JP6468953B2 - Connection phase determination method, determination device, and determination program - Google Patents

Description

  The present invention relates to a connection phase determination method, a determination device, and a determination program. More specifically, the present invention relates to a technique suitable for use in changing the connection phase of a pole transformer already installed in a distribution line of a distribution system or selecting a connection phase of a pole transformer to be newly installed. .

  A pole transformer is provided between the power distribution system and the customer, and basically power is transmitted to the customer via the pole transformer. As such a pole transformer, specifically, for example, there is a primary bushing and a secondary bushing at the upper part of the side surface of the transformer case, and the voltage of the distribution system is connected to the primary bushing and There is one which performs voltage transformation and transmits power to a customer by secondary bushing (Patent Document 1). A plurality of pole transformers are provided in the three-phase distribution line, and are connected to any two phases of the three phases in the three-phase distribution line. At this time, if multiple pole transformers are connected in a specific two-phase configuration among the three phases of the three-phase distribution line, the reverse phase voltage of the three-phase distribution line increases, There is a possibility that the degree of unbalance of the phase alternating voltage increases.

JP 2012-216567 A

  In recent years, the interconnection of distributed power sources such as solar power generation facilities has been expanding mainly in the distribution system. Since photovoltaic power generation is also spreading to detached houses, the connection to single-phase low-voltage systems is increasing. On the other hand, all electrification of detached houses is widespread, and large-capacity loads such as electric water heaters and heat pump water heaters are connected to a single-phase low-voltage system.

  Under these circumstances, the distribution line voltage is expected to be three-phase unbalanced, so power companies have been implementing power management and voltage management for power distribution systems. Management methods that assume voltage three-phase balance may not be sufficient. In addition, the output of solar power generation is affected by the weather, and the state of voltage three-phase imbalance changes from time to time, such as water heaters increasing the load in the morning, making management extremely difficult. As described above, there is a problem that the three-phase voltage balance may not be maintained in the phase management that has been performed by the electric power company to maintain the voltage balance.

  As a specific example where voltage three-phase unbalance is a problem, for example, voltage control devices in the distribution system often monitor only the voltage of the representative phase, so when voltage three-phase unbalance occurs. An example is that the monitoring phase may maintain the proper voltage, but the other phases may deviate from the proper voltage. In addition, it has been confirmed that voltage three-phase imbalance causes motor stoppage and failure.

  On the other hand, although electric power companies have begun installing switches with a three-phase measurement function for the purpose of grasping the actual situation of voltage three-phase imbalance, the specific equipment configuration method using measurement data obtained by these devices is clear Not been.

  Therefore, the present invention eliminates a great deal of effort and requires a large mechanism for connecting phases to which pole transformers should be connected in order to correct voltage three-phase imbalance in distribution lines. It is an object of the present invention to provide a connection phase determination method, a determination device, and a determination program that can be easily determined.

  The inventor investigated the mechanism of occurrence of the voltage three-phase unbalance as follows, while examining the method of determining the connection phase of the pole transformer to correct the voltage three-phase unbalance. In the description of the present invention, the phases of the three-phase AC power supplied from the distribution substation to the distribution lines are referred to as A phase, B phase, and C phase. The B phase is a phase delayed by 120 ° from the A phase, and the C phase is a phase delayed by 120 ° from the B phase.

(1) Basic analysis First, analysis was performed using the high-voltage distribution line model shown in FIG. This model is generally used for various evaluations related to distribution lines, and is a standard residential area model of the Electric Cooperative Study Group (General Electric Corporation Electric Cooperative Study Group “High Voltage Power Receiving Equipment” "Current Status and Countermeasures for Harmonic Problems in Japan", Vol. 54, No. 2, 1998).

  In the residential area model of the Electric Cooperative Society, the line type is determined, but the line impedance for three-phase unbalance calculation is not determined. Therefore, the unbalanced line impedance in the delta arrangement shown in FIG. 5 was used. In the delta arrangement, since the distance between the wires is equal, it is generally confirmed that the unbalance of the line impedance is small.

At the end of the distribution line of the high-voltage distribution line model in FIG. 4, an all-electric apartment with a load curve as shown in FIG. 6, for example, a morning (or late-night) load such as a heat pump water heater and solar power The case where the simulated load is connected as in the following patterns 1 to 3 is set. The power factor of the load was set to 1.
Pattern 1: Connect to CA phase only (no connection load for other phases)
Pattern 2: Connected to BC phase and CA phase (no connection load on other phases)
Pattern 3: Connected to all of the AB phase, BC phase, and CA phase

1) Pattern 1: Analysis result when connected to CA phase only Under basic analysis conditions, in the morning (late night) when the morning (late night) load is applied, the line voltage rises in the BC phase as shown in FIG. 7A. , AB phase and CA phase decreased. Further, as shown in FIG. 7B, the phase voltage did not change, the C phase voltage slightly decreased, and the A phase voltage significantly decreased.

  This mechanism can be explained as follows. That is, when a load having a power factor close to 1 such as a house load is connected to the CA phase, the line current is in phase with the CA phase line voltage, so the voltage drop in the distribution line pushes down the A phase voltage. In addition, it works to delay the phase of the C-phase voltage. As a result, the absolute value of the phase voltage greatly decreases in the A phase, but does not decrease as much in the C phase as in the A phase. Moreover, as the phase A voltage decreases and the phase of the phase C voltage delays, the absolute value of the line voltage decreases in the AB phase and the CA phase and increases in the BC phase.

  On the other hand, during the daytime when the photovoltaic power output increases, as shown in FIG. 7A, the line voltage increases in the AB phase and the CA phase and decreases in the BC phase. Further, as shown in FIG. 7B, the phase voltage did not change, the A phase voltage increased significantly, and the C phase voltage increased slightly.

  This mechanism has the same basic principle as the morning (late night) phenomenon, and can be explained as follows. That is, when a photovoltaic power generation with a power factor of 1 is connected to the CA phase, a reverse power flow occurs in the distribution line, and the phase of the current is reversed by 180 °, so that the voltage drop in the distribution line pushes up the A-phase voltage. Also, it works to advance the phase of the C phase voltage. As a result, the absolute value of the phase voltage increases greatly in the A phase, but does not increase as much in the C phase as in the A phase. Further, as the A-phase voltage increases and the phase of the C-phase voltage advances, the absolute value of the line voltage increases in the AB phase and the CA phase, and decreases in the BC phase.

  The above has been found as a mechanism of voltage three-phase unbalance that occurs when a low-voltage single-phase load and low-voltage single-phase photovoltaic power generation are connected to the CA phase only at the end of the distribution line.

Here, the relationship between the unbalanced connection load (in other words, unbalanced due to unbalanced connection of low-voltage single-phase load or low-voltage single-phase photovoltaic power generation) obtained from the above analysis results and the unbalance of line voltage 8 is obtained, and it was found from FIG. 8 that the following relationship is established.
《Knowledge》
Due to the reactance of the line impedance, the line voltage of the phase advanced by 120 ° from the heavy load phase or the phase with a small amount of photovoltaic power generation is higher than the other phase, and the light load phase or the amount of photovoltaic power generation The line voltage of the phase whose phase is advanced by 120 ° from many phases becomes lower than that of the other phases.

2) Pattern 2: Analysis results when connected to the BC phase and the CA phase In the morning (late night) when the morning (late night) load works, the line voltage slightly decreases in the AB and BC phases as shown in FIG. 9A. Only the CA phase was significantly reduced. Further, as shown in FIG. 9B, the phase voltage slightly decreased for the B phase voltage, and greatly decreased for the A phase voltage and the C phase voltage.

  On the other hand, during the daytime when the photovoltaic power output increased, as shown in FIG. 9A, the line voltage increased significantly in the CA phase and slightly increased in the AB phase and the BC phase. Further, as shown in FIG. 9B, the phase voltage greatly increased in the A phase voltage and the C phase voltage, and the B phase voltage slightly increased.

