JP2019004572A - Voltage regulating device and voltage regulating system - Google Patents

Abstract

To provide a voltage regulating device and a voltage regulating system capable of appropriately adjusting a voltage of a power transmission line while suppressing unnecessary switching of a switch.SOLUTION: The voltage regulating device comprises: a detection unit for detecting a voltage of a power transmission line; an A/D conversion unit for digitizing the voltage detected by the detection unit; an effective value computing unit for computing an effective value of the voltage digitized by the A/D conversion unit and outputting an effective value signal; a digital filter for removing an abrupt variation component from the effective value signal output by the effective value computing unit and outputting an operation determination voltage signal; a determination unit for determining whether or not switching of a switch for connecting a reactor or a capacitor in parallel to the power transmission line is required, on the basis of the operation determination voltage signal output by the digital filter; and a switching command unit for outputting a switching command to the switch so that the voltage of the power transmission line approaches a reference voltage when the determination unit determines that switching is required.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a voltage adjustment device and a voltage adjustment system for adjusting a voltage change occurring in a power transmission line of a power system.

  In recent years, distributed power sources using natural energy, which have been widely introduced, vary in the amount of power generated irregularly depending on the season, weather, region, etc. The fluctuation tends to be relatively large. In order to appropriately control the system voltage of such a power system, tap switching type such as SVR (Step Voltage Regulator), LRT (Load Ratio control Transformer), etc. is used for power transmission lines such as transmission lines, distribution lines, and service lines. The voltage regulator is provided.

  These voltage regulation devices transform the AC voltage from the power system and switch the tap of the transformer with the tap applied to the power transmission line to adjust the transformation ratio, thereby adjusting the secondary side voltage (of the voltage regulation device). The output voltage is controlled to fall within a predetermined range including an appropriate voltage value (reference voltage). In this case, a time determination method (see Patent Document 1) and an integral determination method (see Patent Document 2) are used as methods for determining whether or not it is necessary to switch taps.

  In the time determination method, the time when the voltage of the power transmission line deviates from a preset dead zone is measured, and when the measurement result exceeds a predetermined time, the tap is switched so as to obtain an appropriate voltage. In the integration judgment method, the deviation amount (the difference voltage between the power transmission line voltage and the dead band area) when the power transmission line voltage deviates from the preset dead band area is integrated, and the integration result exceeds the predetermined range. Switch the tap so that the voltage is appropriate.

  Among the voltage regulators, there are SSR (Step Switched Reactor) and ShR (Shunt Reactor) that lower the voltage of the raised power transmission line by connecting a reactor to the power transmission line in parallel via a switch. . Moreover, there exists SSC (Step Switched Capacitor) which raises the voltage of the reduced power transmission line by connecting a capacitor in parallel to the power transmission line via a switch (see Patent Document 3). The above-described time determination method and integral determination method are also used when the switch is switched by SSR, ShR, and SSC.

JP 2011-217581 A Japanese Patent Laid-Open No. 11-24863 JP 2012-228045 A

  However, when the time determination method is used in the voltage regulator described above, a delay occurs until the control for switching the tap or switch occurs, and the tap or switch is switched with respect to the voltage fluctuation in which the voltage steeply fluctuates. There may not be. Also, for voltage fluctuations with a period longer than the operation time limit, the direction of control and the direction of fluctuations are reversed, and frequent switching or unnecessary switching may occur. On the other hand, when the integral determination method is used, the tap can be switched so as to be an appropriate voltage even when a steep voltage fluctuation occurs, but the tap or the switch is switched whenever the voltage fluctuates. And may unnecessarily switch taps or switches.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a voltage adjusting device and a voltage capable of appropriately adjusting the voltage of the power transmission line while suppressing unnecessary switch switching. It is to provide an adjustment system.

  The voltage regulator according to the present invention is a voltage regulator that regulates the voltage of the power transmission line by controlling switching of a switch that connects a reactor or a capacitor in parallel to the power transmission line, the power transmission line A detection unit for detecting the voltage of the line, an A / D conversion unit for digitizing the voltage detected by the detection unit, and calculating an effective value signal by calculating an effective value of the voltage digitized by the A / D conversion unit. An effective value calculation unit for output, a digital filter for removing an abrupt voltage fluctuation component from the effective value signal output by the effective value calculation unit and outputting an operation determination voltage signal, and an operation determination voltage signal output by the digital filter Based on the above, when the determination unit determines whether or not the switch needs to be switched, and the determination unit determines that the switching is necessary, the voltage of the power transmission line is brought close to the reference voltage. In, and a switching instruction unit for outputting a switching command to the switch.

  In the present invention, the voltage of the power transmission line is sampled and A / D converted, and the RMS value of the converted voltage is filtered by a digital filter to generate an operation determination voltage signal. The generated operation determination voltage signal Based on the above, when it is determined that switching of the switch connecting the reactor or the capacitor in parallel with the power transmission line is necessary, a switch switching command is output. Thus, since it is determined whether or not switching is necessary based on the operation determination voltage signal obtained by removing the steep voltage fluctuation component from the effective value signal, unnecessary switching of the switch is suppressed.

  In the voltage regulator according to the present invention, the digital filter performs a filtering process on the effective value signal output by the effective value calculator during a predetermined period.

  In the present invention, since the effective value signal during the predetermined period is filtered, the longer the predetermined period, the more voltage fluctuation components are removed, and the unnecessary switching of the switch is reduced.

  In the voltage regulator according to the present invention, the determination unit determines that the switch needs to be switched when the operation determination voltage signal deviates from a preset dead zone.

  In the present invention, when the operation determination voltage signal deviates from the dead zone region, the switching command is output in response quickly, so that the voltage of the power transmission line deviates from the appropriate range.

In the voltage regulator according to the present invention, the digital filter is configured such that the effective value signal is Vs, the sampling period is Ts, the predetermined period is Tperiod, the number of effective value signals in the predetermined period is Nperiod, and Z conversion is performed. The operation determination voltage signal VTp is calculated and output by performing the calculation shown in the following equation (1), where Z is the operator.

  In the present invention, the operation determination voltage signal is calculated by the filtering process represented by the equation (1). Thus, since it is determined whether or not switching is necessary based on the operation determination voltage signal obtained by removing the steep voltage fluctuation component from the effective value signal, unnecessary switching of the switch is preferably suppressed.

In the voltage regulator according to the present invention, the digital filter is configured such that the effective value signal is Vs, the Z conversion operator is Z, the predetermined filter order is M and N, and the predetermined coefficient is ai (i = 0, 1,. .., M), bj (j = 0, 1,... N), and by performing the calculation shown in the following equation (2), the operation determination voltage signal VTp is calculated and output, The filter orders M and N and the predetermined coefficients a i and b j are set so that the digital filter functions as a low-pass filter or a band-pass filter.

  In the present invention, the operation determination voltage signal is calculated by a filtering process using a low-pass filter or a band-pass filter expressed by equation (2). As a result, a steep voltage fluctuation component within the time corresponding to the filter order and the filter coefficient is removed from the effective value signal, or only the voltage fluctuation component of the time corresponding to the filter order and the filter coefficient is passed. Can do.

In the voltage adjustment apparatus according to the present invention, the digital filter includes the effective value signal Vs, the Z conversion operator Z, a predetermined filter order M, a predetermined coefficient hi (i = 0, 1,... , M), and the operation determination voltage signal VTp is calculated and output by performing the calculation shown in the following equation (3). The predetermined filter order M and the predetermined coefficient hi are determined by the digital filter being low-pass. It is set to function as a filter or a bandpass filter.

