JP4691630B2 - Voltage adjustment device, voltage adjustment method, and voltage adjustment program - Google Patents

Description

  The present invention provides a voltage adjustment device, a voltage adjustment method, and a voltage adjustment method for adjusting a voltage of a distribution line by switching a tap of a transformer in preparation for a voltage drop in a distribution line that distributes an AC voltage of a plurality of phases to a load. The present invention relates to a program for causing a device to execute a voltage adjustment method.

  Since stabilization of voltage in power supply is essential, for example, in substation equipment, voltage adjustment of the distribution line is performed by a voltage adjustment device. In particular, when the distribution line from the transformer facility to the user is long, the voltage fluctuation also increases according to the load of the user. Therefore, when the substation equipment distributes power by lowering the voltage to the user's usage level by the transformer provided in the voltage regulator, the transformer is automatically switched to tap to maintain the specified voltage.

For example, when distributing a three-phase AC voltage to a load through three distribution lines, a voltage regulator is known that collectively adjusts a three-phase load voltage applied to the load by a tap switching transformer ( For example, see Patent Document 1.)
Japanese Patent Laid-Open No. 11-273972

  By the way, the voltage regulator disclosed in Patent Document 1 described above measures any of the three-phase voltages, and switches the taps of the tap switching transformer based on the measured values, thereby uniformizing the three-phase voltages. To raise or lower. For example, even when only one or two-phase voltage of three-phase voltages drops, this voltage regulator adjusts the three-phase voltage uniformly. For this reason, for example, while the load voltage increases excessively in a certain phase, there is a possibility that the increase of the load voltage is insufficient in another phase. That is, there is a possibility that unbalance occurs in the three-phase voltage to be applied to the load. In particular, when the load is a three-phase motor, a three-phase voltage balance is indispensable for its normal rotation. By the way, as a demand for three-phase AC voltage, any one of the three phases may be used. If a three-phase AC voltage is supplied to a three-phase motor and an AC voltage of only one phase is further supplied to a single-phase load, There is a possibility that the imbalance of the single-phase voltage fluctuation cannot be solved, and thus there is a possibility that the rotation of the three-phase motor will not be normal.

  This invention is made | formed in view of this subject, The place made into the objective is the multiple phase applied to the said load in the transformer which distributes the alternating voltage of multiple phases with respect to load through several distribution lines. Is to adjust the AC voltage in a well-balanced manner.

  The invention for solving the above problems is provided in a plurality of distribution lines for distributing a plurality of phases of AC voltage to a load, respectively, and a plurality of transformers each having a tap for switching the load voltage applied to the load; A tap changer that switches between the taps, a voltage adjustment device that measures the voltages of the plurality of distribution lines, a current measurement unit that measures the currents of the plurality of distribution lines, The plurality of differential voltages between the voltage actually applied to the load obtained based on the voltage measured by the voltage measuring unit and the current measured by the current measuring unit and the voltage to be applied to the load Differential voltage calculation unit for each distribution line, and differential voltage determination for determining whether or not the plurality of differential voltages calculated by the differential voltage calculation unit are within a predetermined differential voltage range And when the difference voltage determination unit determines that any one of the difference voltages is not within the predetermined difference voltage range, the difference voltage is set to be within the predetermined difference voltage range. And a tap switching control unit that controls the tap switching unit.

  According to this voltage regulator, a differential voltage is calculated and determined for each of a plurality of distribution lines, that is, for each of a plurality of phases. Further, if it is determined that any of the differential voltages is not within the predetermined differential voltage range, the tap changer is configured to set the corresponding differential voltage within the predetermined differential voltage range based on the determination result. Is controlled. For example, if the differential voltage of a part of a plurality of phases is not within a predetermined differential voltage range and the differential voltage of another phase is within a predetermined differential voltage range, the part The tap provided in the transformer corresponding to the differential voltage of the phase is the switching target. In other words, only taps corresponding to a phase whose differential voltage is larger than the allowable displacement from the voltage to be applied to the load, for example, can be switched, so that the AC voltages of a plurality of phases can be adjusted with good balance.

  Further, in such a voltage regulator, the differential voltage calculation unit calculates a voltage drop to the load in the distribution line based on the current measured by the current measurement unit for each of the plurality of distribution lines, It is preferable to subtract the voltage drop from the voltage measured by the voltage measuring unit to obtain the voltage actually applied to the load.

  According to this voltage regulator, the voltage drop from, for example, a transformer to a load in the distribution line is calculated for each of the plurality of distribution lines, that is, for each of a plurality of phases. In addition, for each of a plurality of phases, a voltage drop is subtracted from the voltage measured by the voltage measuring unit to obtain a voltage that is actually applied to the load. Thereby, according to the voltage drop which changes for every several phases, the alternating voltage of several phases can be adjusted with sufficient balance, for example.

  Further, in such a voltage regulator, the tap switching control unit is applicable when the differential voltage determination unit continues to determine for a predetermined time that any of the differential voltages is not within the predetermined differential voltage range. It is preferable that the tap changer is controlled so that the difference voltage is within the predetermined difference voltage range.

  According to this voltage regulator, it is determined that one of the differential voltages is not within the predetermined differential voltage range, for example, once in a predetermined time or continuously several times in a predetermined time instead of instantaneously. Each time, the operation of the tap switching control unit is executed. Therefore, the operation accuracy of the tap switching control unit is further improved, and the AC voltages of a plurality of phases can be adjusted with good balance.

