JP2019097325A - Calculation apparatus for voltage control, calculation method for voltage control, and calculation program for voltage control - Google Patents

Abstract

To prevent in advance a setting of setting values that are not appropriate.SOLUTION: The calculation apparatus for voltage control for calculating a settling value used to control a voltage at a control target point of a distribution system includes a settling value calculation pre-processing unit and a settling value calculation unit. The settling value calculation pre-processing unit compares values obtained by statistical processing using measurement data including active power and reactive power at a measurement point or real and imaginary parts of a current value at the measurement point with a threshold, and determines whether an appropriate settling value can be calculated. When determined that any appropriate settling value cannot be calculated, a fixed value is used as a settling value. If the settling value calculation pre-processing unit determines that an appropriate settling value can be calculated, the settling value calculation unit calculates the settling value.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a calculation device for voltage control, a calculation method for voltage control, and a calculation program for voltage control.

  In the power distribution system, voltage control devices such as a load ratio control transformer (LRT) and a step voltage regulator (SVR) are installed. The voltage control device adjusts the voltage of the distribution line on the load side by controlling the transformation ratio on the secondary side of the built-in transformer with a tap operation.

  When the installation position of the voltage control device (also described as an installation point) is apart from the position where the value of the voltage is to be compensated (also described as a control target point), the voltage of the control target point is between these two positions The voltage output from the voltage control device changes due to the impedance of the line in the circuit and the voltage drop or rise caused by the load current. Therefore, even if the secondary side voltage of the voltage control device is maintained at a constant value, the voltage fluctuates due to load fluctuation at the control target point from the voltage control device via the impedance.

  FIG. 1 illustrates the change in voltage on the line between the installation point and the control target point. In FIG. 1, there is a case where there is a line voltage drop compensator (LDC: Line Drop Compensator) for maintaining the voltage at the control target point within a certain range from the value of the target voltage (also described as target voltage). The change of the voltage when there is no is shown. The target voltage is, for example, 6600 V, and the predetermined range here is, for example, a range of 2% to 5% of 6600 V. The voltage in this range is also referred to as a control target voltage.

Also shown in FIG. 1 are the changes in voltage at high and low loads on the line. When there is no LDC, the voltage at the control target point has a deviation of V _d1 from the target voltage at light load, and a deviation of V _d2 from the target voltage at heavy load. Note that V _d1 <V _d2 . The LDC raises and lowers the voltage at the installation point depending on the load on the line. Therefore, as shown in FIG. 1, in the presence of the LDC, the voltage at the control target point is a target voltage or a voltage within a certain range from the target voltage both at light load and at heavy load.

An example of voltage control in LDC will be briefly described. The secondary voltage value of the voltage control devices V, the current through the voltage control devices (also passing current described) to _{I (I = I re + jI} im), the impedance of the control target point Z (Z = r + jx) Then, the voltage V _{r at} the control target point is approximately calculated from the following equation 1.

Here, I _re is a real part of the passing current and represents an effective current, and I _im is an imaginary part of the passing current and represents a reactive current. Also, j represents an imaginary unit. Also, r represents a resistance, and jx represents a reactance. Moreover, all the units here are pu values by reference voltage [kV] and reference capacity [kVA].

As the voltage V _r of the control target point calculated by the equation (1) becomes the control target voltage V _ref, LDC controls the secondary voltage of the voltage control devices. Therefore, the LDC controls the transformation ratio so that the secondary side voltage value V of the voltage control device satisfies the following equation 2 so that V _r = V _ref .

  Here, since the control target point is not necessarily on the distribution line, the ratio of r and x of the impedance of the control target point may not be equal to the ratio of r and x of the distribution line impedance. This is the same in the following description.

In the equations (1) and (2), x, r, and V _ref are parameters of the voltage control device set by the LDC before control by the voltage control device, and these values are called settling values. In the following, these x, r, and V _ref will be described as settling value parameters. In addition, these values and x, r, and V _ref when each of these parameters is entered are also described as settling values. As a method of calculating the settling value, there is known a method of obtaining it by a calculation formula using the secondary side voltage of the voltage control device under heavy load, the passing current and the target voltage (Non-Patent Document 1).

  On the other hand, in recent years, the introduction of renewable energy to distribution systems is expanding. However, Non-Patent Document 1 does not necessarily take into consideration the power factor change due to the introduction of such renewable energy and the voltage rise during reverse tide. As a method that takes these into consideration, there is a method that calculates the settling value by performing multiple regression analysis using data from sensors in the distribution system, etc. and data in a designated period including heavy load and reverse tide. Proposed. For example, the ideal secondary side voltage of the voltage control device is calculated using the secondary side voltage of the voltage control device at each time and the voltage distribution of the node on the load side, and using the time-series passing current, A method has been proposed in which multiple regression analysis is performed so that the ideal secondary voltage of the voltage control device matches the right side of Equation (2) (Patent Document 1).

JP, 2010-220283, A

Sekine Yuji, "Distribution Technology Comprehensive Manual", Ohmsha, 1991, p. 391-397

  However, when the voltage at the control target point is estimated from the settling values such as r and x using Equation 1, the following problems occur.

  First, if the correlation between the active power and the reactive power of the power input to the voltage control device is strong, the settling values r and x can not be calculated properly, so the voltage at the control target point is properly adjusted. It can not be estimated.

