JP6530698B2 - Apparatus and method for estimating power generation of distributed power source - Google Patents

Description

  The present invention relates to a device and method for estimating the amount of power generation of a distributed power supply connected to a distribution system, and more particularly to a device and method for estimating the amount of power generation of a distributed power supply that can cope with changes in power factor in the distribution system.

  The number of installed solar power generation is increasing with the improvement of efficiency and technology of the solar power generation system, and the national promotion and the spread of distributed power source including wind power generation are progressing.

  The power generated by the power plant is sent from the distribution line to each customer load via the transmission line and the substation. In the past, these dispatching facilities belonged to and were under the control of an electric power company, but recent distributed power sources (wind power generation, solar power generation, etc.) are often owned by customers or power generation companies. doing. The distributed power source owned by the customer or the power producer is often connected to a transmission line (distribution system) managed by the electric power provider, and the power generation amount of the distributed power source is a demand Some electricity not consumed at home is sent to the interconnected distribution system.

  By the way, electric utilities measure the amount of power supplied at power stations such as power stations and substations for the stable supply of power, but in distribution systems where distributed power sources are installed, consumers actually There is a problem that the consumed power (actual load) can not be known and only an apparent load (surface load) can be grasped. Specifically, for example, when the amount of power supplied from an electric station is measured to be 10, and the amount of power generated by the distributed power source is 3, the total amount of loads connected to the electric station should be 13; Can only be recognized as 10. In this case, while the actual load is 13, it means that only 10 can be grasped as an apparent load (surface load). Moreover, the amount of power generated by the distributed power source is unstable due to the weather, which makes it difficult to grasp the actual load in the electric station.

  In order to stabilize power in an electric power company, it is important to supply power appropriately for the power demand, and it is necessary to accurately forecast the power demand. If the impact of distributed power sources such as solar power was small, it was only necessary to estimate the load across the power supply area. However, as the number and capacity of distributed power sources increase in the future, the amount of power generated by distributed power sources will also increase, and the influence thereof will not be negligible. Therefore, in order to accurately predict the power demand, it is necessary to accurately estimate the power generation amount of the distributed power source.

  In this regard, after installing sensors in each facility of the distributed power supply to measure and grasp the individual power generation amount, information is collected to the electric station side via the communication line, and the total amount is collected from time to time by the electric station side It is technically possible to confirm, but in the case of facilities where multiple interconnections such as solar power generation are expected, installing sensors and communication lines individually is not economical and not a practical method.

  In view of the circumstances, if it is possible to estimate the working line of active power P and reactive power Q for a load on the load side from a measurement point, the measured values of active power P and reactive power Q at the measurement point and the power factor of the distributed power supply It is possible to estimate the amount of power generated by the actual load and the distributed power source. For example, as a method of estimating the power generation amount of photovoltaic power generation, Patent Document 1 applies active component power of a load by applying independent component analysis from active power P and reactive power Q measured upstream from load or photovoltaic power generation. And a method for determining the effective power P of solar power generation.

JP, 2012-95478, A

  In the method proposed in Patent Document 1, it is necessary that the active power P of the load power and the reactive power Q always maintain a constant power factor relationship, but in the actual system, the distribution system load as a whole is always constant. There is no fixed power factor, especially the power factor of factory and commercial area changes greatly between one day.

  From the above, it is an object of the present invention to provide a power generation amount estimation apparatus and method for distributed power sources that can cope with changes in power factor in a distribution system with a small number of sensors.