  In the voltage regulator, when the differential voltage determination unit determines that the plurality of differential voltages are not within the predetermined differential voltage range, the tap switching control unit is configured to output the plurality of differential voltages. Obtaining an absolute value, and controlling the tap switch to switch the tap of the transformer provided in the distribution line corresponding to the differential voltage having the maximum absolute value among the plurality of differential voltages. preferable.

  According to this voltage regulator, when a plurality of phases are to be switched, for example, taps are switched preferentially for the phase where the corresponding differential voltage is most shifted from the differential voltage range. Therefore, the operation of the tap switching control unit becomes more efficient, and a plurality of phases of AC voltage can be adjusted in a well-balanced manner.

  In the voltage regulator, the tap switching control unit controls the tap switch to increase the load voltage applied to the load when the differential voltage having the maximum absolute value is negative. When the differential voltage having the maximum absolute value is positive, it is preferable to control the tap changer to lower the load voltage applied to the load. Further, in such a voltage regulator, each of the differential voltage data indicating the plurality of differential voltages calculated by the differential voltage calculation unit, and tap identification data for specifying the tap of the transformer provided in the corresponding distribution line, respectively It is preferable to further include a differential voltage storage unit that stores the data in association with each other. In the voltage regulator, it is preferable that the differential voltage data indicating the differential voltage stored in the differential voltage storage unit is data indicating an absolute value of the differential voltage. In the voltage regulator, when the differential voltage determination unit determines that the plurality of differential voltages are not within the predetermined differential voltage range, the tap switching control unit stores the differential voltage storage unit in the differential voltage storage unit. The tap switch is controlled to switch the tap specified by the tap specifying data corresponding to the differential voltage data having the maximum absolute value among the plurality of stored differential voltage data indicating the plurality of differential voltages. It is preferable.

  In addition, the invention for solving the above-described problems is provided with a plurality of transformers each provided with a plurality of distribution lines for distributing a plurality of phases of AC voltage to the load, each having a tap for switching the load voltage applied to the load. A voltage adjustment method for a voltage adjustment device comprising: a voltage changer; and a tap changer that switches the tap, wherein the voltage / current measurement step measures the voltage and current of the plurality of distribution lines, and the voltage / current measurement. Differential voltage calculation step of calculating a differential voltage between the voltage actually applied to the load obtained based on the voltage and current measured in the step and the voltage to be applied to the load for each of the plurality of distribution lines. And a differential voltage determination step for determining whether or not the plurality of differential voltages calculated in the differential voltage calculation step is within a predetermined differential voltage range. When it is determined in the differential voltage determination step that any of the differential voltages is not within the predetermined differential voltage range, the differential voltage is set to be within the predetermined differential voltage range. And a tap change control step for controlling the tap changer.

  In the voltage adjustment method, the differential voltage calculation step calculates a voltage drop to the load in the distribution line based on the current measured in the voltage / current measurement step for each of the plurality of distribution lines. Preferably, the voltage actually applied to the load is obtained by subtracting the voltage drop from the voltage measured in the voltage / current measurement step.

  Further, in the voltage adjustment method, the tap switching control step is applicable when any of the differential voltages is not within the predetermined differential voltage range and is continuously determined for a predetermined time in the differential voltage determination step. It is preferable that the tap changer is controlled so that the difference voltage is within the predetermined difference voltage range.

  Further, in the voltage adjustment method, when the tap switching control step determines in the differential voltage determination step that the plurality of differential voltages are not within the predetermined differential voltage range, the plurality of differential voltages Controlling the tap changer to switch the tap of the transformer provided in the distribution line corresponding to the differential voltage having the maximum absolute value among the plurality of differential voltages. Is preferred.

  In the voltage adjustment method, the tap switching control step controls the tap switch to increase the load voltage applied to the load when the differential voltage having the maximum absolute value is negative. When the differential voltage having the maximum absolute value is positive, it is preferable to control the tap changer to lower the load voltage applied to the load.

  In addition, the invention for solving the above-described problems is provided with a plurality of transformers each provided with a plurality of distribution lines for distributing a plurality of phases of AC voltage to the load, each having a tap for switching the load voltage applied to the load. A voltage adjustment program for causing a voltage adjustment device comprising a power supply unit and a tap changer to switch the tap to execute a voltage adjustment method, wherein the voltage / current measurement step measures the voltage and current of the plurality of distribution lines, and The differential voltage between the voltage actually applied to the load obtained based on the voltage and current measured in the voltage / current measurement step and the voltage to be applied to the load is determined for each of the plurality of distribution lines. The difference voltage calculation step to be calculated and whether or not the plurality of difference voltages calculated in the difference voltage calculation step are within a predetermined difference voltage range. If the difference voltage determination step and the difference voltage determination step determine that any of the difference voltages is not within the predetermined difference voltage range, the corresponding difference voltage is determined as the predetermined difference. A tap change control step for controlling the tap changer to be within a voltage range.

  In a transformer that distributes a plurality of phases of AC voltage to a load through a plurality of distribution lines, the plurality of phases of AC voltage applied to the load can be adjusted in a well-balanced manner.

