JP2007028813A - State deteminator in single-phase three-wire system and method therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To determine a load state or an outlet assignment system by specifying the cause of momentary voltage fluctuations in charging or releasing load. <P>SOLUTION: A total power computer 21 obtains total electric power supplied to power wires in single-phase three-wire system, while an unbalanced power computer 22 computes unbalanced power which is a difference between first system power between one wire 12A and a neutral conductor 13, and second system power between another wire 12B and the neutral conductor 13. A total power fluctuation computer 23 computes fluctuations in total power and an unbalanced power fluctuation computer 25 computes fluctuations in unbalanced power. A determinator 24 determines possible causes for the voltage fluctuations, load states, and the outlet assignment system in the single-phase three wire system on the basis of the fluctuations in total power and the fluctuations in unbalanced power. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a single-phase three-wire state determination apparatus and method for estimating a cause of voltage fluctuation, a load state, or an outlet affiliation system of a single-phase three-wire type having two voltage lines and a neutral line.

  The single-phase three-wire distribution system has two voltage lines and a neutral line. A 100 V distribution line is drawn from between each voltage line and the neutral line, and a 200 V system is drawn from between the two voltage lines. Each distribution line is pulled out. For example, in a single-phase three-wire 100V distribution system, a 200V distribution line and two 100V distribution lines are drawn. In such a low-voltage distribution system, the electric wire is thin, and a failure such as instantaneous voltage fluctuation may occur when the load is turned on or off. In that case, whether the load causing the failure is a load connected to a 200 V distribution line, a load connected to a 100 V system, or a load connected to any of the 100 V distribution lines It is fundamental to make a countermeasure against instantaneous voltage fluctuation.

Here, if there is a drop or rise in the input voltage of the single-phase three-wire distribution system, this is automatically detected, and the voltage value within the set range is always output by switching the circuit, affecting the load. There is one in which the voltage is adjusted so as not to be applied (see, for example, Patent Document 1).
JP-A-8-191542

  However, in Patent Document 1, the voltage of the distribution system can be adjusted to a voltage value within a set range, but the cause of the instantaneous voltage fluctuation at the time of loading or unloading is either 200V system or two 100V systems. It is not possible to identify. In addition, the load distribution in the 100V system cannot be accurately grasped, and the 100V system to which each outlet belongs cannot be specified, and it is difficult to obtain a countermeasure guideline.

  In general, loads connected to two 100V distribution lines are unbalanced. When the degree of unbalance is excessive, problems such as increased loss and voltage imbalance in distribution lines and indoor wiring occur. For this reason, there is a demand for a technique that accurately grasps the state of an unbalanced load and makes it possible to correct it. However, it is difficult to determine the 100V system to which the outlet to which the load is actually connected by indoor wiring belongs. It becomes a bottleneck in balance correction. Therefore, a method for determining a 100V system to which an arbitrary outlet belongs is desired.

  An object of the present invention is to provide a single-phase three-wire state determination apparatus and method that can identify the cause of instantaneous voltage fluctuation when a load is applied or the load is released, and that can determine the load state or the outlet system.

  The single-phase three-wire state determination device according to the first aspect of the present invention includes a single-phase three-wire type voltage line between two voltage lines and a neutral line, and the other voltage line and neutral line. System power calculation means for calculating the power injected between each system, and the total power calculated by the power calculation means for each system as the total power injected into the single-phase three-wire system Power calculation means, unbalanced power calculation means for calculating the power difference between the two systems calculated by the system power calculation means as unbalanced power of the two voltage lines of the single-phase three-wire system, and the total power calculation A total power fluctuation calculating means for calculating the fluctuation of the total power obtained by the means, an unbalanced power fluctuation calculating means for calculating the fluctuation of the unbalanced power obtained by the unbalanced power calculating means, Total power obtained by the total power calculation means, obtained by the unbalanced power calculation means Causes of voltage fluctuation of a single-phase three-wire system based on the unbalanced power, the total power fluctuation obtained by the total power fluctuation calculating means, and the unbalanced power fluctuation obtained by the unbalanced power fluctuation calculating means And determining means for determining a load state or a system to which the outlet belongs.

  A single-phase, three-wire state determination device according to a second aspect of the present invention is the single-phase three-wire state determination device according to the first aspect, wherein the determination means causes an instantaneous voltage fluctuation when the total power fluctuation is negative. When the total power fluctuation is positive, it is determined that the cause of the instantaneous voltage fluctuation is the load application.

