JP2014239634A - Distribution line voltage control device and voltage control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow proper voltage control by suppressing rising of a distribution line voltage when reverse power flow occurs.SOLUTION: A device controls voltage of a distribution line by switching taps of a transformer in which a primary side is connected to a high-order system and a secondary side is connected to a distribution line system respectively. Relating to a voltage adjusting relay for switching taps of the transformer, a setting value of a target output voltage for an input current is settled to be a voltage characteristic rising from a negative side maximum set value of the input current toward a positive side maximum set value. A phase difference of voltage and current of the distribution line is calculated at a phase difference calculation part 12, and based on the phase difference, direction of power flow is determined by a reverse power flow relay 13. A 1(positive sign) is outputted at forward power flow while -1(negative sign) is outputted at reverse power flow. The positive or negative sign is multiplied with the positive current effective value at a multiplier 14, to provide an effective value that is expanded in negative direction, in other words, a signed current effective value, which is introduced into the voltage adjusting relay.

Description

  The present invention relates to a voltage adjustment relay (90 relay) installed on a transformer control panel or a control device having the same function in a distribution substation of a power company, and a voltage control device and method for a distribution line. About.

  Conventionally, in power distribution substations, reverse power flow for each transformer has not been recognized from the viewpoint of voltage management and protection coordination. Therefore, 90 relays (voltage adjustment relays) that perform tap switching control of transformers each connected to the upper system on the primary side and the distribution system on the secondary side are directed from the upper system to the distribution system. Only forward tides have to be dealt with. For example, the characteristic shown in FIG. 17 was provided (see, for example, Patent Document 1).

  In FIG. 17, the conventional 90 relay performs a relay operation using a positive current effective value. For example, when the load increases and the distribution line current increases, the voltage applied to the distribution line increases. Perform switching control.

On the other hand, with the recent suppression of CO ₂ emissions and the stoppage of nuclear power plants after the earthquake, studies are underway to ease the reverse power flow regulations at distribution substations that restrict the introduction of renewable energy power sources. .

  FIG. 18 shows the voltage / current phase relationship during forward flow and reverse flow. FIG. 18 is a diagram in which a voltage / current vector is expressed on a complex plane with the horizontal axis based on the voltage phase as a real axis and the vertical axis as an imaginary axis. The length (absolute value) of the voltage / current vector is p. . u. (Per unit; unit method).

  Moreover, the distribution line voltage distribution at the time of forward power flow / reverse power flow is shown in FIG. In FIG. 19B, the horizontal axis represents distance, and the vertical axis represents voltage magnitude.

  Due to the influence of the power flow of the distribution line and the line impedance, as shown in FIG. 19B, the voltage drops during the forward flow and increases during the reverse flow.

  In addition, as a conventional distribution line voltage control method, the method of patent document 2, 3 was proposed, for example.

Japanese Patent No. 4758375 JP 2006-262555 A JP 2007-143313 A

  When the reverse power flow becomes significant in the distribution substation, the voltage of the distribution line rises. However, since the relay calculation is performed using the positive current effective value with the 90 relay characteristics shown in FIG. Since it is determined that it is “large” and tap switching is performed to amplify the voltage rise, the voltage of the distribution system cannot be maintained properly.

  The present invention solves the above problems, and an object thereof is to provide a voltage control device and a voltage control method for a distribution line that can perform appropriate voltage control while suppressing an increase in the distribution line voltage when a reverse power flow occurs. It is in.

  The distribution line voltage control apparatus according to claim 1 for solving the above-mentioned problem is to switch the voltage of the distribution line by switching the taps of the transformer respectively connected to the upper system on the primary side and to the distribution system on the secondary side. A phase difference calculating unit that calculates a phase difference between current and voltage of the distribution line, a current effective value calculation unit that calculates an effective value of the current of the distribution line, and the phase difference calculating unit. A reverse flow relay that determines the direction of the tidal current based on the calculated phase difference, outputs a positive sign when it is determined to be a forward power flow, and outputs a negative sign when it is determined to be a reverse power flow. The signed effective current value obtained by multiplying the effective current value calculated by the effective current value calculation unit by the positive or negative sign output from the reverse flow relay is input. The set value of the target output voltage relative to the value is the signed current A voltage adjusting relay that is set to a voltage characteristic that increases from a negative maximum set value of the effective value to a positive maximum set value and that switches the tap of the transformer according to a target output voltage. .