  This mechanism can also be described as the same as the mechanism of the pattern 1 described above.

  Then, FIG. 10 is obtained by organizing the relationship between the unbalance of the connection load and the unbalance of the line voltage obtained from the above analysis result. From FIG. It was confirmed that the knowledge about the imbalance of the inter-voltage was established.

3) Pattern 3: Analysis results when connected to all of the AB phase, BC phase, and CA phase Since the load is three-phase balanced, the line voltage and the phase voltage are not as shown in FIGS. 11A and 11B. Equilibrium is lost.

  This mechanism can also be described as the same as the mechanism of the pattern 1 described above.

  Moreover, although this pattern was a three-phase equilibrium condition, FIG. 12 was obtained by arranging in the same manner as in FIGS. From FIG. 12, it was confirmed that the knowledge about the unbalance of the connection load and the unbalance of the line voltage described above was established even in the case of three-phase balance.

(2) Analysis on confirmation of versatility Next, the knowledge obtained from the results of the above basic analysis, “Relationship between connection load imbalance and line voltage imbalance”, is a condition of basic analysis. In order to confirm that the relationship was established not only in the case but also in the actual power distribution system, the following six analyzes were performed based on the basic analysis conditions.

In the following Analysis I, Analysis II, and Analysis III, the unbalanced load connected to the end of the distribution line has a circuit configuration close to that of the actual distribution system. The following two cases with more than other phases were established. The line impedance was balanced.
Case a) AB phase: BC phase: CA phase = 1: 1: 2
Case b) AB phase: BC phase: CA phase = 1: 2: 2

<Analysis I> Analysis using power factor of unbalanced load as a parameter As a result of analysis under the condition that the power factor of connected unbalanced load is different, the power factor of low-pressure load is often in the range of 0.9 to 1.0 In either case a or case b, it is confirmed that the relationship between the phase with the highest line voltage and the lowest phase, the heavy load phase, and the light load phase according to the above knowledge is established. It was.

<Analysis II> Analysis using the system power factor as a parameter As a result of the analysis under the condition that the system power factor is changed by changing the power factor of the balanced load with large capacity connected separately from the unbalanced load, Even when the rates are different, the relationship between the phase having the highest line voltage and the lowest line voltage, the heavy load phase, and the light load phase is established in both cases a and b. It was confirmed.

<Analysis III> Analysis using the line type (that is, line impedance) as a parameter As a result of the analysis under different conditions (specifically, trunk line: 120 mm ² and 25 mm ² aluminum wire) The line voltage related to the above knowledge is not only in the system where the trunk line close to the actual power distribution system is an aluminum wire of 120 mm ² but also in the system using a 25 mm ² aluminum wire used in places where the passing current is small. It was confirmed that the relationship between the highest and lowest phases and the heavy and light load phases was established.

<Analysis IV> Generation mechanism of voltage three-phase unbalance due to unbalanced line impedance Voltage three due to unbalanced line impedance of high-voltage distribution lines (specifically, due to unbalanced mutual inductance due to different column configuration) An analysis was conducted to verify the mechanism of phase imbalance.

  Specifically, the case of the delta arrangement shown in FIG. 5 (that is, simulating line impedance balance) and the case of the vertical arrangement shown in FIG. 13 (that is, simulating line impedance imbalance) are set. The vertical array is a pillar that is often used in actual tracks.

  Further, an all-electric assembly in which a load curve is as shown in FIG. 6 at the end of the distribution line of the high-voltage distribution model in FIG. 4, for example, a morning (or midnight) load such as a heat pump water heater and solar power generation is attached. A three-phase balanced load was simulated by connecting a load simulating a house to all three phases of the AB phase, the BC phase, and the CA phase.

  First, in the case of line impedance balance (that is, delta arrangement), the analysis conditions are the same as those in the pattern 3 of the basic analysis, and the analysis results are as shown in FIGS. 11A and 11B.

  On the other hand, in the case of the line impedance imbalance (that is, vertical arrangement), the line voltage is as shown in FIG. 14A and the phase voltage is as shown in FIG. 14B. As compared with FIG. 11A, the line voltage (FIG. 14A) increased in the morning (late night) when the morning (late night) load was applied, the AB phase increased, the BC phase decreased, and the CA phase remained almost unchanged. As for the phase voltage (FIG. 14B), compared with FIG. 11B, in the morning (late night) when the morning (late night) load works, the B phase voltage does not change, the A phase voltage increases, and the C phase voltage decreases.

  From the above, it was confirmed that the unbalance increased due to the influence of the line impedance imbalance in the vertical arrangement compared to the delta arrangement. This is because, as a result of complex intertwining of factors such as the difference in mutual impedance due to the difference in line distance and the difference in the magnitude of each phase line current due to the difference in mutual impedance, the magnitude of each voltage drop component, etc. from the equilibrium state. It was thought to appear as a result of changes in the

  14A and 14B, similarly, during the daytime when the photovoltaic power output becomes large, in the case of the vertical arrangement, the imbalance may be expanded due to the influence of the line impedance imbalance in comparison with the case of the delta arrangement. confirmed.

<Analysis V> Verification with a distribution line model at the actual system level 1
In order to verify whether the knowledge about the relationship between the unbalance of the connected load and the unbalance of the line voltage obtained by the basic analysis described above also applies to the distribution line model at the actual system level. Line impedance, multiple load models, and multiple load patterns are prepared, and these are created by changing the connection pattern of the load (specifically, the load curve) to the residential area model of the Electric Cooperative Society. Various settings were analyzed.

  In this analysis, analysis was performed using the high-voltage distribution line model shown in FIG. This model is generally used for various evaluations related to distribution lines, and is a standard residential area model of the Electric Cooperative Study Group (General Electric Corporation Electric Cooperative Study Group “High Voltage Power Receiving Equipment” "Current Status and Countermeasures for Harmonic Problems in Japan", Vol. 54, No. 2, 1998).

  For the line impedance, a line impedance balance pattern (delta arrangement; FIG. 5) and a line impedance unbalance pattern (vertical arrangement; FIG. 13) were set.

  As for the load model, it is assumed that the load curve is assumed as a non-all-electric home, the load curve is assumed as a home where all photovoltaics are not installed, and the all-electric home is installed with solar power. The expected load curve was set.

  About the load pattern, the same consumer is connected to each phase (between lines) of the distribution line evenly, and there is no unbalance of the connection phase. Even though they are equal, the connection positions are different, so a small unbalance occurs due to the influence of the line impedance (this is a simulation of the situation managed by the power company), and in all extreme cases A pattern that maximizes the unbalance by setting the combination of customer connections for both load points was set.

  As a result of the analysis, in the morning (late night) when the morning (late night) load works, the voltage imbalance rate is very small when connected to the balanced load and when the load connection phase is properly managed. It was confirmed that the voltage unbalance rate was large when the unbalance of was large. Furthermore, especially when the voltage three-phase unbalance becomes large, it is considered that the unbalance of the connection load is the main factor and is dominant with respect to the unbalance of the line impedance. In addition, when the voltage three-phase unbalance became large during the daytime, it was considered that the unbalance of photovoltaic power generation was the main factor.

<Analysis VI> Verification with distribution line model at actual system level 2
In order to verify whether the knowledge about the relationship between the unbalance of the connected load and the unbalance of the line voltage obtained by the basic analysis described above also applies to the actual distribution line model, Assuming that the impedance is an equilibrium pattern (delta arrangement; Fig. 5), in addition to the three load curves in the analysis V above as a load model, the load is in the morning (late night) compared to the analysis V in a house where photovoltaic power generation is installed with all electrification A load curve that halves the power consumption of solar power and the output of photovoltaic power generation is added, and the load pattern assumes that the imbalance is maximized, and the load on the residential area model of the Electric Cooperative Research Group (specifically, the load curve) We analyzed various settings created by changing the connection pattern.