  A single-phase three-wire state determination device according to a third aspect of the present invention is the single-phase three-wire state determination device according to the first or second aspect, wherein the determination means is configured such that the absolute value of the total power fluctuation is greater than the absolute value of the unbalanced power fluctuation Determines that the cause of the instantaneous voltage fluctuation is a 200V load fluctuation between the two voltage lines, and when the absolute value of the total power fluctuation and the absolute value of the unbalanced power fluctuation are substantially equal, The cause of the fluctuation is determined to be a load fluctuation of a 100 V system between each voltage line and the neutral line.

  According to a fourth aspect of the present invention, there is provided the single-phase three-wire state determination device according to any one of the first to third aspects, wherein the determination means is 100V between each voltage line and the neutral line. When a load change of the system occurs, it is determined whether the cause of the change is the input of the load or the load is released based on the positive / negative of the total power fluctuation, and the 100V system to which the variable load belongs is specified by the positive / negative of the unbalanced power fluctuation. And

  According to a fifth aspect of the present invention, there is provided the single-phase three-wire state determination device according to any one of the first to fourth aspects, wherein the determination means is an unbalanced power when a load connected to an outlet is turned on / off. It is characterized in that the belonging system to which the outlet belongs is specified based on the positive and negative of the fluctuation.

  The single-phase three-wire state determination method according to the invention of claim 6 is provided between one voltage line and a neutral line of two voltage lines of the single-phase three-wire type and between the other voltage line and the neutral line. Power calculated between the two systems, the sum of the calculated power of both systems is calculated as the total power injected into the single-phase three-wire system, and the calculated power difference between the two systems is calculated as the single-phase three-wire Obtained as the unbalanced power of the two voltage lines in the equation, and determines the cause of the voltage fluctuation, load state or outlet belonging system of the single-phase three-wire system based on the fluctuation of the total power and the fluctuation of the unbalanced power It is characterized by that.

  According to the present invention, the total power injected into the single-phase three-wire system, the two unbalanced power of the 100V system, and their fluctuations are calculated, and based on these, the system state of the three-phase three-wire system is determined. It is possible to determine the cause of voltage fluctuation, load status or outlet belonging system of single-phase three-wire system.

  Embodiments of the present invention will be described below. FIG. 1 is a block diagram of a single-phase three-wire state determination device 11 according to an embodiment of the present invention.

  First, the single-phase three-wire distribution system has three electric wires of two voltage lines 12A and 12B and a neutral wire 13, the voltage wire 12A being a phase, the neutral wire 13 being b phase, and the voltage wire. Let 12B be the c phase. A single-phase voltage power source 14A is connected between the ab phase (hereinafter referred to as the first system) between one voltage line 12A and the neutral line 13, and between the bc phase (hereinafter referred to as the first line) between the other voltage line 12B and the neutral line 13. A single-phase voltage power supply 14B is connected to two systems) to form a 100V system, and a 200V system is formed between ac phases of one voltage line 12A and the other voltage line 12B. 100V loads Rab and Rbc are connected to the single-phase voltage power supplies 14A and 14B, respectively, and a 200V load Rac is connected between the voltage lines 12A and 12B.

  Normally, the voltage Vab of the single-phase voltage power supply 14A and the voltage Vbc of the single-phase power supply voltage 14B have the same voltage value, for example, 100 V in the case of power distribution to a general household. Therefore, in that case, the loads Rab and Rbc connected between the voltage lines 12A and 12B and the neutral line 13 are 100V, and the load Rac connected between the voltage lines 12A and 12B is 200V. When the voltages Vab and Vbc are 200V, the loads Rab and Rbc are 200V and the load Rac is 400V.

  In such a single-phase three-wire distribution system, 100V (200V) system loads Rab and Rbc and 200V (400V) system load Rac are connected. Or unbalanced load. Therefore, the single-phase three-wire state determination device 11 in the embodiment of the present invention is connected to such a single-phase three-wire distribution line, and the cause of instantaneous voltage fluctuation, the load state, or the outlet affiliated system is determined. To do.

  The currents Ia and Ic flowing through the voltage lines 12A and 12B are detected by the current detectors 15A and 15B, respectively, converted into digital signals at a predetermined sampling period by the AD converter 17 of the state determination device 11, and stored in the storage device 18. The Similarly, the voltages Vab and Vbc of the single-phase voltage power supplies 14A and 14B are detected by the voltage detectors 16A and 16B, respectively, and converted into digital signals at a predetermined sampling period by the AD converter 17 of the state determination device 11 to be stored in the storage device. 18 is stored.