=== Configuration of Voltage Regulator ===
As illustrated in the block diagram of FIG. 1, the three-phase voltage regulator 10 of the present embodiment mainly includes a regulation transformer (transformer) 30 provided with taps 20 (20u, 20v, 20w). (30u, 30v, 30w), tap changer 40, instrument transformer (voltage measuring unit) 50 (50u, 50v, 50w), current transformer (current measuring unit) 60 (60u, 60v, 60w) And a control board 70 and a series transformer 80 (80u, 80v, 80w). Terminals corresponding to the U-phase, V-phase, and W-phase are provided on the input side and output side of the voltage regulator 10, respectively, and loads are applied through three distribution lines connected to the three terminals on the output side. Three-phase AC voltage is distributed to 90. In addition, although the voltage regulator 10 of this Embodiment respond | corresponds to a three-phase alternating voltage, it is not limited to this, In general, you may respond | correspond to the alternating voltage of multiple phases.

  The adjusting transformer 30 is an integrated unit in which adjusting transformers 30u, 30v, and 30w each having an independent transformer function are accommodated in the same casing for U-phase, V-phase, and W-phase distribution lines. . The adjustment transformer 30 is not limited to an integral type.

  The tap 20 is provided as three tap units 20u, 20v, and 20w each having four taps with respect to the adjustment transformers 30u, 30v, and 30w. The U-phase regulating transformer 30u includes a 0th tap 200u having a potential of 0V, a first tap 201u having a potential of 140V, a second tap 202u having a potential of 280V, and a third tap 203u having a potential of 420V. It is provided as a tap unit 20u. The V-phase adjusting transformer 30v includes a 0th tap 200v having a potential of 0V, a first tap 201v having a potential of 140V, a second tap 202v having a potential of 280V, and a third tap 203v having a potential of 420V. It is provided as a tap unit 20v. The W-phase adjusting transformer 30w includes a 0th tap 200w having a potential of 0V, a first tap 201w having a potential of 140V, a second tap 202w having a potential of 280V, and a third tap 203w having a potential of 420V. It is provided as a tap unit 20w. The voltage settings of 0V, 140V, 280V, and 420V described above are examples, and the present invention is not limited to this.

  The tap changer 40 includes a switching relay 410 (411u to 414u, 411v to 414v, 411w to 414w) and a bridging relay 420 (420u, 420v, 420w) for each of the U phase, the V phase, and the W phase. It comprises a relay circuit 450 (450u, 450v, 450w) configured to include a relay 430 and a current limiting resistor 440 (441u, 442u, 441v, 442v, 441w, 442w). The switching relay 410 performs tap switching, the bridging relay 420 bridges the taps, and the current limiting resistor 440 limits the current between the taps.

  The U-phase relay circuit 450u will be described. For the third tap 203u and the first tap 201u, the first relay circuit is connected via the first switching relay 411u so that the potential on the intermediate side (X1u, see FIG. 1) of the relay circuit 450u is 420V or 140V. 451u is formed. Here, the first switching relay 411u is configured to connect one of U3 and X1u and between U1 and X1u in FIG. 1 and shut off the other.

  In the present embodiment, for the following explanation, the state of the first switching relay 411u that connects U3 and X1u and disconnects U1 and X1u is turned on, and conversely, U3 and X1u are disconnected and U1 -The state of the 1st switching relay 411u which connects between X1u is made into an OFF state. That is, when the first switching relay 411u is on, a potential of 420V is generated on the intermediate side X1u, and when the first switching relay 411u is off, a potential of 140V is generated on the intermediate side X1u. Further, a fourth switching relay 414u is connected to the intermediate side X1u and the output side Yu (see FIG. 1) of the relay circuit 450u, and the fourth switching relay 414u is turned on or off. Accordingly, X1u and Yu are connected or disconnected.

  For the second tap 202u and the 0th tap 200u, the second relay circuit is passed through the second switching relay 412u so that the potential on the intermediate side (X2u, see FIG. 1) of the relay circuit 450u is 280V or 0V. 452u is formed. Here, the second switching relay 412u is configured to connect one of U2 and X2u and between U0 and X2u in FIG.

  In the present embodiment, the second switching relay 412u, which connects U2 and X2u and disconnects U0 and X2u, is turned on, while U2 and X2u are disconnected and U0 is disconnected. -The state of the 2nd switching relay 412u which connects between X2u is made into an OFF state. That is, when the second switching relay 412u is on, a potential of 280V is generated on the intermediate side X2u, and when the second switching relay 412u is off, a potential of 0V is generated on the intermediate side X2u. Further, a third switching relay 413u is connected to the intermediate side X2u and the output side Yu (see FIG. 1) of the relay circuit 450u, and the third switching relay 413u is turned on or off. Accordingly, the X2u and Yu are connected or disconnected.

  The intermediate side X1u and the output side Yu (see FIG. 1) of the relay circuit 450u are connected to the current-limiting resistor 441u and the bridging relay 420u that are connected in series with each other. A current limiting resistor 442u and a bridging relay 420u, which are connected in series with each other, are connected to the output side Yu (see FIG. 1) of the relay circuit 450u. Here, the bridging relay 420u is configured to connect or block between X1u and Yu and between X2u and Yu in FIG.

  As illustrated in FIG. 1, the V-phase relay circuit 450v has the same configuration as that of the U-phase relay circuit 450u. In other words, the V-phase relay circuit 450v includes four switching relays 411v to 414v, one bridging relay 420v, and two current limiting resistors 441v and 442v.

  Also, as illustrated in FIG. 1, the W-phase relay circuit 450w has the same configuration as that of the U-phase relay circuit 450u. In other words, the W-phase relay circuit 450w includes four switching relays 411w to 414w, one bridging relay 420w, and two current-limiting resistors 441w and 442w. The tap changer 40 is not limited to the relay type.