  In the present invention, the operation determination voltage signal is calculated by a filtering process using a low-pass filter or a band-pass filter expressed by Equation (3). As a result, a steep voltage fluctuation component within the time corresponding to the filter order and the filter coefficient is removed from the effective value signal, or only the voltage fluctuation component of the time corresponding to the filter order and the filter coefficient is passed. Can do.

  The voltage regulator according to the present invention performs a filtering process on the effective value signal output by the effective value calculation unit during the second period shorter than the predetermined period, thereby obtaining the second operation determination voltage signal. A second digital filter that outputs the second digital filter; and a second determination unit that determines whether or not the switch needs to be switched based on the second operation determination voltage signal. When the second determination unit determines that switching is necessary, the switch further outputs a switching command to the switch so that the voltage of the power transmission line approaches the reference voltage.

  In the present invention, when it is determined that the switch needs to be switched based on the second operation determination voltage signal output by filtering the effective value signal during the second period shorter than the predetermined period, Is further output. As a result, even if it is determined that switching of the switch is unnecessary based on the operation determination voltage signal output during the predetermined period, the switch is switched according to the sudden voltage fluctuation during the second period. Done.

  In the voltage regulator according to the present invention, the second determination unit needs to switch the switch when the second operation determination voltage signal deviates from a preset second dead band region. judge.

  In the present invention, when the second operation determination voltage signal deviates from the second dead zone, the switching command is output in response quickly, so that the voltage of the power transmission line may deviate from the appropriate range. It is suppressed.

In the voltage adjustment apparatus according to the present invention, the second digital filter is configured such that the effective value signal is Vs, the sampling period is Ts, the second period is Tbase, and the Z conversion operator is Z. By performing the calculation shown in the equation, the second operation determination voltage signal VTb is calculated and output.

  In the present invention, the second operation determination voltage signal is calculated by the filtering process represented by the equation (4). Thus, since it is determined whether or not switching is necessary based on the second operation determination voltage signal obtained by removing the steep voltage fluctuation component from the effective value signal, unnecessary switching of the switch is suitably suppressed.

In the voltage regulator according to the present invention, the second digital filter includes the effective value signal Vs, a Z conversion operator Z, a predetermined filter order P, Q, and a predetermined coefficient kk (k = 0, 1,..., P), dl (l = 0, 1,..., Q), and the second operation determination voltage signal VTb is calculated by performing the calculation shown in the following equation (5). The predetermined filter orders P and Q and the predetermined coefficients kk and dl are set so that the digital filter functions as a low-pass filter or a band-pass filter.

  In the present invention, the second operation determination voltage signal is calculated by a filtering process using a low-pass filter or a band-pass filter expressed by equation (5). As a result, a steep voltage fluctuation component within the time corresponding to the filter order and the filter coefficient is removed from the effective value signal, or only the voltage fluctuation component of the time corresponding to the filter order and the filter coefficient is passed. Can do.

In the voltage regulator according to the present invention, the second digital filter includes the effective value signal Vs, a Z conversion operator Z, a predetermined filter order P, a predetermined coefficient fk (k = 0, 1, .., P), and calculating and outputting the second operation determination voltage signal VTb by performing the calculation shown in the following equation (6). The predetermined filter order P and the predetermined coefficient fk are The digital filter is set to function as a low-pass filter or a band-pass filter.

  In the present invention, the second operation determination voltage signal is calculated by a filtering process using a low-pass filter or a band-pass filter expressed by equation (6). As a result, a steep voltage fluctuation component within the time corresponding to the filter order and the filter coefficient is removed from the effective value signal, or only the voltage fluctuation component of the time corresponding to the filter order and the filter coefficient is passed. Can do.

  The voltage adjustment device according to the present invention includes a plurality of the digital filters having different predetermined periods, and the determination unit is based on an operation determination voltage signal output by filtering the plurality of digital filters. It is determined whether the switch needs to be switched.

  In the present invention, since it is determined whether or not the switch needs to be switched based on the operation determination voltage signal output from each of the plurality of digital filters, any period can be arbitrarily selected by appropriately selecting a period for filtering by each digital filter. The voltage fluctuation component is removed, and the switch is switched more preferably.

  A voltage regulation system according to the present invention includes the voltage regulation device described above, the switch, and a reactor or a capacitor connected in parallel to the power transmission line via the switch.

  In the present invention, a voltage regulator capable of appropriately regulating the voltage of the power transmission line while suppressing unnecessary switching of the switch is applied to the voltage regulation system.

  According to the present invention, it is possible to appropriately adjust the voltage of the power transmission line while suppressing unnecessary switch switching.

1 is a block diagram illustrating a configuration example of a voltage regulation system according to a first embodiment. It is a flowchart which shows the process sequence of CPU which performs the voltage adjustment process of a distribution line by the voltage adjustment system which concerns on Embodiment 1. 6 is a block diagram illustrating a configuration example of a voltage regulation system according to Embodiment 2. FIG. A is a characteristic diagram showing the frequency characteristics of the digital low-pass filter of Example 1 in the voltage regulator according to the modification, and B is a characteristic chart showing step response characteristics. A is a characteristic diagram showing the frequency characteristic of the digital bandpass filter of the specific example 1 in the voltage regulator according to the modification, and B is a characteristic chart showing the step response characteristic. A is a characteristic diagram showing the frequency characteristic of the digital low-pass filter of the specific example 2 in the voltage regulator according to the modification, and B is a characteristic chart showing the step response characteristic. A is a characteristic diagram showing the frequency characteristic of the digital bandpass filter of the specific example 2 in the voltage regulator according to the modification, and B is a characteristic chart showing the step response characteristic. 12 is a flowchart illustrating a processing procedure of a CPU that executes a voltage adjustment process for a distribution line in the voltage adjustment system according to the third embodiment. A is a graph showing the time transition of the voltage of the distribution line 201 before adjustment, B is a graph showing the time transition of the voltage of the distribution line 201 after adjustment by the conventional method, and C is the opening and closing of the reactor L1 by the conventional method. It is a graph which shows time transition of. A is a graph showing the time transition of the operation determination voltage signal VTp output from the digital filter, B is a graph showing the time transition of the voltage of the distribution line 201 after adjustment by the voltage adjustment system 100, and C is a reactor L1 by the voltage adjustment system 100. It is a graph which shows the time transition of opening and injection | throwing-in.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.
(Embodiment 1)
FIG. 1 is a block diagram illustrating a configuration example of the voltage regulation system according to the first embodiment. The voltage adjustment system 100 is configured to connect the reactors L1 and L2 in parallel to the shunt reactors L1 and L2 (hereinafter simply referred to as reactors L1 and L2) and the distribution line 201 that transmits three-phase power from the substation 200. The switches S1 and S2 to be connected and the voltage regulator 10 for controlling the switching of the switches S1 and S2 are included. The distribution line 201 may be another power transmission line such as a power transmission line or a lead-in line connected to the power system.

  The voltage adjustment system 100 corresponds to a so-called SSR. The numbers of reactors L1 and L2 and switches S1 and S2 are not limited to two. When the voltage regulation system 100 includes one reactor L1 and one switch S1, the voltage regulation system 100 corresponds to ShR.

