Voltage regulating device

Abstract

To provide a voltage regulating device suppressing a switchover of a tap.SOLUTION: A voltage regulating device 100 at a subsequent stage among a plurality of voltage regulating devices serially installed in multiple stages in a power system in which a power substation is on a pre-stage side and a load is on a subsequent stage side has a regulating transformer 10 with tap changers t1-t9, a tap changer 11 switching over a tap of the regulating transformer, and a control unit for performing processing with respect to voltage regulation of AC voltage in the power system by controlling the tap changer. The control unit obtains monitor voltage that is voltage on a load side, calculates a voltage average value by performing processing of a moving average to a plurality of monitor voltages obtained in a predetermined period, performs processing with respect to the voltage regulation when the calculated voltage average value is deviated from a dead zone according to predetermined reference voltage, and performs switchover suppression processing suppressing a switchover of a tap when the present monitor voltage is within the dead zone in performing processing with respect to the voltage regulation.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a voltage regulating device.

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 regulating device is installed in a power distribution path, and the automatic voltage regulating device usually detects the secondary voltage and performs tap-changing so as to bring this closer to the target value to perform secondary voltage adjustment (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, when performing processing related to voltage adjustment using the voltage average value calculated by performing moving average processing on a plurality of monitored voltages acquired within a predetermined period, the automatic voltage regulating device disclosed in Patent Document 1 does not consider suppressing tap switching when the current monitored voltage falls within the dead band.

[0005] The present invention has been made in view of such circumstances, and an object thereof is to provide a voltage regulating device capable of suppressing tap switching when performing processing related to voltage adjustment using the voltage average value calculated by performing moving average processing on a plurality of monitored voltages acquired within a predetermined period.

Means for Solving the Problems

[0006] A voltage regulating device according to an aspect of the present disclosure is any one of a plurality of voltage regulating devices that are serially installed in multiple stages in a power system with a substation on the front stage side and a load on the rear stage side. The voltage regulating device includes a regulating transformer with taps, a tap changer that switches the taps of the regulating transformer, and a control unit that performs processing related to voltage regulation of an AC voltage in the power system by controlling the tap changer. The control unit acquires a monitoring voltage that is the voltage on the load side, calculates a voltage average value by performing a moving average process on a plurality of monitoring voltages acquired over a predetermined period, and performs processing related to voltage regulation when the calculated voltage average value deviates from a dead band corresponding to a predetermined reference voltage. When performing processing related to voltage regulation, if the current monitoring voltage falls within the dead band, a switching suppression process for suppressing tap switching is performed.

[0007] In this aspect, on the distribution line of the power system with a substation as the power source, two or more voltage regulating devices are installed in series, thereby constituting a multi-stage installation system with a plurality of voltage regulating devices. The two or more voltage regulating devices constituting these multi-stage installation systems include a front-stage voltage regulating device (a voltage regulating device installed on the front-stage side) located on the substation side and a rear-stage voltage regulating device (a voltage regulating device installed on the rear-stage side) located on the load side (the side of the load to which AC power from the power system is supplied) relative to the front-stage voltage regulating device. That is, the rear-stage voltage regulating device (a voltage regulating device installed on the rear-stage side) corresponds to any one of the plurality of voltage regulating devices serially installed in multiple stages in the power system. However, any one of these voltage regulating devices is not limited to the rear-stage voltage regulating device, and may be, for example, a front-stage voltage regulating device (a voltage regulating device installed on the front-stage side) such as the foremost voltage regulating device. Hereinafter, in the examples of this embodiment, any one of the voltage regulating devices will be described as the rear-stage voltage regulating device. The rear-stage voltage regulating device (a voltage regulating device installed on the rear-stage side) periodically acquires (detects) the secondary-side voltage in its own device as the monitoring voltage, and continuously calculates the average value of a plurality of monitoring voltages continuously acquired during a predetermined period, thereby performing a moving average process on the monitoring voltage. The rear-stage voltage regulating device (SVR) determines whether the voltage average value calculated by performing the moving average process falls within the dead band corresponding to a predetermined reference voltage (whether it is within the dead band) each time the voltage average value is calculated. When the voltage average value deviates from the dead band, the tap changer is controlled to switch the tap and adjust the transformation ratio to perform voltage regulation so that the monitoring voltage approaches the reference voltage. That is, the control unit of the voltage regulating device (SVR) functions as a moving average filter that removes steep voltage fluctuations by using the voltage average value (the moving average value of the monitoring voltage) based on a plurality of monitoring voltage values periodically sampled in this way (for example, 600-point sampling in 10 minutes at a 1-second interval).Thus, in order to perform an operation determination (tap operation by a moving average method) based on a monitored voltage (voltage average value) smoothed by averaging, for example, when compared with a control method for tap switching in a time-limited control method that performs a tap operation (tap switching) when the dead zone deviation time exceeds a set time limit, the tap switching frequency can be reduced. Even in such a voltage regulator (SVR) using the moving average method, there is a concern that the number of tap switches may increase due to the influence of the operation of a voltage regulator (front-stage voltage regulator) installed on the substation side rather than the own device. The operation of the front-stage voltage regulator includes, for example, a voltage readjustment operation or a tap switching operation within the dead zone. On the other hand, when the monitored voltage at the current time is within the dead zone even though the voltage average value deviates from the dead zone corresponding to the reference voltage, the voltage regulator at the rear stage performs a switching suppression process for suppressing the tap switching, so that the tap switching operation is not excessively performed, and the tap switching frequency can be reduced (the number of tap switches can be decreased).