  Second, if the ratio between the active power and reactive power input to the voltage control device is significantly different, the estimation error of a large ratio component (for example, the real power or the real part of the passing current), the influence of noise, etc. As a result, the coefficient (for example, the settling value x) of a small ratio component (for example, reactive power or the imaginary part of the passing current) can not be properly calculated, whereby the voltage of the control target point can not be appropriately estimated.

  The former may occur when, on the secondary side of the voltage control device, most of the consumers are loads or power sources with a constant power factor. In such a case, since the active power and the reactive power change at a substantially constant rate, a strong correlation is recognized between them. And this appears as a problem of multicollinearity in the calculation of the respective coefficients (setting values r, x) related to the effective current and the reactive current, whereby, in a linear form such as equation 1 or equation 2 The coefficients (setting values r and x) of the active current and the reactive current can not be calculated properly. As a result, the voltage at the control target point can not be properly estimated. Note that multicollinearity refers to a state in which calculation can not be performed correctly because strong correlations between variables are recognized.

  The latter may occur when, for example, the output value or the amount of change of the active power becomes very large compared to the output value or the amount of change of the reactive power due to the increase of the renewable energy. In such a case, the reactive power is affected by the estimation error of active power, noise, and the like, and the settling value x, which is a coefficient of reactive current (imaginary part of the current), can not be uniformly determined. As a result, the voltage at the control target point can not be properly estimated.

  On the secondary side of the voltage control device, the settling value r, x should be a positive value for reasons such as voltage drop due to resistance in the distribution system, but from the above, at least the settling value r, x One of the cases may occur when it is calculated as a negative value outside the setting range of the voltage control device or the like.

  From the above, it is necessary to examine the power (or current) etc. and verify whether or not the appropriate value can be obtained in the calculation of the settling value r, x, or when it is considered that the appropriate settling value can not be obtained Needs to consider what measures to take.

  A voltage control calculation device that calculates a settling value used to control a voltage at a control target point of a distribution system includes a settling value calculation pre-processing unit and a settling value calculation unit. The settling value calculation pre-processing unit compares the threshold value with the value obtained by statistical processing using active power and reactive power at the measurement point, or measurement data including the real part and imaginary part of the current value at the measurement point. If it is determined that an appropriate settling value can be calculated, and if it is determined that an appropriate settling value can not be calculated, the settling value is set as a fixed value. The settling value calculation unit calculates the settling value when it is determined by the settling value calculation pre-processing unit that the appropriate settling value can be calculated.

  According to one aspect of the present invention, it is possible to prevent the setting of improper settling values.

It is a figure which illustrates the change of the voltage in the track between the installation point and the control target point. It is a figure which illustrates the distribution system concerning an embodiment. The flow of the process by the settling value calculation pre-processing part of a settling value calculation apparatus is illustrated. It is a figure which illustrates the flow of the process which concerns on determination of the decision | availability of calculation of a suitable settling value which uses correlation analysis. It is a figure which shows an example of what represented the settling value r and x calculated using the voltage etc. in a distribution system. It is a figure which shows an example of the flow of the process by the settling value calculation apparatus in, when using a hypothesis test. It is a figure which shows an example of the flow of the process by the settling value calculation apparatus in, when using reliability. It is a figure which illustrates the hardware constitutions of a settling value calculation apparatus. It is a figure which illustrates the functional block of the settling value calculation apparatus which concerns on other embodiment. It is a figure which illustrates the picture outputted by an input-and-output part. It is a figure which illustrates the hardware constitutions of a settling value calculation apparatus.

  FIG. 2 illustrates the power distribution system 1 according to the present embodiment. The power distribution system 1 includes a voltage control device 2 and a settling value calculation device (voltage control calculation device) 3 and the like, and appropriately includes a load, a distributed power supply, and the like. Further, the power distribution system 1 may have one or more voltage measurement devices 4 on the secondary side. In FIG. 2, although the voltage control device 2 and the settling value calculation device 3 are shown separately from each other, they may be integrated. The thick lines in FIG. 2 indicate distribution lines, the dashed lines with arrows indicate the flow of data in the direction of the arrows, and the letters below the dashed lines with arrows indicate the data to be exchanged.

  The voltage control device 2 includes a measurement unit 20, a control unit 21, and a communication unit 22. The measuring unit 20 measures each phase of the secondary side voltage, the passing current (or power), the secondary side voltage and the passing current of the voltage control device 2. The data acquired by the measurement unit 20 and the points at which the data are measured will also be described as measurement data and measurement points, respectively.

  The measurement unit 20 transmits measurement data to the settling value calculation device 3 via the communication unit 22 and the communication network.

  The control unit 21 acquires the settling value from the settling value calculating device 3 via the communication network and the communicating unit 22, and controls the transformation ratio by LDC control based on the settling value to compensate the secondary side voltage.

  The communication unit 22 transmits measurement data to the settling value calculation device 3 through the communication network based on an instruction from the measurement unit 20 or the like. The communication unit 22 also outputs the settling value from the settling value calculation device 3 received via the communication network to the control unit 21. The communication network is, for example, the Internet, an intranet, or a dedicated line.