The instrument transformer 50 (50u, 50v, 50w) is a measuring device that measures the voltages of the input terminals U, V, and W with respect to an appropriate ground.
Current transformer 60 (60u, 60v, 60w) is a measuring device which measures the current which flows in output side terminals u, v, and w, respectively.
The control board 70 is a board on which a predetermined circuit including a CPU for controlling the operation of the tap changer 40 is formed.

  The series transformer 80 is a unit in which series transformers 80u, 80v, and 80w having independent transformation functions for U-phase, V-phase, and W-phase distribution lines are housed in the same casing. . For example, the U-phase series transformer 80u has a function of transforming the potential 0V to 420V on the output side (for example, Yu in FIG. 1) of the U-phase relay circuit 450u to 0V to 120V that is, for example, 1 / 3.5. is doing. When the output from the series transformer 80u is added to the voltage 420V of the input side terminal U, the voltage of the output side terminal u becomes 420V to 540V. The V-phase and W-phase series transformers 80v and 80w are the same as the U-phase series transformer 80u. The series transformer 80 is not limited to an integral type.

  As illustrated in the block diagram of FIG. 2, the circuit formed on the control board 70 includes a control unit 500 that controls the above-described tap changer 40, a timer 600, and a memory 700. As will be described later, the control unit 500 switches the switching relays 410u, 410v, 410w and the bridging relays 420u, 420v, 420w constituting the tap switch 40 at predetermined timing for each of the U phase, the V phase, and the W phase. It is turned on or off for a predetermined time. This predetermined time is measured by the timer 600, for example.

  As will be described later, the control unit 500 causes the voltage transformers 50u, 50v, 50w and the current transformers 60u, 60v, 60w to measure the voltage and current, respectively, and then the voltage actually applied to the load 90. Having a function of calculating and determining a differential voltage between the voltage and the voltage to be applied to the load 90 and repeating a series of operations in a predetermined cycle until the tap switch 40 is controlled based on the determination result It is. Prior to this determination, the control unit 500 updates or reads out the differential voltage data 800 stored in a memory (differential voltage storage unit) 700 such as a ROM or a RAM.

  The differential voltage data 800 is obtained by measuring voltage (Vu, Vv, Vw) and current (Vu, Vv, Vw) and current transformers 50u, 50v, 50w and current transformers 60u, 60v, 60w for each of the U phase, V phase, and W phase. Iu, Iv, Iw), information specifying the currently selected tap (U0 to U3, V0 to V3, W0 to W3) (tap specifying data), and differential voltages (Vd, Vd ′) to be described later It is configured with.

  In addition, the control part 500 of this Embodiment controls the tap switch 40 one phase at a time.

=== Tap selection operation after the switching condition for two or more phases is met ===
As illustrated in the flowchart of FIG. 3, first, the control unit 500 resets the timer 600 and then starts measuring time (S100).
The control unit 500 that causes the voltage transformer 50 (50u, 50v, 50w) and the current transformer 60 (60u, 60v, 60w) to constantly measure the voltage and current is the voltage (Vu, Vv, Vw) and current. When (Iu, Iv, Iw) data is received, the tap specific data (U0 to U3, V0 to V3, W0 to W3) is stored in the memory 700 as differential voltage data 800 for each of the U phase, V phase, and W phase. (S101).

  Next, the control unit 500 reads the currents Iu, Iv, Iw from the differential voltage data 800 stored in the memory 700, multiplies them by the impedances (Zu, Zv, Zw) of the distribution lines, and outputs the output side terminals u, The voltage drop from v and w to the load 90 is calculated. Further, the control unit 500 reads out the voltages Vu, Vv, and Vw from the differential voltage data 800 stored in the memory 700, subtracts the above-described voltage drop from each of them, and ends the voltage at the load 90 (VLu = Vu−Iu · Zu). VLv = Vv−Iv · Zv, VLw = Vw−Iw · Zw, voltage actually applied to the load). Further, the control unit 500 determines the differential voltages (Vdu = VLu−E, Vdv = VLv−E, Vdw = VLw−) between these terminal voltages and the reference set voltage (E, voltage to be applied to the load) in the load 90. E) is calculated, written in the differential voltage data 800 stored in the memory 700, and updated (S102). In addition, the impedance (Zu, Zv, Zw) of the distribution line of each phase is stored in the memory 700 in advance, and the control unit 500 may read this impedance from the memory 700. Alternatively, the memory 700 stores the line type (cross-sectional area) and length of the distribution line of each phase, and the control unit 500 reads the line type and length from the memory 700, and calculates the impedance based on the line type and length. It may be calculated. Further, for example, a reference setting voltage (E) common to each phase is stored in the memory 700 in advance, and the control unit 500 may read the reference setting voltage from the memory 700.

  Next, the control unit 500 reads the above-described three differential voltages (Vdu, Vdv, Vdw) from the memory 700 to obtain an absolute value, and at least two of these absolute values are based on a predetermined allowable value. Is also larger (S103, S104, S105). If only one of the absolute values is larger than the allowable value (S114: YES), the controller 500 performs a single-phase tap selection operation to be described later. If any absolute value is less than or equal to the allowable value (S114: NO), the controller 500 repeats the operation of step S100. In the present embodiment, when the above-described allowable value is Q, for example, −Q or more and + Q or less correspond to a predetermined differential voltage range.

