JP3814640B2 - Distribution system state estimation method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to monitoring and control of a distribution system, and in particular, based on limited measurement information, the state of a distribution system suitable for accurately estimating the load current and the like of each section serving as a base for monitoring and control The present invention relates to an estimation method and apparatus.
[0002]
[Prior art]
The power distribution system is usually configured by connecting a distribution substation and a plurality of customers at a supply destination through distribution lines. Each distribution line is operated independently of each other, and each distribution line has switches everywhere so that it can be disconnected from the accident and linked to other distribution lines. It is installed and a plurality of load sections are set. Understanding the power (load current) in the load section, which is the unit of operation for distribution lines and distribution systems, is extremely important, but normally only the send current at the root of the distribution line has been measured. The measured value is apportioned by the contract current value of each section (the total value of the customer contract amount in each section) to obtain the load current and the like of each section.
[0003]
[Problems to be solved by the invention]
Various customers are connected to the distribution line, and because the composition of the types of customers (types) and the characteristics of load changes differ from section to section, delivery is performed on the premise of uniform load changes in all sections as in the conventional technology. The load current cannot be estimated with high accuracy by the method of estimating the load current of each section by dividing the measured current value by the contract current value of each section. As a method for compensating for this, for example, as described in Japanese Patent Application Laid-Open No. 2000-244504, partially available measurement values are used for estimation of the section, and the injection power assumed for each section is calculated. Although it is conceivable to adopt a method for evaluating and estimating the variation, at present, the number of measurement points is small and there is a demand for higher accuracy.
[0004]
The subject of this invention is providing the state estimation method and apparatus of a distribution system which can estimate area load with high precision based on the limited measurement information.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention measures the sending current of a distribution line divided into a plurality of sections, the assumed value of the daily load change characteristic for each consumer type included in each section, and the assumption thereof The load current estimated value for each section and its assumed accuracy are calculated based on the accuracy, the estimated current value is calculated from the load current estimated value for each section, the measured value of the transmitted current and the A deviation from the estimated value of the sending current is calculated, the deviation is distributed according to an assumed accuracy regarding the load current estimated value in each section, a correction amount in each section is calculated, and the load current estimation in each section is calculated. A distribution system state estimation method is adopted in which the value is corrected by the correction amount and the load current or power in each section is estimated.
[0006]
When adopting the state estimation method of the distribution system, the following process can be adopted as a process for calculating an estimated load current value and its assumed accuracy for each section.
[0007]
Based on the assumed value of the daily load change characteristic for each consumer type included in each section, a load current estimated value for each consumer type in each section is calculated, and for each section based on this load current expected value Load current estimated value, and based on the assumed accuracy of the daily load change characteristics for each consumer type included in each section, to calculate the assumed accuracy of the load current estimated value for each consumer type in each section, Based on the assumed accuracy of the assumed load current value, the assumed accuracy relating to the estimated load current value for each section is calculated.
[0008]
In adopting the state estimation method for each distribution system, the following elements can be added.
[0009]
(1) When calculating the correction amount in each of the sections, the correction amount is made smaller for a section with a high assumed accuracy for the load current estimated value than for a low section, and conversely the assumed accuracy for the load current estimated value is The correction amount is set larger for the lower section than for the higher section.
[0010]
(2) The assumed value of the daily load change characteristic for each consumer type included in each section and the assumed accuracy use measurement information obtained by measuring the consumer.
[0011]
(3) The deviation is stored for each state estimation point of the distribution system, and the contribution of the saved deviation is calculated in association with each customer type, and each calculated contribution is assigned to the designated distribution line or all distributions. Add up the wires to calculate the total value and display each total value on demand.