  For example, the reactors L1 and L2 have capacities of 150 kvar and 300 kvar, respectively. One end of the reactors L1 and L2 is connected to, for example, a neutral point. The switches S1 and S2 are, for example, electromagnetic contactors (MC). By controlling switching of the switches S1 and S2 according to a switching command from the voltage regulator 10, a reactor having a capacity of 0 kvar, 150 kvar, 300 kvar, or 450 kvar is input to the distribution line 201. The switching command here is a combination of signals for turning on / off the switches S1 and S2.

  The voltage adjustment device 10 includes a detection unit 21 that detects the voltage of the distribution line 201 and a control unit 1 that controls switching of the switches S1 and S2 based on a result obtained by taking in and calculating the voltage detected by the detection unit 21. Prepare. The detection unit 21 detects the voltage via the measurement transformer 20 that steps down the voltage of the distribution line 201.

  The control unit 1 includes a CPU (Central Processing Unit) 11 that controls the entire apparatus. The CPU 11 is bus-connected to a ROM (Read Only Memory) 12 that stores information such as a control program, a RAM (Random Access Memory) 13 that stores temporarily generated information, and a timer 14 that measures elapsed time and the like. ing. The control unit 1 may include a microcomputer having a CPU. The CPU 11 or the microcomputer may be configured to execute a computer program having a predetermined processing procedure.

  The CPU 11 is also bus-connected to an A / D conversion unit 15 that takes in a detection result from the detection unit 21 and performs A / D conversion, and an output unit 16 that outputs a switching command for the switches S1 and S2. The output unit 16 latches (holds) the output switching command until the next switching command is output. However, when the switches S1 and S2 perform, for example, a toggle operation, the switching command is not latched. May be.

  The A / D converter 15 digitizes the voltage of the distribution line 201 detected by the detector 21 (converts it into a digital signal). The A / D conversion unit 15 samples and quantizes the detection result of the detection unit 21 that is an analog signal every predetermined cycle Tss (for example, 0.1 seconds), and converts the result into a digital signal. The CPU 11 may realize the function of the A / D conversion unit 15 by taking the detection result of the detection unit 21 and sampling and quantizing it.

  The CPU 11 of the control unit 1 configured as described above determines the voltage of the distribution line 201 based on the result of processing such as calculation, filtering, and determination based on the voltage digitized by the A / D conversion unit 15. A switching command is output using the output unit 16 to adjust appropriately. That is, the CPU 11 executes the computer program stored in the ROM 12 to realize the functions of an effective value calculation unit, a digital filter, a determination unit, and a switching command unit.

  The effective value calculation unit converts the effective value of the voltage digitized by the A / D conversion unit 15 every period Tss into a predetermined sampling period Ts (Ts = J × Tss: J is an integer equal to or greater than 2, for example, J = 10 ), And the effective value of the calculated voltage is output as the effective value signal Vs.

  The digital filter performs a filtering process based on a predetermined arithmetic expression for the effective value signal Vs output from the effective value calculation unit cumulatively for a predetermined period Tperiod, thereby causing voltage fluctuations that occur irregularly in the distribution line 201. The steep voltage fluctuation component contained in is removed.

Specifically, the digital filter sets the Z conversion operator to Z, and performs the calculation shown in the following equation (7) using the above-described effective value signal Vs, the sampling period Ts, and the predetermined period Tperiod. An operation determination voltage signal VTp obtained by removing a steep voltage fluctuation component from the value signal Vs is calculated and output. Nperiod in the following equation (7) represents the number of sampling data during a predetermined period Tperiod. Depending on the length of the predetermined period Tperiod, the degree of voltage fluctuation removal (the degree of smoothing) changes. That is, as the predetermined period Tperiod is longer, more rapid voltage fluctuation components are removed, and the fluctuation of the operation determination voltage signal VTp becomes smaller (the degree of smoothing is larger). On the other hand, the shorter the predetermined period Tperiod, the smaller the sudden voltage fluctuation component is removed, and the fluctuation of the operation determination voltage signal VTp becomes larger (the degree of smoothing is smaller).

  The determination unit determines whether the switches S1 and S2 need to be switched according to whether or not the operation determination voltage signal VTp output from the digital filter deviates from a predetermined dead zone including a preset reference voltage. To do. This dead zone region is a voltage region between an upper limit threshold and a lower limit threshold for determining whether or not the switches S1 and S2 need to be switched based on the operation determination voltage signal VTp. For example, when the reference voltage is 6600 [V] and the width of the dead band region centered on the reference voltage is ± 1.5%, the dead band region has a lower limit value of 6501 [V] and an upper limit value of 6699 [V]. ]. Therefore, “the case where the operation determination voltage signal VTp deviates from the dead zone region” means either the case where the operation determination voltage signal VTp is larger than the upper limit value or the lower limit value of the dead zone region.

  Specifically, when the operation determination voltage signal VTp is larger than the upper limit value of the dead zone region, the determination unit determines that the switches S1 and S2 need to be switched to reduce the voltage of the distribution line 201. If the operation determination voltage signal VTp is smaller than the lower limit value of the dead zone, the determination unit determines that the switches S1 and S2 need to be switched to increase the voltage of the distribution line 201. When the operation determination voltage signal VTp does not satisfy both of these, that is, when the operation determination voltage signal VTp is within the range between the upper limit value and the lower limit value of the dead zone (in the dead zone), the determination unit switches the switches S1 and S2. It is determined that it is not necessary (unnecessary).

  Note that the frequency at which the operation determination voltage signal VTp deviates from the dead zone varies depending on the predetermined period Tperiod and the set range of the dead zone. Specifically, the longer the predetermined period Tperiod (the greater the degree of smoothing) and the wider the dead zone region, the harder the operation determination voltage signal VTp deviates from the dead zone region, and the switches S1 and S2 are switched. Although the frequency | count can be suppressed, the voltage of the distribution line 201 may deviate from an appropriate range. On the other hand, the shorter the predetermined period Tperiod (the smaller the degree of smoothing) and the narrower the dead zone region, the easier the operation determination voltage signal VTp deviates from the dead zone region, and the voltage of the distribution line 201 falls within the proper range. Although deviating can be suppressed, the number of switching of the switches S1 and S2 increases. Therefore, the length of the predetermined period Tperiod (degree of smoothing) and the dead band are comprehensively taken into consideration such as suppression of deviation of the voltage of the distribution line 201 from the dead band region and suppression of switching of the switches S1 and S2. What is necessary is just to set the width of the range of an area | region.

  The switching command unit outputs a switching command for instructing switching of the switches S1 and S2 from the output unit 16 based on the determination result of the determination unit. Thereby, switch S1, S2 switches, the reactor L1, L2 connected in parallel with the distribution line 201 is changed, and the voltage of the distribution line 201 is adjusted. Specifically, when switching the switches S1 and S2 to increase the voltage of the distribution line 201 based on the determination result of the determination unit, the switching command unit switches so as to decrease the capacity of the reactor connected to the distribution line 201 by one step. Output a command. Further, when switching the switches S1 and S2 to lower the voltage of the distribution line 201 based on the determination result of the determination unit, the switching command unit outputs a switching command to increase the capacity of the reactor connected to the distribution line 201 by one step. To do. On the other hand, when the switches S1 and S2 are not switched based on the determination result of the determination unit, the switching command unit does not output a new switching command, and thus the switching command is held without change. In addition, you may output the switching instruction | command which the capacity | capacitance of the reactor connected to the distribution line 201 goes up and down only in multiple steps.