The system power calculation means 20 of the calculation control device 19 includes a power Pab (hereinafter referred to as a first system power Pab) injected between one voltage line 12A of the single-phase three-wire system and the neutral line 13, and the other. The power Pbc injected between the voltage line 12B and the neutral line 13 (hereinafter referred to as second system power Pbc) is calculated. The first system power Pab and the second system power Pbc are (1) based on the currents Ia and Ic flowing in the voltage lines 12A and 12B stored in the storage device 18 and the voltages Vab and Vbc of the single-phase voltage power supplies 14A and 14B. ) And (2). Incidentally, integration length T is given by when the commercial frequency _{f N (T = 1 / f} N).

The first grid power Pab and the second grid power Pbc calculated by the grid power calculation means 20 are input to the total power calculation means 21 and the unbalanced power calculation means 22. The total power calculation means 21 is the total power injected into the single-phase three-wire system, as shown in the equation (3), by summing the first system power Pab and the second system power Pbc calculated by the system power calculation means 20. Calculate as _PT . Further, the unbalanced power calculation means 22 calculates the difference between the first system power Pab and the second system power Pbc calculated by the system power calculation means 20 as shown in the equation (4) in a single-phase three-wire system. It is calculated as unbalanced power P _U of two voltage lines. That is, the first system power Pab seeks imbalance power P _U to the case of the larger than the second grid power Pbc positive.

P _T = Pab + Pbc (3)
P _U = Pab−Pbc (4)
The total power P _T calculated by the total power computing means 21 is input to the total power variation calculating means 23, an unbalanced power P _U calculated by the imbalance power calculating means 22 25, and imbalance power fluctuation calculating means Input to the determination means 24.

The total power fluctuation calculating section 23 are those for calculating the variation [Delta] P _T of the total power _{P T,} for example, the total power _P T of the current and (i) 1 cycle before full power _P T and (i-1) the difference is calculated as the total power variation [Delta] P _T, and outputs the total power fluctuation [Delta] P _T to the determining means 24. Similarly, imbalance power variation calculating means 25 is for calculating the variation [Delta] P _U of the imbalance power P _U, for example, current imbalance power P _{U (i)} one cycle before the imbalance power the difference between P T _(i-1) is calculated as the imbalance power fluctuation [Delta] P _U, and outputs the imbalance power fluctuation [Delta] P _U to the determining means 24. Note that the total power fluctuation ΔP _T and the unbalanced power fluctuation ΔP _U may be obtained using data several cycles before instead of the data one cycle before.

  The instantaneous voltage fluctuation detection means 26 detects that the first system voltage Vab and the second system voltage Vbc have changed instantaneously, and the instantaneous voltage fluctuation detection means 26 detects the first system voltage Vab or the second system voltage Vbc. When the instantaneous voltage fluctuation is detected, the determination means 24 is notified accordingly.

Judging means 24, when the instantaneous voltage variation detection unit 26 detects an instantaneous voltage variation is obtained at full power variation [Delta] P _T and imbalance power variation calculating means 25 obtained at full power variation calculating means 23 Based on the unbalanced power fluctuation ΔP _U , the cause of the single-phase three-wire voltage fluctuation is determined. Further, based on the imbalance power P _U obtained in an unbalanced power computing means 22 determines the load state of steady. Further, based on the total power fluctuation ΔP _T obtained by the total power fluctuation calculating means 23 and the unbalanced power fluctuation ΔP _U obtained by the unbalanced power fluctuation calculating means 25, a single-phase three-wire outlet Determine the affiliated line. Then, these determination results are output to the output device 27.

  Next, the determination of the cause of voltage fluctuation in the determination means 24, the determination of the normal load state, or the determination of the outlet affiliated system will be described.

[1] Determination of Cause of Voltage Fluctuation (a) Determination of Open / Close of Load FIG. When there is an instantaneous voltage fluctuation, the determination unit 24 inputs the total power fluctuation ΔP _T (S1) as shown in FIG. 2, and determines whether or not the total power fluctuation ΔP _T is negative. (S2). Cause instantaneous voltage fluctuation when full power fluctuation [Delta] P _T is negative is determined to be open load (S3). On the other hand, in the judgment of step S2, when the total power fluctuation [Delta] P _T is not negative, the total power variation [Delta] P _T is determined whether is positive (S4), the total power variation [Delta] P _T is positive When it is, it is determined that the cause of the instantaneous voltage fluctuation is load input (S5).