  In the voltage control method for a distribution line according to claim 11, the set value of the target output voltage with respect to the input current is set to a voltage characteristic that increases from the negative side maximum set value to the positive side maximum set value. A voltage control method in a device for controlling a voltage of a distribution line, comprising a voltage adjustment relay for switching a tap of a transformer connected to a secondary system on a secondary side and a distribution side on a secondary side, wherein a phase difference calculation unit includes: A phase difference calculation step for calculating a phase difference between the current and voltage of the distribution line, a current effective value calculation step for a current effective value calculation unit to calculate an effective value of the current of the distribution line, and a reverse power flow relay, The direction of the tidal current is determined based on the phase difference calculated in the phase difference calculating step, and a positive sign is output when it is determined to be a forward power flow, and a negative sign is output when it is determined to be a reverse power flow. Steps, A calculator that multiplies the current effective value calculated in the current effective value calculating step by a positive or negative sign output from the reverse power relay and outputs a signed current effective value; and the voltage adjustment. And a relay for switching the transformer tap according to a target output voltage set in accordance with the input current, wherein the output signed current effective value is an input. Yes.

  The voltage control device for a distribution line according to claim 3, wherein the reverse power relay is based on a phase difference calculated by the phase difference calculation unit and a current effective value calculated by the current effective value calculation unit. It is characterized by determining the direction of the tidal current.

  The voltage control device for a distribution line according to claim 4 is characterized in that the phase difference calculation unit, the current effective value calculation unit, and the reverse flow relay are built in the voltage adjustment relay.

  The voltage control device for a distribution line according to claim 8 is characterized in that the reverse flow relay determines that the reverse flow is a reverse flow when the phase difference is 90 degrees or more.

  According to the above configuration, as a result of extending the voltage-current characteristic of the voltage adjusting relay (90 relay) to the negative current region and determining the power flow direction by the reverse power relay, the forward current is a positive current and the reverse power is Is introduced into the voltage adjusting relay as a negative current, so that it is possible to perform appropriate voltage control by suppressing an increase in distribution line voltage when a reverse power flow occurs.

  Further, the distribution line voltage control device according to claim 2 is a device for controlling the voltage of the distribution line by switching taps of the transformers respectively connected to the upper system on the primary side and to the distribution system on the secondary side. The phase difference calculation unit that calculates the phase difference between the current and voltage of the distribution line, the current effective value calculation unit that calculates the effective value of the current of the distribution line, and the phase difference calculated by the phase difference calculation unit Based on the determination result of forward or reverse flow, the reverse flow relay that outputs a switching signal for switching the settling characteristics of the voltage adjustment relay according to the determination result of forward flow or reverse flow, and the current effective value calculation unit A forward current characteristic in which a set value of a target output voltage with respect to the input current effective value increases from a first minimum current set value to a first maximum current set value; From the minimum current setting value to the second maximum current setting A voltage adjusting relay that switches the tap of the transformer in accordance with a target output voltage of a forward flow characteristic or a reverse flow characteristic that is set to a reverse flow characteristic that falls to a value and is switched by a switching signal from the reverse power relay; It is characterized by having.

  The voltage control method for a distribution line according to claim 12 includes a forward power flow characteristic in which a set value of a target output voltage with respect to an input current increases from a first minimum current set value to a first maximum current set value; Voltage adjustment that switches to the reverse power flow characteristic that decreases from the minimum current setting value of 2 to the second maximum current setting value, and switches the taps of the transformers that are respectively connected to the upper system on the primary side and the distribution system on the secondary side A voltage control method in a device including a relay for controlling a voltage of a distribution line, wherein a phase difference calculation unit calculates a phase difference between a current and a voltage of the distribution line, and a current effective value calculation unit A current effective value calculating step for calculating an effective value of the current of the distribution line, and a reverse power relay determines a direction of power flow based on the phase difference calculated in the phase difference calculating step, and a forward power flow or a reverse power flow Judgment result A step of outputting a switching signal for switching the setting characteristics of the voltage adjustment relay according to the voltage adjustment relay, the voltage adjustment relay having the current effective value calculated in the current effective value calculation step as an input, and the reverse power flow relay Switching the tap of the transformer in accordance with the target output voltage of the forward flow characteristic or the reverse flow characteristic switched by the switching signal output from.