  Next, operation | movement of the control part 1 of the voltage regulator 10 which concerns on Embodiment 1 comprised in this way is demonstrated using the flowchart which shows it. The processing shown below is executed by the CPU 11 in accordance with a control program stored in advance in the ROM 12. FIG. 2 is a flowchart showing a processing procedure of the CPU 11 that executes the voltage adjustment processing of the distribution line 201 in the voltage adjustment system 100 according to the first embodiment. The processing in FIG. 2 is started at the sampling period Ts after the CPU 11 is initialized. The timer 14 is used when measuring Ts and Tss described later.

  When the processing of FIG. 2 is started, the CPU 11 causes the A / D conversion unit 15 to apply the voltage of the distribution line 201, which is the detection result of the detection unit 21, to A times J times in the cycle Tss (Tss = Ts / J). / D conversion is performed (S11), and the effective value of the J conversion results is calculated (S12: equivalent to an effective value calculation unit). The calculated effective value signal Vs is stored (output) in, for example, the RAM 13.

  Next, the CPU 11 performs a filtering process for removing a steep voltage fluctuation component from the effective value signal Vs by calculating the above equation (7) using the stored effective value signal Vs (S13: equivalent to a digital filter). . The operation determination voltage signal VTp as a processing result is stored (output) in, for example, the RAM 13.

  Next, the CPU 11 compares the stored operation determination voltage signal VTp with the upper limit value and the lower limit value of the dead zone (S15), and determines whether the switches S1 and S2 need to be switched according to the comparison result. (S16: equivalent to a determination unit). Specifically, when the operation determination voltage signal VTp is larger than the upper limit value of the dead zone, the CPU 11 determines that the switches S1 and S2 need to be switched in order to reduce the voltage of the distribution line 201. When the operation determination voltage signal VTp is smaller than the lower limit value of the dead zone, the CPU 11 determines that the switches S1 and S2 need to be switched to increase the voltage of the distribution line 201.

  If the operation determination voltage signal VTp is within the dead zone, and none of the above, the CPU 11 determines that switching of the switches S1 and S2 is unnecessary (S16: NO), and does not newly output a switching command. The process of FIG. 2 is terminated. In this case, the switching command from the output unit 16 is held as before, and the switches S1 and S2 are not switched.

  On the other hand, when it is determined that switching of the switches S1 and S2 is necessary (S16: YES), the CPU 11 changes the switching command of the switches S1 and S2 so that the voltage of the distribution line 201 approaches the reference voltage, and from the output unit 16. 2 is output (corresponding to the switching command unit), and the process of FIG. 2 is terminated. The voltage of the distribution line 201 is adjusted by switching the switches S1 and S2 based on this switching command.

  More specifically, when it is determined in step S16 that the switches S1 and S2 need to be switched to lower the voltage of the distribution line 201, the CPU 11 increases the capacity of the reactor connected to the distribution line 201 by one level. Change the switching command to output. Based on this switching command, the switches S1 and S2 are switched, and the capacity of the reactor connected to the distribution line 201 is increased by one level, whereby the voltage of the distribution line 201 is decreased by one level. If it is determined in step S16 that the switches S1 and S2 need to be switched to increase the voltage of the distribution line 201, the CPU 11 issues a switching command so as to decrease the capacity of the reactor connected to the distribution line 201 by one step. Change the output. Based on this switching command, the switches S1 and S2 are switched, and the capacity of the reactor connected to the distribution line 201 decreases by one level, whereby the voltage of the distribution line 201 increases by one level.

  The CPU 11 of the voltage regulator 10 calculates the operation determination voltage signal VTp from the voltage of the distribution line 201 by repeatedly performing the voltage adjustment process described above, and based on the calculated operation determination voltage signal VTp, the switches S1 and S2 Control switching. Thereby, the voltage of the distribution line 201 is automatically adjusted so that it may become an appropriate range. 2, the A / D conversion process and the effective value calculation process are performed by separating the process of steps S11 to S12 and the process of steps S13 to S17 into two different process routines (tasks). It is preferable to execute the filtering process, the determination process, and the output process in parallel.

  As described above, according to the first embodiment, the voltage of the distribution line 201 is sampled and A / D converted, and the converted voltage effective value signal Vs is filtered by the digital filter to generate the operation determination voltage signal VTp. . When it is determined that switching of the switches S1 and S2 that connect the reactors L1 and L2 in parallel to the distribution line 201 is necessary based on the generated operation determination voltage signal VTp, a switching command for the switches S1 and S2 is output. To do. Therefore, since it is determined whether or not switching is necessary based on the operation determination voltage signal VTp obtained by removing the steep voltage fluctuation component from the effective value signal Vs, unnecessary switching of the switches S1 and S2 can be suppressed. And if the frequency | count of switching can be suppressed, there exists an effect which the lifetime of switch S1, S2 extends.

(Embodiment 2)
In the first embodiment, it is determined whether or not it is necessary to switch the switches S1 and S2 that connect the reactors L1 and L2 to the distribution line 201 in parallel, and a switching command is output. On the other hand, in the second embodiment, it is determined whether or not it is necessary to switch the switches S1, S2, and S3 that connect a phase advance capacitor (hereinafter simply referred to as a capacitor) in parallel to the distribution line 201, and a switching command is output. To do.

  FIG. 3 is a block diagram illustrating a configuration example of the voltage regulation system according to the second embodiment. The voltage regulation system 100a controls the capacitors C1, C2, C3, the switches S1, S2, S3 that connect the capacitors C1, C2, C3 to the distribution line 201 in parallel, and the switching of the switches S1, S2, S3. The voltage adjusting device 10 is configured to be included. One end of each of the switches S1, S2, S3 is connected to the distribution line 201 via reactors 31, 32, 33 for preventing inrush current of the capacitors C1, C2, C3 and suppressing high frequency current. The voltage adjustment system 100a corresponds to so-called SSC.

  Capacitors C1, C2, and C3 have capacities of, for example, 100 kvar, 200 kvar, and 300 kvar, respectively. One ends of the capacitors C1, C2, and C3 are connected to, for example, a neutral point. The reactors 31, 32, and 33 have, for example, capacities of 6 kvar, 12 kvar, and 18 kvar, respectively. By controlling switching of the switches S1, S2, and S3 according to a switching command from the voltage adjusting device 10, a capacitor having a capacity of 0 kvar, 100 kvar, 200 kvar, 300 kvar, 400 kvar, 500 kvar, or 600 kvar is input to the distribution line 201. The switching command here refers to a combination of signals for turning on / off the switches S1, S2, and S3.

  Of the functions realized by the CPU 11 executing the computer program stored in the ROM 12, the effective value calculation unit, the digital filter, and the determination unit are the same as those in the first embodiment, and only the switching command unit is different. In addition, the same code | symbol is attached | subjected to the location corresponding to Embodiment 1, and the description is abbreviate | omitted.

  The switching command unit outputs a switching command for instructing switching of the switches S1, S2, and S3 from the output unit 16 based on the determination result of the determination unit. Thereby, the switches S1, S2, and S3 are switched, and the capacitors C1, C2, and C3 connected in parallel to the distribution line 201 are changed, and the voltage of the distribution line 201 is adjusted. Specifically, when switching the switches S1, S2, and S3 to increase the voltage of the distribution line 201 based on the determination result of the determination unit, the switching command unit increases the capacity of the capacitor connected to the distribution line 201 by one level. A switching command is output to. In addition, when switching the switches S1, S2, and S3 to lower the voltage of the distribution line 201 based on the determination result of the determination unit, the switching command unit switches the switching command so that the capacity of the capacitor connected to the distribution line 201 is lowered by one step. Is output. On the other hand, when the switches S1, S2, and S3 are not switched based on the determination result of the determination unit, the switching command unit does not output a new switching command, and thus the switching command is held without change. Note that a switching command may be output so that the capacitance of the capacitor connected to the distribution line 201 is increased or decreased by a plurality of levels.

