Voltage regulation system

Abstract

Efficiently set the range of the moving average points, which is the number of times the monitoring voltage is acquired. [Solution] In a voltage regulation system, each of the voltage regulators installed in series in multiple stages is equipped with a tapped regulating transformer 10, a tap changer 11, and a control unit that controls the tap changer to perform voltage regulation of AC voltage in the power system. The control unit acquires a monitoring voltage, which is the voltage on the load side, calculates an average voltage by performing a moving average on the acquired multiple monitoring voltages, and performs voltage regulation when the calculated average voltage deviates from a dead zone corresponding to a predetermined reference voltage. When performing a moving average on the voltage regulator, the setting range of the moving average points, which is the number of times the monitoring voltage is acquired, is predetermined, and in at least two of the multiple voltage regulators, the maximum value in the setting range of the preceding voltage regulator is less than or equal to the minimum value in the setting range of the succeeding voltage regulator.

Description

Technical Field

[0001] The present invention relates to a voltage regulation system.

Background Art

[0002] There is known a method for adjusting the voltage of a power distribution system in which a tap-changing type automatic voltage regulator is installed in a power distribution path, and the automatic voltage regulator usually detects the voltage on the secondary side and performs tap switching to bring it closer to the target value to adjust the voltage on the secondary side (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the automatic voltage regulator disclosed in Patent Document 1 does not consider how to efficiently set the adjustment range of the number of moving average points, which is the number of times of acquiring the monitored voltage, when performing the moving average processing of a plurality of acquired monitored voltages.

[0005] The present invention has been made in view of such circumstances, and an object thereof is to provide a voltage regulation system capable of efficiently setting the adjustment range of the number of moving average points, which is the number of times of acquiring the monitored voltage, when performing the moving average processing of a plurality of acquired monitored voltages.

Means for Solving the Problems

[0006] A voltage regulation system according to one aspect of the present disclosure is a voltage regulation system including a plurality of voltage regulators installed in series in multiple stages in a power system with a substation on the upstream side and a load on the downstream side, wherein each of the plurality of voltage regulators comprises a tapped regulating transformer, a tap changer for switching the taps of the regulating transformer, and a control unit that controls the tap changer to perform voltage regulation of the AC voltage in the power system, wherein the control unit acquires a monitoring voltage which is the voltage on the load side, calculates an average voltage value by performing a moving average processing on the acquired plurality of monitoring voltages, and performs voltage regulation processing when the calculated average voltage value deviates from a dead zone corresponding to a predetermined reference voltage, wherein the setting range of the number of moving average points, which is the number of times the monitoring voltage is acquired, is predetermined when the voltage regulator performs the moving average processing, and in at least two of the plurality of voltage regulators, the maximum value in the setting range of the upstream voltage regulator is less than or equal to the minimum value in the setting range of the downstream voltage regulator.

[0007] In this embodiment, a voltage regulation system is configured as a multi-stage system with multiple voltage regulators by installing two or more voltage regulators in series on the distribution lines of a power system powered by a substation. These two or more voltage regulators that make up the multi-stage system include a front-stage voltage regulator located on the substation side (a voltage regulator installed on the front side) and a rear-stage voltage regulator located on the load side (the side of the load to which AC power from the power system is supplied) of the front-stage voltage regulator (a voltage regulator installed on the rear side). These multiple voltage regulators are SVRs (step voltage regulators). The voltage regulator periodically acquires (detects) the voltage on the secondary side of its own device as a monitoring voltage and performs moving average processing on the monitoring voltage by continuously calculating the average value of multiple monitoring voltages acquired continuously over a predetermined period. The voltage regulator (SVR) checks each time the average voltage is calculated, whether the average voltage calculated by moving average processing falls within a dead zone corresponding to a predetermined reference voltage. If the average voltage deviates from the dead zone, it controls the tap changer to switch taps and adjust the transformation ratio, thereby adjusting the voltage so that the monitored voltage approaches the reference voltage. In other words, the control unit of the voltage regulator (SVR) functions as a moving average filter that removes sharp voltage fluctuations by using the average voltage (moving average value of the monitored voltage) obtained from multiple monitored voltage values ​​sampled periodically (e.g., every 1 second). As a result, operation decisions (tap operation using the moving average method) are made based on the monitored voltage (average voltage), which has been smoothed by averaging. This reduces the frequency of tap switching compared to, for example, a fixed-time control method that controls tap switching when the dead zone deviation time exceeds a set time limit. A voltage regulator periodically acquires a monitoring voltage (secondary voltage), for example, at a 1-second interval, and calculates an average value. In this process, a moving average point corresponding to the number of times the monitoring voltage is acquired is set.In other words, when performing a single moving average operation, the predetermined period (moving average period), which is the period for acquiring each of the multiple monitoring voltages in a time series, corresponds to the value obtained by multiplying the acquisition period (sampling period) of the monitoring voltage by the number of moving average points (moving average period = acquisition period × number of moving average points). In the voltage regulator included in the voltage adjustment system, the number of moving average points is not fixed by a single numerical value, but is set variably as a setting range that is set within a predetermined range. That is, this setting range corresponds to the numerical range that the moving average points can take, and therefore the number of moving average points is variably set to any value from the minimum value (minimum moving average points) to the maximum value (maximum moving average points) within the setting range. By varying the number of moving average points with this setting range, the operating time of the voltage regulator can be efficiently fine-tuned in accordance with the number of tap changes in the voltage regulator or the increase or decrease in the amount of voltage deviation. In a power system, multiple voltage regulators are installed in series in multiple stages. At least two of these regulators correspond to the preceding and succeeding voltage regulators. The maximum moving average score within the setting range of the preceding voltage regulator is less than or equal to the minimum moving average score within the setting range of the succeeding voltage regulator. In other words, the setting ranges of the preceding and succeeding voltage regulators are set to be different, and the maximum moving average score within the setting range of the preceding voltage regulator is less than or equal to the minimum moving average score within the setting range of the succeeding voltage regulator. Therefore, even if the moving average score is changed within the respective setting ranges of each of these voltage regulators, the moving average score of the preceding voltage regulator can always be kept less than or equal to the moving average score of the succeeding voltage regulator. When multiple voltage regulators are installed in series in multiple stages in a power system, the number of tap changes for the later voltage regulators tends to be higher than that of the earlier voltage regulators. However, since the minimum moving average score in the setting range of the later voltage regulator is greater than or equal to the maximum moving average score in the setting range of the earlier voltage regulator, the moving average score of the later voltage regulator can always be kept equal to or greater than that of the earlier voltage regulator.This makes it possible to reduce the overall number of operations and the amount of voltage deviation in a voltage regulation system that includes multiple voltage regulators.