  According to the above configuration, since the forward flow characteristic and the reverse flow characteristic of the voltage adjustment relay are switched according to the determination result of the reverse flow relay, the current effective value is not negatively expanded to the negative side. Appropriate voltage control can be performed while suppressing an increase in the distribution line voltage.

  Further, in the voltage control device for a distribution line according to claim 5, the output voltage set value of the voltage adjusting relay is set in a region where the input voltage is not increased or decreased in a setting range where the input current is close to zero. It is a feature.

  According to the above configuration, when the power flow direction is switched frequently, for example, when the current flows back and forth between the forward power flow and the reverse power flow, the region where the output voltage set in the voltage adjusting relay is not increased or decreased acts as a dead zone. A stable control result can be obtained without voltage fluctuation.

  The voltage control device for a distribution line according to claim 6 is characterized in that the output voltage set value of the voltage adjusting relay is changed in slope between the positive side and the negative side of the signed current effective value. It is said.

  The voltage control device for a distribution line according to claim 7 is characterized in that the output voltage set value of the voltage adjusting relay changes the degree of gradient between the forward flow characteristic and the reverse flow characteristic. .

  According to the above configuration, for example, due to the distribution of the load and the renewable energy power source, when the reverse power flow side has a larger voltage change at the end of the distribution line with respect to the current of the substation than the forward power flow side, or vice versa Good voltage control can be performed when the voltage change at the end of the distribution line with respect to the current at the substation is small.

  The voltage control device for a distribution line according to claim 9 determines that the reverse power relay is a reverse power flow when the phase difference is 90 degrees or more and the current effective value is a set value or more. It is characterized by doing.

  According to the above configuration, in a small region where the effective current value is less than the set value, the forward current flow and the reverse power flow are frequently switched due to a minute current change, or the detection error becomes relatively large. Although errors are likely to occur in the calculation results, it is possible to prevent erroneous judgment of the tidal current direction and hunting of forward tidal current and reverse tidal current judgment due to these minute current changes and errors. You can also prevent information.

  The voltage control device for a distribution line according to claim 10, wherein the reverse power relay is configured such that the phase difference calculated by the phase difference calculation unit is 90 ° + α ° (α ° is a set tolerance) or more. It is characterized by determining a reverse power flow, and otherwise determining a forward power flow.

  According to the above-described configuration, since a margin in consideration of the calculation error of the phase difference calculation unit is provided, it is possible to avoid erroneous detection of reverse power flow.

(1) According to the first to twelfth aspects of the present invention, appropriate voltage control can be performed while suppressing an increase in the distribution line voltage when a reverse power flow occurs.
(2) According to the inventions described in claims 2 and 12, appropriate voltage control can be performed without increasing the effective current value to the negative side and suppressing an increase in distribution line voltage when a reverse power flow occurs.
(3) According to the invention described in claim 5, even when going back and forth between the forward power flow and the reverse power flow, voltage fluctuation does not occur and a stable control result can be obtained. As a result, the voltage control effect is improved in a system in which the distribution line voltage characteristics are different between the forward power flow and the reverse power flow or in a system with many reactive currents.
(4) According to the inventions described in claims 6 and 7, good voltage control can be performed when the voltage change at the end of the distribution line with respect to the current at the substation is different between the reverse power flow side and the forward power flow side.
(5) According to the invention described in claim 9, it is possible to prevent erroneous determination of the tidal direction, hunting of the forward power flow / reverse power flow determination, and unnecessary reporting of the reverse power flow warning.
(6) According to the invention described in claim 10, since the phase difference has a margin, erroneous detection of reverse power flow can be avoided.