  Also in this analysis, the analysis was performed using the high-voltage distribution line model shown in FIG.

  As a result of the analysis, it was confirmed that knowledge about the relationship between unbalanced connection load and unbalanced line voltage was established even in the distribution system model at the actual system level. The following findings were obtained regarding the relationship between unbalanced connection loads and unbalanced voltage between three-phase lines, focusing on classification.

1) About midnight a) The phase with the heaviest load is the phase that is 120 ° behind the phase with the highest line voltage.
B) The phase with the lightest load is the phase that is 120 ° behind the phase with the lowest line voltage.
C) Among the three phases, the intermediate phase is a phase whose line voltage is delayed by 120 ° from the intermediate phase.

2) About daytime a) The phase with the highest photovoltaic power output is in the phase that is 120 ° behind the phase with the lowest line voltage.
B) The phase with the smallest photovoltaic power generation output (or no photovoltaic power generation) is a phase that is delayed by 120 ° from the phase with the highest line voltage.
C) The intermediate phase among the three phases of the photovoltaic power generation output is a phase in which the phase of the line voltage is delayed by 120 ° from the intermediate phase.

  For the above time zone classification, for example, “daytime” means a time zone during which power can be output by solar power generation, specifically, for example, a time zone from sunrise to sunset, and “midnight” Say other time zones.

  The connection phase determination method of the present invention is based on the above-mentioned new knowledge unique to the inventors, and the voltage for each line for each measurement time using the three-phase line voltage measured in the distribution line. The unbalance rate is calculated, and the three-phase line voltage at the measurement time at which the voltage unbalance rate is maximized is used to create a combination of high and low voltage characteristics for each line. The connection phase of the pole transformer is determined based on the maximum measurement time and the combination of high and low voltage characteristics for each line.

  Further, the connection phase determination device of the present invention includes means for calculating a voltage unbalance rate for each line for each measurement time using the three-phase line voltages measured in the distribution line, and the voltage unbalance rate is A means to create a combination of high and low voltage characteristics for each line using the three-phase line voltages at the maximum measurement time, and the measurement time and line-to-line combinations with the highest voltage imbalance rate And means for determining the connection phase of the pole transformer based on the combination of the high and low characteristics of the voltage.

  Further, the connection phase determination program of the present invention includes a process for calculating a voltage unbalance rate for each line for each measurement time using the three-phase line voltages measured in the distribution line, and the voltage unbalance rate is Processing to create a combination of high and low voltage characteristics for each line using the three-phase line voltages at the maximum measurement time, and the measurement time and line-to-line combinations with the highest voltage imbalance rate The computer is caused to perform processing for determining the connection phase of the pole transformer based on the combination of high and low voltage characteristics.

  Therefore, according to the determination method, determination device, and determination program of these connection phases, by measuring each line voltage of the three phases of the distribution line, the above-described connection load unbalance and line voltage unbalance are achieved. Based on such knowledge, the connecting phase of the pole transformer is determined so as to improve the unbalance of the three-phase line voltages.

  In addition, the connection phase determination method, determination apparatus, and determination program of the present invention provide a method for changing the connection phase of an existing pole transformer to improve the current three-phase line voltage unbalance and the future three phases. The determination regarding at least one of the selection of the connection phase of the newly installed pole transformer for suppressing the unbalance of the line voltages of the phases may be performed. In this case, a determination is made regarding at least one of a countermeasure appropriate for correcting the current three-phase voltage imbalance and a countermeasure appropriate for preventing the voltage three-phase imbalance in the future.

  Here, the introduction of a switch with a three-phase measurement function into an actual distribution line is progressing. Under such a background, in the present invention, the connection phase of the pole transformer may be determined by using data measured by an existing switch having a three-phase measurement function. The required cost is reduced. Even if it is necessary to install a new measuring device because there is no switch with a three-phase measurement function on the distribution line under consideration, there are various types of data measured by a switch with a three-phase measurement function. Therefore, the present invention can be implemented by installing a switch with a three-phase measurement function that is not limited to the implementation of the present invention.

  Based on the above, the connection phase determination method, the determination device, and the determination program of the present invention are configured so that each three-phase line voltage is measured by a switch with a three-phase measurement function installed in the distribution line. Also good. In this case, when determining the connection phase of the pole transformer using the data measured by the existing switch with three-phase measurement function, or when installing a new switch with three-phase measurement function However, a switch with a three-phase measurement function that is not limited for the implementation of the present invention is installed to determine the connection phase of the pole transformer.

  According to the determination method, the determination device, and the determination program of the connection phase of the present invention, the pole transformer that can improve the unbalance of the three-phase line voltages by simply measuring the three-phase line voltages of the distribution line. The connection phase of the transformer can be determined, so it is possible to determine the connection phase of the pole transformer without requiring a lot of labor and a large-scale mechanism. Improvements can be made.

  In the connection phase determination method, determination apparatus, and determination program of the present invention, the connection phase is determined for at least one of improvement of the current unbalance and suppression of the future unbalance. Can make decisions on at least one of the appropriate measures to correct the current three-phase voltage imbalance and the appropriate measures to prevent the three-phase voltage imbalance in the future. It is possible to further improve the versatility as a connection phase determination technique by determining the connection phase according to the above.

  In addition, the connection phase determination method, determination device, and determination program of the present invention provide a three-phase measurement function when the three-phase line voltage is measured by a switch with a three-phase measurement function. Since the connection phase of the pole transformer can be determined using data measured by the attached switch, the cost can be reduced. In addition, even when a switch with a three-phase measurement function is newly installed, it is possible to determine the connection phase of the pole transformer by installing a switch with a three-phase measurement function that is not limited for the implementation of the present invention. Therefore, it is possible to secure the possibility of various effective utilization of equipment and reduce the cost of the entire monitoring and operation of the distribution system.

It is a flowchart explaining an example of embodiment of the determination method of the connection phase of this invention. It is a functional block diagram of a connection phase determination device realized by the program when the connection phase determination method of the embodiment is implemented using a connection phase determination program. It is a connection phase determination chart used in determination of the connection phase of a pole transformer. It is the distribution line model used for the analysis of the voltage three-phase imbalance of a distribution line. It is a figure which shows a delta arrangement | sequence among the line impedances used for the analysis of the voltage three-phase imbalance of a distribution line. It is a figure which shows the load curve used for the analysis of the voltage three-phase imbalance of a distribution line. It is a figure which shows the line voltage as an analysis result in the case of the pattern 1 of the load of a basic analysis. It is a figure which shows the phase voltage as an analysis result in the case of the pattern 1 of the load of a basic analysis. It is a figure which shows the relationship between the unbalance of a connection load and the unbalance of a line voltage as an analysis result in the case of the load pattern 1 of a basic analysis. It is a figure which shows the line voltage as an analysis result in the case of the load pattern 2 of a basic analysis. It is a figure which shows the phase voltage as an analysis result in the case of the pattern 2 of the load of a basic analysis. It is a figure which shows the relationship between the unbalance of a connection load and the unbalance of a line voltage as an analysis result in the case of the load pattern 2 of a basic analysis. It is a figure which shows the line voltage as an analysis result in the case of the pattern 3 of the load of a basic analysis. It is a figure which shows the phase voltage as an analysis result in the case of the pattern 3 of the load of a basic analysis. It is a figure which shows the relationship between the unbalance of a connection load and the unbalance of a line voltage as an analysis result in the case of the load pattern 3 of a basic analysis. It is a figure which shows a vertical arrangement | sequence among the line impedances used for the analysis of the voltage three-phase imbalance of a distribution line. It is a figure which shows the line voltage as an analysis result of the analysis IV regarding confirmation of versatility. It is a figure which shows the phase voltage as an analysis result of the analysis IV regarding confirmation of versatility. It is the distribution line model used for the analysis V and analysis VI regarding confirmation of versatility. It is a figure which shows the line voltage as an analysis result before implementation of the improvement measure of Example 1. FIG. It is a figure which shows the line voltage as an analysis result after changing the connection phase of a pole transformer based on the conventional method in Example 1. FIG. In Example 1, it is a figure which shows the line voltage as an analysis result after changing the connection phase of a pole transformer based on this invention. It is a figure which shows the line voltage as an analysis result before implementation of the improvement measure of Example 2. FIG. It is a figure which shows the line voltage as an analysis result after a new pole transformer is connected based on the conventional method in Example 2. FIG. In Example 2, it is a figure which shows the line voltage as an analysis result after a new pole transformer is connected based on this invention.

  Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings.

  1 to 3 show an example of embodiments of a connection phase determination method, a determination device, and a determination program according to the present invention.

  The connection phase determination method of the present embodiment uses the three-phase line voltages measured in the distribution line to calculate the voltage unbalance rate for each line for each measurement time (S1, S2). The three-phase line voltage at the measurement time at which the unbalance rate is maximized is used to create a combination of high and low voltage characteristics for each line (S3, S4), and the voltage unbalance rate is maximized. The connection phase of the pole transformer is determined based on the measurement time and the combination of the high and low voltage characteristics of each line (S5) (see FIG. 1).

  The connection phase determination method may be implemented by a connection phase determination device. The connection phase determination device 10 of the present embodiment is measured using a data receiving unit 11a as a means for receiving an input of a measured value of each three-phase line voltage measured in the distribution line, and each three-phase line voltage. An unbalance rate calculation unit 11b as a means for calculating a voltage unbalance rate for each line by time, a time specification unit 11c as a means for specifying a measurement time at which the voltage unbalance rate is maximum, a voltage A voltage level judgment unit 11d as means for creating a combination of voltage level characteristics for each line using the three-phase line voltage at the measurement time at which the unbalance rate is maximized, and the voltage unbalance rate is maximum And a connection phase determination unit 11e as means for determining the connection phase of the pole transformer based on the measurement time and the combination of the high and low voltage characteristics for each line.

  Further, the connection phase determination method and the connection phase determination device can be implemented and realized by executing a connection phase determination program on a computer. Here, a case will be described in which a connection phase determination apparatus is implemented and a connection phase determination method is implemented by executing a connection phase determination program on a computer.

  FIG. 2 shows an overall configuration of a computer 10 (which is also a connection phase determination device 10 in the present embodiment) for executing the connection phase determination program 17 of the present embodiment. The computer 10 (connection phase determination device 10) includes a control unit 11, a storage unit 12, an input unit 13, a display unit 14, and a memory 15, which are connected to each other by a signal line such as a bus.

  The control unit 11 performs calculation related to the control of the entire computer 10 and the determination of the connection phase of the pole transformer by the connection phase determination program 17 stored in the storage unit 12. Device).

  The storage unit 12 is a device that can store at least data and programs, and is, for example, a hard disk.

  The input unit 13 is an interface (that is, an information input mechanism) for giving at least an operator's command and various information to the control unit 11, and is, for example, a keyboard or a mouse. For example, a plurality of types of interfaces such as a keyboard and a mouse may be provided as the input unit 13.

  The display unit 14 performs drawing / display of characters, figures, images, and the like under the control of the control unit 11 and is, for example, a display.

  The memory 15 serves as a memory space that is a work area when the control unit 11 executes various controls and operations, and is, for example, a RAM (abbreviation of Random Access Memory).

  Then, the control unit 11 of the computer 10 (hereinafter referred to as the connection phase determination device 10) executes the connection phase determination program 17 so that the three-phase line voltages measured in the distribution lines are measured. A data receiving unit 11a that performs a process of receiving measurement values; an unbalance rate calculating unit 11b that performs a process of calculating a voltage unbalance rate for each line for each measurement time using the three-phase line voltages; A time specifying unit 11c that performs processing for specifying a measurement time at which the voltage unbalance rate is maximum, and three-phase line voltages at the measurement time at which the voltage unbalance rate is maximum are used for each line. A pole-top transformer based on a voltage level judgment unit 11d that performs processing for creating a combination of voltage level characteristics, a measurement time at which the voltage unbalance rate is maximized, and a combination of voltage level characteristics for each line. To determine the connection phase of And connecting phase determination unit 11e for performing is formed.

  And as execution of the determination method of a connection phase, first, measurement of each line voltage of the three phases of a distribution line is performed, and measurement data are acquired (S1).

  How to measure the voltage (here AB phase, BC phase, and CA phase) between the three phases of the distribution line (here, A phase, B phase, and C phase) As long as the voltage between the lines can be measured, the method is not limited to a specific method or device, and a method or device that can measure the voltage between the three phases of the distribution line can be appropriately selected. Specifically, for example, an existing or new switch with a three-phase measurement function can be used.

  The measurement interval of each line voltage of the three phases of the distribution line is not limited to a specific time [second, minute]. For example, the fluctuation pitch assumed for the line voltage of the distribution line and the required accuracy Can be appropriately set to an appropriate value. Specifically, for example, it may be set to an appropriate value in a range of about 15 minutes to 60 minutes.

  Note that the following processing according to the present invention can be performed if there is at least one day of measurement data regarding the three-phase line voltages of the distribution line. However, it is desirable that the measurement data be measured data on a day when the weather is good at least during the day so that the solar power generation facility can generate a power output of about the performance of the daytime.

  Also, the three-phase line voltage of the distribution line is preferably measured data for 24 hours because the time at which the voltage imbalance rate becomes maximum differs depending on the system.

  The measured value of the three-phase line voltage of the distribution line obtained by the measurement is input to the connection phase determining device 10 via the data receiving unit 11a.

  The measurement data (specifically, the measured value of each line voltage of the three phases of the distribution line and the measurement time corresponding to the measured value) are input to the connection phase determination device 10 via a recording medium or a data server. Alternatively, the connection phase determination device 10 and the measurement device may be electrically connected and input so that signals such as data and control commands can be transmitted and received (that is, input / output). Anyway.

  When the measurement data is input via the recording medium, the measurement data relating to the three-phase line voltage of the distribution line is recorded on the recording medium, and the recording medium is connected to the recording medium connection terminal of the connection phase determination device 10. Measurement data may be input by being inserted into (not shown).

  When measurement data is input via a data server, the data server is connected to the connection phase determination device 10 via a signal line such as a bus, and the data server relates to the three-phase line voltages of the distribution lines. The measurement data may be stored (saved) as a data file or the like, and the measurement data saved as the data file or the like may be read.

  In addition, when the connection phase determination device 10 and the measurement device are electrically connected and measurement data is input, for example, a wired signal transmission / reception mechanism in which cables connected to each other are used. May be electrically connected so that signals can be transmitted / received via a wireless signal, and signals can be transmitted / received via a wireless signal transmission / reception mechanism using a wireless signal transceiver connected to each. It may be electrically connected as possible. Then, measurement data may be input by such a signal transmission / reception mechanism.

  Furthermore, the measurement data may be input to the connection phase determination device 10 by using a combination of a recording medium, a data server, and a wired / wireless signal transmission / reception mechanism.

  Then, the data receiving unit 11a stores in the memory 15 the measurement values of the three-phase line voltages of the distribution lines as the input measurement data and the measurement times corresponding to the measurement values (in other words, for each measurement value). Be made.

  Next, the unbalance rate calculation unit 11b of the control unit 11 calculates the voltage unbalance rate for each line by measurement time using the measurement data measured and acquired by the process of S1 (S2). ).

  Specifically, the measurement data stored in the memory 15 in the process of S1 (that is, the measurement values and measurement times of the three-phase line voltages of the distribution lines) are read by the unbalance rate calculation unit 11b, and the measurement time Separately, the voltage imbalance ratio [%] is calculated by dividing the negative phase voltage [V] by the positive phase voltage [V] for each line.