[0008] In the voltage regulator according to one aspect of the present disclosure, when the tap of another voltage regulator installed on the substation side is switched and the monitored voltage at the current time is closer to the reference voltage than the voltage average value, the control unit corrects the voltage average value and performs a process related to voltage adjustment using the corrected voltage average value, thereby performing the switching suppression process.

[0009] In this aspect, the control unit of the voltage regulating device, for example, detects voltage fluctuations of the monitored voltage on the secondary side, and based on the detection result, determines that the tap has been switched by another voltage regulating device (the voltage regulating device in the previous stage) installed on the substation side. That is, the control unit of the voltage regulating device determines that the tap has been switched (tap operation) by another voltage regulating device located on the substation side when the amount of change (voltage fluctuation) of the monitored voltage (secondary side voltage) within a predetermined processing unit time (for example, within 1 second, the required time for tap switching) corresponds to the tap voltage width (step voltage for one tap: 100V) of another voltage regulating device (the voltage regulating device in the previous stage) (corresponding to ±30% of 100V). When the control unit of the voltage regulating device detects the tap switching by the voltage regulating device located on the substation side rather than its own device in this way, it determines whether the current monitored voltage is closer to the reference voltage than the voltage average value. That is, the control unit of the voltage regulating device calculates the absolute value of the difference between the reference voltage and the current monitored voltage (monitored voltage difference absolute value) and the absolute value of the difference between the reference voltage and the current voltage average value (voltage average value difference absolute value), and determines whether the current monitored voltage is closer to the reference voltage than the voltage average value by comparing these two calculated absolute values. When the control unit of the voltage regulating device determines that the current monitored voltage is closer to the reference voltage than the voltage average value (monitored voltage difference absolute value < voltage average value difference absolute value), it performs a switching suppression process by correcting the voltage average value. When correcting the voltage average value, the control unit of the voltage regulating device may replace the voltage average value with the current monitored voltage or the reference voltage. As a result, the corrected voltage average value becomes closer to the reference voltage than the voltage average value before correction. Therefore, by using the corrected voltage average value hereafter, it is possible to efficiently suppress the excessive tap switching operation. Alternatively, when correcting the voltage average value, the control unit of the voltage regulating device may add or subtract a correction value that is a fixed value (for example, ±30% of the tap voltage width (100V): any value between 70 and 130V) to the voltage average value to make the corrected voltage average value closer to the reference voltage value than the voltage average value before correction.When the control unit of the voltage regulating device detects the tap switching by the voltage regulating device (the voltage regulating device in the previous stage) located on the substation side, if the detected fluctuation amount of the monitored voltage is a positive value, it may be determined that the voltage regulating device in the previous stage has performed a step-up tap switching, and a correction value may be added to the voltage average value. When the control unit of the voltage regulating device detects the tap switching by the voltage regulating device (the voltage regulating device in the previous stage) located on the substation side, if the detected fluctuation amount of the monitored voltage is a negative value, it may be determined that the voltage regulating device in the previous stage has performed a step-down tap switching, and a correction value may be subtracted from the voltage average value. In this way, when the monitored voltage at the current time is closer to the reference voltage than the voltage average value according to the operation of another voltage regulating device (the voltage regulating device in the previous stage) installed on the substation side, the control unit of the voltage regulating device corrects the voltage average value to perform the switching suppression process, so as to suppress the excessive tap switching operation and reduce the tap switching frequency (reduce the number of tap switching times).

[0010] In the voltage regulating device according to one aspect of the present disclosure, when the tap of another voltage regulating device installed on the substation side is switched, if the monitored voltage at the current time is closer to the reference voltage than the voltage average value, the control unit recalculates the voltage average value within a predetermined period starting from the tap switching time of the other voltage regulating device, and performs the process related to voltage regulation using the recalculated voltage average value, thereby performing the switching suppression process.

[0011] In this aspect, the control unit of the voltage regulator detects voltage fluctuations of the monitored voltage on the secondary side, for example, and based on the detection result, determines that the tap has been switched by another voltage regulator (the previous-stage voltage regulator) installed on the substation side. When the control unit of the voltage regulator determines that the tap has been switched by another voltage regulator (the previous-stage voltage regulator) located on the substation side, it determines whether the current monitored voltage is closer to the reference voltage than the voltage average value. When the control unit of the voltage regulator determines that the current monitored voltage is closer to the reference voltage than the voltage average value (monitoring voltage difference absolute value < voltage average value difference absolute value), it recalculates the voltage average value within a predetermined period starting from the tap switching time point by the other voltage regulator. That is, when the previous-stage voltage regulator switches the tap, if the current monitored voltage is closer to the reference voltage than the voltage average value, the control unit of the voltage regulator discards the voltage average value calculated using the monitored voltages in the past from the current time, and calculates the voltage average value within a predetermined period (for example, 10 minutes) starting from the tap switching time point by the previous-stage voltage regulator. By performing the voltage regulation-related processing using the voltage average value recalculated in this way, the control unit of the voltage regulator performs the voltage regulation-related processing using a voltage average value (recalculated voltage average value) closer to the reference voltage than the previous voltage average value (discarded voltage average value), so as to suppress excessive tap switching operations and reduce the tap switching frequency (reduce the number of tap switches).