In this way, when there is a load fluctuation, an instantaneous voltage fluctuation occurs. Therefore, the cause of the instantaneous voltage fluctuation in that case is an instantaneous voltage fluctuation due to the load application when the total power fluctuation ΔP _T is positive. When the power fluctuation amount ΔP _T is negative, it is determined that the voltage fluctuation is an instantaneous voltage fluctuation due to the opening of the load.

(B) Determination of 200V system / 100V system Next, the determination of whether the system in which the load fluctuation has occurred is the 200V system or the 100V system will be described. FIG. 3 is a flowchart showing the contents of determination processing in the determination means 24 regarding whether the cause of voltage fluctuation is the 200V system or the 100V system. As shown in FIG. 3, the total power fluctuation ΔP _T and the unbalanced power fluctuation ΔP _U are input (S1), and the absolute values | ΔP _T | and | ΔP _U | are obtained (S2). Then, it is determined whether or not the absolute value | ΔP _T | of the total power fluctuation is larger than the absolute value | ΔP _U | of the unbalanced power fluctuation (S3). When the absolute value | ΔP _T | of the total power fluctuation is larger than the absolute value | ΔP _U | of the unbalanced power fluctuation, the cause of the instantaneous voltage fluctuation is the load of the 200V system between the two voltage lines 12A and 12B. It is determined that it is a fluctuation (S4).

On the other hand, if the absolute value | ΔP _T | of the total power fluctuation is not larger than the absolute value | ΔP _U | of the unbalanced power fluctuation in the determination in step S3, the absolute value | ΔP _T | the absolute value of the imbalance power fluctuation | [Delta] P U _| and it is determined whether approximately equal, the absolute value of the total power fluctuation | [Delta] P T _| unbalanced power fluctuation in the absolute value | [Delta] P U _| Togahobo If equal, it is determined that the cause of the instantaneous voltage fluctuation is a 100V load fluctuation between the voltage lines 12A, 12B and the neutral line 13 (S6).

Thus, the absolute value | ΔP _U | for the unbalanced power fluctuation indicates an unbalance of the load fluctuation of the 100V system. Therefore, when the load fluctuation occurs, the absolute value | ΔP _T | When the absolute value of the unbalanced power fluctuation is larger than | ΔP _U |, it can be determined that the load fluctuation is 200V. On the other hand, when the absolute value | ΔP _T | of the total power fluctuation is almost equal to the absolute value | ΔP _U | of the unbalanced power fluctuation, the total power fluctuation is reflected as it is in the load fluctuation of the 100V system. Therefore, it can be determined that the load fluctuation is 100V.

(C) Determination of input / release of 100V load Next, determination of input / release of a 100V load will be described. FIG. 4 is a flowchart showing the content of determination processing for turning on / off the 100V system load by the determination means 24. As shown in FIG. 4, the total power fluctuation ΔP _T and the unbalanced power fluctuation ΔP _U are input (S1), and it is determined whether or not the total power fluctuation ΔP _T is positive (S2). When full power variation [Delta] P _T is positive, the imbalance power fluctuation [Delta] P _U is determined whether is positive (S3), when the imbalance power fluctuation [Delta] P _U is positive, first It is determined that the system (between ab phases) is loaded (S4). If it is determined in step S3 that the unbalanced power fluctuation ΔP _U is not positive, it is determined whether or not the unbalanced power fluctuation ΔP _U is negative (S5). When the unbalanced power fluctuation ΔP _U is negative, it is determined that the second system (between bc phases) is loaded (S6).

That is, a load variation is turned on when full power fluctuation [Delta] P _T is positive, so when the imbalance power P _U is positive is the first system power Pab is when larger than the second grid power Pbc, total power When both the variation ΔP _T and the unbalanced power variation ΔP _U are positive, it is determined that the load is applied to the first system (between the ab phases). Similarly, when the total power fluctuation ΔP _T is positive and the unbalanced power fluctuation ΔP _U is negative, it is determined that the load is applied to the second system (between the bc phases).

On the other hand, if it is determined in step S2 that the total power fluctuation ΔP _T is not positive, it is determined whether or not the unbalanced power fluctuation ΔP _U is negative (S7). When the unbalanced power fluctuation ΔP _U is negative, it is determined that the load of the first system (between the ab phases) is released (S8). If it is determined in step S7 that the unbalanced power fluctuation amount ΔP _U is not negative, it is determined whether or not the unbalanced power fluctuation amount ΔP _U is positive (S9). When the unbalanced power fluctuation ΔP _U is positive, it is determined that the load of the second system (between the bc phases) is released (S10).