  The settling value calculation device 3 includes a communication processing unit 30, a storage unit 31, a settling value calculation pre-processing unit 32, a settling value calculation unit 33, and the like. The communication processing unit 30 exchanges information with the voltage control device 2 or the voltage measurement device 4 via a communication network. The communication processing unit 30 stores, in the storage unit 31, measurement data received from the voltage control device 2, data relating to a voltage received from the voltage measurement device 4, and the like. The communication processing unit 30 also transmits the settling value calculated by the settling value calculation unit 33 to the voltage control device 2.

  The storage unit 31 stores measurement data received from the voltage control device 2. The measurement data is held in the storage unit 31 for a fixed period. The predetermined period is, for example, one week, one month, one year, and the like.

  The settling value calculation pre-processing unit 32 reads measurement data in a designated period (for example, one day) from the storage unit 31, and executes settling value calculation pre-processing described later based on this. At this time, the settling value calculation pre-processing unit 32 determines whether or not the appropriate settling value can be calculated, and when the proper settling value can not be calculated, the settling value parameter corresponding to the settling value is determined. Give a fixed value. The appropriate settling value is a value in the setting range of the voltage control target device 2, and indicates an optimal settling value for controlling the voltage at the control target point to the control target voltage. In addition, that the settling value can be appropriately calculated means that the settling value calculation device 3 can calculate an appropriate settling value. Further, the fixed value is a predetermined value in the setting range of the settling value, and even if it is used as the settling value, the voltage at the control target point is a value that does not deviate from the control target voltage.

  The settling value calculation pre-processing unit 32 outputs the determination result, the settling value as a fixed value, and the like to the settling value calculation unit 33.

  The settling value calculation unit 33 calculates the settling value determined to be appropriately computable using the measurement data read from the storage unit 31 based on the processing by the settling value calculation pre-processing unit 32. The settling value calculation unit 33 transmits the calculated settling value or the settling value calculated as the fixed value by the settling value calculation pre-processing unit 32 to the voltage control device 2 via the communication processing unit 30 and the communication network.

  One or more voltage measurement devices 4 are installed on the secondary side, each measure the voltage at the installation position, and transmit the measured voltage to the settling value calculation device 3 via the communication network. At least one of the one or more voltage measuring devices 4 may be installed at the control target point.

  The communication processing unit 30 of the settling value calculation device 3 stores data of each voltage received from one or more voltage measurement devices 4 in the storage unit 31. Further, the settling value calculation pre-processing unit 32 reads these data from the storage unit 31 and determines whether or not the settling value can be appropriately calculated.

  The load in FIG. 2 is any node that consumes power, such as a consumer, connected to a distribution line on the secondary side. Further, the distributed power supply is a power supply which is distributed in the distribution system and supplies power to the distribution line.

  FIG. 3 illustrates the flow of processing by the settling value calculation pre-processing unit 32 of the settling value calculation device 3. The settling value calculation pre-processing unit 32 acquires measurement data in a designated period from the storage unit 31 (step S100).

  Subsequently, the settling value calculation pre-processing unit 32 performs statistical processing to be described later using the measurement data acquired in step S100, and determines whether or not the appropriate settling value can be calculated (step S101).

  Subsequently, the settling value calculation pre-processing unit 32 sets a fixed value for a settling value parameter for which an appropriate settling value can not be calculated. Then, the settling value calculation pre-processing unit 32 can calculate information on the settling value parameter for which the appropriate settling value can not be calculated, the fixed value to be set in the settling value parameter, the determination result in step S101, or the appropriate settling value. Information and the like of the settling value parameter are output to the settling value calculation unit 33 (step S102). As described above, information necessary for processing by the settling value calculation unit 33 and output from the settling value calculation pre-processing unit 32 to the settling value calculation unit 33 is also referred to as determination result information hereinafter. Describe.

  The statistical processing performed in step S101 is, for example, processing such as correlation analysis or hypothesis test, and the secondary side voltage of the voltage control device 2, real part and imaginary part (or active power and reactive power) of passing current, etc. The measurement is performed using information contained in the measurement data or derived from the measurement data.

  First, a process of performing correlation analysis to determine whether an appropriate settling value can be calculated will be described. In correlation analysis, active power and reactive power in measurement data or obtained from measurement data are used, and the presence or absence of a correlation between them is checked.

  When the correlation between the active power and the reactive power is strong, the independence of the variables from each other, which is the premise of the linear model, will be lost. That is, the variables active power and reactive power are not independent of each other. In such a case, the sign of the obtained settling value may be negative except for the setting target of the voltage control device 2, or one of the powers (for example, active power) is much more than the other power (for example, reactive power). The possibility of the other power receiving the influence of the noise from one power and the settling value related to the other power can not be calculated properly by becoming large, and there are innumerable candidates for the combination of the settling value r and x. It may not be possible to get an appropriate settling value.

  The settling value calculation pre-processing unit 32 according to the present embodiment uses the VIF (Variance Inflation Factor) statistic to determine whether or not there is a correlation between active power and reactive power. However, the statistic used is not limited to this.

  When the settling value calculation pre-processing unit 32 determines that there is a correlation between the active power and the reactive power, it sets, for example, 0 as a fixed value to the settling value parameter x. As a result, the settling value calculation pre-processing unit 32 excludes the settling value set as the fixed value from the target of the calculation process by the subsequent settling value calculation unit 33. In this case, the settling value calculation unit 33 sets the settling value of the settling value parameter x to 0 based on the determination result information from the settling value calculation pre-processing unit 32, and executes the process of calculating the settling value r.