The voltage-current characteristic view of 90 relay in Example 1 of this invention. The block diagram of the effective current value calculation showing the principal part structure of Example 1 of this invention. The complex top view which shows the characteristic of the reverse power flow relay in Example 1 of this invention. The voltage-current characteristic view for demonstrating the difference of Example 1 of this invention and the conventional voltage control result. In Example 2 of this invention, the current phase characteristic figure in the case of containing many reactive currents. The voltage-current characteristic view of 90 relay in Example 2 of this invention. The voltage-current characteristic view for demonstrating the difference of the voltage control result of Example 2 and Example 1 of this invention. Explanatory drawing which shows the example from which the voltage characteristic of a distribution line differs in the forward power flow and the reverse power flow in Example 3 of this invention. The voltage-current characteristic view of 90 relay in Example 3 of this invention. The block diagram of the effective current value calculation showing the principal part structure of Example 4 of this invention. The complex top view which shows the characteristic of the reverse power flow relay in Example 4 of this invention. The block diagram which shows the structure of Example 5 of this invention. The voltage-current characteristic view of 90 relay in Example 5 of this invention. The complex top view explaining the misjudgment in the reverse power flow relay by phase difference calculation error. The complex top view which shows an example of the characteristic of the reverse power relay in Example 6 of this invention. The complex top view which shows the other example of the characteristic of the reverse power relay in Example 6 of this invention. The voltage-current characteristic view of the conventional 90 relay. The complex top view which shows the voltage-current phase relationship at the time of a forward power flow and a reverse power flow. Explanatory drawing which shows the distribution line voltage distribution at the time of forward power flow / reverse power flow. Explanatory drawing of the current effective value calculation in the conventional 90 relay.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. In the following embodiments, the present invention is applied to a 90 relay (voltage adjusting relay) that controls the voltage of the distribution line by switching the taps of the transformer connected to the upper system on the primary side and the distribution system on the secondary side. Although an applied embodiment will be described, the present invention is not limited to this and may be applied to a device having the same function as a 90 relay.

  In the first embodiment, the voltage-current characteristic of the 90 relay (voltage adjusting relay) is expanded to a negative current region as shown in FIG. 1 instead of the conventional characteristic of FIG. By calculating as a negative current during reverse current flow, it was configured to enable appropriate voltage control during reverse flow.

  The effective value calculation of the current introduced into the 90 relay is conventionally performed by calculating the effective value of the instantaneous value obtained by detecting the distribution line current with a current transformer as shown in FIG. Value (effective value without sign).

  On the other hand, in the present invention, in order to give a negative value to the effective value calculation result, as shown in FIG. 2, the voltage (instantaneous value of the detected voltage) and current (instantaneous value of the detected current) of the distribution line are changed. The phase difference is calculated by the phase difference calculation unit 12, and based on the phase difference, the direction of the tidal current is determined by the reverse power relay (reverse power relay) 13. The forward power is 1 (positive sign) and the reverse power is − 1 (negative sign) is output, and the positive or negative sign is multiplied by the positive current effective value calculated by the current effective value calculation unit 11 in the multiplier 14 to expand the effective value in the negative direction. Value, that is, a signed current effective value.

As shown in FIG. 1, the voltage-current characteristic of the 90 relay in the first embodiment is set to a voltage characteristic that increases from the minimum value I _MIN (negative value) to the maximum value I _MAX (positive value) of the signed current effective value. Has been.

  The slope of the voltage-current characteristic is arbitrarily set.

  The characteristic of the reverse power relay 13 is that when the phase difference between the voltage and the current is less than 90 degrees as shown in FIG. 3 representing a complex plane with the horizontal axis as the real axis and the vertical axis as the imaginary axis, it is a forward power flow. If it is 90 degrees or more, it is determined that the current is a reverse power flow.

  The voltage-current characteristic diagram of FIG. 4 shows the case where the distribution line voltage is controlled by the configuration of the first embodiment (FIGS. 1 and 2) and the case where the distribution line voltage is controlled by the conventional 90 relay (FIG. 17). It explains together.