[0012]
Further, the present invention is based on a sending current measuring means for measuring a sending current of a distribution line divided into a plurality of sections, and an assumed value of daily load change characteristics for each consumer type included in each section. A load current estimated value calculating means for calculating an estimated load current value for each section, and a load for each section based on an assumed accuracy regarding an assumed value of a daily load change characteristic for each consumer type included in each section. Assumed accuracy calculating means for calculating assumed accuracy related to the estimated current value, sent current estimated value calculating means for calculating an estimated value of the sent current from the calculation result of the load current estimated value calculating means, and measurement of the sent current A deviation calculating means for calculating a deviation between a value and an estimated value of the delivery current, and a correction amount for calculating a correction amount in each section by allocating the deviation according to the assumed accuracy calculated by the assumed accuracy calculating means Calculating means and the negative The state of the distribution system comprising: an estimation unit that estimates the load current or power in each section by correcting the load current estimation value in each section calculated by the current estimation value calculation unit with the correction amount calculated by the correction unit An estimation apparatus is configured.
[0013]
When configuring the distribution system state estimation device, instead of the load current estimated value calculation means, the assumed accuracy calculation means, and the correction amount calculation means, daily load change for each consumer type included in each section Load current estimated value calculation means for calculating the load current expected value for each consumer type in each section based on the assumed value of the characteristic, and the load current estimated value is calculated based on the calculation result of the load current assumed value calculation means The estimated accuracy of the load current estimated value for each consumer type in each section based on the estimated accuracy regarding the estimated value of the load current estimated value calculating means and the daily load change characteristic for each consumer type included in each section A first assumed accuracy calculating means for calculating; a second assumed accuracy calculating means for calculating an assumed accuracy relating to a load current estimated value for each section based on a calculation result of the first assumed accuracy calculating means; It can be a deviation by calculating the difference calculating means and distributed according to the assumed accuracy of calculation of the second assumed accuracy computing means using the correction amount calculating means for calculating a correction amount in each section.
[0014]
According to the above-described means, the load current estimated value and the assumed accuracy for each section are calculated based on the assumed value of the daily load change characteristic for each consumer type included in each section and the assumed accuracy, and each section is calculated. For example, the estimated load current value is added for each section to calculate the estimated current value, and the deviation between the measured current value and the estimated current value is calculated as a mismatch. Since the amount of correction for each section is calculated according to the assumed accuracy of the value and the estimated load current value for each section is corrected according to the amount of correction, the load current or power is increased as the section load of each section. The accuracy can be estimated.
[0015]
In addition, when different types of customers are connected to each section, the load current estimated value for each customer type in each section based on the assumed daily load change characteristics for each customer type included in each section Calculate the assumed accuracy of the load current assumption value for each consumer type in each section based on the assumed accuracy of the daily load change characteristics for each consumer type included in each section, and estimate the load current for each section By calculating the assumed accuracy regarding the value and the assumed load current value, the load current or power in each section can be estimated with high accuracy.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a power distribution system to which the present invention is applied and its monitoring / control system. In FIG. 1, a distribution transformer 100 connected to an upper distribution system is connected to a plurality of distribution lines 110 through a bus 101, and a breaker is included in the distribution line 110. 105, division switches 111, 112, 113, 114 are installed. The distribution line 110 is divided into a plurality of sections # 1, # 2, # 3, and # 4 by section switches 111, 112, 113, and 114. For example, ordinary houses, factories, offices, schools, and the like are connected to the section # 1 as consumers. Consumers such as ordinary houses and factories are also connected to the sections # 2 to # 4.
[0017]
In order to monitor and control the state of the distribution line 110, a current transformer 121 is installed in the distribution line 110 between the circuit breaker 105 and the section switch 111. The current transformer 121 is configured as a delivery current measuring unit that measures the delivery current of the distribution line 110. The send-out current measured by the current transformer 121 is transmitted to the communication slave station 131 and the communication master station 150, and stored in the database 160 as send-out current measurement data.