  On the other hand, when the settling value calculation preprocessing unit 32 determines that there is no correlation between the active power and the reactive power, the settling value calculation unit 33 uses the determination result information from the settling value calculation preprocessing unit 32 as the determination result information. Based on the calculation processing of the settling values r and x.

  Hereinafter, the possibility of calculation of an appropriate settling value using correlation analysis will be described in detail. The settling value calculation pre-processing unit 32 calculates the correlation coefficient using the following equation (3).

Here, i is a continuous number of 1 <i <N, and corresponds to an index of measurement data in a designated period. Also, N corresponds to the total number of measurement data in a designated period, and P _i and Q _i correspond to active power and reactive power in the ith measurement data, respectively. Moreover, what attached "^" to the upper part of P and Q is the average value of N measurement data of active power and reactive power, respectively. Here, r in the equation (3) indicates a correlation coefficient, which is different from r of the settling value and the settling value parameter. In order to distinguish this correlation coefficient r from the settling value or the settling value parameter r, it may be described as R in the following. In the equation (3), the numerator shows the covariance of the active power and the reactive power, and the denominator shows the product of the standard deviation of the active power and the reactive power. The settling value calculation pre-processing unit 32 uses the correlation coefficient R to obtain the VIF statistic from the following equation 4.

Here, r corresponds to the correlation coefficient R.
The VIF statistic has a larger value as the correlation coefficient R is larger, that is, as the correlation coefficient R is closer to one. Generally, if the VIF statistic is greater than 10, then multicollinearity between active and reactive power is suspected. In such a case, the settling value calculation pre-processing unit 32 sets 0 as a fixed value to the settling value parameter x related to reactive power. Then, the settling value calculation pre-processing unit 32 outputs, to the settling value calculation unit 33, determination result information including the settling value x (= 0) and an instruction for calculating the settling value r related to the active power.

  On the other hand, when the VIF statistic is 10 or less, the settling value calculation pre-processing unit 32 determines that there is no multicollinearity between the active power and the reactive power, and the settling value calculation unit 33 based on the determination result. Calculates each settling value r, x regarding the active power and the reactive power.

  When the settling value calculation device 3 according to the present embodiment determines that there is a correlation between the active power and the reactive power, x is set to 0, and the reactive power is not calculated, and only the active power is calculated. Calculation (calculation of settling value r) is performed. The reason for this is that in the distribution system, the absolute value of the temporal variation of active power is larger than the absolute value of the temporal variation of reactive power. As a result, it is considered that the reactive power is affected by noise or the like from the active power, and the settling value x is not properly obtained.

  As described above, instead of setting the settling value x to 0, for example, the ratio between the settling value r and the settling value x is estimated at an arbitrary point on the distribution line, and the settling value r is estimated based on this estimated ratio. , X may be calculated. For example, the power factor on the customer side may be estimated and the settling values r and x may be calculated using this. Alternatively, with a certain point on the distribution line as an estimation point, the ratio r and x of the distribution line impedance at the estimation point may be used to calculate the settling values r and x.

  FIG. 4 exemplifies the flow of processing relating to the determination of whether or not calculation of an appropriate settling value is possible using correlation analysis. In step S200, the settling value calculation pre-processing unit 32 calculates a correlation coefficient R from active power and reactive power from measurement data in a designated period. Subsequently, the settling value calculation pre-processing unit 32 calculates a VIF statistic from the calculated correlation coefficient R (step S201).

  When the VIF statistic is 10 or less (step S202: NO), the settling value calculation pre-processing unit 32 determines that the settling values r and x can be appropriately calculated (step S203).

  On the other hand, when the VIF statistic is larger than 10 (step S202: YES), the settling value calculation pre-processing unit 32 determines that the settling value r or x can not be calculated appropriately. Then, the settling value calculation pre-processing unit 32 sets a fixed value (for example, 0) to the settling value parameter x (or r), and outputs an instruction for calculating the settling value r (or x) to the settling value calculation unit 33 (Step S204).

  The settling value calculation unit 33 calculates the settling value r, x based on the determination result of step S203, or the settling value x (= 0) (or r (= 0)) based on the determination result information based on step S204. Is calculated, and the settling value r (or x) which can be appropriately calculated is calculated (step S205). In addition, holding | maintenance here points out the thing of the fixed period for the output to the voltage control apparatus 2 of the fixed value made into the fixed value.

  The calculation of the settling value using the above correlation analysis is an effective method when the correlation between the active power and the reactive power is recognized. However, even when there is no correlation between active power and reactive power, it may not always be possible to calculate the settling value appropriately. For example, due to the large introduction of distributed power sources including renewable energy into the distribution system, the temporal variation of the active power can be very large compared to the temporal variation of the reactive power, which makes it ineffective against voltage variations. The influence of power may be very small, and it may be difficult to properly calculate the settling value x. In this case, it is necessary to estimate the voltage variation using a settling value r which is dominant for the voltage variation. As statistical processing used in this case, a hypothesis test may be used instead of the correlation analysis. This hypothesis test may also be used when there is a correlation between active power and reactive power.

  First, a linear model is given by the following equation 5 for the settling values r and x.

  Vc here is the voltage measured at the control target point or the estimated voltage. P and Q are respectively active power and reactive power at the measurement point. Also, b corresponds to a bias. Here, r, x, and b are targets of estimation for voltage control at the control target point, but r and x should be derived as settling values, and are easily understood in the following description. In some cases, b will be described as a constant value.