  In FIG. 4, in the conventional 90 relay, when a reverse power flow occurs, the actual current considering the power flow direction is determined to be B even though it is in the A state, and the voltage is set to C. Be controlled. On the other hand, according to the first embodiment, since the current is determined as A by the signed current effective value, it can be controlled to D having a voltage lower than C. For this reason, it is possible to make it difficult to raise the voltage of the power distribution system.

Note that the voltage-current characteristics of the 90 relay are such that by setting the I _MIN setting in FIG. 1 to be positive, the tap switching of the transformer is controlled as usual during forward power flow, and the operation is locked during reverse power flow. It is also possible to realize special characteristics.

  The effective value calculation unit 11, the phase difference calculation unit 12, the reverse power relay 13 and the multiplier 14 may be incorporated in a 90 relay (voltage adjustment relay).

  When the distribution line voltage is controlled according to the first embodiment, as shown in the current phase characteristic of FIG. 5, if the distribution line current includes a lot of reactive current components, the current has a value before and after the direction of the power flow is changed. There is a possibility that a jump occurs in which the sign changes (the output of the multiplier 14 in FIG. 2 changes).

Thus, in the second embodiment, the voltage-current characteristics of the 90 relay are configured to have a dead zone at the boundary of forward and reverse power flow as shown in FIG. In FIG. 6, the output voltage set value of the 90 relay is a set range including a positive side and a negative side where the signed current effective value is close to zero, that is, from the negative side minimum setting value I _{N_MIN} to the positive side minimum setting value I _{P_MIN} . The range is set as a region where the output voltage is not increased or decreased (dead zone).

  The case where the voltage of the distribution line is controlled by the configuration of the second embodiment (FIG. 6) and the case where the voltage of the distribution line is controlled by the 90 relay (FIG. 1) of the first embodiment will be described together with the voltage-current characteristic diagram of FIG. To do.

  In FIG. 7, in the state of going back and forth between the forward flow and the reverse flow, the method of the second embodiment goes back and forth between A and A '. In the first embodiment, the voltage is controlled between B and B ′ in accordance with that, which causes voltage fluctuation. In the second embodiment, however, the target value of the voltage does not change between the currents A⇔A ′. Stable control results can be obtained.

  As described above, according to the second embodiment, since the dead zone region near the current zero is provided in the voltage-current characteristics of the 90 relay, systems having different distribution line voltage characteristics between forward power and reverse power or systems with a large amount of reactive power In this case, the voltage control effect is enhanced.

  In actual distribution lines, the voltage does not change linearly as shown in FIG. 19, but often changes with a curve as shown in FIG. 8 depending on the distribution of loads and renewable energy power sources. It may be desirable to change the characteristics of the 90 relay on the reverse power flow side.

  FIG. 8 shows an example in which the voltage characteristics of the distribution line are different between the forward flow and the reverse flow. In FIG. 8B, the horizontal axis indicates the distance, and the vertical axis indicates the voltage magnitude. FIG. 8 shows an example in which the voltage change at the end of the distribution line with respect to the current at the substation is larger on the reverse power flow side than on the forward power flow side.

  In such a case, better voltage control can be achieved if the gradient of the voltage-current characteristic of the 90 relay is made tight on the reverse power flow side.

Therefore, in the third embodiment, the voltage-current characteristics of the 90 relay are as shown in FIG. 9 with the voltage-current characteristics in the range from the negative maximum value I _{N_MAX} to the negative minimum value I _{N_MIN} of the signed current effective value. The slope was set suddenly. The other current ranges (within the range from the negative side minimum value I _{N_MIN} to the positive side maximum value I _{P_MAX} ) are set in the same manner as in FIG.

  By performing voltage control according to the characteristics shown in FIG. 9, good voltage control can be performed when the voltage change at the end of the distribution line with respect to the current at the substation is larger on the reverse flow side than on the forward flow side.

  In the voltage-current characteristics of 90 relay, the setting range of the dead zone in Example 2 (FIG. 6), the steep slope degree in Example 3 (FIG. 9), and the range of the steep slope region are shown in FIG. It is not limited to FIG. 9 and is set arbitrarily.