  If at least two absolute values are larger than the allowable values (S103: YES, S104: YES, S105: YES), the controller 500 determines whether or not the time measured by the timer 600 has reached a predetermined time. Determine (S106). Here, if the predetermined time has been reached (S106: YES), as will be described later, the control unit 500 performs predetermined processing on the differential voltages Vdu, Vdv, and Vdw when selecting the phase corresponding to the maximum absolute value. (S107). On the other hand, if the predetermined time has not been reached (S106: NO), control unit 500 repeats the operation of step S101. In the present embodiment, the details of the processing procedure in step S107 in FIG. 3 are composed of steps S10701 through S10720 in FIG.

  As illustrated in the flowchart of FIG. 4, for the U phase (S1071: U), the control unit 500 determines whether or not this is a tap switching target (S10702). If the U phase is not a switching target (S10702: NO), the control unit 500 sets Vdu ′ = 0 as a new differential voltage (S10707), writes it in the differential voltage data 800 stored in the memory 700, and writes this. Update (S10720).

  If the U phase is a tap switching target (S10702: YES), the control unit 500 determines whether Vdu is positive or negative (S10703). Here, when Vdu is positive (S10703: Vdu> 0), the control unit 500 refers to the tap specifying data of the differential voltage data 800 stored in the memory 700, and the current tap of the U phase is the lowest position. It is determined whether or not it is the 0th tap 200u (S10704). On the other hand, when Vdu is negative (S10703: Vdu <0), the control unit 500 refers to the tap specifying data of the differential voltage data 800 stored in the memory 700, and the current tap of the U phase is the highest rise position. It is determined whether or not there are 3 taps 203u (S10706).

  If Vdu> 0 and the current tap is the 0th tap 200u (S10704: YES), the control unit 500 sets Vdu ′ = 0 as a new differential voltage (S10705), and stores the differential voltage stored in the memory 700. The data 800 is written and updated (S10720).

  If Vdu> 0 and the current tap is not the 0th tap 200u (S10704: NO), the control unit 500 stores Vdu ′ = Vdu, that is, Vdu without any processing in the memory 700 as a new differential voltage. The stored differential voltage data 800 is written and updated (S10720).

  If Vdu <0 and the current tap is the third tap 203u (S10706: YES), the control unit 500 sets Vdu ′ = 0 as a new differential voltage (S10707) and stores the differential voltage stored in the memory 700. The data 800 is written and updated (S10720).

  If Vdu <0 and the current tap is not the third tap 203u (S10706: NO), the control unit 500 stores Vdu ′ = Vdu, that is, Vdu without any processing in the memory 700 as a new differential voltage. The stored differential voltage data 800 is written and updated (S10720).

  As illustrated in the flowchart of FIG. 4, for the V phase and the W phase (S10701: V and S10701: W), the operation of the control unit 500 (S10708 to S10713 and S10714 to S10719) is the case of the U phase described above. The same as (S10702 to S10707).

  As described above, for the U phase, the V phase, and the W phase, new differential voltages Vdu ′, Vdv ′, and Vdw ′ are written and updated in the differential voltage data 800 stored in the memory 700 (S10720). By the processing of step S107 (FIG. 3), that is, steps S10701 to S10720 (FIG. 4), the differential voltage is reset to 0 for the phase where the tap is not a switching target and the phase where the tap cannot be further raised or lowered. Will be.

  Returning to the flowchart of FIG. 3, the control unit 500 obtains absolute values of new differential voltages Vdu ′, Vdv ′, and Vdw ′, compares the two absolute values twice, and obtains the maximum value (S108, S109). , S112), the phase corresponding to the maximum value is found from the differential voltage data 800, and the tap of this phase is switched (S110, S111, S113). In this case, the control unit 500 controls the tap changer 40 to lower or raise the tap according to the sign of the differential voltage. In addition, the control unit 500 controls the tap switch 40 to lower or raise the tap in increments (1 to 3 increments) according to the magnitude of the absolute value of the differential voltage.

  As described above, after the switching condition of two or more phases is satisfied, the phase tap corresponding to the differential voltage having the maximum absolute value is first switched, and then the process of measuring the voltage and current of each phase is performed again.

=== Tap selection operation after single-phase switching condition is satisfied ===
As illustrated in step S114 in the flowchart of FIG. 3 after YES, when only one of the absolute values of Vdu, Vdv, and Vdw is greater than the allowable value, the control unit 500 uses the timer 600 to measure. It is determined whether or not the set time has reached a predetermined time (S115).

  If the predetermined time has been reached (S115: YES), the controller 500 finds the phase corresponding to the differential voltage having an absolute value larger than the allowable value from the differential voltage data 800, and the tap of this phase is determined as the difference voltage. The tap changer 40 is controlled to be lowered or raised according to positive and negative. Further, the control unit 500 controls the tap switch 40 to lower or raise the tap in steps (1 to 3 steps) according to the absolute value of the differential voltage (S116).

On the other hand, if the predetermined time has not been reached (S115: NO), control unit 500 repeats the operation of step S101.
Note that immediately after step S115, for example, the processing of steps S10703 to S10707 (FIG. 4) described above may be performed, and if the tap cannot be further raised or lowered, the differential voltage may be reset to zero.

=== Tap switching operation from 460V to 420V ===
As an example of the tap switching operation in steps S110, S111, S113, and S116 described above, the control unit 500 switches from the first tap 203u to the 0th tap 200u in order to switch the voltage at the output terminal u from 460V to 420V. Will be described.