  This is used as Vc when the voltage at the control target point is measured, but a midpoint between the maximum value and the minimum value of the voltage on the secondary side of the voltage control device 2 may be used. Vc is obtained from the voltage obtained by each of all or part of the one or more voltage measurement devices 4 described above. Here, the voltage used as Vc is not limited to one value determined by the voltage acquired by each of all or a part of the one or more voltage measuring devices 4, and a plurality of values may be used. Further, each value of Vc which changes with time may be used.

  In order to conduct the hypothesis test, the settling value calculation pre-processing unit 32 measures the voltage Vc obtained from the voltage at each of the installation points measured by all or a part of the one or more voltage measuring devices 4 described above, and the measurement data The set values r and x are calculated using the electric power (or the passing current of the voltage control device 2), the equation (5) (or the equation 1), and the impedance obtained in advance, for example.

  FIG. 5 shows an example of the settling values r and x calculated using voltages and the like in the power distribution system as described above. The black points in FIG. 5 are points having coordinates of the settling value r, x (here, -x) calculated using the above equation (5), the value of power, the voltage in the distribution system, or the like. The settling value r, x is a value on a straight line with a slope of (−Q / P) according to Eq. 5 (in the case of the settling value r, −x, the value on a straight line with a slope of (Q / P)) It should be However, when Q is extremely small with respect to P, that is, when the reactive power is small with respect to the active power, as described above, x is not uniformly determined. In FIG. 5, α is shown as a straight line with a small Q relative to P, but it can be seen that x in this case can not be determined uniformly.

  The settling value calculation pre-processing unit 32 in the present embodiment calculates the standard deviation of each of the settling values r and x calculated using the voltage or the like in the distribution system as described above. Then, the settling value calculation pre-processing unit 32 derives a statistical distribution of settling values r and x from these standard deviations. In the present embodiment, this distribution is assumed to be t distribution. This t distribution is used in the hypothesis test described below.

  The settling value calculation pre-processing unit 32 uses a hypothesis test for the settling values r and x, and determines whether to set the settling values r and x as a calculation target based on the result of the hypothesis test. In this hypothesis test, either one of the settling values r and x is set to 0 as a null hypothesis H0 (a hypothesis expected to be denied). In addition, it is set as x = 0 as null hypothesis H0 here for easy understanding. The alternative hypothesis H1 for this is x ≠ 0.

  The settling value calculation preprocessing unit 32 determines whether or not the null hypothesis is rejected at the significance level of, for example, 1% in the t distribution. In other words, the settling value calculation pre-processing unit 32 determines whether the probability that the null hypothesis is satisfied in the t distribution is equal to or greater than the significance level, and if it is less than the significance level, the hypothesis Reject. In the above null hypothesis, x = 0. However, the present invention is not limited to this. The null hypothesis may be r = 0, or r or x may be another value.

  According to the hypothesis test, when H1 is adopted, it is determined that the settling values r and x can be appropriately calculated. On the other hand, when H0 is adopted, the settling value calculation pre-processing unit 32 sets the settling value x to 0, for example, and excludes it from the target of calculation processing, and sets the settling value r, for example, as the calculation target.

  FIG. 6 shows an example of the process flow of the settling value calculator 3 when using a hypothesis test.

  The settling value calculation pre-processing unit 32 calculates the settling values r and x using the value of the power at the measurement point, the data of the voltage (Vc) at the distribution line, and the like (step S300).

  The settling value calculation pre-processing unit 32 calculates each standard deviation of the settling values r and x calculated in step S300 (step S301).

  Subsequently, the settling value calculation pre-processing unit 32 derives these t distributions from the calculated settling values r and x and the respective standard deviations (step S302). The settling value calculation preprocessing unit 32 performs a hypothesis test based on the t distribution. In this hypothesis test, the null hypothesis is, for example, x = 0 (or r = 0), the significance level is, for example, 1%, and the settling value calculation preprocessing unit 32 determines whether to reject the null hypothesis (Step S303).

  If the null hypothesis is rejected (step S304: YES), the settling value calculation pre-processing unit 32 determines that the appropriate settling values r and x can be calculated (step S305). When the null hypothesis is not rejected (step S305), the settling value calculation pre-processing unit 32 fixes the settling value x (or r) to 0, and sets the settling value so as to calculate the other non-fixed settling value. An instruction is output to the calculation unit 33 (step S306).

  The settling value calculation unit 33 calculates the settling value or holds the fixed value in accordance with the determination result information output from the settling value calculation pre-processing unit 32 (step S307). Here, holding is assumed to be until the settling value calculation device 3 outputs the settling value set as the fixed value to the voltage control device 2.

  Confidence may be used instead of or in addition to the hypothesis test described above. In this case, respective confidence intervals of the settling values r and x are provided in advance. The reliability used here is the reliability of each of the settling values r and x, and indicates the ratio in which the settling values r and x calculated in step S300 are included in the confidence interval. The settling value calculation pre-processing unit 32 determines the reliability of each settling value from the t distribution and the confidence interval of each settling value, and when the reliability is equal to or more than a threshold, determines that appropriate calculation can be performed for the settling value If the reliability is smaller than the threshold, it may be determined that the settling value can not be properly calculated. Then, when it is determined that the appropriate settling value can not be calculated, the settling value calculation pre-processing unit 32 may set one of the settling value r and x as a fixed value such as 0.