That is, the load fluctuation when the total power fluctuation [Delta] P _T is negative is open, so when the imbalance power P _U is negative is when the first system power Pab smaller than the second grid power Pbc, total power When the variation ΔP _T is negative and the unbalanced power variation ΔP _U is negative, it is determined that the load of the first system (between the ab phases) is released. Similarly, when the total power fluctuation ΔP _T is negative and the unbalanced power fluctuation ΔP _U is positive, it is determined that the load of the second system (between the bc phases) is released.

As described above, when the 100V load fluctuation between the voltage lines 12A and 12B and the neutral line 13 occurs, the determination means 24 determines whether the cause of the fluctuation is the load input or not depending on whether the total power fluctuation ΔP _T is positive or negative. Whether it is open or not is determined, and the 100V system to which the fluctuating load belongs is specified by whether the unbalanced power fluctuation ΔP _U is positive or negative.

[2] determining the determination means 24 of the load condition of the steady state monitors the imbalance power P _U in the absence of detection of the instantaneous voltage variation due to instantaneous voltage change detecting unit 26. FIG. 5 is a flowchart showing the determination processing contents of the load state at the steady state in the determination means 24. As shown in FIG. 5, enter the imbalance power P _U obtained in an unbalanced power computing means 22 (S1), it determines whether the imbalance power P _U is positive (S2). When the imbalance power P _U is positive, it is determined that the load of the ab phases (first line) is greater than the load of bc phases (second line) (S3). On the other hand, in the judgment of step S3, if the imbalance power P _U is not positive is the imbalance power P _U is equal to or negative (S4), imbalance power P _U is negative In this case, it is determined that the load between the bc phases (second system) is larger than the load between the ab phases (first system) (S6). Thereby, the magnitude of the load of the 1st system and the 2nd system which are 100V systems can be detected also at the time of steady state.

[3] Identification of outlet affiliated system Next, the determination unit 24 identifies the affiliated system to which the outlet belongs based on the positive / negative of the unbalanced power fluctuation ΔP _U when the load connected to the outlet is turned on / off. . FIG. 6 is a flowchart showing the contents of determination processing for identifying the affiliation system to which the outlet belongs in the determination means 24. As shown in FIG. 6, a load is connected to an outlet where the first system or the second system is unknown (S1). Then, the load connected to the outlet is turned on / off (S2). Since the total power fluctuation ΔP _T and the unbalanced power fluctuation ΔP _U fluctuate due to the on / off of the load connected to the outlet, the fluctuation is monitored and the belonging system to which the outlet belongs is specified.

That is, the total power fluctuation ΔP _T and the unbalanced power fluctuation ΔP _U are input (S3), and it is determined whether or not the total power fluctuation ΔP _T is positive (S4). When full power variation [Delta] P _T is positive, it is determined whether further imbalance power fluctuation [Delta] P _U is positive (S5), when the imbalance power fluctuation [Delta] P _U is positive, the load Is determined to belong to the ab phase (first system) (S6). On the other hand, the determination in step S5, when the imbalance power fluctuation [Delta] P _U is not positive, the imbalance power fluctuation [Delta] P _U is equal to or negative (S7), the imbalance power fluctuation [Delta] P _U When it is negative, it is determined that the outlet connected to the load belongs to the bc phase (second system) (S8).

Thus, it can be determined that the total power variation [Delta] P _T is load application since it is positive, as further first system power Pab is the imbalance power P _U is positive when greater than the second grid power Pbc Therefore, when the unbalanced power fluctuation ΔP _U is positive, it can be determined that the load is applied to the first system, and when the unbalanced power fluctuation ΔP _U is negative, it can be determined that the load is applied to the second system. .

Next, if it is determined in step S4 that the total power fluctuation ΔP _T is not positive, it is determined whether or not the unbalanced power fluctuation ΔP _U is negative (S9), and the unbalanced power fluctuation ΔP _U is determined. When it is negative, it is determined that the load between the ab phases (first system) is released (S10). Further, when the imbalance power fluctuation [Delta] P _U is not negative, the imbalance power fluctuation [Delta] P _U is determined whether is positive (S11), when the imbalance power fluctuation [Delta] P _U is positive, It is determined that the load between the bc phases (second system) is released (S12).

In this case, it can be determined that the total power variation [Delta] P _T is load open because it is negative, as further first system power Pab is the imbalance power P _U is positive when greater than the second grid power Pbc Therefore, when the unbalanced power fluctuation amount ΔP _U is negative, it can be determined that the load is released in the first system, and when the unbalanced power fluctuation amount ΔP _U is positive, it can be determined that the load is released in the second system. .