  In the region where the current of the distribution line is small, the detection error is relatively large, and the calculation result of the phase difference calculation unit 12 in FIG. In addition, hunting between forward and reverse flow may occur due to a small current change. Therefore, in the fourth embodiment, as shown in FIG. 10, the positive current effective value calculated by the current effective value calculation unit 11 is added to the input of the reverse flow relay 23, and the characteristics of the reverse flow relay 23 are plotted on the horizontal axis. As shown in FIG. 11, which represents a complex plane with the real axis as the real axis and the vertical axis as the imaginary axis, a characteristic having a dead zone is obtained when the phase difference between the voltage and current is 90 degrees or more and the current effective value is smaller than the set value. . In this dead zone region, it is determined that the current is a forward tide and “1” is output.

  Thus, by making the characteristic of the reverse flow relay 23 the characteristic of FIG. 11 having a dead zone, the reverse flow relay 23 is prevented from erroneously determining the flow direction due to the error. Moreover, it is possible to prevent hunting of forward / reverse flow determination caused by a minute current change, and it is possible to prevent unnecessary notification when a reverse flow occurrence is output as an alarm.

  Even if a dead zone is provided in the characteristics of the reverse flow relay 23 as shown in FIG. 11, since the dead zone is a range where the current is small, the target voltage does not change so much in the voltage-current characteristics of the 90 relay. There is no problem with doing this.

  In the fifth embodiment, instead of setting the power flow direction determination result of the reverse power flow relay to output positive and negative signs as in the first to fourth embodiments, as shown in FIG. By using it as the 90 relay characteristic switching signal of the voltage calculation unit, the effect of the present invention can be obtained without extending the effective current value to the negative side. 12, the same parts as those in FIGS. 2 and 10 are denoted by the same reference numerals.

  Reference numeral 30 denotes a target voltage calculation unit in the 90 relay, which receives the current (unsigned effective value) calculated by the current effective value calculation unit 11 and outputs a target voltage in accordance with the voltage-current characteristics of the 90 relay.

As shown in FIG. 13, the voltage-current characteristics of the 90 relay used in the target voltage calculation unit 30 have two types of characteristics, a forward power flow and a reverse power flow. 6 is set to a characteristic that increases from the first minimum setting value corresponding to the positive-side minimum setting value I _{P_MIN} to the first maximum setting value corresponding to the positive-side maximum setting value I _{P_MAX} . The characteristic decreases from the second minimum setting value corresponding to the absolute value of the negative side minimum setting value I _{N_MIN} shown in the negative current region to the second maximum setting value corresponding to the absolute value of the negative side maximum setting value I _{N_MAX.} Settling.

In addition, the range from the first minimum set value corresponding to I _{P_MIN} in the forward flow characteristics to zero current, and the range from the second minimum set value corresponding to the absolute value of I _{N_MIN} in the reverse flow characteristics to zero current Is set as a region where the output voltage is not increased or decreased (dead zone).

  Therefore, the forward flow characteristic in FIG. 13 is equivalent to the voltage characteristic in the positive current region in FIG. 6, and the reverse flow characteristic is equivalent to the voltage characteristic in the negative current region in FIG.

  33 determines the direction of the power flow based on the phase difference calculated by the phase difference calculation unit 12 or based on the positive current effective value calculated by the phase difference and the current effective value calculation unit 11, A characteristic switching command (switching signal) is output according to the determination result. When the determination result is a forward power flow, the 90 relay characteristic of the target voltage calculation unit 30 is switched to the forward power flow characteristic, and when the determination result is a reverse power flow This is a reverse flow relay that switches the 90 relay characteristic of the target voltage calculation unit 30 to the reverse flow characteristic.

  When the input to the reverse flow relay 33 is only the output of the phase difference calculation unit 12, the relay characteristics shown in FIG. 3 are obtained. Further, when the input of the reverse power relay 33 is the output of both the effective current value calculation unit 11 and the phase difference calculation unit 12, the relay characteristic having the dead band shown in FIG. It is determined to be a tidal current.

  By configuring as described above, the effect of the present invention can be obtained with the conventional calculation method without a sign in the effective current value.

  Note that the slope degree of the voltage-current characteristics (forward power flow characteristics, reverse power flow characteristics) of the 90 relay set in the target voltage calculation unit 30 is arbitrarily set. For example, the reverse flow characteristic shown in FIG. 13 may be set abruptly like the voltage characteristic in the negative current region shown in FIG.