[0012] In the voltage regulator according to one aspect of the present disclosure, even when the voltage average value deviates from the dead zone, while the current monitored voltage is within the dead zone, the control unit continues the process of calculating the voltage average value without switching the tap by the tap changer, thereby performing the switching suppression process.

[0013] In this aspect, the control unit of the voltage regulating device determines whether to switch the tap by the tap changer based on the current voltage average value and the monitored voltage. That is, even when the current voltage average value deviates from the dead zone, as long as the current monitored voltage is within the dead zone, the control unit of the voltage regulating device continues the process of calculating the voltage average value without switching the tap by the tap changer, thereby performing a switching suppression process. Further, when both the current voltage average value and the monitored voltage deviate from the dead zone, the control unit of the voltage regulating device switches the tap by the tap changer. Further, even when the current monitored voltage deviates from the dead zone, as long as the current voltage average value is within the dead zone, the control unit of the voltage regulating device does not switch the tap. Further, as long as both the current voltage average value and the monitored voltage are within the dead zone, the control unit of the voltage regulating device does not switch the tap. Thus, based on the current voltage average value and the monitored voltage, the control unit of the voltage regulating device does not switch the tap even when the voltage average value deviates from the dead zone as long as the monitored voltage is within the dead zone, and continues the process of acquiring the monitored voltage and calculating the voltage average value. Subsequently, when the monitored voltage deviates from the dead zone, if the voltage average value also deviates from the dead zone, the control unit of the voltage regulating device switches the tap by the tap changer. However, the longer the period during which the monitored voltage is within the dead zone, the closer the calculated voltage average value approaches the reference voltage each time the monitored voltage is acquired. That is, the voltage average value converges to be within the dead zone, so that the tap switching operation is suppressed from being performed excessively, and the tap switching frequency can be reduced (the number of tap switches can be decreased).

[0014] In the voltage regulating device according to an aspect of the present disclosure, even when the voltage average value deviates from the dead zone, when the current monitored voltage is within the dead zone, the control unit corrects the voltage average value and performs a process related to voltage regulation using the corrected voltage average value, thereby performing the switching suppression process.

[0015] In this aspect, even when the current voltage average value deviates from the dead band, if the current monitored voltage is within the dead band, the voltage average value is corrected so that the corrected voltage average value falls within the dead band. The correction of the voltage average value may be to replace the voltage average value (the voltage average value that has deviated from the dead band at the current time) with the monitored voltage or the reference voltage. As a result, the corrected voltage average value (the voltage average value after correction) becomes closer to the reference voltage than the voltage average value before correction. Therefore, by using the corrected voltage average value hereafter, it is possible to efficiently suppress the excessive switching operation of the tap. Alternatively, the correction of the voltage average value may be to add or subtract a correction value that is a fixed value (for example, ±20% of the tap voltage width (100V): any value between 80 and 120V) to or from the voltage average value (the voltage average value that has deviated from the dead band at the current time), so that the voltage average value after correction is closer to the reference voltage value than the voltage average value before correction. Even after correcting the voltage average value as a switching suppression process, the control unit of the voltage adjustment device periodically acquires (detects) the monitored voltage (the secondary-side voltage to which the load is connected), and calculates the voltage average value each time the monitored voltage is acquired. At this time, when calculating the voltage average value including (using) the acquired (detected) monitored voltage after the correction of the voltage average value as a switching suppression process, the corrected voltage average value is reflected. That is, for example, when calculating a moving average based on 600 sampling points (a moving average in units of 10 minutes when the monitored voltage is detected at a 1-second cycle), the control unit of the voltage adjustment device adds the value obtained by multiplying the corrected voltage average value by 599 to the monitored voltage acquired immediately after the correction of the voltage average value, and divides the added value by 600 "(corrected voltage + corrected voltage average value * 599) / 600" to calculate the moving average after the correction of the voltage average value. By performing such a switching suppression process, it is possible to suppress the excessive switching operation of the tap and reduce the tap switching frequency (reduce the number of tap switches).

[0016] The voltage regulating device according to one aspect of the present disclosure is the voltage regulating device located at the last stage among the plurality of voltage regulating devices serially installed in multiple stages.

[0017] In this aspect, the plurality of voltage regulating devices serially installed in multiple stages consists of, for example, four voltage regulating devices. The voltage regulating device (the latter stage) that performs the switching suppression process is the voltage regulating device located at the last stage (the end) that is farthest from the substation. Thus, when, for example, four voltage regulating devices are serially installed, the influence of the tap operations of the other three voltage regulating devices located in the previous stage on the voltage regulating device located at the last stage becomes relatively large, and there is a concern that the number of tap switches will increase. On the other hand, by performing the switching suppression process on the voltage regulating device located at the last stage, it is possible to suppress the excessive occurrence of tap switching operations in the voltage regulating device at the last stage and promote the operation coordination among the plurality of voltage regulating devices serially installed in multiple stages.

[0018] The voltage regulating device according to one aspect of the present disclosure includes any one of the voltage regulating devices and another voltage regulating device other than any one of the voltage regulating devices among the plurality of voltage regulating devices serially installed in multiple stages, and the other voltage regulating device also performs the switching suppression process in the same manner as any one of the voltage regulating devices.