<<<< (Ry1u, Ry2u, Ry3u, Ry4u, Ry5u) = (OFF, OFF, OFF, ON, OFF) >>
In the time domain T1 in the diagram of FIG. 5, the first switching relay 411u is in the off state, the second switching relay 412u is in the off state, the third switching relay 413u is in the off state, The four-switching relay 414u is in an on state, and the bridging relay 420u is in an off state. This is abbreviated as, for example, (Ry1u, Ry2u, Ry3u, Ry4u, Ry5u) = (OFF, OFF, OFF, ON, OFF). In this case, the potential of the path from U1 to the series transformer 80u via X1u and Yu (see the thick line in FIG. 6) is 140V everywhere, and the path from the series transformer 80u to the first tap 200u (FIG. 6). The potential of the thick line is 0V everywhere. That is, the first tap 201u is selected, and the voltage of the output side terminal u is 460 (= 420 + 140 / 3.5) V. Note that the relay 430 is on.

<<<< (Ry1u, Ry2u, Ry3u, Ry4u, Ry5u) = (OFF, OFF, OFF, ON, ON) >>
In the time domain T2 in the diagram of FIG. 5, an ON signal is transmitted from the controller 500 to the bridging relay 420u, and (Ry1u, Ry2u, Ry3u, Ry4u, Ry5u) = (OFF, OFF, OFF, ON, ON) And

  The resistance values of the current-limiting resistors 441u and 442u of the present embodiment are the paths from U1 to the series transformer 80u through X1u, Ry4u, and Yu (see the thick line in FIG. 7), and from Yu to R2U and X2u. Thus, the current is set in advance so as to mainly flow through the path leading to U0 (see the thick line in FIG. 7). Note that the potential of the path from the series transformer 80u to the first tap 200u (see the thick line in FIG. 7) is 0V everywhere. In this case, the state where the first tap 201u is selected is maintained, and the voltage of the output side terminal u is 460V.

<<<< (Ry1u, Ry2u, Ry3u, Ry4u, Ry5u) = (OFF, OFF, OFF, OFF, ON) >>
In the time domain T3 in the diagram of FIG. 5, an OFF signal is transmitted from the controller 500 to the fourth switching relay 414u, and (Ry1u, Ry2u, Ry3u, Ry4u, Ry5u) = (OFF, OFF, OFF, OFF, ON ).

  In the present embodiment, the time difference from when control unit 500 transmits an ON signal to bridging relay 420u to when it transmits an OFF signal to fourth switching relay 414u is 200 ms. When (Ry1u, Ry2u, Ry3u, Ry4u, Ry5u) = (OFF, OFF, OFF, OFF, ON), the current in the relay circuit 450u is transferred from U1 to the series transformer 80u via Ry1u, R1U, and Yu. And a route from Yu through R2U and X2u to U0 (see the thick line in FIG. 8). Note that the potential of the path from the series transformer 80u to the first tap 200u (see the thick line in FIG. 8) is 0V everywhere. In this case, when the load current measured by the current transformer 60u is 0A, the potential on the primary side of the series transformer 80u is 70V obtained by dividing 140V of U1 into two by the current-limiting resistors 441u and 442u. . On the other hand, when the load current is 23.8 A, for example, the primary side potential of the series transformer 80 u is 2 V, for example, according to the impedance of the series transformer 80 u and the resistance values of the current-limiting resistors 441 u and 442 u. Therefore, the secondary side potential of the series transformer 80u is about 1V (= 2V / 3.5) to 20V (= 70V / 3.5), and the voltage of the output side terminal u is about 421V to 440V.

  As described above, in the present embodiment, in the middle of switching the tap so that the voltage at the output side terminal u is changed from 460 V to 420 V, the voltage does not drop suddenly to 420 V, and a voltage of about 1 to 70 V with respect to 420 V is applied. It has come to be added.

<<<< (Ry1u, Ry2u, Ry3u, Ry4u, Ry5u) = (OFF, OFF, ON, OFF, ON) >>
In the time domain T4 in the diagram of FIG. 5, an ON signal is transmitted from the control unit 500 to the third switching relay 413u, and (Ry1u, Ry2u, Ry3u, Ry4u, Ry5u) = (OFF, OFF, ON, OFF, ON ). In the present embodiment, the time difference from when control unit 500 transmits an OFF signal to fourth switching relay 414u until it transmits an ON signal to third switching relay 413u is 100 ms.

  The resistance values of the current limiting resistors 441u and 442u of the present embodiment are the paths from U1 to Ry1u, R1U and Yu to the series transformer 80u (see the thick line in FIG. 9), and Yu to Ry3u and Ry2u. Thus, the current is set in advance so as to mainly flow through the path leading to U0 (see the thick line in FIG. 9). Note that the potential of the path from the series transformer 80u to the first tap 200u (see the thick line in FIG. 9) is 0V everywhere. In this case, the 0th tap 200u is selected, and the voltage at the output side terminal u is 420V.