  Of the operations of the control unit 1 of the voltage regulator 10 according to the second embodiment configured as described above, the flowchart showing the processing procedure of the CPU 11 that executes the voltage adjustment processing of the distribution line 201 is the diagram of the first embodiment. This is the same as that shown in FIG. However, only the processing content of step S17 corresponding to the switching command unit is different.

  Specifically, when it is determined in step S16 that the switches S1, S2, and S3 need to be switched to reduce the voltage of the distribution line 201, the CPU 11 decreases the capacitance of the capacitor connected to the distribution line 201 by one step. In this manner, the switching command is changed and output (S16). Based on this switching command, the switches S1, S2, and S3 are switched, and the capacitance of the capacitor connected to the distribution line 201 decreases by one step, so that the voltage of the distribution line 201 decreases by one step. If it is determined in step S16 that the switches S1, S2, and S3 need to be switched to increase the voltage of the distribution line 201, the CPU 11 switches the capacity of the capacitor connected to the distribution line 201 to increase by one step. The command is changed and output (S16). Based on this switching command, the switches S1, S2, and S3 are switched, and the capacitance of the capacitor connected to the distribution line 201 is increased by one step, whereby the voltage of the distribution line 201 is increased by one step.

  As described above, according to the second embodiment, the voltage of the distribution line 201 is sampled and A / D converted, and the converted voltage effective value signal Vs is filtered by the digital filter to generate the operation determination voltage signal VTp. . When it is determined that switching of the switches S1, S2, and S3 that connect the capacitors C1, C2, and C3 in parallel to the distribution line 201 is necessary based on the generated operation determination voltage signal VTp, the switches S1, S2, and S3 The switching command of S3 is output. Therefore, since it is determined whether or not switching is necessary based on the operation determination voltage signal VTp obtained by removing a steep voltage fluctuation component from the effective value signal Vs, unnecessary switching of the switches S1, S2, and S3 can be suppressed. And if the frequency | count of switching can be suppressed, there exists an effect which the lifetime of switch S1, S2, S3 extends.

  In addition, according to the first embodiment (or the second embodiment), since the effective value signal Vs during a predetermined period is filtered, more voltage fluctuation components are removed as the predetermined period is longer, and the switch S1 , S2 (or S1, S2, S3) is less unnecessary switching.

  Furthermore, according to the first embodiment or the second embodiment, when the operation determination voltage signal VTp deviates from the dead zone region, the switching command is output in response quickly, so the voltage of the distribution line 201 deviates from the appropriate range. Can be suppressed.

  Furthermore, according to the first embodiment (or the second embodiment), the operation determination voltage signal is calculated by the filtering process represented by the equation (7). Therefore, since the necessity of switching is determined based on the operation determination voltage signal VTp obtained by removing the steep voltage fluctuation component from the effective value signal Vs, unnecessary switching of the switches S1, S2 (or S1, S2, S3) is performed. It can suppress suitably.

  In the determination unit according to the first embodiment (or second embodiment), when the operation determination voltage signal VTp deviates from the dead zone, the switches S1, S2 (or S1, S2, S3) are switched. Although the case where it determined with requiring was demonstrated to the example, it is not limited to this. For example, the switch S1, S2 (or S1, S2, S3) needs to be switched when a period in which the operation determination voltage signal VTp input from the digital filter deviates from the dead zone continues for a predetermined time or longer. You may determine that there is. Further, when the determination unit integrates the difference voltage between the operation determination voltage signal VTp and the dead zone region, and the integrated value becomes equal to or greater than a predetermined value, the switches S1, S2 (or S1, S2, S3) are switched. It may be determined that it is necessary. Further, when the determination unit integrates not the difference voltage but the operation determination voltage signal VTp, and the integration value deviates from a predetermined range, switching of the switches S1, S2 (or S1, S2, S3) is necessary. May be determined. In this way, when a plurality of voltage regulators 10 are connected in series, operation hunting (a phenomenon in which unnecessary operations are repeated between the front and rear voltage regulators 10) can be prevented.

  In the determination unit in the first embodiment (or the second embodiment), the switches S1 and S2 (or S1, S2, and S3) need to be switched based on the operation determination voltage signal VTp from the digital filter. The case of determining whether or not there is an example has been described. However, if at least the operation determination voltage signal VTp is used to determine whether or not the switches S1, S2 (or S1, S2, S3) need to be switched, It is not limited to. For example, the determination unit monitors the voltage of the distribution line 201 detected by the detection unit 21 in addition to the operation determination voltage signal VTp, and when the operation determination voltage signal VTp deviates from the dead zone region, and the voltage of the distribution line 201 is When both of the cases where the dead zone region for the voltage is deviated are satisfied, it may be determined that the switching of the switches S1, S2 (or S1, S2, S3) is necessary. As the voltage of the distribution line 201 at this time, the effective value signal Vs calculated by the effective value calculation unit is used. Note that the above-described time determination method or integral determination method may be used in determining whether or not the switches S1, S2 (or S1, S2, S3) need to be switched by the voltage of the distribution line 201.

  Furthermore, in the first or second embodiment, the reactors L1, L2 or the capacitors C1, C2, C3 are connected via the switches S1, S2 or the switches S1, S2, S3 and the reactors 31, 32, 33. In the above description, the case of being connected in parallel to the distribution line 201 has been described as an example, but the present invention is not limited to this. For example, capacitors C1, C2, and C3 may be connected in parallel to the secondary winding of a transformer in which the primary winding is connected in parallel to the distribution line 201 via switches S1, S2, and S3, respectively. Also, for example, between a tap (corresponding to a switch) of a single-winding transformer in which a winding is connected in parallel to the distribution line 201 and the other end opposite to one end of the winding connected to the distribution line 201 A capacitor may be connected in parallel. In this case, the primary conversion value of the capacitance of the capacitor changes according to the change in the transformation ratio accompanying the switching of the tap (switch).

(Modification)
In the first embodiment, the case where the filtering process is performed on the digital filter using the arithmetic expression (7) is described as an example. However, the present invention is not limited to this. For example, the following equation (8) or the following equation (9) may be used. In this case, the digital filter functions as a low-pass filter that passes a low frequency band or a band-pass filter that passes only a necessary frequency band in a low frequency range, and the equations (8) and (9) The filter order and filter coefficient in the equation are set in advance.

For example, when the above equation (8) is used as the specific example 1, the digital filter follows the second order that follows in 10 minutes by setting the filter order and the filter coefficient as in the following equation (8-1). Functions as a low-pass filter and removes steep voltage fluctuation components of 10 minutes or less. 4A is a characteristic diagram showing the frequency characteristics of the digital low-pass filter of Example 1 in the voltage regulator 10 according to the modification, and B is a characteristic chart showing the step response characteristics.

Further, when the above equation (8) is used, by setting the filter order and the filter coefficient as in the following equation (8-2), the digital filter extracts the second-order voltage fluctuation component only for 30 seconds. Functions as a bandpass filter. 5A is a characteristic diagram showing the frequency characteristics of the digital bandpass filter of the specific example 1 in the voltage regulator 10 according to the modification, and B is a characteristic chart showing the step response characteristics.