[0019] In this aspect, a plurality of voltage regulators installed in series in multiple stages are all configured by SVRs. Each of the plurality of voltage regulators configured by these SVRs performs a switching suppression process for suppressing tap switching. In this way, each of all the voltage regulators installed in series in multiple stages can individually execute the switching suppression process by performing arithmetic processing using the monitored voltage acquired by itself (the device itself), and it is possible to reduce the number of tap switches in the whole of the plurality of voltage regulators. That is, even when there is an influence due to the voltage trend in the power system, even if the voltage average value deviates from the dead band, but the monitored voltage remains within the dead band and the voltage average value tends to return to the dead band, by not performing tap switching, as a voltage regulation system composed of a plurality of voltage regulators installed in series in multiple stages, it is possible to suppress an increase in the number of tap switches.

Effect of the Invention

[0020] When performing processing related to voltage regulation using the voltage average value calculated by performing moving average processing on a plurality of monitored voltages acquired during a predetermined period, it is possible to provide a voltage regulator capable of suppressing tap switching.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0022] (Embodiment 1) Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 is a configuration diagram showing a power system including voltage adjustment devices 101 and 100 according to Embodiment 1 (correction during tap switching). FIG. 2 is a block diagram showing a configuration example of the voltage adjustment device 100. A plurality of voltage adjustment devices 101 and 100 are installed in series on the distribution line (system) where the substation is arranged. That is, these voltage adjustment devices 101 and 100 are connected in series so as to be multi-stage (connected to the same system), thereby constituting a multi-stage installation system. In these plurality of voltage adjustment devices 101 and 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 installed voltage adjustment devices 101 and 100 controls the tap positions (tap switching operations) of the tap changers 11u, 11v, and 11w so that the voltage on the secondary side (output voltage) is close to a preset reference voltage.

[0023] In the illustration of this embodiment, there are four multi-stage installed voltage adjustment devices 101 and 100. When the substation side is the front stage and the load side is the rear stage, the voltage adjustment device installed at the end corresponds to the rear-stage voltage adjustment device 100. The rear-stage voltage adjustment device 100 is, for example, an SVR (Step Voltage Regulator). In this case, three voltage adjustment devices up to the third stage with respect to the substation correspond to the front-stage voltage adjustment device 101 (other voltage adjustment devices). The front-stage voltage adjustment device 101 is, for example, an SVR (Step Voltage Regulator), a TVR (Thyristor type Step Voltage Regulator), or an LRT (Load Ratio Control Transformer) installed in the substation, etc.

[0024] In this embodiment, the subsequent voltage regulator 100 is not limited to being the terminal voltage regulator that is the farthest from the substation among the plurality of voltage regulators 101 and 100 installed in multiple stages, and may be a voltage regulator located in the second or third stage. That is, the front stage and the subsequent stage indicate the relative positional relationship among the plurality of voltage regulators 101 and 100 installed in multiple stages. Any voltage regulator other than the frontmost voltage regulator 101 (the first-stage voltage regulator closest to the substation) can be the subsequent voltage regulator 100 with respect to the front-stage voltage regulator 101. Alternatively, the voltage regulator 100 that performs the switching suppression process is not limited to being the subsequent voltage regulator 100, and may be a front-stage voltage regulator 101 such as the frontmost stage. In this case, all the voltage regulators 100 and 101 in the plurality of voltage regulators 100 and 101 installed in series perform the switching suppression process in this embodiment, so that each voltage regulator 100 and 101 can perform substantial operation coordination while performing autonomous control.

[0025] The subsequent voltage regulator 100 (SVR) periodically acquires (detects) the value of the secondary-side voltage, which is the output voltage, as the monitoring voltage. When the monitoring voltage deviates from the dead band, it controls the tap changers 11u, 11v, and 11w to perform processing related to voltage regulation of the AC voltage in the power system. The dead band is determined based on the value of the set reference voltage and is defined within a predetermined width with respect to the reference voltage.

[0026] When determining whether the monitoring voltage has deviated from the dead band, the subsequent voltage regulator 100 may continuously calculate the average value of a plurality (for example, 600 points) of monitoring voltages continuously acquired at a predetermined period (for example, 1-second period) within a predetermined period (for example, 10 minutes) to perform a moving average process on the monitoring voltage. Then, when the voltage average value, which is the calculation result of the moving average process, deviates from the dead band, the subsequent voltage regulator 100 may control the tap changers 11u, 11v, and 11w to perform processing related to voltage regulation of the AC voltage in the power system.

[0027] In this way, the subsequent voltage regulator 100 performs an operation determination (tap operation by the moving average method) based on the monitored voltage (voltage average value) smoothed by being averaged. As a result, for example, compared with the case of controlling the tap switching by the fixed-time control method of performing a tap operation (tap switching) when the dead zone deviation time exceeds a set time limit, the tap switching frequency can be reduced.

[0028] Even in the case of the voltage regulator 100 (SVR) using the moving average method, it is conceivable that the number of tap switches increases due to the influence of the operation of another voltage regulator (the preceding voltage regulator 101) installed on the substation side rather than the own device (the subsequent voltage regulator 100). That is, due to the influence of the operation of another voltage regulator (the preceding voltage regulator 101) installed on the substation side, even if the monitored voltage at the current time in the subsequent voltage regulator 100 is within the dead zone, it is assumed that the voltage average value processed by the moving average deviates from the dead zone.