  Therefore, it is possible to know whether the 100V system power outlet is the first system (between the ab phases) or the second system (between the bc phases), which is useful for improving the actual load unbalance state. In other words, it is possible to determine which system belongs to an on / off load connected to the outlet.

The block block diagram of the single-phase three-wire-type state determination apparatus concerning embodiment of this invention. The flowchart which shows the determination processing content of the voltage fluctuation cause in the determination means in embodiment of this invention. The flowchart which shows the determination processing content whether the voltage fluctuation cause in the determination means in embodiment of this invention is a 200V type | system | group or a 100V type | system | group. The flowchart which shows the determination processing content of the input / release of a 100V type | system | group load in the determination means in embodiment of this invention. The flowchart which shows the determination processing content of the load state at the time of the steady state in the determination means in embodiment of this invention. The flowchart which shows the determination processing content for specifying the affiliation system to which the outlet in the determination means in embodiment of this invention belongs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... State determination apparatus, 12 ... Voltage line, 13 ... Neutral line, 14 ... Single phase voltage power supply, 15 ... Current detector, 16 ... Voltage detector, 17 ... AD converter, 18 ... Memory | storage device, 19 ... Calculation Control device, 20: System power calculation means, 21: Total power calculation means, 22 ... Unbalanced power calculation means, 23 ... Total power fluctuation calculation means, 24 ... Determination means, 25 ... Unbalance power fluctuation calculation means, 26 ... Instantaneous voltage fluctuation detecting means, 27 ... Output device

Claims (6)

A system-by-system power calculation means for calculating power injected between one voltage line and a neutral line of the two voltage lines of the single-phase three-wire system and between the other voltage line and the neutral line; ,
Total power calculation means for calculating the sum of the powers of both systems calculated by the system power calculation means as the total power injected into the single-phase three-wire system,
Unbalanced power computing means for computing the power difference between the two systems computed by the system power computing means as unbalanced power of the two voltage lines of the single-phase three-wire system,
A total power fluctuation calculating means for calculating a fluctuation of the total power obtained by the total power calculating means;
Unbalanced power fluctuation calculating means for calculating the fluctuation of the unbalanced power obtained by the unbalanced power calculating means;
Determining means for determining a single-phase three-wire voltage fluctuation cause based on the total power fluctuation obtained by the total power fluctuation computing means and the unbalanced power fluctuation obtained by the unbalanced power fluctuation computing means; A single-phase, three-wire state determination device characterized by comprising:   The determination means determines that the cause of the instantaneous voltage fluctuation is an open load when the total power fluctuation is negative, and the cause of the instantaneous voltage fluctuation is a load input when the total power fluctuation is positive. The single-phase three-wire state determination device according to claim 1, wherein the state determination device is determined to be present.   When the absolute value of the total power fluctuation is larger than the absolute value of the unbalanced power fluctuation, the determination unit determines that the cause of the instantaneous voltage fluctuation is a 200 V load fluctuation between two voltage lines, When the absolute value of the total power fluctuation and the absolute value of the unbalanced power fluctuation are approximately equal, it is determined that the cause of the instantaneous voltage fluctuation is a 100V load fluctuation between each voltage line and the neutral line. The single-phase three-wire state determination apparatus according to claim 1 or 2, wherein   The determination means determines whether the cause of the change is a load on or a load release based on the positive / negative of the total power fluctuation when a 100V load fluctuation occurs between each voltage line and the neutral line. The single-phase three-wire state determination device according to any one of claims 1 to 3, wherein a 100V system to which a fluctuating load belongs is specified based on whether the power fluctuation is positive or negative.   5. The system according to claim 1, wherein the determination unit specifies a system to which the outlet belongs, based on whether the unbalanced power fluctuation at the time of turning on / off the load connected to the outlet is positive or negative. The single-phase three-wire state determination device according to one. Calculating the electric power injected between one of the two voltage lines of the single-phase three-wire system and the neutral line and between the other voltage line and the neutral line;
Calculate the sum of the calculated power of both systems as the total power injected into the single-phase three-wire system,
The difference between the calculated powers of both systems is determined as the unbalanced power of the two voltage lines of the single-phase three-wire system,
A single-phase three-wire state determination method, wherein the single-phase three-wire voltage fluctuation cause, load state, or outlet affiliation system is determined based on the total power fluctuation and the unbalanced power fluctuation .

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