  From the above, according to the present invention, the power generation amount estimation device of the distributed power supply which obtains the active power P and the reactive power Q at a predetermined location of the distribution line to which the distributed power supply is connected and estimates the power generation of the distributed power supply. There is a measurement value storage unit that stores active power P and reactive power Q at predetermined locations of the distribution line as time-series data, and active power P when there is no generated power of the distributed power source from the data of the measurement value storage unit. PQ motion straight line estimation unit that estimates the first PQ motion straight line that indicates the relationship between power and reactive power Q, the power factor of the distributed power source is calculated from the data of the measured value storage unit, and active power at the time of The second PQ operation line indicating the relationship between active power P and reactive power Q at the time of power generation is estimated from the measured value of P and reactive power Q and the power factor of the distributed power source, and the first PQ At the intersection of the operating line and the second PQ operating line Estimating the distributed power source from the actual load estimation part that uses the active power P and reactive power Q as the actual load estimated value, the measured values of the active power P and reactive power Q at the time when you want to estimate power generation, and the actual load estimated value And a power generation amount estimation unit that calculates the power generation amount.

  Further, in the present invention, the power generation amount estimation method of the distributed power source is obtained by obtaining the active power P and the reactive power Q at a predetermined location of the distribution line to which the distributed power source is connected and estimating the power generation amount of the distributed power source. First, the relationship between active power P and reactive power Q when there is no generated power of distributed power from the stored data is stored as time series data of active power P and reactive power Q at a predetermined location of a distribution line Estimate the PQ operation line, calculate the power factor of the distributed power source from the stored data, and estimate the power generation amount from the measured value of active power P and reactive power Q at the time of distributed power source and distributed power source The second PQ operation line indicating the relationship between active power P and reactive power Q during power generation is estimated, and active power P and reactive power Q at the intersection of the first PQ operation line and the second PQ operation line are The time to estimate the amount of power generation as a load estimate The measured value of the active power P and reactive power Q, and calculates the estimated amount of power generation of the distributed power from the difference between the actual load estimate.

  According to the present invention, it is possible to provide a power generation amount estimation apparatus and method of a distributed power supply which can cope with a change in power factor in a distribution system with a small number of sensors. More specifically, the embodiment of the present invention estimates the amount of power generation without installing a measuring instrument in a distributed power supply, because the power utility uses measured values that are being measured and collected for constant current monitoring. it can. Also, assuming that the load does not fluctuate rapidly in a short time, it is possible to read the sudden fluctuation of the power generation amount by monitoring the sudden fluctuation of the measured value, and the power factor of the distributed power source It can be estimated.

FIG. 1 is a block diagram showing a functional configuration of a power generation amount estimation device 10 of the present invention. The figure which shows the data of active power P and reactive power Q which were measured in A substation. The figure which plotted the magnitude | size of the active power P and the reactive power Q in each time of FIG. 2 on the PQ coordinate plane. The figure which showed the way of thinking for calculating | requiring PQ straight line L1 of load. The figure which shows an analysis result. The figure which divided and displayed the data for a specific one day out of all measurement data in four. The figure which showed the knowledge and the processing procedure of this invention on the 4th quadrant. The figure which shows the example of the distribution system to which this invention is applied.

  Examples of the present invention will be described in detail below.

  The present invention has been made based on the findings obtained from actual measurement at an electric station. For this reason, prior to the description of the embodiment, measurement of the actual place in the electric station and knowledge obtained will be described using the measurement result and the drawing of the analysis result.

  FIG. 2 shows the measurement of active power P and reactive power Q in the A substation over a week in summer. The measurement cycle is shown as an average value of 2 seconds and 3 minutes in the figure. Distributed power supply (wind power generation and solar power generation) owned by the demander or the power producer as a power generation facility, including large customers and general customers as general load on the feeder line (distribution line) side of the A substation Etc.) is included. FIG. 2 shows the time of one week on the horizontal axis and the positive and negative active powers P and reactive powers Q on the vertical axis. According to the measurement results, sudden changes in the active power P can be seen. This part can be considered to reflect the fluctuation of the output due to the weather change of the solar power generation. This event observed at A substation can be said to be measurement of apparent load (surface load).