[0018]
In addition, communication slave stations 132, 133, 134, and 135 are provided to control opening and closing of the division switches 111 to 114, and each of the communication slave stations 132 to 135 is connected to the communication master station 150 via the communication line 130. It is connected to the. In addition, a communication slave station 136 is connected to the interconnection switch 115 provided in the line of another distribution line connected to the distribution line 110 in the section # 2, and the communication slave station 136 is connected to the communication line 130. To the communication master station 150. Each of the communication slave stations 132 to 136 is configured to transmit information about the switching state of the switch to the communication master station 150 via the communication line 130, and these are as online information together with the information such as the sending current. It is stored in the database 160. The offline database 170 stores information about the connection state of each switch and the impedance of the distribution line 110 as equipment information (equipment data). The data stored in the databases 160 and 170 is processed by the monitoring / control server 180, and the processing result is transmitted as command information to each of the communication slave stations 131 to 136 via the communication master station 150. The image is transferred to the interface terminal 190, and an image according to the command information is displayed on the screen of the man-machine interface terminal 190.
[0019]
The monitoring / control server 180 is configured as a distribution system state estimation device that estimates load current or power of each section of the distribution line 110 and other distribution lines as section load based on data stored in the databases 160 and 170. In this embodiment, when the load current or power in each section of each distribution line is estimated by the monitoring / control server 180, in this embodiment, as shown in FIG. It is assumed that the distribution line 210 having only 1 and # 2 is estimated. In this case, it is assumed that a school is connected to the section # 1 as a consumer, and a general house is connected to the section # 2 as a consumer. And the total value of the load current of each section assumes that it will correspond with the sending electric current value of the distribution line 210, if the difference in power factor and a loss are disregarded.
[0020]
Here, the load current value of each section is not usually measured, but the standard pattern of daily load change characteristics (characteristics indicating how the load current changes during 24 hours) is a customer type, for example, Note that it can be roughly assumed for each contract type based on past results, etc., and is accumulated as a daily load curve for each power company, and an outline can be estimated. At this time, since there is a difference from the actual daily load curve of each customer or group (each supply area), the range of error (variation) is also taken into consideration. Further, the standard pattern of the daily load curve for each consumer type is normalized with the contract value of each consumer so that it can be used in common by consumers with different contract power. For example, when the load current for each customer type in the two sections # 1 and # 2 is measured and this measured value is normalized with the contract value of each consumer, the demand included in each section # 1 and # 2 The assumed value Nj (t) of the daily load change characteristic for each house type is obtained, and the assumed accuracy (variation) ΔNj (t) is obtained, and these data are stored in the database 170.
[0021]
In addition, the estimated values of the load currents in the respective sections at the time t in the daily load curves in the sections # 1 and # 2 are distributed with the probabilities shown as I1 ′ and I2 ′ as shown in FIG. . Here, if the load current is adjusted so that the load current does not exceed the contract current by a breaker or the like installed in the consumer, the distribution range falls within each contract current value. In addition, in FIG. 3, the distribution of the estimated values is shown as a graph with the median in between, but the shape is not limited to the shape of the graph, and distribution functions of various shapes can be applied. . Also, the daily load curve graph shown in FIG. 2 does not need to have a uniform vertical interval. For example, a curve having a predetermined ratio with respect to the estimated value may be used, or the ratio may not be constant. .
[0022]
The total value Is ′ of the estimated values I1 ′ and I2 ′ should coincide with the measured value Is of the distribution line sending current, but actually, there is a slight mismatch ΔIs ′. Therefore, in the present embodiment, the mismatch ΔIs ′ indicating the deviation between the estimated value of the load current and the measured value of the delivery current is distributed according to the assumed variation (ΔI1, ΔI2) of the estimated load current values I1 ′ and I2 ′. I am going to do that. That is, the correction amount (ΔI1 ′) is reduced for the load current estimated value I1 ′ (the width of the graph is narrow and the mountain is high) that is considered to be highly accurate, and the load current estimated value I2 ′ that is considered to be lowly accurate. In contrast, the correction amount (ΔI2 ′) is increased.