  FIG. 7 is a diagram showing an example of the flow of processing by the settling value calculation device 3 when using the reliability as described above. Note that the flow in this case corresponds to that in which each process of steps S303, S304, and S306 in the flow shown in FIG. 6 is replaced with each process of steps S403, S404, and S406. For this reason, each process of step S403, S404, and S406 shall be demonstrated, and description about another process is abbreviate | omitted.

  The settling value calculation pre-processing unit 32 uses the t distribution of each settling value derived in step S302 to calculate the ratio in which each settling value obtained in step S300 is included in each confidence interval provided in advance. Then, the reliability of each settling value is obtained (step S403).

  The settling value calculation pre-processing unit 32 determines whether each reliability is a threshold, for example, 98 to 99% or more, and when each reliability of the settling values r and x is more than the threshold (see FIG. Step S404: YES), the process of step S305 is performed. On the other hand, when at least one of the reliability values of the settling values r and x is smaller than the threshold (step S404: NO), the settling value calculation pre-processing unit 32 determines the settling value for which the reliability is smaller than the threshold. Assuming that this can not be calculated appropriately, for example, a fixed value of 0 is set, and for a settling value whose reliability is equal to or higher than a threshold value, the settling value calculation unit 33 is instructed to calculate the settling value (step S406).

  Note that the method for determining whether the settling value calculation pre-processing unit 32 can calculate the appropriate settling value is not limited to the statistical method described above, and other methods for determining the presence or absence of correlation between active power and reactive power. And a method capable of determining the presence or absence of the influence of the active power and the reactive power on the voltage fluctuation.

  Next, the details of the process executed by the settling value calculator 33 will be described. As described above, the settling value calculation unit 33 sets only the settling value determined to be able to calculate an appropriate settling value by the settling value calculation pre-processing unit 32 as a calculation target. The settling value calculation unit 33 sets the settling value determined to be impossible to calculate an appropriate settling value as the fixed value given by the settling value calculation pre-processing unit 32 and is not a calculation target.

  In order to set the voltage at the control target point as the control target voltage, the settling value calculator 33 calculates settling values r and x at which the function value in the following equation 6 becomes minimum.

Here, F is an evaluation function, and t is time (t = 1 to T) in a designated period. Also, i is an index attached to the voltage at the control target point or the measurement point. Further, V ′ (i, t) is a voltage at a control target point when LDC control or the like is performed, and V _C is a target voltage.

  V '(i, t) is represented by the following equation 7 using the voltage V (i, t) at the measurement point at time t.

  Here, P (t) and Q (t) are the active power and the reactive power at the measurement point at time t, respectively, and d is the bias.

At this time, the control target voltage V _ref is expressed by the following equation 8.

  As described above, the target voltage Vc is, for example, 6600 V, and the bias d is, for example, about 2% to 5% of the voltage value.

  When it is determined by the settling value calculation pre-processing unit 32 that an appropriate settling value can be calculated, the settling value calculation unit 33 determines that Vc = 6600 V in the above equation 6, for example. A settling value r, x giving V ′ (i, t) that minimizes F (r, x) is calculated using equation 7 or the like.

  On the other hand, when it is determined that the settling value calculation pre-processing unit 32 can not calculate an appropriate settling value, the settling value calculation unit 33 determines that the settling value calculation pre-processing unit 32 does not set the settling value r as a fixed value. Perform the calculation for either or x. For example, when x is set to 0 by the settling value calculation pre-processing unit 32, the settling value calculation unit 33 calculates the settling value r by setting x to 0 in Equation 7 and the like.

  The settling value calculated in the settling value calculation unit 33 or the settling value set as the fixed value acquired from the settling value calculation pre-processing unit 32 by the settling value calculation unit 33 is controlled via the communication processing unit 30 described above. It is sent to the device 2. The voltage control device 2 controls the voltage based on the settling value received from the settling value calculation device 3.

  The processes by the settling value calculation pre-processing unit 32 and the settling value calculation unit 33 described above may be executed at timing when the user updates the settling value as needed. Further, the settling value calculation pre-processing unit 32 and the settling value calculation unit 33 update the settling value from the deviation degree of the voltage of the control target point detected or calculated in the designated period based on the accumulated measurement data etc. If it is determined whether or not it is necessary, and it is determined that this update is necessary, processing such as calculation of the settling value described above may be performed.

  FIG. 8 is a diagram illustrating the hardware configuration of the settling value calculation device 3. Here, the settling value calculation device 3 has hardware as a general computer, and the processing by the settling value calculation device 3 is executed by specifically using the hardware 5 shown below.

  The hardware 5 includes a processor 50, a memory 51, a communication interface circuit 52, a storage device 53, and the like connected to one another by a bus 54.

  The processor 50 is, for example, a single core, dual core, or multi-core processor.

  The memory 31 is, for example, a read only memory (ROM), a random access memory (RAM), a semiconductor memory, or the like, or a combination thereof.

  When the processor 50 uses information such as various programs stored in the memory 51, each function of the settling value calculation pre-processing unit 32 and the settling value calculation unit 33 can be realized.

  The communication interface circuit 52 is a circuit for the settling value calculation device 3 to exchange information with a device such as the voltage control device 2 via the Internet, an intranet, a dedicated line or the like.