[0029] On the other hand, when the voltage average value deviates from the dead zone corresponding to the reference voltage, but the current monitored voltage is within the dead zone, the subsequent voltage regulator 100 performs a switching suppression process to suppress the tap switching. By performing the switching suppression process, the influence of the operation of another voltage regulator (the preceding voltage regulator 101) installed on the substation side is mitigated, and it is suppressed that the tap switching operation is excessively performed, and the tap switching frequency can be reduced (the number of tap switches is decreased).

[0030] In FIG. 2, 1u, 1v, and 1w are power transmission and distribution lines on the primary side (substation side) that transmit and distribute three-phase AC voltages including the U-phase, V-phase, and W-phase, and 2u, 2v, and 2w are power transmission and distribution lines on the secondary side (load side). The subsequent voltage regulator 100 (hereinafter simply referred to as the voltage regulator 100) includes tapped regulating transformers 10u, 10v, and 10w that step up or step down 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 switches 11u, 11v, and 11w that switch the respective taps, and a control unit 20 that controls the entire device.

[0031] The regulating transformers 10u, 10v, and 10w are each connected at one end of each winding to the power transmission and distribution lines 2u, 2v, and 2w with the windings star (Y) connected. 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.

[0032] Each of the tap changers 11u, 11v, and 11w switches the taps of the regulating transformers 10u, 10v, and 10w, and the switched taps are respectively connected to the power transmission and distribution lines 1u, 1v, and 1w. The tap switching is performed by a switching command from the control unit 20.

[0033] The control unit 20 has an MPU or a CPU (Central Processing Unit), etc., and by the CPU executing a control program (program product) stored in a RAM or a ROM (Read Only Memory), processes such as input / output, calculation, and time measurement are performed. Connected to the control unit 20 are the secondary windings of the measuring transformers 22vw, 22wu, and 22uv respectively, and an input section for switching commands for each of the tap changers 11u, 11v, and 11w. The measuring transformers 22vw, 22wu, and 22uv may be included in the voltage regulating device 100. The control unit 20 may be configured by a microcomputer (microcontroller) having a storage section such as a memory, or a dedicated hardware circuit such as an FPGA, an ASIC, or a circuit board body.

[0034] 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, the line voltages between the WU phases on the secondary side, and the line voltages between the UV phases on the secondary side as monitoring voltages. Then, the control unit 20 gives switching commands to the tap changers 11u, 11v, and 11w based on the detected line voltages. When voltage detection units are provided in the secondary windings of the measuring transformers 22vw, 22wu, and 22uv respectively, the control unit 20 may acquire the detection results of the line voltages from these voltage detection units. Alternatively, the control unit 20 of the voltage regulating device 100 may detect the voltage (monitoring voltage) at the monitoring point (LDC monitoring point) by the LDC (Line Drop Compensator) connected to the secondary side. As described above, the control unit 20 periodically samples the monitoring voltages in each phase (for example, 600 points are sampled in 10 minutes at a cycle of 1 second), and functions as a moving average filter that removes steep voltage fluctuations by using the voltage average value (moving average value of the monitoring voltage) based on a plurality of monitoring voltage values.

[0035] Figure 3 is a flowchart showing the processing procedure of the control unit 20 of the voltage regulating device 100. When performing processing related to voltage regulation of the AC voltage in the power system (control processing of the tap changers 11u, 11v, and 11w) according to a control program (program product) stored in advance in a storage unit such as a ROM, the control unit 20 of the voltage regulating device 100 (the voltage regulating device 100: SVR in the subsequent stage) executes this processing (switching suppression processing).

[0036] The control unit 20 acquires the monitoring voltage (S101). As described above, the control unit 20 acquires (detects) the line voltages in each phase as monitoring voltages via the measuring transformers 22vw, 22wu, and 22uv. The control unit 20 stores the acquired monitoring voltage in the storage unit in association with the acquisition time point (detection time point). The control unit 20 may detect the monitoring voltage at a cycle of 1 second, for example.

[0037] The control unit 20 calculates the average voltage value (S102). The control unit 20 continuously calculates the average value of the monitored voltages by performing a moving average process on a plurality (for example, 600 points) of monitored voltages acquired at a predetermined period (for example, 10 minutes) for each of the line voltages between the phases. That is, each time the control unit 20 acquires the (latest) monitored voltage at the current time, with the monitored voltage at the current time as the latest value, it calculates the average value by taking into account a plurality of monitored voltages (for example, 599 points) at past sampling points, thereby continuously and periodically performing the moving average process. The control unit 20 stores the calculated average voltage value (the calculated value of the moving average process) in the storage unit in association with the detection time of the latest (acquisition time) monitored voltage when calculating the average voltage value. By continuing such processing, the storage unit such as the microcomputer constituting the control unit 20 stores the latest average voltage value corresponding to the monitored voltage acquired (detected) most recently (at the current time).

[0038] The control unit 20 determines whether the monitored voltage at the current time is within the dead band (S103). The control unit 20 determines whether the monitored voltage at the current time is within the dead band determined based on a reference voltage set in advance by referring to the storage unit.

[0039] If it is determined that the monitored voltage at the current time is within the dead band (S103: YES), the control unit 20 determines whether the tap has been switched by another voltage regulating device installed on the substation side (S104). When the monitored voltage at the current time is within the dead band, the control unit 20 refers to the storage unit and determines whether the tap has been switched by another voltage regulating device (the voltage regulating device 101 in the previous stage) installed on the substation side based on the amount of change (voltage change) from the monitored voltages in the past (within a predetermined period such as within 1 second from the current time) with respect to the monitored voltage at the current time.

