to these, which is capable of high-speed transmission), the speed or variation speed of the generator can be controlled. . In addition, the cooperative control with the turbine can compensate the high-speed response area where the response speed of the turbine is not in time, so that the compensation voltage applying means can keep the speed stable in the event of a power transmission system failure or after recovery, and the phase difference during the same period. Can be suppressed. As a result, it is possible to suppress step-out and phase differential swing after recovery,
A large effect of suppressing the first wave and a transient stabilizing effect can be obtained.

[0103]

As described above, according to the invention of claim 1, since the electric variable of the power system is detected and controlled by the compensating voltage applying means, the pulsation involving the series capacitor may occur. This can be suppressed, and there is an effect that it is possible to prevent the transient characteristics and the dynamic characteristics from being deteriorated by the series capacitor.

According to the second aspect of the invention, the line current of the power system is detected and controlled by the compensating voltage applying means. Therefore, even if line current pulsation involving the series capacitor occurs, it is suppressed. Therefore, there is an effect that the transient ripple of the line current due to the series capacitor can be prevented. Further, there is an effect that it is possible to suppress an adverse effect on the shaft torsional vibration of the generator.

According to the third aspect of the present invention, the transmission power of the electric power system is detected and controlled by the compensating voltage applying means. Therefore, even if a pulsation of the transmission power related to the series capacitor occurs, it is suppressed. It is possible to prevent transient pulsation of transmitted power due to the series capacitor. Further, there is an effect that it is possible to suppress an adverse effect on the shaft torsional vibration of the generator.

According to the fourth aspect of the present invention, since both the real axis and the imaginary axis component and thus the effective and invalid components can be feedback-controlled, the effect of suppressing the pulsation and shaking of both components can be obtained. Further, if the detecting means also detects the biaxial components, it is possible to obtain the action of distinguishing both components and controlling them independently. Thus, there is an effect that more precise control of the two components can be realized.

According to the fifth aspect of the present invention, since the electric power present in the compensation voltage applying means can be suppressed, the transient pulsation of current or electric power can be prevented by the more economical compensation voltage applying means. There is an effect that can be.

According to the sixth aspect of the present invention, the phase difference between the voltage and the current on the AC side of the compensation voltage applying means is adjusted by a very simple means of correcting (adjusting) the phase to reduce the intervening power. Since the adjustment is made, there is an effect that a simpler control method of the compensation voltage applying means can be provided.

According to the seventh aspect of the invention, since the compensating voltage applying means is constituted by the static power converter, there is an effect that the response characteristic of the compensating voltage applying means and hence the pulsation preventing response characteristic can be improved.

According to the invention of claim 8, since the compensating voltage applying means is constituted by the winding type AC machine, there is an effect that the overcurrent withstanding capacity or overload withstanding capacity of the compensating voltage applying means can be improved. Alternatively, there is an effect that the variable control width necessary for system stabilization can be widened.

According to the ninth aspect of the invention, the compensating voltage applying means is arranged in a distributed manner with respect to the power system, so that the local voltage rise of the line voltage is prevented and the compensating voltage used in the invention is provided. There is an effect that redundancy can be given to the failure of the applying means.

According to the tenth aspect of the present invention, since the overcurrent detecting means and the short-circuiting means for short-circuiting the capacitor when the overcurrent is detected, the overcurrent at the time of an accident is suppressed. There is an effect that can be done. Further, there is an effect that it can be applied to an interconnection device between electric power systems.

According to the eleventh aspect of the present invention, the compensating voltage applying means is configured to give a voltage drop that is summed with the voltage of the system reluctance. Therefore, the effect of suppressing the overcurrent at the time of an accident can be further improved. There is an effect that can be done.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a compensation system for an AC power system according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing an embodiment of a compensation voltage applying means used in the present invention.

FIG. 3 is a vector diagram for explaining the operation of the present invention.

FIG. 4 is a configuration diagram showing a detailed example of a control means of a compensation voltage applying means used in the present invention.