<<<< (Ry1u, Ry2u, Ry3u, Ry4u, Ry5u) = (OFF, OFF, ON, OFF, OFF) >>
In the time domain T5 in the diagram of FIG. 5, an OFF signal is transmitted from the control unit 500 to the bridging relay 420u, and (Ry1u, Ry2u, Ry3u, Ry4u, Ry5u) = (OFF, OFF, ON, OFF, OFF). And In the present embodiment, the time difference from when the control unit 500 transmits an ON signal to the third switching relay 413u to when it transmits an OFF signal to the bridging relay 420u is 200 ms. When (Ry1u, Ry2u, Ry3u, Ry4u, Ry5u) = (OFF, OFF, ON, OFF, OFF), the potential of the path (see the bold line in FIG. 10) from U0 to the series transformer 80u via Ry2u and Ry3u It is 0V everywhere, and the potential of the path from the series transformer 80u to the first tap 200u (see the thick line in FIG. 10) is 0V everywhere. That is, the state where the 0th tap 200u is selected is maintained, and the voltage of the output side terminal u is 420V.

  As illustrated in the diagram of FIG. 11, the operation of the control unit 500 for raising or lowering the tap to set the voltage of the output terminal u to any of 420V, 460V, 500V, and 540V is the series of operations described above. The operation is similar to the operation. For example, the tap switching operation from 500 V to 460 V in FIG. 11 is performed by changing (Ry1u, Ry2u, Ry3u, Ry4u, Ry5u) from the (OFF, ON, ON, OFF, OFF) state to (OFF, ON, ON, (OFF, ON), (OFF, ON, OFF, OFF, ON), (OFF, ON, OFF, ON, ON) through the states (OFF, ON, OFF, ON, OFF) Realized.

  The tap switching operation in the V phase and the W phase is the same as the tap switching operation in the U phase described above.

=== Balance of each phase ===
According to the voltage regulator 10 of the present embodiment, the absolute value of the differential voltage of some phases of the U phase, the V phase, and the W phase is larger than the allowable value, and the absolute values of the differential voltages of the other phases are When the value is equal to or less than the allowable value, taps provided in the transformer corresponding to the differential voltage of the partial phase are to be switched. That is, only the tap corresponding to the phase in which the differential voltage is larger than the allowable displacement from the reference setting voltage to be applied to the load 90 can be switched, so that the three-phase AC voltage can be adjusted in a well-balanced manner.

  Further, according to the voltage regulator 10 of the present embodiment, it is not instantaneously, for example, once in a predetermined time or within a predetermined time that any one of the absolute values of Vdu, Vdv, and Vdw is larger than the allowable value. The tap selection operation by the control unit 500 is executed every time a plurality of times are continuously determined (steps S106 and S115). Therefore, the operation accuracy of the control unit 500 is further improved, and the three-phase AC voltage can be adjusted with a good balance.

  Furthermore, according to the voltage regulating apparatus 10 of the present embodiment, when two or more phases are to be switched, the tap is switched preferentially for the phase having the maximum absolute value of the corresponding differential voltage. Therefore, the operation of the control unit 500 becomes more efficient, and the three-phase AC voltage can be adjusted with good balance.

  Note that the control unit 500 of the present embodiment and the program that causes the control unit 500 to execute the operation of step S101 (FIG. 3) described above correspond to the differential voltage calculation unit. In addition, the control unit 500 of the present embodiment and the program that causes the control unit 500 to execute the operations of the above-described steps S103, S104, S105, and S114 (FIG. 3) correspond to the differential voltage determination unit. In addition, the control unit 500 of the present embodiment and the program that causes the control unit 500 to execute the operations of the above-described steps S106 to S113, S115, and S116 (FIG. 3) correspond to the tap switching control unit.

  The above-described embodiments of the present invention are intended to facilitate understanding of the present invention, and are not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and equivalents thereof are also included in the present invention.

It is a block diagram which shows the circuit structural example of the voltage regulator of this Embodiment. It is a block diagram which shows the example of a control structure of the voltage regulator of this Embodiment. It is a flowchart for demonstrating the tap selection operation | movement of the voltage regulator of this Embodiment. It is another flowchart for demonstrating the tap selection operation | movement of the voltage regulator of this Embodiment. It is a diagram for demonstrating the operation timing of the switching relay of the voltage regulator of this Embodiment, and the bridging relay. It is a circuit diagram for demonstrating the state of the switching relay and bridge relay in the time domain T1. It is a circuit diagram for demonstrating the state of the switching relay and bridge relay in the time domain T2. It is a circuit diagram for demonstrating the state of the switching relay and bridge relay in the time area | region T3. It is a circuit diagram for demonstrating the state of the switching relay and bridge relay in the time domain T4. It is a circuit diagram for demonstrating the state of the switching relay and bridge relay in the time domain T5. It is another diagram for demonstrating the operation timing of the switching relay of the voltage regulator of this Embodiment, and the bridging relay.

Explanation of symbols

10 Voltage regulator 20u, 20v, 20w Tap 30u, 30v, 30w Adjustment transformer 40 Tap changer 410u, 410v, 410w Switching relay 420u, 420v, 420w Bridge relay 430 Relay 441u, 442u, 441v, 442v, 441w 442w Current-limiting resistors 450u, 450v, 450w Relay circuits 451u, 451v, 451w First relay circuits 452u, 452v, 452w Second relay circuits 50u, 50v, 50w Instrument transformer 60u, 60v, 60w Current transformer 70 Control board 80u, 80v, 80w Series transformer 90 Load 500 Control unit 600 Timer 700 Memory 800 Differential voltage data

Claims (12)