[0040] Based on the change amount of the values of a plurality of monitored voltages arranged in time series and stored in the storage unit, the control unit 20 calculates the fluctuation amount (voltage fluctuation) of the monitored voltage (secondary-side voltage). When the calculated fluctuation amount (voltage fluctuation) is equal to or greater than a predetermined threshold value, it may be determined that the tap has been switched by another voltage regulating device (the voltage regulating device 101 in the previous stage) installed on the substation side. When the fluctuation amount (voltage fluctuation) does not exceed the threshold value (is less than the threshold value), the control unit 20 may determine that the tap has not been switched by another voltage regulating device (the voltage regulating device 101 in the previous stage) installed on the substation side.

[0041] The threshold value may be a value corresponding to the tap voltage width (step voltage for one tap) during tap switching in the voltage regulating device 101 in the previous stage, or may be a value determined according to the number of other voltage regulating devices (the voltage regulating device 101 in the previous stage) constituting the multi-stage installation system, the type, product specifications, etc. The threshold value for determining the presence or absence of tap operation by another voltage regulating device (the voltage regulating device 101 in the previous stage) installed on the substation side may be set to be changeable (tuned according to the configuration of the multi-stage installation system). In this case, the control unit 20 may receive the threshold value input from an operation panel or the like provided in the voltage regulating device 100 and store it in the storage unit.

[0042] When it is determined that the tap has been switched (S104: YES), the control unit 20 determines whether the monitored voltage at the current time is closer to the reference voltage than the voltage average value (S105). The control unit 20 refers to the storage unit and determines whether the monitored voltage at the current time is closer to the reference voltage than the voltage average value at the current time (the voltage average value calculated using the monitored voltage at the current time). The control unit 20 may calculate the absolute value of the difference between the reference voltage and the monitored voltage at the current time (monitoring voltage difference absolute value) and the absolute value of the difference between the reference voltage and the voltage average value at the current time (voltage average value difference absolute value), and determine whether the monitored voltage at the current time is closer to the reference voltage than the voltage average value by comparing these two calculated absolute values.

[0043] When the current monitored voltage is closer to the reference voltage than the average voltage (S105: YES), the control unit 20 corrects the average voltage (S106). When the current monitored voltage is closer to the reference voltage than the average voltage, the control unit 20 corrects the average voltage and stores the corrected average voltage (the average voltage after correction) in the storage unit as the latest average voltage. In this way, the control unit 20 uses the corrected average voltage (the average voltage after correction) as the latest average voltage to perform various processes including the determination of the necessity of tap switching (control of tap switching operation, etc.).

[0044] When correcting the average voltage, the control unit 20 may reset (replace) the average voltage to the reference voltage. Alternatively, when correcting the average voltage, the control unit 20 may reset (replace) the average voltage to the monitored voltage at the current time. Alternatively, when correcting the average voltage, the control unit 20 may add or subtract a certain value (±30% of the tap voltage width of 100V: any value from 70 to 130V) to or from the average voltage. At this time, when the control unit 20 determines that the tap switching by another voltage regulating device (the previous voltage regulating device 101) installed on the substation side is a step-up tap, it may add the certain value, and when it determines that it is a step-down tap, it may subtract the certain value.

[0045] By correcting the average voltage in this way, the average voltage after correction becomes closer to the reference voltage value than the average voltage before correction, that is, the average voltage after correction falls within the dead zone. As a result, the influence of the tap operation by another voltage regulating device (the previous voltage regulating device 101) installed on the substation side is mitigated, and in the subsequent voltage regulating device 100, excessive tap switching operations are suppressed, and the tap switching frequency can be reduced (the number of tap switches can be decreased).

[0046] After executing the process of S106, the control unit 20 performs a loop process to execute the process from S101 again. When the voltage average value is corrected in this way, the subsequent voltage average value is calculated using the corrected voltage average value and the monitored voltage acquired (detected) thereafter.

[0047] If it is determined that the current monitored voltage does not fall within the dead zone (S103: NO), or If it is determined that the tap switching has not been performed (S104: NO), or if the current monitored voltage is not closer to the reference voltage than the voltage average value (S105: NO), the control unit 20 determines whether the voltage average value has deviated from the dead zone (S107). The control unit 20 determines whether the voltage average value at the current time has deviated from the dead zone by referring to the storage unit.

[0048] If it is determined that the voltage average value has deviated from the dead zone (S107: YES), the control unit 20 executes a process related to tap switching (S108). When it is determined that the voltage average value has deviated from the dead zone, the control unit 20 controls the tap positions (tap switching operations) of the tap changers 11u, 11v, and 11w so that the voltage on the secondary side (output side) (output voltage) approaches a preset reference voltage.

[0049] If it is determined that the voltage average value has not deviated from the dead zone (S107: NO), or after executing S108, the control unit 20 performs a loop process to execute the process from S101 again. When it is determined that the voltage average value has not deviated from the dead zone, the control unit 20 continues to periodically execute the acquisition of the monitored voltage and the calculation of the voltage average value without performing control processing related to the change of the tap position.