  The function of the communication processing unit 30 can be realized by the processor 50 using the communication program or the like stored in the memory 51 or the storage device 53 via the communication interface circuit 52.

  The storage device 53 is, for example, a hard disk drive, an optical disk device, or the like, or a combination thereof, and may include a portable storage medium or the like. The storage device 53 can realize the functions of the storage device 31 described above.

  In addition to the case described above, all or some of the functions of the functional blocks of the settling value calculation device 3 shown in FIG. 2 may be realized by dedicated hardware as appropriate.

  According to the settling value calculation device 3 according to the present embodiment, it is possible to prevent in advance the setting of the settling value that is not appropriate, and it is possible to set the settling value according to the actual operation. Can be controlled to a more appropriate value.

<Other Embodiments>
When the settling value calculation device 3 described above is used, the user can not necessarily recognize each of the settling values r and x from the settling value calculation device 3. The settling value calculation device 3 'according to the present embodiment has a function for the user to confirm the settling values r and x obtained by the settling value calculation device 3'. In addition, the settling value calculation device 3 'may have a function of receiving a more appropriate settling value from the user and outputting the entered settling value to the voltage control device 2.

  FIG. 9 exemplifies a functional block of the settling value calculation device 3 ′ according to the present embodiment. The settling value calculation device 3 'further includes an input / output unit 34 and the like in the settling value calculation device 3 described above. Here, since the functional blocks other than the input / output unit 34 of the settling value calculation device 3 ′ are the same as those in the settling value calculation device 3 unless otherwise noted, the description thereof will be omitted.

After the settling value calculation unit 33 performs the processing such as calculation of the settling value as described above, the calculated settling value, or the settling value determined as a fixed value, and the determination result from the settling value calculation pre-processing unit 32 The determination result included in the information is output to the input / output unit 34. Note that, as described above, this determination result is a determination result regarding whether or not the appropriate settling value can be calculated. Further, the settling value calculation unit 33 calculates the voltage V _ref which is the voltage at the control target point when the calculated settling value is used and which is the control target voltage, and sends it to the input / output unit 34. Output.

  The input / output unit 34 includes a display device using, for example, a liquid crystal or a CRT (Cathode Ray Tube). The input / output unit 34 also includes input devices such as a keyboard and a touch panel.

  The input / output unit 34 processes the information such as the settling value output from the settling value calculation unit 33 into an image recognizable by the user, and displays the image.

FIG. 10 illustrates an image output by the input / output unit 34. In FIG. 10, the images (1) to (3) are displayed on the display screen separately or adjacent to each other in the present embodiment. In addition, although these (1)-(3) are images of a tabular form, respectively, it is not limited to this. In each of these (1) to (3), "determination" means the determination result of the appropriateness of calculation of the settling value, and "-", "O", "x" in the row of "determination" Each of these shows that it is undecided whether the calculation of a suitable settling value is possible, that a suitable settling value can be calculated, and that a suitable settling value can not be calculated. Further, r and x in (1) to (3) represent settling values r and x output from the settling value calculation unit 33, respectively. Similarly, V _ref represents the voltage at the control target point output from the settling value calculator 33.

Here, the image of (1) corresponds to one in the case where the settling value is undecided and the like, and the input / output unit 34 does not input information such as the settling value. Here, "-" is shown in each row of "judgement", "V _ref ", "r" and "x".

  The images of (2) and (3) correspond to images when there is a transition from the state of (1).

The image of (2) corresponds to the case where it is determined that the calculation of the appropriate settling value is impossible, and in this case, a predetermined fixed value is given to x. Also, in this case, it is found that the settling value r is b (b: positive real number), and the voltage V _ref at the control target point calculated from the settling value r is a (a: positive real number) I understand.

The image of (3) corresponds to an image having a determination result that the calculation of an appropriate settling value is possible. Here, it can be seen that d and e (d and e: positive real numbers) are calculated as the settling values r and x, respectively. Further, it is understood from these d and e that the voltage V _ref at the control target point is c (c: positive real number).

By visually recognizing the image of (1), the user can instruct the settling value calculation device 3 'to execute calculation of settling value and the like via the input device. In addition, the user can confirm whether or not the appropriate settling value or the like by the image of (2) or (3). If the user determines from the image in (2) or (3) that the settling value is not a suitable settling value, the user can change the settling value or the value of the voltage V _ref via the input device.

The changed settling value or the value of the voltage V _ref or an instruction to calculate the settling value is output to the settling value calculator 33 as shown in FIG.

When the settling value calculation unit 33 acquires an instruction such as calculation of settling value from the user via the input / output device 34, the setting value calculation unit 33 outputs the instruction to the settling value calculation preprocessing unit 32. In response to this instruction, the settling value calculation pre-processing unit 32 reads the measurement data from the storage unit 31, executes the determination processing as described in the above embodiment, and calculates the settling value of the determination result information including the determination result by this. Output to section 33. The settling value calculation unit 33 executes processing such as calculation of settling value in the same manner as described above based on the determination result information. The settling value calculation unit 33 outputs the settling value obtained thereby to the communication processing unit 30, and also outputs this settling value, the value of the voltage V _ref obtained from this settling value, and the like to the input / output unit 34. . The communication processing unit 30 notifies the voltage control device 2 of the settling value output from the settling value calculation unit 33, and the input / output unit 34 displays the settling value etc. output from the settling value calculation unit 33.