  Then, the value of the voltage unbalance rate calculated by the unbalance rate calculation unit 11b is stored in the memory 15 in association with the measurement time and the line type (in other words, together with the measurement time and the line type).

  Next, the time specifying unit 11c of the control unit 11 specifies the measurement time at which the voltage unbalance rate is maximum based on the voltage unbalance rate for each line for each measurement time calculated by the process of S2. Performed (S3).

  Specifically, the time specifying unit 11c reads the measurement time stored in the memory 15 in the process of S2 and the value of the voltage unbalance rate for each line at the measurement time, and the voltage unbalance rate is maximized. Measurement time is identified.

  Here, when the voltage unbalance rate of a certain line type at a certain measurement time is maximum compared with the voltage unbalance rate of another line type at another measurement time, the certain measurement time Regardless of the voltage unbalance rate of other line types, the certain measurement time is the measurement time at which the voltage unbalance rate is maximum (hereinafter referred to as “unbalance maximum time”). The

  Then, the specified unbalanced maximum time is stored in the memory 15 by the time specifying unit 11c.

  Next, the voltage level determination unit 11d of the control unit 11 determines the level characteristics of each line voltage based on the unbalance maximum time specified by the process of S3 and the measurement data at the maximum unbalance time (S4). ).

  Specifically, the voltage high / low determination unit 11d reads the unbalanced maximum time stored in the memory 15 in the process of S3, and further, the unbalanced maximum time of the measurement data stored in the memory 15 in the process of S1. The measured value of each line voltage of the three phases of the distribution line is read.

  Then, the voltage level determination unit 11d determines the level of the voltage for each line by mutual comparison of the line voltages at the unbalanced maximum time.

The high and low characteristics (in other words, relative to each other) of the voltages between the three-phase lines are expressed as “low”, “medium”, and “high” representing the level of high and low in the relative relationship. Indicators are used to fit into one of the following combinations:
1) Low: One, Middle: One, High: One 2) Low: One, High: Two 3) Low: Two, High: One

  Here, the threshold of the voltage difference for distinguishing between “intermediate” and “low” or “high” by inter-comparison of each line voltage, or to distinguish between “low” and “high” is specified. It is not limited to this value, and is set as appropriate in consideration of the load connected to the distribution line, the rated capacity of solar power generation, and the like.

  The threshold value for the voltage difference may be set as an absolute value of the difference between the voltages, or may be set as a relative ratio of the absolute value of the difference between the voltages.

  As a result of the process of S2, specifically, for example, a combination of voltages between the three phases AB, BC, and CA of the A phase, B phase, and C phase of the distribution line is set to [AB phase. , BC phase, CA phase], combinations such as [low, high, middle], [high, low, high] and [low, low, high] are created as combinations of line voltages.

  Then, the voltage high / low determination unit 11d stores in the memory 15 a combination of the generated voltage high / low characteristics for each line.

  Next, the connection phase determination unit 11e of the control unit 11 based on the combination of the maximum unbalance time specified by the process of S3 and the voltage high / low characteristic of each line created by the process of S4. The connection phase of the pole transformer is determined (S5).

  Specifically, the connection phase determination unit 11e reads the maximum unbalance time stored in the memory 15 in the process of S4 and the combination of high and low voltage characteristics for each line.

  And in this invention, the connection phase determination chart shown in FIG. 3 derived | led-out based on the inventor's new new knowledge regarding the unbalance of a connection load and the unbalance of a line voltage is used. The connection phase of the transformer (specifically, a transformer connected to any two of the three phases of the three-phase distribution line such as a single-phase transformer or a lighting common transformer) is determined.

  The connection phase determination chart shown in FIG. 3 has a division by “time zone” basically corresponding to a time zone in which voltage three-phase imbalance occurs, specifically “midnight” and “daytime”. It is divided into.

  The basic concept of this connection phase determination chart is that “voltage three-phase unbalance due to the influence of connection load” is a combination of the high and low characteristics of the line voltage listed in the “midnight” category (in FIG. (Measured data) / AB phase | BC phase | CA phase "), while" voltage three-phase imbalance due to solar power generation " The improvement measures corresponding to the combination of the high and low characteristics of the line voltage listed in the “medium” category are implemented.

  It should be noted that the time for distinguishing between “daytime” and “midnight”, in other words, the time for specifying “daytime” time zone and “midnight” time zone is not limited to a specific time, Based on the time zone in which power can be output by photovoltaic power generation, specifically, for example, the sunrise time or sunset time can be taken into consideration, and the time can be set appropriately.

  The connection phase determination chart shown in FIG. 3 is also divided into measures for improving the current voltage three-phase unbalance and measures for suppressing the future voltage three-phase unbalance. To improve the current voltage three-phase unbalance, specifically, it corresponds to the case of changing the connection phase of the pole transformer that has already been installed. Specifically, this corresponds to the case where the connection phase of the pole transformer to be newly installed is selected.

Specifically, the connection phase determination chart shown in FIG. 3 is used by the following procedure.
1) First, it is determined whether the unbalanced maximum time is daytime or midnight.
2) When the maximum unbalance time is “daytime”, the “time zone” in FIG. 3 is referred to in principle as “daytime”, and the maximum unbalance time is “midnight”. In FIG. 3, the “time zone” section of “midnight” is referred to.
3) However, if the maximum unbalanced time is during the day, but the line voltage does not rise at the maximum unbalanced time, refer to the “midnight” section for “time zone” in FIG. Is done.
4) In addition, when a pole transformer without a connected solar power generation facility is newly installed even though the unbalanced maximum time is during the day, the “time zone” in FIG. Reference is made to the “Midnight” category.

  Specifically, the connection phase determination chart shown in FIG. 3 includes <I> a case where current three-phase unbalance is improved and <II> a case where future voltage three-phase unbalance is suppressed. Used as follows.

<I> To improve the current voltage three-phase imbalance

  An example will be described in which it is determined that the “time zone” is “late night” in consideration of the fact that the maximum unbalance time read from the memory 15 is 4 am, for example, after sunset and before sunrise. .

  First, when the combination of the high and low characteristics of the line voltage read from the memory 15 is [AB phase, BC phase, CA phase] = [intermediate, high, low], “the three-phase lines in the processing of S1”. Installed on the distribution line connected to the distribution line where the three-phase line voltage was measured in the process of S1 " The connection to the CA phase is changed to the connection to the AB phase for the “pole transformer” (refer to the seventh stage of the “midnight” section in FIG. 3).

  When the combination of the high and low characteristics of the line voltage in the “midnight” time zone is [AB phase, BC phase, CA phase] = [intermediate, high, low], the load status is [AB phase, BC phase] , CA phase] = [light, intermediate, heavy] (refer to the 7th stage of “midnight” in FIG. 3).

  For this reason, in order to improve the current voltage three-phase imbalance, the connection phase of the pole transformer is changed so that the load is shifted from the heaviest phase to the lightest phase. Therefore, the connection to the CA phase is changed to the connection to the AB phase.

  Further, when the combination of the high and low characteristics of the line voltage read from the memory 15 is [AB phase, BC phase, CA phase] = [high, high, low], “three-phase lines in the processing of S1”. Installed on the distribution line connected to the distribution line where the three-phase line voltage was measured in the process of S1 " The connection to the BC phase or the connection to the CA phase is changed to the connection to the AB phase for the “post-pole transformer” (refer to the fourth stage of the “midnight” section in FIG. 3).

  When the combination of the high and low characteristics of the line voltage is [AB phase, BC phase, CA phase] = [high, high, low] in the “midnight” time zone, the load status is [AB phase, BC phase] , CA phase] = [light, heavy, heavy] (refer to the fourth stage of “midnight” in FIG. 3).