[0050] In this embodiment, the control unit 20 of the subsequent voltage regulator 100 performs a switching suppression process by correcting the voltage average value when the current monitored voltage is within the dead zone. However, the present invention is not limited to this. Even when the current monitored voltage is not within the dead zone, if the control unit 20 of the subsequent voltage regulator 100 detects a tap operation by the previous voltage regulator 101 and the current monitored voltage is closer to the reference voltage than the voltage average value, it may always correct the voltage average value.

[0051] (Embodiment 2) FIG. 4 is a flowchart showing the processing procedure of the control unit 20 of the voltage regulator 100 according to Embodiment 2 (recalculation at the time of tap switching). The control unit 20 of the voltage regulator 100 (the subsequent voltage regulator 100: SVR) performs this process (switching suppression process) when performing processing related to voltage adjustment of the AC voltage in the power system (control processing of the tap changers 11u, 11v, 11w) according to a control program (program product) stored in advance in a storage unit such as a ROM.

[0052] The control unit 20 acquires the monitored voltage (S201). The control unit 20 calculates the voltage average value (S202). The control unit 20 determines whether the current monitored voltage is within the dead zone (S203). The control unit 20 determines whether the tap of another voltage regulator installed on the substation side has been switched (S204). The control unit 20 determines whether the current monitored voltage is closer to the reference voltage than the voltage average value (S205). The control unit 20 performs the processes of S201 to S205 in the same manner as S101 to S105 in Embodiment 1.

[0053] When the monitored voltage at the current time is closer to the reference voltage than the average voltage (S205: YES), the control unit 20 recalculates the average voltage (S206). When the monitored voltage at the current time is closer to the reference voltage than the average voltage, the control unit 20 recalculates the average voltage within a predetermined period starting from the switching time point of the tap by another voltage regulating device (the previous voltage regulating device 101) installed on the substation side. That is, when the control unit 20 detects the tap operation of another voltage regulating device (the previous voltage regulating device 101), if the monitored voltage at the current time is closer to the reference voltage than the average voltage, after the detection time point of the tap operation, the control unit 20 recalculates the average voltage using a plurality of monitored voltages periodically acquired (detected) within a certain period.

[0054] When performing the switching suppression process by recalculating the average voltage, since the condition that the monitored voltage is closer to the reference voltage than the average voltage is satisfied, the average voltage after recalculation becomes closer to the reference voltage than the average voltage before recalculation and falls within the dead band. When the average voltage is recalculated in this way, the average voltage after that is calculated using the average voltage after recalculation and the monitored voltages acquired (detected) thereafter. Thereby, the influence of the tap operation by another voltage regulating device (the previous voltage regulating device 101) installed on the substation side is mitigated, and in the subsequent voltage regulating device 100, it is possible to suppress the excessive tap switching operation and reduce the tap switching frequency (reduce the number of tap switches).

[0055] When the monitored voltage at the current time is not closer to the reference voltage than the average voltage (S205: NO), the control unit 20 determines whether the average voltage has deviated from the dead band (S207). The control unit 20 executes the process related to tap switching (S208). The control unit 20 performs the processes from S207 to S208 in the same manner as from S107 to S108 in Embodiment 1.

[0056] (Embodiment 3) FIG. 5 is a flowchart showing the processing procedure of the control unit 20 of the voltage adjustment device 100 according to Embodiment 3 (continuous calculation of the voltage average value). When performing processing related to voltage adjustment of the AC voltage in the power system (control processing of the tap changers 11u, 11v, and 11w) according to a control program (program product) stored in advance in a storage unit such as a ROM, the control unit 20 of the voltage adjustment device 100 (the voltage adjustment device 100: SVR in the subsequent stage) executes this processing (switching suppression processing).

[0057] The control unit 20 acquires the monitored voltage (S301). The control unit 20 calculates the voltage average value (S302). The control unit 20 performs the processing from S301 to S302 in the same manner as from S101 to S102 in Embodiment 1.

[0058] The control unit 20 determines whether or not the voltage average value has deviated from the dead band (S303). The control unit 20 performs the processing of S303 in the same manner as S107 in Embodiment 1. When it is determined that the voltage average value has deviated from the dead band (S303: YES), the control unit 20 determines whether or not the current monitored voltage is within the dead band (S304). The control unit 20 performs the processing of S304 in the same manner as S103 in Embodiment 1.

[0059] When it is determined that the current monitored voltage is within the dead band (S304: YES), the control unit 20 performs a loop process to execute the processing from S101 again. That is, even when the voltage average value has deviated from the dead band, as long as the current monitored voltage is within the dead band, the control unit 20 continues the process of calculating the voltage average value without switching the tap by the tap changers 11u, 11v, and 11w, thereby performing the switching suppression processing. Even when the voltage average value has deviated from the dead band due to the tap operation of another voltage adjustment device (the voltage adjustment device 101 in the previous stage) installed on the substation side, the control unit 20 can suppress excessive tap switching operations and reduce the tap switching frequency (reduce the number of tap switches).

[0060] When it is determined that the current monitored voltage does not fall within the dead zone (S304: NO), the control unit 20 executes processing related to tap switching (S3041). The control unit 20 performs the processing of S3041 in the same manner as S108 of Embodiment 1. After executing S3041 or when it is determined that the voltage average value does not deviate from the dead zone (S303: NO), the control unit 20 performs loop processing to execute the processing from S301 again.