On the other hand, when the above expression (9) is used as the specific example 2, the digital filter follows the 540th order in 10 minutes by setting the filter order and the filter coefficient as in the following expression (9-1). Functions as a low-pass filter and removes steep voltage fluctuation components of 10 minutes or less. 6A is a characteristic diagram showing the frequency characteristics of the digital low-pass filter of the specific example 2 in the voltage regulator 10 according to the modification, and B is a characteristic chart showing the step response characteristics. The coefficient Xi is a coefficient with which the digital filter has frequency characteristics shown in A of FIG. 6 and step response characteristics shown in B of FIG. Further, the filter order at this time is an order calculated with the sampling period set to 1 [s], and may be enormous in actual application, so the sampling period Ts is increased. It is preferable to deal with this.

In addition, when the above equation (9) is used, the digital filter extracts only the voltage fluctuation component for 30 seconds by setting the filter order and the filter coefficient as in the following equation (9-2). Functions as a bandpass filter. 7A is a characteristic diagram showing the frequency characteristics of the digital bandpass filter of the specific example 2 in the voltage regulator 10 according to the modification, and B is a characteristic chart showing the step response characteristics. The coefficient Xi is a coefficient with which the digital filter has frequency characteristics shown in A of FIG. 7 and step response characteristics shown in B of FIG.

  As described above, by setting the filter order and filter coefficient of the equation (8) or (9) so that the digital filter functions as a low-pass filter or a band-pass filter, instead of the equation (7), (8) You may substitute Formula or Formula (9). However, when the arithmetic expression (7) is used for the digital filter, it is not necessary to set the filter order and the filter coefficient as in the expressions (8) and (9), and the digital filter can be designed easily. On the other hand, when the equation (8) or the equation (9) is used for the digital filter, the frequency to be removed can be adjusted according to the set filter order and filter coefficient. Therefore, when the voltage fluctuation component to be removed is known, fine adjustment can be performed so as to remove only the voltage fluctuation component. Depending on the voltage adjustment device 10 to be used, either the expression (7) or the expression (9) may be used as appropriate. The filter orders and filter coefficients in the equations (8-1), (8-2), (9-1), and (9-2) are examples, and are not limited to those described above.

  As described above, according to the present modification, the operation determination voltage signal VTp may be calculated by a filtering process using a low-pass filter or a band-pass filter expressed by Expression (8) or Expression (9). In this case, a steep voltage fluctuation component within a time corresponding to the filter order and the filter coefficient is removed from the effective value signal Vs, or only a voltage fluctuation component of a time corresponding to the filter order and the filter coefficient is passed. be able to.

(Embodiment 3)
While the first embodiment is a mode for determining whether or not the switches S1 and S2 need to be switched based on the operation determination voltage signal VTp output from the digital filter, the third embodiment has two different digital filters. This is a mode for determining whether or not the switches S1 and S2 need to be switched based on the operation determination voltage signals respectively output. The CPU 11 further implements the functions of the second digital filter and the second determination unit by executing a computer program stored in the ROM 12.

  In the voltage adjustment apparatus 10 according to the first embodiment, the filtering process performed by the digital filter can remove the voltage fluctuation component that is steep in the predetermined period Tperiod. However, in the actual system, there are voltage fluctuations due to various factors. doing. For example, a sudden change (under high fluctuation) may occur in a short period of time. In such a situation, in the digital filter according to the first embodiment, in order to remove the steep voltage fluctuation in the predetermined period Tperiod, the steep voltage fluctuation in a period shorter than the period Tperiod is removed by the filtering process. May end up. For this reason, in Embodiment 1, there is a possibility of ignoring the sudden fluctuation that adversely affects the equipment connected to the distribution line 201. In this case, the switches S1 and S2 are not switched. Therefore, in the third embodiment, a second digital filter different from the above-described digital filter is further added so as to cope with a sudden voltage fluctuation in a short period.

  Since the block configuration of the voltage regulation system according to the third embodiment is the same as that of the voltage regulation system 100 according to the first embodiment, the illustration is omitted, and the same reference numerals are given to the portions corresponding to the first embodiment. A description thereof will be omitted.

  The second digital filter receives the effective value signal Vs and removes a steep voltage fluctuation component in the second period Tbase shorter than the predetermined period Tperiod filtered in the first embodiment from the effective value signal Vs. To do.

Specifically, the second digital filter performs an operation represented by the following expression (10) using the above-described effective value signal Vs, sampling period Ts, second period Tbase, and Z conversion operator Z. Thus, the second operation determination voltage signal VTb obtained by removing the steep voltage fluctuation component from the effective value signal Vs is calculated and output. Nbase in the following equation (10) represents the number of sampling data in the second period Tbase (Tbase <Tperiod). In the second digital filter, since the second period Tbase is shorter than the predetermined period Tperiod, the voltage fluctuation component to be removed is reduced, and the second operation determination voltage signal VTb is an operation determination voltage signal in the same period. Compared with VTp, the voltage fluctuation becomes large (the degree of smoothing is small).

Note that, in the second digital filter, similarly to the digital filter of the first embodiment, the filtering process may be performed using the arithmetic expression shown in the following formula (11) or the following formula (12). However, when the arithmetic expression (10) is used for the second digital filter, the second digital filter is easier than when the arithmetic expression (11) or (12) is used. Can be designed to

  The second determination unit operates when the second operation determination voltage signal VTb output from the second digital filter deviates from the second dead zone including the preset reference voltage. Regardless of the determination result based on the determination voltage signal VTp, it is determined that switching of the switches S1 and S2 is necessary. The second dead zone region is a voltage region between an upper limit threshold value and a lower limit threshold value for determining whether or not switching of the switches S1 and S2 is necessary based on the second operation determination voltage signal VTb. It is.

  Specifically, the second determination unit needs to switch the switches S1 and S2 to decrease the voltage of the distribution line 201 when the second operation determination voltage signal VTb is larger than the upper limit value of the second dead zone. Judge that there is. Further, when the second operation determination voltage signal VTb is smaller than the lower limit value of the second dead zone, the second determination unit determines that the switches S1 and S2 need to be switched to increase the voltage of the distribution line 201. To do. Then, when the second operation determination voltage signal VTb does not satisfy both of these, that is, within the range between the upper limit value and the lower limit value of the second dead zone area (within the second dead zone area), it continues. The determination unit determines whether or not the switches S1 and S2 need to be switched based on whether or not the operation determination voltage signal VTp is out of the dead zone. About the processing content of the determination part, it is the same as that of Embodiment 1. FIG.

  As in the first embodiment, the width of the second dead zone region is comprehensively taken into consideration such as suppression of deviation of the voltage of the distribution line 201 from the dead zone region and suppression of switching of the switches S1 and S2. And the length (degree of smoothing) of the second period Tbase may be set.

  The switching command unit outputs a switching command for instructing switching of the switches S1 and S2 from the output unit 16 based on the determination results of the determination unit and the second determination unit. Specifically, when switching the switches S1 and S2 to increase the voltage of the distribution line 201 based on the determination result of the determination unit or the second determination unit, the switching command unit determines the capacity of the reactor connected to the distribution line 201. A switching command is output so that the level is lowered by one step. Further, when switching the switches S1 and S2 to lower the voltage of the distribution line 201 based on the determination result of the determination unit or the second determination unit, the switching command unit increases the capacity of the reactor connected to the distribution line 201 by one step. The switching command is output as follows. On the other hand, when the switches S1 and S2 are not switched based on the determination results of the determination unit and the second determination unit, the switching command unit holds the switching command without changing it.