  In the above embodiment, the reverse power flow determination of the reverse power relays 13 and 23 is performed on the left side of the complex plane of FIGS. 3 and 11, that is, when the phase difference between the voltage and the current is 90 degrees or more (in FIG. 11, the dead zone is excluded) (Part) was determined to be a reverse current.

  Actually, in the relay calculation (the calculation of the phase difference calculation unit 12), an error is included in the phase angle calculation result, and thus there is a possibility that an erroneous power flow determination is performed.

  For example, in FIG. 14 showing the phase difference between voltage and current on the complex plane, when the true phase angle of the current I is point A, the point B is calculated by the calculation error of the phase difference calculation unit 12. Even though it is a forward tide, it is determined to be a reverse tide.

  Therefore, in the sixth embodiment, as shown in FIG. 15 showing the characteristics of the reverse flow relay on the complex plane, a margin is provided for the determination phase angle on the reverse flow side, and the phase difference between the voltage and the current is 90 ° + α ° (α It was determined that the reverse flow was determined when the angle was greater than the set tolerance (°), and the forward flow was determined otherwise.

  In addition, in the relay characteristics with a dead band as shown in FIG. 11, as shown in FIG. 16 showing the characteristics of the reverse power relay on the complex plane, the judgment phase angle on the reverse power side is given a margin, and the voltage and current When the phase difference is 90 ° + α ° (α ° is a set tolerance) or more, it is determined that the current is a reverse power flow, and in other cases, it is determined that the current is a forward power flow.

  As shown in FIGS. 15 and 16, the phase angle on the reverse power flow side has a tolerance α ° (the characteristic of the reverse power relay is a characteristic offset by α ° on the reverse power flow detection side). Even when the true phase angle of the current I is the point A as described above, even if the phase calculation unit 12 calculates the point B, the reverse flow relay erroneously determines that the current is a reverse flow. There is no.

  The margin α ° is set in consideration of a further phase error due to frequency variation based on the phase management value of the fundamental wave characteristic, for example.

DESCRIPTION OF SYMBOLS 11 ... Current effective value calculating part 12 ... Phase difference calculating part 13, 23, 33 ... Reverse power flow relay 14 ... Multiplier 30 ... Target voltage calculating part

Claims (12)