[0008] A voltage adjustment system according to one aspect of the present disclosure includes a control unit which acquires terminal information of a voltage adjustment device on which the control unit is mounted, and which changes the moving average score within the setting range based on the acquired terminal information.

[0009] In this embodiment, the control unit installed in each of the multiple voltage regulators included in the voltage regulation system acquires local terminal information for the voltage regulator on which the control unit (itself) is installed. That is, the control unit of a voltage regulator changes the moving average score of the voltage regulator on which it is installed, within the settling range set for the voltage regulator on which it is installed, based on the local terminal information that it can autonomously acquire in the voltage regulator on which it is installed, without mutual communication with the control units of other voltage regulators. In this way, each control unit of a voltage regulator does not require cooperative control through mutual communication with the control units of other voltage regulators, and autonomously performs the process of changing the moving average score using local terminal information that it can autonomously acquire in the voltage regulator on which it is installed. This is expected to suppress the complexity of the configuration of the voltage regulators (SVRs) and reduce equipment costs. When multiple voltage regulators composed of SVRs are installed in a multi-stage configuration, it is expected that fine-tuning the setting values ​​while coordinating the operation of each voltage regulator (SVR) and monitoring the trade-off relationship between the number of operations and the voltage deviation will be complicated. However, by changing the moving average point within the setting range, automatic setting can be performed, thereby reducing the labor required for setting.

[0010] A voltage adjustment system according to one aspect of the present disclosure includes, in the terminal information, the number of operations, which is the number of times the tap has been switched during a predetermined period, and the control unit increases the moving average score within the settling range when the number of operations is increasing.

[0011] In this embodiment, the control unit of the voltage regulator is configured with a microcontroller or the like, which includes a memory unit configured with ROM or RAM, for example. The control unit of the voltage regulator stores in its memory unit the voltage information of its own end, such as the monitoring voltage (secondary voltage) acquired via a measuring transformer installed in the voltage regulator (self-device) on which the control unit itself is mounted, and the number of times the tap has been switched (number of operations) during a predetermined period, such as 30 minutes, as self-end information of the voltage regulator (self-device). The control unit of the voltage regulator compares the number of operations during a predetermined period for aggregating the number of operations in the previous predetermined period (previous predetermined period) with the number of operations aggregated during the current predetermined period, and determines whether the number of operations in the current predetermined period has increased compared to the number of operations in the previous predetermined period. In determining whether the number of operations has increased, the control unit of the voltage regulator may determine that the number of operations has increased if the rate of increase of the number of operations in the current predetermined period (current operations / previous operations) compared to the number of operations in the previous predetermined period (previous operations) exceeds a predetermined threshold (for example, 1.2). Alternatively, the control unit of the voltage regulator may determine that the number of operations has increased if the number of operations during the current predetermined period exceeds a predetermined threshold for the number of operations. When the control unit of the voltage regulator determines that the number of operations is increasing in this way, or when the number of operations exceeds a predetermined threshold for the number of operations, it increases the moving average score within the settling range of the voltage regulator. When increasing the moving average score, the control unit of the voltage regulator may determine the amount of increase in the moving average score according to the rate of increase (current number of operations / previous number of operations). That is, the control unit of the voltage regulator may increase the amount of increase in the moving average score or increase the rate of increase in the moving average score before and after the increase as the rate of increase increases. Alternatively, when increasing the moving average score, the control unit of the voltage regulator may increase the amount of increase in the moving average score or increase the rate of increase in the moving average score before and after the increase according to the difference between the threshold for the number of operations and the current number of operations (current number of operations - threshold for the number of operations). In other words, the control unit of the voltage regulator may increase the number of increments in the moving average score as the difference increases.By increasing the number of moving average points, the moving average period (moving average period = acquisition period × number of moving average points), which is the period over which multiple consecutive monitoring voltages are acquired in a time series, becomes longer. As a result, even if sudden deviations in the monitoring voltage occur, the average value of the monitoring voltage tends to be smoothed out and approach the reference voltage, thereby reducing the number of operations.