[0023]
In the conventional method, since I1 ′ and I2 ′ are uniformly obtained by dividing the measured value Is of the sending current by the contract current of each section, the width of the graph is as shown by the broken line in FIG. It is assumed that the load current distribution is wide and low. In addition, the area of the portion surrounded by the graph of each distribution and the horizontal axis in FIG.
[0024]
Next, a processing method for estimating the load current or power in each section using the monitoring / control server 180 will be described with reference to FIGS. As shown in FIG. 6, the monitoring / control server 180 includes a processing overall function unit 610, a related information extraction function unit 620, an assumed value / assumed variation calculating function unit 630 for each type, and an estimated value / variation calculation of the section current. A function unit 640, a sending current estimation / mismatch calculation function unit 650, a section current correction function unit 660, an estimation result evaluation function unit 670, a display data editing function unit 680, and files 625, 635, 645, 655, 665, 675 are provided. It shall be.
[0025]
First, in step 410 of FIG. 4, as a pre-process by the related information extraction function unit 620, as shown in FIG. 5, the customer's contract current is classified into type j for each section (# 1, # 2) of the distribution line 210. The contract current Kij is calculated by adding each time. For example, based on the data stored in the database 170, the contract current in the section # 1 is determined as 120A, and the contract current in the section # 2 is determined as 90A. Next, the process proceeds to step 420, and the processing of the calculation function unit 630 multiplies the daily load curve Nj (t) for each consumer type j by the contract current Kij for each section i, and the time t in each section i. The assumed value Iij (t) of the load current for each consumer type j is calculated. Subsequently, in step 430, the calculation function unit 630 processes the assumed variation (assumed accuracy) ΔIij (t) of the estimated load current value Iij (t) to the daily load change characteristic Nj (t) of each consumer type j. Is calculated based on the assumed accuracy (variation) ΔNj (t). For example, ΔNj (t) of each section is added to calculate the assumed variation ΔIij (t).
[0026]
Next, the process proceeds to step 440, where all the types j in each section are added by the processing of the calculation function unit 640, and the load current estimated value Ii ′ (t) = ΣIij (t) in the section i is calculated. An assumed variation ΔIi (t) = ΣΔIij (t) with respect to Ii ′ (t) is calculated. The variation can be defined and calculated by the square of ΣΔIij (t) in addition to ΣΔIij (t). As a result of this processing, as shown in FIG. 5, the estimated load current value I1 ′ (t) = 30A, I2 ′ (t) = 70A, the assumed variation ΔI1 ′ (t) = 5A, ΔI2 ′ (t) = 15A is calculated.
[0027]
Next, in the process of step 450, the estimated value Ii ′ (t) of the load current in each section is accumulated for the distribution line 210 by the process of the calculation function unit 650, that is, added for all the sections i to estimate the sending current. The value Is ′ (t) = ΣIi ′ (t) is calculated. For example, the estimated value Is ′ (t) = 30A + 70A = 100A of the delivery current is calculated.
[0028]
Next, in the process of step 460, the mismatch ΔIs ′ (t) indicating the deviation between the measured value Is (t) of the delivery current and the estimated value Is ′ (t) of the delivery current is calculated by the process of the calculation function unit 650. Is done. In this case, when the measured value of the delivery current is 110 A, mismatch ΔIs ′ (t) = 110A−100A = 10A is calculated.
[0029]
Next, the process proceeds to step 470, and the processing of the section current correction function unit 660 distributes the estimated mismatch ΔIs' (t) of the delivery current according to the assumed variation ΔIi (t) of each section i, and the correction amount in each section ΔIi ′ (t) is obtained, and a process for correcting the estimated load current Ii ′ (t) in each section according to each correction amount ΔIi ′ (t) is performed.