When the settling value calculation unit 33 acquires the value of the voltage V _ref from the user via the input / output device 34, it calculates a settling value that can be appropriately calculated based on the determination result information and the voltage value. Further, the settling value obtained by this calculation processing is output to the communication processing unit 30 and the input / output unit 34. The subsequent processes by the communication processing unit 30 and the input / output unit 34 are the same as described above.

  When the settling value calculation unit 33 newly acquires a settling value from the user via the input / output device 34, the settling value calculation unit 33 outputs this to the communication processing unit 30. The subsequent processing by the communication processing unit 30 is similar to that described above.

  FIG. 11 is a diagram illustrating the hardware configuration of the settling value calculation device 3 ′ according to this embodiment. The settling value calculation device 3 'has hardware as a general computer as in the above embodiment, and the processing by the settling value calculation device 3' is performed by specifically using the hardware 5 'shown below. To be executed.

  The hardware 5 ′ corresponds to the hardware 5 in the above embodiment with the user interface circuit 55 further added. The components other than the user interface circuit 55 are the same as those described above, and thus the description thereof is omitted.

  The user interface circuit 55 is a circuit for connecting an output device such as the display as described above, an input device such as a keyboard, etc. to the settling value calculation device 3 ′. The function of the input / output unit 55 is realized by the user interface circuit 55 and the input device and the output device connected thereto.

  According to the present embodiment, the user can confirm the settling value and the like used for voltage control. And thereby, it becomes possible for a user to select a better settling value etc., and more appropriate voltage control can be performed.

DESCRIPTION OF SYMBOLS 1 Power distribution system 2 Voltage control apparatus 3, 3 'setting value calculation apparatus 4 Voltage measurement apparatus 5, 5' hardware 20 Measurement part 21 Control part 22 Communication part 30 Communication processing part 31 Storage part 32 Sett value calculation pre-processing part 33 Settling Value calculation unit 34 Input / output unit 50 Processor 51 Memory 52 Communication interface circuit 53 Storage device 54 Bus 55 User interface circuit

Claims (9)

A voltage control computing device for calculating a settling value used to control a voltage at a control target point of a distribution system,
A value obtained by statistical processing using measurement data including active power and reactive power at the measurement point or real part and imaginary part of the current value at the measurement point is compared with a threshold, and the appropriate settling value is It is determined whether or not calculation is possible, and when it is determined that the appropriate settling value can not be calculated, a settling value calculation pre-processing unit that sets the settling value as a fixed value;
A settling value calculation unit that calculates the settling value when it is determined by the settling value calculation pre-processing unit that the appropriate settling value can be calculated;
A voltage control computing device comprising: The statistical process is
The process of analyzing the correlation between the active power and the reactive power at the measurement point, or the process of analyzing the correlation between the real part and the imaginary part of the current value at the measurement point,
The settling value calculation pre-processing unit
It is determined that the appropriate settling value can not be calculated if the statistic indicating the correlation is larger than the threshold value. The statistical process is
Including a process of deriving a statistical distribution of the settling values using voltages in the distribution system and values of active power and reactive power at the measurement points,
The settling value calculation pre-processing unit
Based on the statistical distribution of the settling value, it is determined whether the probability that the hypothesis that the settling value is a predetermined value holds is equal to or more than the threshold value.
When the probability is equal to or more than the threshold value, it is determined that the appropriate settling value can not be calculated, and the settling value is set to the fixed value equal to the predetermined value. Voltage control computing device as described. The statistical process is
A process of deriving a statistical distribution of the settling value using voltages in the distribution system and values of active power and reactive power at the measurement point, and deriving the reliability of the settling value based on the distribution Including
The settling value calculation pre-processing unit
The voltage control calculation device according to claim 1, wherein it is determined that the appropriate settling value can not be properly calculated when the reliability is smaller than the threshold.   The voltage control calculation device according to any one of claims 1 to 4, wherein the fixed value is 0. The voltage control calculation device further includes:
The voltage control calculation apparatus according to any one of claims 1 to 5, further comprising: an output unit that displays the settling value and a voltage at a control target point calculated using the settling value. . The voltage control calculation device further includes:
It has an input unit for receiving an instruction for changing the settling value or the voltage displayed by the output unit,
The voltage control calculation device according to claim 6, wherein the settling value calculation unit derives the settling value based on the instruction. A voltage control calculation method for calculating a settling value used to control a voltage at a control target point of a distribution system, comprising:
A value obtained by statistical processing using measurement data including active power and reactive power at the measurement point or real part and imaginary part of the current value at the measurement point is compared with a threshold, and the appropriate settling value is If it is determined whether calculation is possible and it is determined that the appropriate setting value can not be calculated, the setting value is set as a fixed value,
A calculation method for voltage control to be executed by a voltage control calculation device, which calculates the settling value when it is determined that the appropriate settling value can be calculated. A program for calculating a settling value used to control a voltage at a control target point of a distribution system,
A value obtained by statistical processing using measurement data including active power and reactive power at the measurement point or real part and imaginary part of the current value at the measurement point is compared with a threshold, and the appropriate settling value is If it is determined whether calculation is possible and it is determined that the appropriate setting value can not be calculated, the setting value is set as a fixed value,
A voltage control calculation program for causing a voltage control calculation device to execute a process of calculating a settling value when it is determined that the appropriate settling value can be calculated.

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