A plurality of transformers each provided with a plurality of taps for switching a load voltage applied to the load, a tap changer for switching the tap; A voltage regulation device comprising:
A voltage measuring unit for measuring voltages of the plurality of distribution lines;
A current measuring unit that measures currents of the plurality of distribution lines;
The plurality of differential voltages between the voltage actually applied to the load obtained based on the voltage measured by the voltage measuring unit and the current measured by the current measuring unit and the voltage to be applied to the load A differential voltage calculation unit to calculate for each distribution line,
A differential voltage determination unit that determines whether or not the plurality of differential voltages calculated by the differential voltage calculation unit are within a predetermined differential voltage range;
When the difference voltage determination unit determines that any two or more of the plurality of difference voltages are not within the predetermined difference voltage range, obtain an absolute value of the two or more difference voltages; The tap of the transformer provided in the distribution line corresponding to the differential voltage with the maximum absolute value is switched so that the differential voltage with the maximum absolute value falls within the predetermined differential voltage range. the tap switching control unit for controlling the tap changer as,
A voltage regulating device comprising: The differential voltage calculator is provided for each of the plurality of distribution lines.
Calculate the voltage drop to the load in the distribution line based on the current measured by the current measuring unit,
Subtracting the voltage drop from the voltage measured by the voltage measurement unit to obtain the voltage actually applied to the load,
The voltage regulator according to claim 1. The tap switching control unit, when any of the differential voltage is the difference component voltage determination unit not within the differential voltage range predetermined continued to determine the predetermined time, determines the differential voltage of the corresponding said pre The voltage regulator according to claim 1, wherein the tap changer is controlled so as to be within a set differential voltage range. The tap switching control unit controls the tap switch to increase the load voltage applied to the load when the differential voltage having the maximum absolute value is negative, and the difference having the maximum absolute value. If the voltage is positive, voltage regulator of claim 1, wherein controlling the tap changer in order to lower the load voltage applied to the load, characterized in that. Differential voltage storage that stores differential voltage data indicating a plurality of differential voltages calculated by the differential voltage calculation unit in association with tap specifying data that specifies taps of the transformer provided in the corresponding distribution line. voltage regulator according to any one of claims 1 to 4, further comprising a part. 6. The voltage regulator according to claim 5 , wherein the differential voltage data indicating the differential voltage stored in the differential voltage storage unit is data indicating an absolute value of the differential voltage . When the differential voltage determination unit determines that the plurality of differential voltages are not within the predetermined differential voltage range, the tap switching control unit is configured to store the plurality of differential voltages stored in the differential voltage storage unit. The tap switch is controlled to switch a tap specified by the tap specifying data corresponding to the differential voltage data having the maximum absolute value among a plurality of differential voltage data indicating 6. The voltage regulator according to 6. A plurality of transformers each provided with a plurality of taps for switching a load voltage applied to the load, a tap changer for switching the tap; A voltage regulation method for a voltage regulation device comprising:
A voltage / current measurement step for measuring the voltage and current of the plurality of distribution lines;
The differential voltage between the voltage actually applied to the load obtained based on the voltage and current measured in the voltage / current measurement step and the voltage to be applied to the load is calculated for each of the plurality of distribution lines. Differential voltage calculation step,
A differential voltage determination step for determining whether or not the plurality of differential voltages calculated in the differential voltage calculation step are within a predetermined differential voltage range;
When the differential voltage determination unit determines that any two or more of the differential voltages are not within the predetermined differential voltage range in the differential voltage determination step, the two or more differential voltages Of the distribution line corresponding to the differential voltage with the maximum absolute value so that the differential voltage with the maximum absolute value is within the predetermined differential voltage range. A tap change control step for controlling the tap changer to change the tap of the transformer;
Voltage adjustment how to comprising the. In the differential voltage calculation step, for each of the plurality of distribution lines,
Calculate the voltage drop to the load in the distribution line based on the current measured in the voltage / current measurement step,
Subtracting the voltage drop from the voltage measured in the voltage / current measurement step to obtain a voltage that is actually applied to the load;
The voltage adjustment method according to claim 8, wherein: In the tap switching control step, if any of the differential voltages is not within the predetermined differential voltage range and the determination is continued in the differential voltage determination step for a predetermined time, the corresponding differential voltage is determined in advance. 10. The voltage adjusting method according to claim 8 , wherein the tap changer is controlled so as to be within a differential voltage range . The tap switching control step controls the tap switch to increase the load voltage applied to the load when the differential voltage having the maximum absolute value is negative, and the difference having the maximum absolute value. 9. The voltage adjustment method according to claim 8 , wherein when the voltage is positive, the tap changer is controlled to decrease a load voltage applied to the load . A plurality of transformers each provided with a plurality of taps for switching a load voltage applied to the load, a tap changer for switching the tap; A voltage adjustment program for executing a voltage adjustment method of a voltage adjustment apparatus comprising:
A voltage / current measurement step for measuring the voltage and current of the plurality of distribution lines;
The differential voltage between the voltage actually applied to the load obtained based on the voltage and current measured in the voltage / current measurement step and the voltage to be applied to the load is calculated for each of the plurality of distribution lines. Differential voltage calculation step,
A differential voltage determination step for determining whether or not the plurality of differential voltages calculated in the differential voltage calculation step are within a predetermined differential voltage range;
When the differential voltage determination unit determines that any two or more of the differential voltages are not within the predetermined differential voltage range in the differential voltage determination step, the two or more differential voltages Of the distribution line corresponding to the differential voltage with the maximum absolute value so that the differential voltage with the maximum absolute value is within the predetermined differential voltage range. A tap change control step for controlling the tap changer to change the tap of the transformer;
Comprising the voltage adjustment programs.

Images