A device for controlling the voltage of the distribution line by switching the taps of the transformer connected to the primary system on the primary side and to the distribution system on the secondary side,
A phase difference calculating unit for calculating a phase difference between current and voltage of the distribution line;
A current effective value calculation unit for calculating an effective value of the current of the distribution line;
The direction of the tidal current is determined based on the phase difference calculated by the phase difference calculator, and a positive sign is output when it is determined to be a forward power flow, and a negative sign is output when it is determined to be a reverse power flow. A reverse power relay to output,
Signed current effective value obtained by multiplying the current effective value calculated by the current effective value calculation unit by a positive or negative sign output from the reverse power relay, and the input signed current effective value The set value of the target output voltage with respect to is set to a voltage characteristic that rises from the negative maximum set value of the signed current effective value to the positive maximum set value, and the voltage that switches the tap of the transformer according to the target output voltage A relay for adjustment,
A voltage control device for a distribution line, comprising: A device for controlling the voltage of the distribution line by switching the taps of the transformer connected to the primary system on the primary side and to the distribution system on the secondary side,
A phase difference calculating unit for calculating a phase difference between current and voltage of the distribution line;
A current effective value calculation unit for calculating an effective value of the current of the distribution line;
Inverse to determine the direction of power flow based on the phase difference calculated by the phase difference calculation unit and to output a switching signal for switching the settling characteristics of the voltage adjustment relay according to the determination result of forward power flow or reverse power flow Tidal current relay,
The current effective value calculated by the current effective value calculation unit is input, and the set value of the target output voltage with respect to the input current effective value increases from the first minimum current set value to the first maximum current set value. Forward power characteristics or reverse power characteristics that are set by the second minimum current setting value and the reverse power characteristics that decrease from the second maximum current setting value and are switched by the switching signal from the reverse power relay. A voltage adjusting relay that switches the tap of the transformer according to a target output voltage of the characteristic;
A voltage control device for a distribution line, comprising:   The reverse power flow relay determines the direction of power flow based on the phase difference calculated by the phase difference calculation unit and the current effective value calculated by the current effective value calculation unit. The voltage control apparatus of the distribution line of 2.   The voltage control of a distribution line according to any one of claims 1 to 3, wherein the phase difference calculation unit, the current effective value calculation unit, and the reverse power flow relay are built in the voltage adjustment relay. apparatus.   5. The output voltage settling value of the voltage adjusting relay is set to a region in which the output voltage is not increased or decreased in a setting range in which the input current is close to zero. Distribution line voltage control device.   6. The distribution according to claim 1, 3, 4, or 5, wherein the output voltage set value of the voltage adjusting relay has a slope changed between a positive side and a negative side of the signed current effective value. Electric wire voltage control device.   The distribution line according to any one of claims 2 to 5, wherein the output voltage settling value of the voltage adjusting relay changes a degree of gradient between the forward flow characteristic and the reverse flow characteristic. Voltage control device.   The said reverse power relay determines that it is a reverse power flow when the said phase difference is 90 degree | times or more, The voltage control of the distribution line of Claim 1 or 2 or 4 or 5 or 6 or 7 characterized by the above-mentioned. apparatus.   8. The reverse power relay according to claim 3, wherein the reverse power relay determines that the current is a reverse power flow when the phase difference is 90 degrees or more and the effective current value is a set value or more. The voltage control apparatus of the distribution line as described in a term.   The reverse power relay determines a reverse power flow when the phase difference calculated by the phase difference calculation unit is 90 ° + α ° (α ° is a set tolerance) or more, and otherwise determines a forward power flow. The voltage control device for a distribution line according to any one of claims 1 to 7, wherein: The set value of the target output voltage with respect to the input current is set to a voltage characteristic that rises from the maximum negative set value to the maximum positive set value of the input current, and the primary side is connected to the upper system and the secondary side is connected to the distribution system. A voltage control method in an apparatus for controlling a voltage of a distribution line, comprising a voltage adjusting relay for switching a tap of a transformer,
A phase difference calculating step in which a phase difference calculating unit calculates a phase difference between the current and voltage of the distribution line;
A current effective value calculation step in which the current effective value calculation unit calculates the effective value of the current of the distribution line; and
The reverse power relay determines the direction of the power flow based on the phase difference calculated in the phase difference calculation step, and outputs a positive sign when it is determined to be a forward power flow, and is determined to be a reverse power flow. When outputting a negative sign,
A multiplier that multiplies the current effective value calculated in the current effective value calculating step by a positive or negative sign output from the reverse flow relay and outputs a signed current effective value;
The voltage adjusting relay has the output of the output signed current effective value as an input, and switches the tap of the transformer according to a target output voltage set according to the input current;
A voltage control method for a distribution line, comprising: The forward flow characteristic in which the set value of the target output voltage with respect to the input current increases from the first minimum current setting value to the first maximum current setting value, and from the second minimum current setting value to the second maximum current setting value. Voltage in a device for controlling the voltage of a distribution line, which is provided with a voltage adjustment relay that switches between taps of a transformer that is set to a reverse power flow characteristic that is connected to the upper system on the primary side and to the distribution system on the secondary side. A control method,
A phase difference calculating step in which a phase difference calculating unit calculates a phase difference between the current and voltage of the distribution line;
A current effective value calculation step in which the current effective value calculation unit calculates the effective value of the current of the distribution line; and
Switching for reverse power flow relay to determine the direction of power flow based on the phase difference calculated in the phase difference calculation step, and to switch the setting characteristics of the voltage adjustment relay according to the determination result of forward power flow or reverse power flow Outputting a signal;
The voltage adjusting relay has the effective value calculated in the current effective value calculating step as an input, and corresponds to a target output voltage of a forward flow characteristic or a reverse flow characteristic switched by a switching signal output from the reverse flow relay. Switching the transformer taps;
A voltage control method for a distribution line, comprising:

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