  For this reason, in order to improve the current voltage three-phase imbalance, the connection phase of the pole transformer is changed to shift the load from the heavy load phase to the lightest phase. One of the connection to the BC phase and the connection to the CA phase is changed to the connection to the AB phase.

  Next, in the case where it is determined that the “time zone” is “daytime” in consideration of the fact that the maximum unbalance time read from the memory 15 is 1:00 pm, for example, after sunrise and before sunset An example will be described.

  In this case, among the measurement data stored in the memory 15 in the process of S1, the measured value of each line voltage of the three phases of the distribution line at the maximum unbalance time (specifically, 1 pm in this example). Is read.

  When at least one of the line voltages is significantly higher than the positive phase voltage (hereinafter referred to as “when voltage rises”), refer to the “daytime” category in the connection phase determination chart. When the line voltage is not much higher than the positive phase voltage (hereinafter referred to as “when there is no voltage rise”), the “late night” section of the connection phase determination chart is referred to.

  Note that the threshold value of the voltage difference from the positive phase voltage for determining whether or not the line voltage greatly exceeds the positive phase voltage is not limited to a specific value, and is appropriately set to an appropriate value. Is done.

  When the voltage rise is present and the combination of the high and low characteristics of the line voltage read from the memory 15 is [AB phase, BC phase, CA phase] = [high, low, middle], “S1 Connected to the distribution line where the three-phase line voltage was measured in the process of S1, or the transformer on the pole installed in the distribution line where the three-phase line voltage was measured in the process of The connection to the CA phase is changed to the connection to the BC phase for the pole transformer installed on the distribution line (see the 9th stage of the “daytime” category in FIG. 3) ).

  Here, when the maximum unbalance time is daytime and voltage rises during the daytime, the cause of voltage three-phase unbalance is considered to be solar power generation. Refer to the category.

  When the voltage rises in the “daytime” time zone and the combination of the high and low characteristics of the line voltage is [AB phase, BC phase, CA phase] = [high, low, middle], solar power generation It is assumed that the output status is [AB phase, BC phase, CA phase] = [intermediate, few, many] (see “9th stage of“ day ”” category in FIG. 3). . Here, the situation where the photovoltaic power output is low includes the case where there is no photovoltaic power output.

  For this reason, in order to improve the current voltage three-phase imbalance, the pillars where the photovoltaic power generation facilities are connected to distribute the photovoltaic power output from the phase with the largest photovoltaic power output to the phase with the smallest photovoltaic power output. The connection phase of the transformer is changed. In the above case, the connection to the CA phase is specifically changed to the connection to the BC phase.

  On the other hand, when there is no voltage rise and the combination of the high and low characteristics of the line voltage read from the memory 15 is [AB phase, BC phase, CA phase] = [high, low, middle], “S1 Connected to the distribution line where the three-phase line voltage was measured in the process of S1, or the transformer on the pole installed in the distribution line where the three-phase line voltage was measured in the process of Change the connection to the BC phase to the connection to the CA phase for the pole transformer installed on the distribution line (see the 10th stage of the “midnight” section in FIG. 3) .

  Here, even if the maximum unbalance time is during the daytime, if there is no voltage rise during the daytime, it is considered that the cause of the voltage three-phase unbalance is not the photovoltaic power generation but the connected load. Refer to the “Midnight” category for “Obi”.

  In the “midnight” section, when [AB phase, BC phase, CA phase] = [high, low, intermediate], the load status is [AB phase, BC phase, CA phase] = [intermediate, Heavy (light) ”(refer to the 10th stage of“ midnight ”in FIG. 3).

  For this reason, in order to improve the current voltage three-phase imbalance, the connection phase of the pole transformer is changed so that the load is shifted from the heaviest phase to the lightest phase. Therefore, the connection to the BC phase is changed to the connection to the CA phase.

<II> When suppressing future voltage three-phase imbalance

  An example will be described in which it is determined that the “time zone” is “late night” in consideration of the fact that the maximum unbalance time read from the memory 15 is 4 am, for example, after sunset and before sunrise. .

  First, when the combination of the high and low characteristics of the line voltage read from the memory 15 is [AB phase, BC phase, CA phase] = [intermediate, high, low], “the three-phase lines in the processing of S1”. To the distribution line connected to the distribution line for which the three-phase line voltage was measured in the process of S1, or to the newly installed pole transformer for the distribution line for which the voltage measurement was performed On the other hand, the pole transformer to be newly installed is connected to the AB phase (refer to the 7th stage of “midnight” in FIG. 3).

  When the combination of the high and low characteristics of the line voltage in the “midnight” time zone is [AB phase, BC phase, CA phase] = [intermediate, high, low], the load status is [AB phase, BC phase] , CA phase] = [light, intermediate, heavy] (refer to the 7th stage of “midnight” in FIG. 3).

  For this reason, in order to suppress future voltage three-phase imbalance, the connection phase of the newly installed pole transformer is selected so that the load is shared with the lightest phase in the current situation. To the AB phase.

  When the combination of the high and low characteristics of the line voltage read from the memory 15 is [AB phase, BC phase, CA phase] = [low, low, high], “the three-phase lines in the processing of S1”. To the distribution line connected to the distribution line for which the three-phase line voltage was measured in the process of S1, or to the newly installed pole transformer for the distribution line for which the voltage measurement was performed On the other hand, the newly installed pole transformer is connected to the BC phase or the CA phase (refer to the second stage of “midnight” in FIG. 3).

  When the combination of the high and low characteristics of the line voltage is [AB phase, BC phase, CA phase] = [low, low, high] in the “midnight” time zone, the load status is [AB phase, BC phase] , CA phase] = [heavy, light, light] (refer to the second stage of “midnight” in FIG. 3).

  For this reason, in order to suppress future voltage three-phase imbalance, the connection phase of the pole transformer to be newly installed should be selected so that the load is shared with the currently lighter phase. Connect to BC phase or CA phase.

  Next, in the case where it is determined that the “time zone” is “daytime” in consideration of the fact that the maximum unbalance time read from the memory 15 is 1:00 pm, for example, after sunrise and before sunset An example will be described.

  In this case, refer to the “Daytime” section of the connection phase determination chart when installing a pole transformer that is connected to a photovoltaic power generation facility (hereinafter referred to as “when power generation is present”). On the other hand, when installing a pole transformer that is not connected to photovoltaic power generation facilities (hereinafter referred to as “when no power generation is connected”), refer to the “midnight” section of the connection phase determination chart. .

  Then, when there is power generation interconnection and the combination of the high and low characteristics of the line voltage read from the memory 15 is [AB phase, BC phase, CA phase] = [high, low, middle], “ Newly installed pole transformer for the distribution line in which the three-phase line voltage is measured in the process of S1 or the distribution line in which the three-phase line voltage is measured in the process of S1 The pole-mounted transformer newly installed for the distribution line connected to is connected to the BC phase (refer to the ninth stage of the “daytime” category in FIG. 3).

  Here, when solar power generation equipment is connected to a pole transformer newly installed on the distribution line when the maximum unbalance time is during the day, care should be taken to suppress voltage three-phase unbalance. Considering that solar power generation should be an element, refer to “Daytime” category for “Time zone”.

  If the combination of high and low characteristics of the line voltage is [AB phase, BC phase, CA phase] = [high, low, intermediate] when there is power generation interconnection in the “daytime” time zone, It is assumed that the status of power generation output is [AB phase, BC phase, CA phase] = [intermediate, low, high] (see "9th stage" in Fig. 3 where "time zone" is "daytime") ). Here, the situation where the photovoltaic power output is low includes the case where there is no photovoltaic power output.

  For this reason, in order to suppress future voltage three-phase imbalance, a new pillar where photovoltaic power generation facilities are connected to distribute the photovoltaic power generation output to the phase where the photovoltaic power generation output is the smallest in the present situation. The connection phase of the transformer is selected, and in the above case, it is specifically connected to the BC phase.