FIG. 5 is a block diagram showing a detailed embodiment of a control means of the compensation voltage applying means used in the present invention.

FIG. 6 is a configuration diagram showing a detailed embodiment regarding a compensating means used in the present invention.

FIG. 7 is a block diagram showing another detailed embodiment of the compensation voltage applying means used in the present invention.

FIG. 8 is a configuration diagram showing another detailed embodiment of the compensating means used in the present invention.

FIG. 9 is a configuration diagram showing a compensation system for an AC power system according to another embodiment of the present invention.

FIG. 10 is a configuration diagram showing a compensation system for an AC power system according to another embodiment of the present invention.

FIG. 11 is a configuration diagram showing a conventional AC power system compensation method using a series capacitor.

FIG. 12 is a graph showing how the active and inactive components of the line current fluctuate due to series resonance.

[Explanation of symbols]

5 power transmission line (line of electric power system), 7 series capacitor, 8 current detection means, 9 voltage detection means, 10 power detection means (power calculation means), 11 command value generation means, 1
2 compensation voltage applying means (dependent voltage source), 33 static power converter, 50 winding AC machine.

Claims (11)

[Claims] 1. A compensation control device for a power system, which is inserted in series to a line of a power system and includes a capacitor for compensating a reactance voltage of the power system, wherein the compensation control device is inserted in series to the line of the power system and is based on a command value. Compensation voltage applying means composed of a dependent voltage source for generating a voltage, detection means for detecting an electric variable of the power system, and command value generating means for receiving an output of the detection means and generating a command value for the compensation voltage applying means. And a compensation control device for a power system. 2. A capacitor which is inserted in series to a line of a power system and which compensates a reactance voltage of the power system,
A current detecting means for detecting a line current flowing in the line of the power system or a proportional amount thereof, a command value generating means for generating a command value for setting the line current detected by the current detecting means to a desired value, and the command value. A compensation control device for a power system, comprising: a compensation voltage applying unit that applies a compensation voltage to a line of the power system based on a command value generated by the generation unit. 3. A capacitor which is inserted in series in a line of a power system and which compensates a reactance voltage of the power system,
Current detecting means for detecting a line current flowing in the line of the power system or a proportional amount thereof, voltage detecting means for detecting a voltage of the power system or a proportional amount thereof, line current detected by the current detecting means and the above Power calculation means for calculating the electric power transmitted through the line from the system voltage detected by the voltage detection means, and command value generation means for generating a command value for making the power calculated by the power calculation means a desired value And a compensation voltage application means for applying a compensation voltage to the line of the power system based on the command value generated by the command value generation means. 4. The command value generating means outputs a vector command value composed of at least two axis vector components, and the compensation voltage applying means outputs a voltage vector based on the vector command value. 1 to claim 3
The compensation control apparatus for the electric power system according to any one of the above. 5. The command value generating means generates a command value having a phase for making the compensation voltage orthogonal to the current of the line, according to any one of claims 1 to 4. The compensation control device for the electric power system according to the item. 6. The command value generating means comprises means for correcting the phase of the command value, and the power or power amount intervening in the compensation voltage applying means is adjusted by the correction of the phase. Any one of claim 1 to claim 5
The compensation control device for the electric power system according to the item. 7. The compensation control device for the electric power system according to claim 1, wherein the compensation voltage applying means is constituted by a static power converter. 8. The compensating voltage applying means comprises a wire-wound AC machine.
The compensation control apparatus for the electric power system according to any one of the above. 9. The compensation control apparatus for the power system according to claim 1, wherein the compensation voltage applying means is distributedly installed in the power system. 10. Overcurrent detection means for detecting that the line current of the line of the power system exceeds an upper limit value, and short-circuit means for short-circuiting the capacitor when an overcurrent is detected by the overcurrent detection means. The compensation control device for the electric power system according to any one of claims 1 to 9, further comprising: 11. The power system according to claim 10, wherein when the overcurrent is detected by the overcurrent detecting unit, the compensating voltage applying unit applies a voltage drop that is summed with the voltage of the system reactance. Compensation control device.