[0012] A voltage adjustment system according to one aspect of the present disclosure includes, in the terminal information, a voltage deviation amount which is the integral value of the voltage value that has deviated from the dead zone during a predetermined period, and the control unit reduces the moving average score within the settling range when the voltage deviation amount is increasing.

[0013] In this embodiment, the control unit of the voltage regulator stores in its memory the voltage information of its own end, such as the monitoring voltage (secondary voltage) acquired via a measuring transformer installed in the voltage regulator (self-device) on which the control unit itself is mounted, and the voltage deviation amount, which is the integral value of the voltage value that deviated from the dead zone during a predetermined period, such as 30 minutes, as self-end information of the voltage regulator (self-device). The control unit of the voltage regulator compares the voltage deviation amount during a predetermined period for accumulating the previous voltage deviation amount (previous predetermined period) with the voltage deviation amount accumulated during the current predetermined period, and determines whether the voltage deviation amount during the current predetermined period has increased compared to the voltage deviation amount during the previous predetermined period. When determining whether the voltage deviation amount has increased, the control unit of the voltage regulator may determine that the voltage deviation amount has increased if the rate of increase of the voltage deviation amount during the current predetermined period (current voltage deviation amount / previous voltage deviation amount) compared to the voltage deviation amount during the previous predetermined period (previous voltage deviation amount) exceeds a predetermined threshold (for example, 1.2). Alternatively, the control unit of the voltage regulator may determine that the voltage deviation has increased if the current voltage deviation for a predetermined period exceeds a predetermined voltage deviation threshold. When the control unit of the voltage regulator determines that the voltage deviation is trending upward, or when the voltage deviation exceeds a predetermined voltage deviation threshold, it reduces the moving average score within the settling range of the voltage regulator. When reducing the moving average score, the control unit of the voltage regulator may determine the amount of reduction in the moving average score according to the rate of increase (current voltage deviation / previous voltage deviation). That is, the control unit of the voltage regulator may increase the amount of reduction in the moving average score or increase the rate of reduction in the moving average score before and after the reduction as the rate of increase increases. Alternatively, when reducing the moving average score, the control unit of the voltage regulator may determine the amount of reduction in the moving average score according to the difference between the voltage deviation threshold and the current voltage deviation (current voltage deviation - voltage deviation threshold). That is, the control unit of the voltage regulator may increase the amount of reduction in the moving average score as the difference increases.By reducing the number of moving average points, the moving average period (moving average period = acquisition period × number of moving average points), which is the period over which multiple consecutive monitoring voltages are acquired in a time series, becomes shorter. This improves the frequency of tap switching and enhances the responsiveness to voltage fluctuations on the primary or secondary side, thereby reducing the amount of voltage deviation.

[0014] In one aspect of the present disclosure, the predetermined period for calculating the terminal information is longer than the moving average period obtained by multiplying the moving average points by the period for acquiring the monitoring voltage.

[0015] In this embodiment, the predetermined period for calculating terminal information is, for example, 30 minutes, which is longer than the moving average period obtained by multiplying the moving average points by the period (1 second) for acquiring the monitoring voltage. That is, the moving average period is a variable period within a set range, and is the period from the minimum value (minimum moving average points) to the maximum value (maximum moving average points) within the set range. The predetermined period for calculating terminal information is set to be longer than the maximum moving average period obtained by multiplying the maximum moving average points by the period for acquiring the monitoring voltage. Therefore, multiple moving average periods are included within a single predetermined period. Using the moving average period as the processing unit time, a determination of whether tap switching is necessary and, if tap switching is necessary, processing related to voltage adjustment by tap switching are performed. In the predetermined period for calculating terminal information, the number of voltage adjustment processes (processing count) is determined according to the number of moving average periods included in the predetermined period, and terminal information can be suitably calculated according to the number of processing counts.

[0016] In one aspect of the present disclosure, a voltage regulation system is provided in which all of the plurality of voltage regulation devices have a defined setting range, and when the devices are installed in series in multiple stages, the maximum value of the setting range of the preceding voltage regulation device is less than or equal to the minimum value of the setting range of the succeeding voltage regulation device.