[0030]
For example, as shown in FIG. 5, for section # 1, I1 ′ (t) = 30A + 10A × 25 / (5 + 15) = 32.5A is obtained, and for section # 2, I2 ′ (t) = 70A + 10A × 15 / (5 + 15) = 77.5A is obtained.
[0031]
When the conventional method is adopted, I1 ′ (t) = 110A × 120 / (120 + 90) = 62.8A is calculated for the section #, and I2 ′ (t) = 110A × for the section # 2. 90 / (120 + 90) = 47.2A is calculated and is greatly improved by the present invention.
[0032]
Next, the process proceeds to step 408, and when the processing at the time section t is completed for the distribution line 210 to be estimated, whether to proceed to the processing of another distribution line or whether to proceed to the next time point (time section) When the determination is made and all the processes are finished, the process in this routine is finished.
[0033]
In the processing of steps 410, 420, and 430, the data in the file 625 is used. To be stored in. Further, in the process of step 440, the data stored in the file 635 is also used, and the load current estimation value and the assumed variation calculation result of each section are stored in the file 645.
[0034]
Moreover, since it is assumed that the voltage of the distribution line is managed within a specified range, the power in each section can be easily estimated by estimating the load current in each section.
[0035]
The section load estimation and correction processing is performed as described above, but in the present invention, the load characteristics of each consumer are assumed in the form of applying a standard daily load curve of the corresponding type, and these daily changes The premise is that the characteristics are in line with the actual situation. That is, the mismatch value for each distribution line is small if the assumption is based on the actual situation, and is large if the assumption is not.
[0036]
Therefore, in the present invention, the estimation result evaluation function unit 670 stores and records in the file 675 the estimation results, in particular, the distribution status of mismatches in each distribution line and mismatches in each contract type at each estimation time point. It is supposed to be displayed upon request. The evaluation result of the estimation result evaluation function unit 670 is edited by the display data editing function unit 680 and displayed on the display screen of the man-machine interface terminal 190. A display example at this time is shown in FIG.
[0037]
In FIG. 7A, the mismatch of each distribution line is displayed as a bar graph for each estimated time point. Each bar graph also shows a breakdown of contract types ((b) b, b, c). For example, at 17:00 in section # 1, it is evaluated that most of the mismatches are related to contract type b. ing. Each bar graph is displayed on the upper or lower side of the line indicating the position of 0 according to the sign of the mismatch (deviation = measured value−estimated value). In the example shown in the figure, the mismatch values are all positive at 17:00 and 18:00, but at 19:00, the mismatch is negative in the sections # 1 and # 4. The sign of the mismatch may be displayed by display color classification, or the mismatch may be represented by a line graph with respect to the time axis.
[0038]
In FIG. 7 (b), each contract type a, b, and c is displayed as a bar graph with respect to the mismatch of all distribution lines. Each bar graph is the same type at the same time from the bar graph shown in (a). This is the result of extracting and adding things. As a result, it can be seen that at 17:00, type 2 and type 18 at 18 o'clock are greatly involved in the mismatch, exceeding the management standard indicated by the broken line. In the illustrated example, the management standard is uniform regardless of the type, but may not be uniform. In other words, since the main purpose of managing mismatches is to improve the accuracy of estimated values and daily load curves, there is also a method of setting a part of the whole, for example, a few percent to exceed the standard (in this case, the initial May be a large value, and may be a small value as the assumed accuracy is improved.
[0039]
In particular, for cases where management standards are exceeded, data will be stored separately in preparation for a future review of the daily load curve. Also, for cases that do not exceed, the portion of each time involved is stored for each type. As described above, each type of daily load curve is defined for each time as Nj (t). Therefore, it is possible to improve accuracy by comparing management data at the same time or statistically processing them. Can be achieved. In this case, it is possible to make corrections online in parallel with estimation at relatively short intervals, or to make corrections every year for a long period.