  Next, operation | movement of the control part 1 of the voltage regulator 10 which concerns on Embodiment 3 comprised in this way is demonstrated using the flowchart which shows it. FIG. 8 is a flowchart illustrating a processing procedure of the CPU 11 that executes the voltage adjustment processing of the distribution line 201 in the voltage adjustment system 100 according to the third embodiment. The process of FIG. 8 is started at the above-described sampling period Ts after the CPU 11 is initialized.

  The processing contents of steps S21 to 23 and steps S29 and S27 shown in FIG. 8 are the same as steps S11 to 13 and steps S16 and S17 shown in FIG. . Hereinafter, filtering by the digital filter used in Embodiment 1 is referred to as first filtering processing, and filtering by the second digital filter is referred to as second filtering processing.

  When the processing of FIG. 8 is activated, the CPU 11 causes the A / D conversion unit 15 to apply the voltage of the distribution line 201, which is the detection result of the detection unit 21, to J times (J = Ts / Tss) A times Tss. / D conversion (S21), the effective value of the J conversion result is calculated (S22: equivalent to the effective value calculation unit), and the effective value signal Vs of the calculation result is stored in the RAM 13.

  Next, the CPU 11 performs the first filtering process by calculating the above-described equation (7) using the stored effective value signal Vs (S23: equivalent to a digital filter), and the operation determination voltage as the first process result. The signal VTp is calculated and stored in the RAM 13. Further, the CPU 11 performs the second filtering process by calculating the above equation (10) using the stored effective value signal Vs (S24: equivalent to the second digital filter), and the second processing result is the second. 2 operation determination voltage signal VTb is calculated and stored in RAM 13.

  Next, the CPU 11 compares the stored second operation determination voltage signal VTb, which is the second processing result, with the upper limit value and the lower limit value of the second dead zone (S25), and switches S1 according to the comparison result. , S2 is determined whether or not it is necessary to switch (S26: equivalent to a second determination unit). Specifically, when the second operation determination voltage signal VTb is larger than the upper limit value of the second dead zone, the CPU 11 determines that the switches S1 and S2 need to be switched to reduce the voltage of the distribution line 201. . When the second operation determination voltage signal VTb is smaller than the lower limit value of the second dead zone, the CPU 11 determines that the switches S1 and S2 need to be switched to increase the voltage of the distribution line 201.

  If the second operation determination voltage signal VTb is in the second dead zone region (S26: NO), the CPU 11 determines the stored operation determination voltage signal VTp as the first processing result and the dead zone. The upper limit value and the lower limit value of the area are compared (S28), and it is determined whether or not the switches S1 and S2 need to be switched according to the comparison result (S29: equivalent to a determination unit). When the operation determination voltage signal VTp is in the dead zone region, the CPU 11 determines that switching of the switches S1 and S2 is not necessary (S29: NO), and ends the processing of FIG. 8 without newly outputting a switching command. To do.

  On the other hand, if it is determined in step S26 that the switches S1 and S2 need to be switched (S26: YES), or if it is determined in step S29 that the switches S1 and S2 need to be switched (S29: YES), the CPU 11 The switching command of the switches S1 and S2 is changed so that the voltage of the distribution line 201 approaches the reference voltage and is output from the output unit 16 (S27: corresponding to the switching command unit), and the processing of FIG.

  The CPU 11 of the voltage adjustment device 10 repeatedly performs the voltage adjustment process described above to calculate the operation determination voltage signal VTp and the second operation determination voltage signal VTb from the voltage of the distribution line 201, and the operation determination voltage signal VTp and the second operation determination voltage signal VTp. The switching of the switches S1 and S2 is controlled based on the operation determination voltage signal VTb. Thereby, the voltage of the distribution line 201 is automatically adjusted so that it may become an appropriate range.

  In the third embodiment, the case where two types of digital filters are realized by the CPU 11 has been described as an example. However, the present invention is not limited to this, and a plurality of types of digital filters may be realized. Good. In this case, since arbitrary voltage fluctuation components are removed by changing the filtering periods of the respective digital filters, the switches S1 and S2 are appropriately switched in accordance with various voltage fluctuation components. be able to.

  As described above, according to the third embodiment, the switch S1 is based on the second operation determination voltage signal VTb output by filtering the effective value signal Vs in the second period Tbase shorter than the predetermined period Tperiod. , S2 is further output, a switching command for the switches S1, S2 is further output. Therefore, even if it is determined that the switching of the switches S1 and S2 is not required based on the operation determination voltage signal VTp output during the predetermined period Tperiod, in response to a sudden voltage change during the second period Tbase. The switches S1 and S2 can be switched.

  Further, according to the third embodiment, when the second operation determination voltage signal deviates from the second dead zone, the switching command is output in response quickly, so that the voltage of the distribution line 201 deviates from the appropriate range. Can be suppressed.

  Furthermore, according to the third embodiment, the second operation determination voltage signal is calculated by the filtering process represented by the equation (10), and accordingly, the second voltage component in which the steep voltage fluctuation component is removed from the effective value signal Vs. Since the necessity of switching is determined based on the operation determination voltage signal VTb, unnecessary switching of the switches S1 and S2 can be suitably suppressed.

  Furthermore, according to the third embodiment, the second operation determination voltage signal VTb may be calculated by a filtering process using a low-pass filter or a band-pass filter expressed by the equation (11) or (12). . In this case, a steep voltage fluctuation component within a time corresponding to the filter order and the filter coefficient is removed from the effective value signal Vs, or only a voltage fluctuation component of a time corresponding to the filter order and the filter coefficient is passed. be able to.

  Furthermore, according to the third embodiment, it may be determined whether or not the switches S1 and S2 need to be switched based on the operation determination voltage signal output from each of the plurality of digital filters. In this case, since an arbitrary voltage fluctuation component is removed by appropriately selecting the period during which each digital filter performs filtering, the switches S1 and S2 can be switched more suitably.

  Furthermore, according to the first, second, third, or modification examples, the voltage adjusting device 10 that can appropriately adjust the voltage of the distribution line 201 while suppressing unnecessary switching of the switch is used as the voltage adjusting system 100 or 100a can be applied.

  Below, the result of having compared and verified by the simulation the case where the voltage of the distribution line 201 is adjusted with the voltage adjustment system 100 which concerns on Embodiment 1, and the case where it adjusts with the conventional time determination system is demonstrated. The voltage adjustment system 100 uses a digital filter that performs the calculation shown in Equation (7), switches the switch S1 to turn on / off the reactor L1, that is, operates as ShR. The analysis conditions are as follows.

(A) Voltage sampling period Ts: 1 second (b) Reference voltage: 6600V
(C) Width of dead zone region with respect to reference voltage: 1.5% (± 99 V)
(D) Control amount by turning on / off the reactor L1: 100V
(E) Time limit operation time limit by conventional time determination method: 15 seconds (f) Predetermined period Tperiod in digital filtering processing: 120 seconds

  9A is a graph showing the time transition of the voltage of the distribution line 201 before adjustment, B is a graph showing the time transition of the voltage of the distribution line 201 after adjustment by the conventional method, and C is the graph of the reactor L1 by the conventional method. It is a graph which shows the time transition of opening and injection | throwing-in. 10A is a graph showing the time transition of the operation determination voltage signal VTp output from the digital filter, B is a graph showing the time transition of the voltage of the distribution line 201 after adjustment by the voltage adjustment system 100, and C is the voltage adjustment system 100. It is a graph which shows the time transition of opening and injection | throwing-in of reactor L1.