[0017] In this embodiment, a setting range is set for all voltage regulators in the multiple voltage regulators included in the voltage regulation system. That is, each voltage regulator in the voltage regulation system can change its own moving average score within the setting range set for it. Each voltage regulator included in the voltage regulation system is installed in series with the power grid, and when the substation is the upstream side and the load is the downstream side, the combination of two voltage regulators arranged in series before and after is determined according to the number of voltage regulators included in the voltage regulation system. In this case, in each of these combinations of two voltage regulators arranged in series before and after, the maximum value in the setting range of the upstream voltage regulator is less than or equal to the minimum value in the setting range of the downstream voltage regulator. Therefore, each voltage regulator included in the voltage regulation system is configured such that the moving average score that can be taken within the setting range increases in stages from the upstream side to the downstream side. By gradually increasing the numerical range of the setting width, i.e., the number of possible moving average points, set for all voltage regulators included in the voltage regulation system, it is possible to suppress the excessive number of operations of the downstream voltage regulators. In other words, in a multi-stage series-installed voltage regulator system, there is a tendency for the number of operations (e.g., the number of tap changes within a predetermined period such as 30 minutes) to increase as the system progresses to the downstream stage. By suppressing the excessive number of operations of the downstream voltage regulators, the overall operation of the voltage regulation system can be optimized.

[0018] In one aspect of the present disclosure, the voltage adjustment system is such that the difference between the maximum and minimum values ​​in the setting range of each of the plurality of voltage adjustment devices is the same.

[0019] In this aspect, in a plurality of voltage adjustment devices included in a voltage adjustment system, the difference between the maximum value and the minimum value in the setting range is set to the same value. By setting the difference between the maximum value and the minimum value in the setting range of each voltage adjustment device included in the voltage adjustment system to the same value, for example, 120, etc., the control specifications of each of these voltage adjustment devices can be made common or standardized, and the control of the voltage adjustment system can be optimized.

Effect of the Invention

[0020] It is possible to provide a voltage adjustment device that efficiently sets the setting range of the moving average number of points, which is the number of times of obtaining the monitored voltage, when performing the moving average process on the plurality of obtained monitored voltages.

Brief Description of the Drawings

[0021] [Figure 1] It is a configuration diagram showing a voltage adjustment system including a voltage adjustment device according to Embodiment 1. [Figure 2] It is a block diagram showing a configuration example of a voltage adjustment device. [Figure 3] It is an explanatory diagram showing the setting and change of the moving average number of points. [Figure 4] It is an explanatory diagram showing the setting range in all voltage adjustment devices of the voltage adjustment system. [Figure 5] It is a flowchart showing the processing procedure of the control unit of the voltage adjustment device.

Modes for Carrying Out the Invention

[0022] (Embodiment 1) The embodiments will be described below with reference to the drawings. Figure 1 is a configuration diagram showing a voltage regulation system S including a voltage regulator 100 according to Embodiment 1. Figure 2 is a block diagram showing an example of the configuration of the voltage regulator 100. Multiple voltage regulators 100 are installed in series on a distribution line (system) where a substation is located. That is, these voltage regulators 100 are connected in series (connected to the same system) in a multi-stage configuration, thereby forming a multi-stage system. In these multiple voltage regulators 100, the substation side is the primary side (input side), and the load side is the secondary side (output side). Each of these multi-stage voltage regulators 100 controls the tap positions (tap switching operations) of the tap changers 11u, 11v, and 11w so that the voltage (output voltage) on the secondary side (output side) is close to a predetermined reference voltage. In the illustration of this embodiment, the voltage regulator 100, which is installed in a multi-stage configuration using four units as an example, is a Step Voltage Regulator (SVR). When the substation side is considered the first stage and the load side the second stage, the devices are installed in series in multiple stages (four stages) from the first stage to the second stage within the same power system.

[0023] The voltage regulator 100 (SVR) periodically acquires (detects) the value of the secondary voltage, which is the output voltage, as a monitoring voltage. When the monitoring voltage deviates from the dead zone, it controls the tap changers 11u, 11v, and 11w to perform voltage adjustment processing for the AC voltage in the power system. The dead zone is determined based on the value of a set reference voltage and is defined by a predetermined width relative to the reference voltage.

[0024] The voltage regulator 100 may perform a moving average processing on the monitored voltage by continuously calculating the average value of multiple (e.g., 600 points) of monitored voltages acquired continuously at a predetermined period (e.g., a 1-second period) over a predetermined period (e.g., 10 minutes) to determine whether the monitored voltage has deviated from the dead zone. The multiple points acquired in this manner correspond to the moving average points. As will be described in detail later, the voltage regulator 100 changes the moving average points based on terminal information. Then, if the average voltage value calculated by the moving average processing deviates from the dead zone, the voltage regulator 100 may perform voltage adjustment processing for the AC voltage in the power system by controlling the tap changers 11u, 11v, and 11w.

[0025] In this way, the voltage regulator 100 performs operation determination (tap operation using a moving average method) based on a smoothed monitoring voltage (average voltage). This reduces the tap switching frequency compared to, for example, a fixed-time control method that controls tap operation (tap switching) when the dead zone deviation time exceeds a set time limit.