[0040]
As a specific method, when the average value of mismatches at the same time exceeds a predetermined value (may be smaller than the management standard) for each type, the value of the daily load curve at the time of the type is averaged. Change to a value. The variation is also corrected by obtaining the variance based on the value of the new daily load curve. When reviewing the daily load curve, the season and day of the week are taken into account. In addition, since it is somewhat impossible to cover all customers of the same contract type with a uniform daily load curve, it is also possible to define a daily load curve taking into account differences between distribution lines or distribution line segments. It is done.
[0041]
Furthermore, the daily load characteristic curve for each consumer type used in the present invention and its variation can be evaluated or corrected based on some actual measurement results in addition to the mismatch with the delivery current of each distribution line. it can.
[0042]
Moreover, about a consumer who can use some online measurement information, besides using that information for direct estimation, it can also be used for a cross-sectional evaluation as a daily load characteristic of the consumer of that type. For example, if the difference between the assumed value and the measured value is small, the assumed value is supported, and if the difference is large, it becomes a candidate for review. Note that an assumed value that is involved in a large mismatch and has low credibility can also be extracted as a survey target for updating the expected daily load characteristics. Also, in the case of online measurement in the middle of the distribution line, it is regarded as sending out, and the same processing can be performed on the downstream side of the measurement location.
[0043]
In the present embodiment, the power distribution system has been described as an example.For example, in a factory where devices with various characteristics are operated in a plurality of buildings, and only the power for each building is measured, the actual load of each building work place It can also be applied to estimation and energy saving studies based on the estimation. Further, when the distributed power source is interconnected, it can be dealt with in the same way by regarding the output power as a reverse load.
[0044]
As described above, according to the present embodiment, the load current or power of each section of the distribution line can be estimated with high accuracy based on the current very small online information (measurement information). As a result, it is useful for a wide range of operations and planning such as prevention of equipment overload, proper voltage management of distribution lines, reduction of power transmission loss, and proper accommodation during accidents and work. In addition, since the reliability of the expected daily load characteristics can be constantly evaluated, it is also effective in obtaining a guideline for determining the survey implementation time and target for the update.
[0045]
【The invention's effect】
As described above, according to the present invention, the section load of each section of the distribution line can be estimated with high accuracy even with limited measurement information.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a power distribution system and a monitoring / control system to which the present invention is applied.
FIG. 2 is a diagram for explaining a relationship between a delivery current of a distribution line and a load current estimated value in each section.
FIG. 3 is a diagram for explaining a relationship between an estimated value of a section load current of a distribution line and its estimated variation.
FIG. 4 is a flowchart for explaining processing of the monitoring / control server.
FIG. 5 is a diagram for explaining an estimated value of distribution line section current and a method of calculating the estimated variation.
FIG. 6 is a block configuration diagram showing a specific configuration of a monitoring / control server.