  The horizontal axis of each graph in FIG. 9 and FIG. 10 represents time (s), and the vertical axis represents the voltage (kV) or the open / close state of the reactor L1. The broken lines shown in A and B of FIG. 9 and A and B of FIG. 10 are the upper limit voltage and the lower limit voltage of the dead zone. The broken line shown in FIG. 10A is a temporal transition of the temporary operation determination voltage signal before the reactor L1 is opened / closed, and the solid line is the actual operation determination voltage signal VTp after the reactor L1 is opened / closed. It is time transition of.

  As a result of the simulation, the number of times of control (number of times of switching of the switch S1) in 16000 seconds is 56 times according to the conventional time determination method, but is reduced to 20 times according to the voltage adjustment system 100. Therefore, in the voltage adjustment system 100, it was shown that switching of the switch S1 is preferably suppressed as compared with the conventional one. Hereinafter, a description will be given with reference to FIGS.

  As shown in FIG. 9A, the voltage of the distribution line 201 before adjustment is about 100 V higher than the reference voltage as a whole, and fluctuates due to voltage fluctuations with a relatively short cycle. As a result of adjusting this voltage by the time determination method, as shown in FIG. 9B, the adjusted voltage is adjusted so as to be substantially equal to the reference voltage on average, but is relatively short (however, the operation It can be seen that the dead zone region is frequently deviated with a period longer than the time limit. For this reason, as shown in FIG. 9C, the introduction and release of the reactor L1 are performed in a relatively short cycle.

  On the other hand, as shown in FIG. 10A, in the operation determination voltage signal VTp obtained by subjecting the voltage of the distribution line 201 to A / D conversion processing, effective value calculation processing, and filtering processing, voltage fluctuations having a relatively short cycle are smoothed. I understand that. As a result of adjusting the voltage of the distribution line 201 based on the operation determination voltage signal VTp, as shown in FIG. 10B, the adjusted voltage is adjusted so as to substantially match the reference voltage on average. It can be seen that deviation from the dead zone region at a relatively short period is suppressed. For this reason, as shown to C of FIG. 10, the injection | throwing-in and release of the reactor L1 are not performed with a comparatively short period, and the total frequency | count of control is fully suppressed. Therefore, also in the result of this simulation, it can be said that the voltage adjustment system 100 suppresses unnecessary switching of the switch S1.

  The embodiment disclosed this time is to be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims. In addition, the technical features described in each embodiment can be combined with each other.

DESCRIPTION OF SYMBOLS 1 Control part 10 Voltage regulator 11 CPU
12 ROM
13 RAM
14 timer 15 A / D converter 16 output 20 measurement transformer 21 detector 31, 32, 33 reactor S1, S2, S3 switch L1, L2 reactor C1, C2, C3 capacitor 100, 100a voltage regulation system 200 substation 201 Distribution line

Claims (13)

A voltage adjusting device that adjusts the voltage of the power transmission line by controlling switching of a switch that connects a reactor or a capacitor in parallel to the power transmission line,
A detection unit for detecting a voltage of the power transmission line;
An A / D converter for digitizing the voltage detected by the detector;
An effective value calculating unit that calculates an effective value of the voltage digitized by the A / D converter and outputs an effective value signal;
A digital filter that removes steep voltage fluctuation components from the effective value signal output by the effective value calculation unit and outputs an operation determination voltage signal;
A determination unit that determines whether or not switching of the switch is necessary based on an operation determination voltage signal output by the digital filter;
And a switching command unit that outputs a switching command to the switch so that the voltage of the power transmission line approaches a reference voltage when the determination unit determines that switching is necessary.   The voltage regulator according to claim 1, wherein the digital filter performs a filtering process on an effective value signal output by the effective value calculation unit during a predetermined period.   The voltage regulator according to claim 2, wherein the determination unit determines that the switch needs to be switched when the operation determination voltage signal deviates from a preset dead band region. The digital filter has Vs as the effective value signal, Ts as the sampling period, Tperiod as the predetermined period, Nperiod as the number of effective value signals during the predetermined period, and Z as the Z conversion operator as follows. 4. The voltage regulator according to claim 2, wherein the operation determination voltage signal VTp is calculated and output by performing an operation shown in equation (4).

In the digital filter, the effective value signal is Vs, the Z conversion operator is Z, the predetermined filter order is M, N, the predetermined coefficients are ai (i = 0, 1,..., M), bj (j = 0, 1,..., N), and the operation determination voltage signal VTp is calculated and output by performing the calculation shown in the following equation (2).
4. The voltage regulator according to claim 2, wherein the predetermined filter orders M and N and the predetermined coefficients a i and b j are set so that the digital filter functions as a low-pass filter or a band-pass filter.

In the digital filter, the effective value signal is Vs, the Z conversion operator is Z, the predetermined filter order is M, the predetermined coefficient is hi (i = 0, 1,..., M), and the following (3) By performing the calculation shown in the equation, the operation determination voltage signal VTp is calculated and output,
The voltage adjustment device according to claim 2 or 3, wherein the predetermined filter order M and the predetermined coefficient hi are set so that the digital filter functions as a low-pass filter or a band-pass filter.

A second digital filter that outputs a second operation determination voltage signal by performing a filtering process on the effective value signal output during a second period shorter than the predetermined period by the effective value calculation unit;
A second determination unit that determines whether the switch needs to be switched based on the second operation determination voltage signal;
The switching command unit further outputs a switching command to the switch so that the voltage of the power transmission line approaches a reference voltage when the second determination unit determines that switching is necessary. The voltage regulator according to any one of the preceding claims.   The voltage according to claim 7, wherein the second determination unit determines that the switch needs to be switched when the second operation determination voltage signal deviates from a preset second dead zone. Adjustment device. The second digital filter performs the calculation shown in the following equation (4) by setting the effective value signal as Vs, the sampling period as Ts, the second period as Tbase, and the Z conversion operator as Z. The voltage regulator according to claim 7 or 8, wherein the second operation determination voltage signal VTb is calculated and output.

In the second digital filter, the effective value signal is Vs, the Z conversion operator is Z, the predetermined filter order is P, Q, the predetermined coefficient is ck (k = 0, 1,..., P), dl (l = 0, 1,..., Q), and the second operation determination voltage signal VTb is calculated and output by performing the calculation shown in the following equation (5).
The voltage regulator according to claim 7 or 8, wherein the predetermined filter orders P and Q and the predetermined coefficients kk and dl are set so that the digital filter functions as a low-pass filter or a band-pass filter.

In the second digital filter, the effective value signal is Vs, the Z conversion operator is Z, the predetermined filter order is P, the predetermined coefficient is fk (k = 0, 1,..., P), By performing the calculation shown in the equation (6), the second operation determination voltage signal VTb is calculated and output,
The voltage regulator according to claim 7 or 8, wherein the predetermined filter order P and the predetermined coefficient fk are set so that the digital filter functions as a low-pass filter or a band-pass filter.

A plurality of the digital filters having different predetermined periods from each other;
7. The determination unit according to claim 2, wherein the determination unit determines whether or not the switch needs to be switched based on an operation determination voltage signal output by filtering each of the plurality of digital filters. The voltage regulator described in 1. The voltage regulator according to any one of claims 1 to 12,
The switch;
A voltage regulation system including a reactor or a capacitor connected in parallel to the power transmission line via the switch.

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