[0026] Even with a voltage regulator 100 (SVR) using the moving average method, the number of tap changes may increase due to the influence of other voltage regulators 100 (preceding voltage regulators 100) installed closer to the substation than the SVR itself. In response to this, the voltage regulator 100 (SVR) changes the moving average point within a predetermined setting range based on its own terminal information, thereby suppressing an increase in the number of tap changes while also suppressing an increase in the voltage deviation. This allows for the overall optimization of the voltage regulation system S, even as individual voltage regulators 100 perform autonomous control.

[0027] In Figure 2, 1u, 1v, and 1w are primary (substation side) transmission and distribution lines that transmit and distribute three-phase AC voltages including U-phase, V-phase, and W-phase, while 2u, 2v, and 2w are secondary (load side) transmission and distribution lines. The voltage regulator 100 includes tapped regulator transformers 10u, 10v, and 10w that transform the AC voltages of the U-phase, V-phase, and W-phase from the primary side to the secondary side, or from the secondary side to the primary side, tap changers 11u, 11v, and 11w that switch between the respective taps, and a control unit 20 that controls the entire device.

[0028] The regulating transformers 10u, 10v, and 10w have their windings connected in a star (Y) configuration, with one end of each winding connected to the transmission and distribution lines 2u, 2v, and 2w, respectively. Each of the regulating transformers 10u, 10v, and 10w has nine taps, from tap t1 to tap t9, but the number of taps is not limited to nine.

[0029] Tap changers 11u, 11v, and 11w switch the taps of the regulating transformers 10u, 10v, and 10w, respectively, and the switched taps are connected to the power transmission and distribution lines 1u, 1v, and 1w, respectively. The tap switching is performed by a switching command from the control unit 20.

[0030] The control unit 20 has an MPU or CPU (Central Processing Unit), and the CPU executes a control program (program product) stored in RAM or ROM (Read Only Memory) to perform processing such as input / output, calculation, and time measurement. The control unit 20 is connected to the secondary windings of the measuring transformers 22vw, 22wu, and 22uv, and to the input units for switching commands for the tap changers 11u, 11v, and 11w, respectively. The measuring transformers 22vw, 22wu, and 22uv may be included in the voltage regulator 100. The control unit 20 may be composed of a microcomputer (MPC) with a memory or other storage unit, or a dedicated hardware circuit such as an FPGA, ASIC, or circuit board.

[0031] The control unit 20 acquires voltages from the secondary windings of the measuring transformers 22vw, 22wu, and 22uv, respectively, and detects the line voltages between the VW phases on the secondary side, between the WU phases on the secondary side, and between the UV phases on the secondary side as monitoring voltages. The control unit 20 then issues switching commands to the tap changers 11u, 11v, and 11w based on the detected line voltages. If voltage detection units are provided on the secondary windings of the measuring transformers 22vw, 22wu, and 22uv, the control unit 20 may acquire the detection results of each line voltage from these voltage detection units. Alternatively, the control unit 20 of the voltage regulator 100 may detect the voltage (monitoring voltage) at a monitoring point (LDC monitoring point) by an LDC (Line Drop Compensator) connected to the secondary side. As described above, the control unit 20 periodically samples the monitoring voltage in each phase using a moving average number of points (for example, 600 points [moving average number of points] sampled in 10 minutes with a 1-second period), and functions as a moving average filter that removes sharp voltage fluctuations by using the voltage average value (moving average value of the monitoring voltage) of multiple monitoring voltage values.

[0032] Figure 3 is an explanatory diagram showing the setting and modification of the moving average score. In this embodiment, the illustration describes any two voltage regulators 100 that are arranged in series one before the other, among the multiple voltage regulators 100 that are installed in series in multiple stages in the power system in the voltage regulation system S. These any two voltage regulators 100 that are arranged in series one before the other represent the minimum configuration of the voltage regulation system S. A setting range for the moving average score is set for each of these voltage regulators 100.

[0033] The preceding voltage regulator 100 (SVR1) is set to a setting range of 180 to 420 for the moving average score, and the initial value of the moving average score is set to, for example, 300, which is the median of the setting range. The succeeding voltage regulator 100 (SVR2) is set to a setting range of 480 to 600 for the moving average score, and the initial value of the moving average score is set to, for example, 540, which is the median of the setting range. Thus, the maximum setting range (420) of the preceding voltage regulator 100 (SVR1) is set to be less than or equal to the minimum setting range (480) of the succeeding voltage regulator 100 (SVR2). The setting ranges described above are just examples; for example, the maximum setting range of the preceding voltage regulator 100 (SVR1) and the minimum setting range of the succeeding voltage regulator 100 (SVR2) may both be the same value, such as 500. In other words, the setting range for each of the individual voltage regulators 100 may be set individually for each of these voltage regulators 100, as long as the maximum setting range of the preceding voltage regulator 100 (SVR1) is set to be less than or equal to the minimum setting range of the succeeding voltage regulator 100 (SVR2).