  On the other hand, when there is no power generation interconnection and the combination of the high and low characteristics of the line voltage read from the memory 15 is [AB phase, BC phase, CA phase] = [high, low, intermediate], “ Newly installed pole transformer for the distribution line in which the three-phase line voltage is measured in the process of S1 or the distribution line in which the three-phase line voltage is measured in the process of S1 The pole-mounted transformer newly installed with respect to the distribution line connected to is connected to the CA phase (refer to the 10th stage of “midnight” in FIG. 3).

  Here, even if the maximum unbalance time is during the daytime, in order to suppress voltage three-phase unbalance when solar power generation equipment is not connected to the pole transformer newly installed on the distribution line We consider that the factor to be noted is connected load, not photovoltaic power generation, and refer to the “midnight” category for “time zone”.

  In the “midnight” section, when [AB phase, BC phase, CA phase] = [high, low, intermediate], the load status is [AB phase, BC phase, CA phase] = [intermediate, Heavy (light) ”(refer to the 10th stage of“ midnight ”in FIG. 3).

  For this reason, in order to suppress future voltage three-phase imbalance, the connection phase of the newly installed pole transformer is selected so that the load is shared with the lightest phase in the current situation. To the CA phase.

  When power generation is connected and there is no voltage rise, even if the unbalanced maximum time is during the daytime, if there is no voltage rise during the daytime (for example, the pole transformer newly installed on the distribution line) The current voltage three-phase imbalance is improved because the cause of the voltage three-phase imbalance is not the photovoltaic power generation but the connected load. As a general rule, refer to the “midnight” category for “time zone”. However, when it is assumed that the photovoltaic power generation equipment connected to the pole transformer newly installed in the distribution line is large and the power generation output is large when there is power generation connection and there is no voltage increase When the unbalanced maximum time is during the daytime and a large-scale / high-output photovoltaic power generation facility is connected to the pole transformer newly installed on the distribution line (for example, the current To improve the future voltage three-phase imbalance because the factor to be noted to suppress the voltage three-phase imbalance (even if there is no voltage rise in the middle) is also considered to be solar power generation The “daytime” section may be referred to for the “time zone” with emphasis on the “time zone”.

  Examples of how to use the connection phase determination chart shown in FIG. 3 in the case of <I> improving the current voltage three-phase unbalance and in the case of <II> suppressing the voltage three-phase unbalance in the future. It is as follows.

  The contents of the connection phase determination chart shown in FIG. 3 are defined in the connection phase determination program 17, and the connection phase determination unit 11e reads the combination of the maximum unbalance time and the high / low characteristics of the line voltage, and When necessary, reading of the measured value of each line voltage at the unbalanced maximum time and determination of presence / absence of voltage increase are performed, and the connection phase of the pole transformer is changed or selected according to the connection phase determination chart.

  In addition, regarding the case of improving the current voltage three-phase imbalance and the case of suppressing the voltage three-phase imbalance in the future, it corresponds to the case where the operator has designated in advance via the input unit 13 and the designation is made. Only countermeasures to be performed may be determined, or countermeasures corresponding to both cases may be determined.

  In other words, the present invention may determine at least one of a countermeasure for improving the current voltage three-phase imbalance and a countermeasure for suppressing the future voltage three-phase imbalance. In other words, when considering only changing the connection phase of an existing pole transformer without assuming the installation of a pole transformer, determine only the measures to improve the current voltage three-phase imbalance and establish a new one. When considering only the selection of the connection phase of the pole transformer, decide only the countermeasures to suppress the future voltage three-phase imbalance, and change the connection phase of the existing pole transformer and establish a new one When considering from the viewpoint of selection of the connecting phase of the pole transformer, determine both the measures to improve the current voltage three-phase imbalance and the measures to suppress the voltage three-phase imbalance in the future Like that.

  In addition, regarding the case where a pole transformer that is connected to solar power generation equipment is newly installed and the case where a pole transformer that is not connected to solar power generation equipment is newly installed, Only the countermeasure corresponding to the case where the operator has designated in advance via the input unit 13 and the designation is made may be determined, or the countermeasure corresponding to each of both cases may be determined. May be.

  Then, the connection phase determination unit 11e changes the connection phase of the existing pole transformer when the current voltage three-phase unbalance is improved, or a new pole transformer that suppresses the future voltage three-phase imbalance. The selection contents of the connection phase of the device are recorded in a data file or the like and stored (saved) in the storage unit 12 or displayed on the display unit 14.

  And the control part 11 complete | finishes the process regarding a certain existing pole transformer or the newly installed pole transformer (END).

  According to the connection phase determination method, determination apparatus, and determination program configured as described above, the unbalance of the three-phase line voltages can be improved by simply measuring the three-phase line voltages of the distribution lines. Because the connection phase of the pole transformer can be determined, it is possible to determine the connection phase of the pole transformer without requiring a lot of effort and a large-scale mechanism. It is possible to improve the versatility.

  According to the connection phase determination method, determination apparatus, and determination program configured as described above, it is also appropriate to correct current three-phase voltage imbalance and prevent voltage three-phase imbalance in the future. Since it is possible to make decisions regarding appropriate countermeasures, it is possible to determine the connection phase according to need in various situations, and in this respect as well, to improve the versatility as a connection phase determination technique Is possible.

  Although the above-described embodiment is an example of a preferred embodiment for carrying out the present invention, the embodiment of the present invention is not limited to the above-described embodiment, and the present invention is not deviated from the gist of the present invention. Various modifications can be made. For example, in the above-described embodiment, the “midnight” category corresponding to “voltage three-phase imbalance due to the influence of connected load” and the “daytime” category corresponding to “voltage three-phase imbalance due to the effect of photovoltaic power generation” are classified. The connection phase determination chart (see FIG. 3) is used, but the present invention is not limited to this, and the connection phase of the pole transformer that is not connected to the photovoltaic power generation facility or the photovoltaic power generation facility is connected. When selecting a connection phase when newly installing a pole transformer that is not connected, a connection phase determination chart for only the “late night” section may be used.

  The verification example of the improvement effect of the voltage three-phase imbalance of the distribution line by the determination method of the connection phase of this invention is demonstrated using FIG. 16, FIG. 17A and FIG. 17B. In this embodiment, as a measure for improving the voltage three-phase unbalance, a pole transformer (specifically, any two of the three phases in a three-phase distribution line such as a single-phase transformer or a lighting common transformer) Transformer connected to) The effect is verified by taking up the case of changing the connection phase.

  In this example, the analysis case used in <Analysis VI> arranged in [Means for Solving the Problems] is the case before implementation of the improvement measure.

  As a measure for improvement, consider a case where the connection phase of the pole transformer is changed on the load side (that is, the downstream side opposite to the distribution substation) from the 32nd load point.

  First, the state before the implementation of the improvement measure is as shown in FIG. That is, when the three-phase line voltage of the distribution line is measured, the measurement data shown in FIG. 16 is acquired as the actual state before the improvement measure is implemented.

  Here, when the connection phase of the pole transformer is changed as a measure for improving the voltage three-phase imbalance, conventionally, the following measures may be taken based on the absolute value of the line voltage. It is common.

  Focusing on the midnight time zone, it is determined that the CA phase with the lowest line voltage is a heavy load phase, the AB phase with the highest line voltage is determined to be a light load phase, and the connection phase of the pole transformer Is determined to be appropriate from CA phase to AB phase.

  Also, paying attention to daytime hours, the CA phase with the highest line voltage is determined to be a phase with many photovoltaic power generation interconnections, and the AB phase with the lowest line voltage is the PV power generation interconnection. It is determined that there are few phases, and it is determined that it is appropriate to change the connection phase of the pole transformer from the CA phase to the AB phase.