FIG. 7 is a diagram illustrating a display example of an estimated deviation.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 100 Distribution transformer 101 Bus 105 Breaker 111-114 Section switch 115,116 Interconnection switch 130 Communication line 131-136 Communication slave station 150 Communication master station 160, 170 Database 180 Monitoring / control server 190 Man-machine interface terminal 210 Distribution line 211, 212 Section switch

Claims (7)

Measure the sending current of the distribution lines divided into a plurality of sections, and estimate the load current for each section based on the assumed value of the daily load change characteristic for each consumer type included in each section and its assumed accuracy Value and its assumed accuracy, calculate the estimated current value from the estimated load current for each section, and calculate the deviation between the measured current value and the estimated current value. The deviation is distributed according to the assumed accuracy related to the load current estimated value in each section to calculate a correction amount in each section, and the load current estimated value in each section is corrected with the correction amount to each section. Method for estimating the state of a distribution system for estimating the load current or power of the power distribution system. Measure the sending current of the distribution lines divided into a plurality of sections, and assume the load current for each consumer type in each section based on the assumed daily load change characteristics for each consumer type included in each section A value is calculated, a load current estimated value for each section is calculated based on the estimated load current value, and each section is calculated based on the assumed accuracy of daily load change characteristics for each consumer type included in each section. The assumed accuracy of the load current assumption value for each consumer type is calculated, the assumed accuracy regarding the load current estimated value for each section is calculated based on the assumed accuracy of the load current assumption value, and the load for each section is calculated. An estimated current value is calculated from the estimated current value, a deviation between the measured current value and the estimated current value is calculated, and the deviation is assumed for the estimated load current value in each section. The correction amount in each section is distributed according to Out, state estimation method of distribution system by correcting the load current estimate of the respective sections in the correction amount estimating the load current or power of the each section. 3. The distribution system state estimation method according to claim 1, wherein when calculating the correction amount in each section, the correction amount is made smaller than a lower section for a section having a high assumed accuracy regarding the load current estimation value. On the contrary, the state estimation method of the distribution system is characterized in that the correction amount is set larger for the section where the assumed accuracy regarding the load current estimated value is lower than that for the higher section. In the distribution system state estimation method according to any one of claims 1, 2, and 3, the assumed value of the daily load change characteristic and the assumed accuracy of the consumer included in each section are determined by the consumer. A method for estimating the state of a power distribution system, characterized by using measurement information obtained by measurement. 5. The distribution system state estimation method according to claim 1, wherein the deviation is stored at each distribution system state estimation time point, and the stored deviation is requested for its contribution. Distribution calculated by associating each type of house, calculating the total value by adding the calculated contributions for the specified distribution line or all distribution lines, and displaying each total value as requested System state estimation method. A load current measuring means for measuring a send current of a distribution line divided into a plurality of sections, and a load for each section based on an assumed value of a daily load change characteristic for each consumer type included in each section Load current estimated value calculating means for calculating a current estimated value, and assumed accuracy for the load current estimated value for each section based on the assumed accuracy for the assumed value of the daily load change characteristic for each consumer type included in each section An assumed accuracy calculating means for calculating the estimated value, a sending current estimated value calculating means for calculating an estimated value of a sending current from a calculation result of the load current estimated value calculating means, a measured value of the sending current and the sending current A deviation calculating means for calculating a deviation from the estimated value of the output, a correction amount calculating means for calculating the correction amount in each section by allocating the deviation according to the assumed accuracy calculated by the assumed accuracy calculating means, and the load Current estimation value calculation Stage calculation by the correction amount in correcting the state estimating device for a power distribution system comprising a estimating means for estimating a load current or power of the each section of the correction means the load current estimated value of each section by calculating the. Consumers in each section based on an assumed value of a daily load change characteristic for each consumer type included in each section, and a transmission current measuring means for measuring a transmission current of a distribution line divided into a plurality of sections A load current estimated value calculating means for calculating a load current estimated value for each type; a load current estimated value calculating means for calculating a load current estimated value based on a calculation result of the load current estimated value calculating means; and A first assumed accuracy calculation means for calculating an assumed accuracy of a load current assumed value for each consumer type in each section based on an assumed accuracy relating to an assumed value of a daily load change characteristic for each included customer type; Based on the calculation result of the first assumption accuracy calculation means, the second assumption accuracy calculation means for calculating the assumption accuracy regarding the load current estimation value for each section, and the calculation result of the load current estimation value calculation means Calculate the estimated current An estimated current calculation value calculating means, a deviation calculating means for calculating a deviation between the measured value of the output current and the estimated value of the output current, and calculating the deviation by the second assumed accuracy calculating means. A correction amount calculating means for allocating according to the assumed accuracy and calculating a correction amount in each section; and a load current estimated value in each section calculated by the load current estimated value calculating means as a correction amount calculated by the correcting means. A distribution system state estimation apparatus comprising: an estimation unit that corrects and estimates the load current or power in each section.

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