[0034] The initial value of the moving average point is not limited to the median of the setting range, but may be configured to be configurable in each individual voltage regulator 100. Alternatively, the moving average point may be reset (initialized) periodically, and in this case, the initial value may be changed according to the date and time (day of the week, time of day, or a combination thereof).

[0035] Alternatively, each voltage regulator 100 may set a setting width according to the number of stages (installation order) set for itself (the device). Each memory unit of each voltage regulator 100 stores a setting width table in which the number of stages when installed in series in multiple stages in a power system, that is, the installation order based on the substation, and the setting width for that number of stages (installation order) are defined in association. Each voltage regulator 100 may refer to the setting width table, derive a setting width corresponding to the number of stages (installation order) set for itself (the device), and set the derived setting width.

[0036] Each voltage regulator 100 (SVR1, SVR2), which has a set setting range and a moving average point within that setting range, calculates the average value of multiple monitored voltages obtained using the moving average point. If the calculated average value deviates from within the dead zone, it performs tap switching based on the positive or negative sign of the deviation and controls the monitored voltage (secondary voltage) to bring it closer to the target value (reference voltage) (tap switching process). While continuing the tap switching process, each voltage regulator 100 (SVR1, SVR2) continuously acquires the number of operations, which is the number of times the tap has been switched, and the voltage deviation amount, which is the integral value of the voltage value that has deviated from the dead zone, as terminal information within a predetermined period, such as 30 minutes used in the calculation of the demand value. Each voltage regulator 100 (SVR1, SVR2) associates this terminal information, including the number of operations and the voltage deviation amount, with the time of acquisition of the terminal information (a timestamp indicating a predetermined period) and stores it in the storage unit, for example, as operation log information.

[0037] Each voltage regulator 100 (SVR1, SVR2) acquires and stores its own terminal information, and based on the acquired terminal information, determines whether or not to change the moving average score within a set range. That is, each voltage regulator 100 (SVR1, SVR2) performs processing related to changing the moving average score within a set range as an autonomous or independent process based on its own terminal information. In the preceding voltage regulator 100 (SVR1), its terminal information indicates that the number of operations has increased, and in response, the preceding voltage regulator 100 (SVR1) increases the moving average score from 300 to 400 within a set range (180 to 420). In the subsequent voltage regulator 100 (SVR2), if its own terminal information indicates an increase in the voltage deviation, the subsequent voltage regulator 100 (SVR2) reduces the moving average score from 540 to 480 within the setting range (480 to 600). In this way, the moving average score is automatically changed according to the number of tap changes (number of operations) and the voltage deviation, so that each voltage regulator 100 (SVR) is set appropriately, stable voltage regulation can be achieved, and the setting work can be made more efficient or labor-saving. As a result, in a voltage regulation system S equipped with multiple voltage regulators 100, each voltage regulator 100 can perform processing autonomously, while the overall voltage regulation system S can be optimized.

[0038] Figure 4 is an explanatory diagram showing the setting ranges for all voltage regulators 100 in the voltage regulation system S. In this embodiment, as an example, the voltage regulation system S has four voltage regulators 100 (SVR1, SVR2, SVR3, SVR4) installed in series in multiple stages in the power system. Even in this case of four stages with four voltage regulators 100 (SVR1, SVR2, SVR3, SVR4), all voltage regulators 100 are given a setting range, and an appropriate setting value (moving average point) can be selected by automatically setting them based on terminal information, etc.

[0039] The first-stage voltage regulator 100 (SVR1) is set to a moving average score range of 120 to 240. The second-stage voltage regulator 100 (SVR2) is set to a moving average score range of 300 to 420. The third-stage voltage regulator 100 (SVR3) is set to a moving average score range of 480 to 600. The fourth-stage voltage regulator 100 (SVR4) is set to a moving average score range of 660 to 780. In this way, the difference between the maximum and minimum values ​​of the setting range for each voltage regulator 100 may be set to be the same value, such as 120.

[0040] Figure 5 is a flowchart showing the processing procedure of the control unit 20 of the voltage regulator 100. Each control unit 20 of all voltage regulators 100 in the voltage regulator system S changes its own moving average score within a set range based on the terminal information obtainable in the voltage regulator 100 on which it is installed. In other words, each voltage regulator 100 included in the voltage regulator system S can autonomously or independently change its own moving average score within a set range within a set range without communicating with other voltage regulators 100.

[0041] The following describes the process of changing the moving average score by any of the multiple voltage regulators 100 included in the voltage regulation system S. The control unit 20 of the voltage regulator 100 performs this process (changing the moving average score) when performing voltage regulation processing of AC voltage in the power system (control processing of tap changers 11u, 11v, and 11w) in accordance with a control program (program product) that is pre-stored in a storage unit such as ROM.