  On the other hand, according to the connection phase determination method of the present invention, the combination of the high and low characteristics of the line voltage in the midnight time zone is [AB phase, BC phase, CA phase] = [high, middle, low] In FIG. 3, the “time zone” corresponds to the eighth stage of the “midnight” section, and it is determined that it is optimal to change the connection phase of the pole transformer from the BC phase to the AB phase.

  Further, since the combination of the high and low characteristics of the line voltage in the daytime time zone is [AB phase, BC phase, CA phase] = [low, middle, high], the “time zone” in FIG. It is determined that it is optimal to change the connection phase of the pole transformer from the BC phase to the AB phase.

  That is, according to the connection phase determination method of the present invention, it is possible to change the connection phase of the pole transformer from the BC phase to the AB phase regardless of whether it is focused on the midnight time zone or the daytime time zone. Determined to be optimal.

  The result shown in FIG. 17A is obtained as the three-phase line voltage after changing the connection phase of the pole transformer from the CA phase to the AB phase based on the conventional method. The result shown in FIG. 17B was obtained as the line voltage of each of the three phases after changing the connecting phase of the vessel from the BC phase to the AB phase.

  From the results shown in FIG. 17A, in the conventional method, although the voltage imbalance rate is slightly reduced, the BC phase voltage is separated from the AB phase voltage and approaches the CA phase voltage so as to approach the three phase line voltage. It was confirmed that the imbalance improvement effect of bringing the two close to each other cannot be obtained.

  On the other hand, from the result shown in FIG. 17B, according to the present invention, the ideal unbalance improvement effect that the voltage unbalance rate is greatly reduced as compared with the conventional method and the three-phase line voltages approach each other. It was confirmed that

  From the above results, the present invention has an ideal unbalance improvement effect of reducing the voltage unbalance rate and bringing the three-phase line voltages close to each other when changing the connection phase of the pole transformer. It was confirmed that the connection phase before and after the change can be determined so as to be obtained.

  Another verification example of the effect of improving the voltage three-phase imbalance of the distribution line by the connection phase determination method of the present invention will be described with reference to FIGS. 18, 19A, and 19B. In this example, as a measure for improving the voltage three-phase imbalance, a pole transformer in which photovoltaic power generation facilities are connected (specifically, in a three-phase distribution line such as a single-phase transformer or a lighting common transformer) The effect is verified by taking up the case where a transformer connected to any two of the three phases) is newly connected.

  In this example, the analysis case used in <Analysis VI> arranged in [Means for Solving the Problems] is the case before implementation of the improvement measure.

  Then, consider a case where a morning (late night) load such as a heat pump type hot water heater and a load simulating an all-electric apartment house to which photovoltaic power generation is attached are newly installed at the 39th load point.

  First, the state before implementation of the improvement measures is as shown in FIG. That is, when the three-phase line voltage of the distribution line is measured, the measurement data shown in FIG. 18 is acquired as the actual state before implementation of the improvement measure.

  Here, when a pole transformer connected to a photovoltaic power generation facility is newly connected, conventionally, the following measures are generally taken based on the absolute value of the line voltage. is there.

  Focusing on the midnight time zone, it is determined that the AB phase with the highest line voltage is a light load phase, and it is appropriate to connect a new pole transformer to the AB phase.

  In addition, paying attention to the daytime hours, it is appropriate to determine that the AB phase with the lowest line voltage is a phase with less photovoltaic power generation equipment interconnection, and connect a new pole transformer to the AB phase. It is judged that.

  On the other hand, according to the connection phase determination method of the present invention, the combination of the high and low characteristics of the line voltage in the midnight time zone is [AB phase, BC phase, CA phase] = [high, low, middle] In FIG. 3, “time zone” corresponds to the tenth stage of the “midnight” section, and it is determined that it is optimal to connect a new pole transformer to the CA phase.

  Further, since the combination of the high and low characteristics of the line voltage in the daytime time zone is [AB phase, BC phase, CA phase] = [low, high, middle], the “time zone” in FIG. It is determined that it is optimal to connect a new pole transformer to the CA phase.

  That is, according to the connection phase determination method of the present invention, the new pole transformer with the photovoltaic power generation system connected to the CA phase, regardless of whether it is focused on the midnight time zone or the daytime time zone. Is determined to be optimal.

  Then, the results shown in FIG. 19A are obtained as the three-phase line voltages after the pole transformer is newly connected to the AB phase based on the conventional method, and the pole transformer is connected to the CA phase based on the present invention. The results shown in FIG. 19B were obtained as the three-phase line voltages after the new connection.

  From the results shown in FIG. 19A, it was confirmed that the conventional method cannot obtain the imbalance improvement effect of bringing the three-phase line voltages close to each other.

  On the other hand, from the result shown in FIG. 19B, according to the present invention, it is confirmed that the ideal unbalance improvement effect that the voltage unbalance rate is reduced and the three-phase line voltages approach each other can be obtained. It was.

  From the above results, the present invention is ideal in reducing the voltage imbalance rate and bringing the three-phase line voltages close to each other when newly connecting a pole transformer to which a photovoltaic power generation facility is connected. It was confirmed that the connected phase can be determined so as to obtain an unbalance improvement effect.

10 Connection Phase Determination Device 17 Connection Phase Determination Program

Claims (9)

  The voltage of each three-phase line measured in the distribution line is used to calculate the voltage unbalance rate for each line for each measurement time, and the three-phase voltage at the measurement time at which the voltage unbalance rate is maximum is calculated. Each line voltage is used to create a combination of high and low voltage characteristics for each line, based on the measurement time at which the voltage unbalance rate is maximized and the combination of high and low voltage characteristics for each line. A method for determining a connection phase, wherein a connection phase of a pole transformer is determined.   Changing the connection phase of the existing pole transformer to improve the current unbalance of the three-phase line voltage, and a new pillar to suppress the unbalance of the three-phase line voltage in the future The method for determining a connection phase according to claim 1, wherein determination regarding at least one of selection of a connection phase of the upper transformer is performed.   The connection phase determination method according to claim 1, wherein each of the three-phase line voltages is measured by a switch equipped with a three-phase measurement function installed in the distribution line.   Means for calculating a voltage unbalance rate for each line by measurement time using each of the three-phase line voltages measured in the distribution line, and the three phases at the measurement time at which the voltage unbalance rate is maximum A means for creating a combination of high and low voltage characteristics for each line using each line voltage, a measurement time at which the voltage imbalance rate is maximized, and a combination of high and low voltage characteristics for each line. Means for determining a connection phase of the pole transformer based on the connection phase.   Changing the connection phase of the existing pole transformer to improve the current unbalance of the three-phase line voltage, and a new pillar to suppress the unbalance of the three-phase line voltage in the future 5. The connection phase determination device according to claim 4, wherein determination regarding at least one of selection of a connection phase of the upper transformer is performed.   The connection phase determination device according to claim 4, wherein the three-phase line voltage is measured by a switch with a three-phase measurement function installed in the distribution line.   A process of calculating a voltage unbalance rate for each line by measurement time using each of the three-phase line voltages measured in the distribution line, and the three phases at the measurement time at which the voltage unbalance rate is maximum A process for creating a combination of high and low voltage characteristics for each line using each line voltage, a measurement time at which the voltage imbalance rate is maximized, and a combination of high and low voltage characteristics for each line. A connection phase determination program characterized by causing a computer to perform processing for determining a connection phase of a pole transformer based on the computer.   Changing the connection phase of the existing pole transformer to improve the current unbalance of the three-phase line voltage, and a new pillar to suppress the unbalance of the three-phase line voltage in the future 8. The connection phase determination program according to claim 7, wherein determination regarding at least one of selection of a connection phase of the upper transformer is performed.   The connection phase determination program according to claim 7, wherein the three-phase line voltage is measured by a switch with a three-phase measurement function installed in the distribution line.

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