[0061] (Embodiment 4) FIG. 6 is a flowchart showing the processing procedure of the control unit 20 of the voltage adjustment device 100 according to Embodiment 4 (correction when within the dead zone). When performing processing related to voltage adjustment of the AC voltage in the power system (control processing of the tap changers 11u, 11v, 11w) according to a control program (program product) stored in advance in a storage unit such as a ROM, the control unit 20 of the voltage adjustment device 100 (voltage adjustment device 100: SVR in the subsequent stage) executes this processing (switching suppression processing).

[0062] The control unit 20 acquires the monitored voltage (S401). The control unit 20 calculates the voltage average value (S402). The control unit 20 determines whether the voltage average value deviates from the dead zone (S403). The control unit 20 determines whether the current monitored voltage falls within the dead zone (S404). When it is determined that the current monitored voltage does not fall within the dead zone (S404: NO), the control unit 20 executes processing related to tap switching (S4041). The control unit 20 performs the processing from S401 to S4041 in the same manner as from S301 to S3041 of Embodiment 3.

[0063] When it is determined that the current monitored voltage is within the dead zone (S404: YES), the control unit 20 corrects the voltage average value (S405). The control unit 20 performs the process of S405 in the same manner as S106 of Embodiment 1. In this way, even when the voltage average value deviates from the dead zone, if the current monitored voltage is within the dead zone, the control unit 20 corrects (resets to the reference voltage or the current monitored voltage) the voltage average value to perform the switching suppression process. Even when the voltage average value deviates from the dead zone due to the tap operation of another voltage regulating device (the preceding voltage regulating device 101) installed on the substation side, the control unit 20 can suppress the excessive tap switching operation and reduce the tap switching frequency (reduce the number of tap switches).

[0064] Including this embodiment, a plurality of processing modes in the switching suppression process have been shown in Embodiments 1 to 4. However, the switching suppression process is not limited to the processing mode according to any one of these embodiments, and the control unit 20 may perform a combination of two or more of these processing modes. For example, when the control unit 20 detects the tap operation by the preceding voltage regulating device 101 described in Embodiment 1 or 2, it suppresses the tap switching by correcting or recalculating the reference voltage to reset it. In other cases, for example, when the voltage average value described in Embodiment 3 deviates from the dead zone and the monitored voltage is within the dead zone, it may further suppress the tap switching by not performing the tap switching.

[0065] It should be considered that all the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

[0066] Regarding the multiple claims recited in the claims, regardless of the citation format, they can be combined with each other. In the claims, multiple dependent claims that depend on multiple claims are recited. In the claims, multiple dependent claims that depend on multiple dependent claims are not recited, but multiple dependent claims that depend on multiple dependent claims may be recited.

Description of the Signs

[0067] 100 Voltage regulator (voltage regulator for the latter stage) 1u, 1v, 1w (primary side) power transmission and distribution lines 2u, 2v, 2w (secondary side) power transmission and distribution lines 10u, 10v, 10w Regulating transformer 11u, 11v, 11w Tap changer 20 Control unit 22vw, 22wu, 22uv Measuring transformer 101 Voltage regulator for the former stage (other voltage regulator)

Claims

1. Any one of a plurality of voltage regulators serially installed in multiple stages in a power system with a substation on the front stage side and a load on the rear stage side, An autotransformer with taps, A tap changer for switching the taps of the autotransformer, And a control unit that performs processing related to voltage regulation of the AC voltage in the power system by controlling the tap changer, The control unit, Obtains a monitoring voltage that is the voltage on the load side, Calculates a voltage average value by performing a moving average process on a plurality of monitoring voltages obtained during a predetermined period, When the calculated voltage average value deviates from the dead zone corresponding to a predetermined reference voltage, performs processing related to voltage regulation, When performing processing related to voltage regulation, if the current monitoring voltage falls within the dead zone, performs a switching suppression process to suppress tap switching Voltage regulator.

2. The control unit, When the taps of another voltage regulator installed on the substation side are switched, if the current monitoring voltage is closer to the reference voltage than the voltage average value, corrects the voltage average value, Performs the switching suppression process by performing processing related to voltage regulation using the corrected voltage average value The voltage regulator according to claim 1.

3. The control unit, When the taps of another voltage regulator installed on the substation side are switched, if the current monitoring voltage is closer to the reference voltage than the voltage average value, recalculates the voltage average value during a predetermined period starting from the tap switching time of the other voltage regulator, Performs the switching suppression process by performing processing related to voltage regulation using the recalculated voltage average value The voltage regulator according to claim 1.

4. The control unit Even when the average voltage deviates from the dead zone, while the current monitored voltage remains within the dead zone, the control unit continues the process of calculating the average voltage without switching the tap by the tap changer, thereby performing the switching suppression process. The voltage regulation device according to claim 1.

5. The control unit Even when the average voltage deviates from the dead zone, if the current monitored voltage remains within the dead zone, the control unit corrects the average voltage, and performs the switching suppression process by performing processes related to voltage regulation using the corrected average voltage. The voltage regulation device according to claim 1.

6. The voltage regulation device located at the last stage among the plurality of voltage regulation devices serially installed in multiple stages The voltage regulation device according to any one of claims 1 to 5.

7. The plurality of voltage regulation devices serially installed in multiple stages include any one of the voltage regulation devices and another voltage regulation device other than any one of the voltage regulation devices, and the other voltage regulation device also performs the switching suppression process in the same manner as any one of the voltage regulation devices. The voltage regulation device according to any one of claims 1 to 5.

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