[0042] The control unit 20 acquires local terminal information including the number of operations and the voltage deviation (S101). The control unit 20 acquires local terminal information from the voltage regulator 100 on which the control unit 20 (itself) is mounted. Local terminal information includes, for example, voltage information of the local terminal such as the monitoring voltage (secondary voltage) acquired via a measuring transformer provided in the voltage regulator 100 (itself) on which the control unit 20 itself is mounted, as well as the number of operations and the voltage deviation. For example, the control unit 20 counts the number of operations, which is the number of times the tap has been switched, in a predetermined period (local terminal information acquisition unit period), such as 30 minutes, used in calculating the demand value, and further calculates the voltage deviation, which is the integral value of the voltage amount that has deviated from the dead zone, and stores these number of operations and voltage deviation in the storage unit in association with a timestamp indicating the predetermined period. The control unit 20 may also calculate the voltage deviation by integrating the absolute value of the voltage amount when the monitoring voltage deviates from the dead zone over the period in which the deviation occurred.

[0043] The control unit 20 determines whether the number of operations has increased (S102). In determining whether the number of operations has increased during the current predetermined period (the predetermined period immediately preceding this determination process), the control unit 20 compares, for example, the number of operations during the previous predetermined period for aggregating the number of operations (the previous predetermined period) with the number of operations aggregated during the current predetermined period, and determines whether the number of operations in the current predetermined period has increased compared to the number of operations in the previous predetermined period. In this case, the control unit 20 may determine that the number of operations has increased if the rate of increase of the number of operations in the current predetermined period (current operations / previous operations) compared to the number of operations in the previous predetermined period (previous operations) exceeds a predetermined threshold (for example, 1.2). Alternatively, the control unit 20 may determine that the number of operations has increased if the number of operations in the current predetermined period exceeds a predetermined threshold for the number of operations.

[0044] If the number of operations increases (S102: YES), the control unit 20 increases the moving average score within the set range (S1021). If the number of operations increases, the control unit 20 increases the moving average score within the set range. In this case, the control unit 20 may increase the moving average score in stages.

[0045] If the number of operations has not increased (S102: NO), the control unit 20 determines whether the voltage deviation has increased (S103). If the number of operations has not increased, the control unit 20 determines whether the voltage deviation has increased during the current predetermined period (the predetermined period immediately preceding this determination process) by comparing the voltage deviation during the previous predetermined period (the previous predetermined period) with the voltage deviation accumulated during the current predetermined period, and determines whether the voltage deviation during the current predetermined period is greater than the voltage deviation during the previous predetermined period. In this case, the control unit 20 may determine that the voltage deviation has increased if the rate of increase of the voltage deviation during the current predetermined period (current voltage deviation / previous voltage deviation) compared to the voltage deviation during the previous predetermined period (previous voltage deviation) exceeds a predetermined threshold (for example, 1.2). Alternatively, the control unit 20 may determine that the voltage deviation has increased if the voltage deviation during the current predetermined period exceeds a predetermined voltage deviation threshold.

[0046] If the voltage deviation increases (S103: YES), the control unit 20 reduces the moving average score within the set range (S1031). If the voltage deviation increases, the control unit 20 reduces the moving average score within the set range. In this case, the control unit 20 may reduce the moving average score in stages.

[0047] In this embodiment, the control unit 20 made a determination regarding the voltage deviation amount after making a determination regarding the number of operations, but is not limited to this. The control unit 20 may make a determination regarding the number of operations after making a determination regarding the voltage deviation amount. Alternatively, the control unit 20 may refer to a lookup table (increase / decrease table) in which the manner of increasing or decreasing the moving average score is defined according to the increase or decrease in the number of operations and the voltage deviation amount, and perform an increase or decrease processing of the moving average score.

[0048] The increase / decrease table is pre-stored in the memory unit and may be configured in a matrix format in which, for example, the increase / decrease in the number of operations is defined in the vertical column and the increase / decrease in the voltage deviation is defined in the horizontal column. The number of operations defined in the vertical column includes, for example, the steady-state operation range (minimum steady-state operation: Dmin to maximum steady-state operation: Dmax) as the center, the range below the minimum steady-state operation (Dmin) of the steady-state operation range, and the range exceeding the maximum steady-state operation (Dmax) of the steady-state operation range. The voltage deviation in the horizontal column includes, for example, the steady-state deviation range (minimum steady-state deviation: Vmin to maximum steady-state deviation: Vmax) as the center, the range below the minimum deviation (Vmin) of the steady-state deviation range, and the range exceeding the maximum deviation (Vmax) of the steady-state deviation range.

[0049] In the increase / decrease table, which is structured in a matrix format, the manner in which the control unit 20 modifies the moving average score is defined according to the combination of definition items for the vertical items (increase / decrease in the number of operations) and the horizontal items (increase / decrease in the voltage deviation). For example, in the combination of the steady-state range of the number of operations (definition item for the vertical item) and the steady-state range of the voltage deviation (definition item for the horizontal item), it is defined that no change to the moving average score is necessary. For example, in the combination of the number of operations being less than the steady-state range (definition item for the vertical item) and the voltage deviation being greater than the steady-state range (definition item for the horizontal item), it is defined that the change to the moving average score is a decrease. For example, in the combination of the number of operations being greater than the steady-state range (definition item for the vertical item) and the voltage deviation being less than the steady-state range (definition item for the horizontal item), it is defined that the change to the moving average score is an increase. Thus, the increase / decrease table defines the manner in which the control unit 20 performs the process of changing the moving average score for each combination of definition items, namely the vertical item (increase / decrease in the number of operations) and the horizontal item (increase / decrease in the voltage deviation). The control unit 20 may refer to the increase / decrease table based on the number of operations and the voltage deviation included in the terminal information acquired at the present time, and determine the manner in which the process of changing the moving average score is performed.

[0050] If the voltage deviation is not increasing (S103: NO), after the execution of S1021 or S1031, the control unit 20 calculates the average voltage according to the moving average score (S104). If the voltage deviation is not increasing, the currently applied moving average score is maintained without change, and the monitoring voltage averaging process (calculation of average voltage) is performed using the said moving average score. If the moving average score is changed by the execution of S1021 or S1031, the control unit 20 performs the monitoring voltage averaging process (calculation of average voltage) using the moving average score changed (updated) in S1021 or S1031.

[0051] The control unit 20 determines whether the average voltage has deviated from the dead zone (S105). The control unit 20 determines whether the current average voltage has deviated from the dead zone by referring to the memory unit.

[0052] If the control unit 20 determines that the average voltage has deviated from the dead zone (S105: YES), it executes a process related to tap switching (S106). When the control unit 20 determines that the average voltage has deviated from the dead zone, it controls the tap positions (tap switching operation) of the tap changers 11u, 11v, and 11w so that the voltage (output voltage) on the secondary side (output side) approaches a predetermined reference voltage.

[0053] If the control unit 20 determines that the average voltage has not deviated from the dead zone (S105: NO), or after the execution of S106, the control unit 20 performs loop processing to execute the process from S101 again. If the control unit 20 determines that the average voltage has not deviated from the dead zone, it continues to periodically acquire the monitoring voltage and calculate the average voltage without performing control processing related to changing the tap position, and also continues processing related to changing the moving average points based on the terminal information.

[0054] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims, not in the sense described above, and all modifications within the sense and scope equivalent to the claims are intended.

[0055] Regarding the multiple claims described in the patent claims, they can be combined with each other regardless of the form of citation. The patent claims include multiple dependent claims that depend on multiple claims. The patent claims do not include multiple dependent claims that depend on multiple dependent claims, but multiple dependent claims that depend on multiple dependent claims may be included. [Explanation of Symbols]

[0056] S Voltage Regulation System 100 Voltage Regulator 1u, 1v, 1w (primary side) transmission and distribution lines 2u, 2v, 2w (secondary side) transmission and distribution lines 10u, 10v, 10w adjustable transformer 11u, 11v, 11w tap changer 20 Control Unit 22VW, 22WU, 22UV measuring transformer

Claims

1. A voltage regulation system including multiple voltage regulators installed in series in multiple stages in a power system with a substation on the upstream side and a load on the downstream side, Each of the multiple voltage regulators is, A regulating transformer with taps, A tap changer for switching the taps of the aforementioned regulating transformer, The system includes a control unit that controls the tap changer and performs voltage adjustment of the AC voltage in the power system, The control unit, The monitoring voltage, which is the voltage on the load side, is acquired. The average voltage is calculated by applying a moving average process to the multiple monitoring voltages that have been acquired. When the calculated average voltage deviates from the dead zone corresponding to a predetermined reference voltage, voltage adjustment processing is performed. In the voltage regulator, when performing the moving average processing, the settling range of the moving average points, which is the number of times the monitoring voltage is acquired, is predetermined. In at least two of the multiple voltage regulators, the maximum value in the setting range of the preceding voltage regulator is less than or equal to the minimum value in the setting range of the succeeding voltage regulator. Voltage regulation system.

2. The control unit, The voltage regulator on which the control unit is installed acquires its own terminal information, Based on the acquired terminal information, the moving average score is changed within the set range. The voltage regulation system according to claim 1.

3. The aforementioned terminal information includes the number of operations, which is the number of times the tap has been switched during a predetermined period. The control unit increases the moving average score within the set range when the number of operations increases. The voltage regulation system according to claim 2.

4. The terminal information includes a voltage deviation amount, which is the integral value of the voltage value that deviates from the dead zone during a predetermined period. The control unit reduces the moving average score within the settling range if the voltage deviation is increasing. The voltage regulation system according to claim 2.

5. The predetermined period for calculating the terminal information is longer than the moving average period obtained by multiplying the moving average points by the period for acquiring the monitoring voltage. The voltage regulation system according to claim 3 or claim 4.

6. In all of the aforementioned voltage regulators, the setting range is defined. When multiple voltage regulators are installed in series, in the case of two voltage regulators arranged one before the other, the maximum value of the setting range of the preceding voltage regulator is less than or equal to the minimum value of the setting range of the succeeding voltage regulator. The voltage regulation system according to claim 1.

7. The difference between the maximum and minimum values ​​in the setting range of each of the aforementioned multiple voltage regulators is the same. The voltage regulation system according to claim 1.

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