  In addition, since this measurement value is a measurement result of one week including measurement time and information of measurement location, it is a trend on weekdays, a trend on holidays, a trend on daytime, a trend on night, a weather condition, a situation by region etc. From the point of view, it is understood as information that can be organized and used. For example, it means that it is extracted from the whole data from the viewpoint of the daytime of a weekday in area A, and it is measured as a state where it is possible to analyze a peculiar phenomenon etc. of the extracted data.

  FIG. 3 is a graph in which the magnitudes of the active power P and the reactive power Q at each time of FIG. Although many plotting results are mainly displayed in the fourth quadrant of the coordinate plane of positive and negative PQ, it can be seen that the combination of + P and -Q values has a limit at which the absolute value does not increase further. Assuming that this limit line is L1, the straight line L1 should be called a PQ operation straight line of the load side load. In other words, it should be called a PQ operation line that represents the state of the load in the state where the distributed power source (wind power generation, solar power generation, etc.) is not outputting, that is, in the non-distributed power state.

  More specifically, the reason why the determination can be made in this way is that in the plot of FIG. 3, the active power P is measured at the A electrical station, and the fact that the active power P is large means that the distributed power supply Since it does not supply (or there is little power supply), it is appropriate to estimate that it is a state which is supplying large active power from A station as a result. In this state, the power supplied by the distributed power supply is zero, and even if it is small, the value of PQ on the straight line L1 can be considered to represent the state of the load.

The load PQ straight line L1 can be calculated, for example, as follows. FIG. 4 is a diagram for explaining a method of deriving the PQ straight line L1 of the load. The left side of FIG. 4 is obtained by dividing the reactive power in the range of 25 kVar in the plot of FIG. 3 and plotting only the top 5 data in the descending order of the active power. The right part of FIG. 4 is a straight line simulation from the plot tendency in the area of 200 kVar or more, and in this case, it can be expressed by a simulated straight line y = 0.6189X-727.26 in this case. This is the PQ straight line L1 of the load. In this case, the variance R ² was 0.987. In addition, although examination of FIG. 4 was on the conditions (a measurement period is an average value for 2 seconds and 3 minutes) described previously, conditions are changed (average is for 3 minutes, 15 minutes, 30 minutes, 1 Even if analysis was performed in the same way, the results of the same slope and intercept were obtained.

  FIG. 3 shows the results of plotting all measured data for one week. For this reason, this content includes not only information on daytime when solar power is generated, but also information on nighttime, or information on fine weather and cloudy weather without distinction even if power generation is possible. Alternatively, it is the result of plotting the information of the major customers who dominate the measurement value and the information of the general consumers without distinction.

  Therefore, the results of sorting the data according to the conditions were summarized as follows. FIG. 5 is a diagram showing an analysis result. First, the PQ operation straight line L1 of the load side load tends to generate a large delayed reactive power (-Q) as the load of a large customer who is a high voltage customer increases. There is. Secondly, as a result of plotting PQ data under the weather conditions under which solar power generation is performed, it is considered to be distributed within the range of region Z according to the fluctuation of passing effective power P due to solar power generation .

  By the process of FIG. 4, the state of the load in the non-distributed power supply state was found. Next, I will clarify the relationship of PQ by solar power generation. Figure 6 shows the data for a specific day for which photovoltaic power generation has significantly functioned from among all the measurement data, from 1 o'clock to 6 o'clock, from 7 o'clock to 12 o'clock, 13 hours of the measurement day It is the figure which divided into 4 in 18 o'clock stand from 19 o'clock to 24 o'clock stand, and displayed the coordinate. In this case, many daytime conditions are plotted in the third quadrant on the PQ coordinates, and many nighttime conditions are plotted in the fourth quadrant on the PQ coordinates. Moreover, in this display, it is not a mere plot display, but is displayed by connecting lines so that the time change can be seen.

  In FIG. 6, when the information of the night is excluded and the information of the day is examined, it can be understood that the value of the active power is sliding laterally due to the stable solar power generation from 7 o'clock to 12 o'clock. In addition, even at 13:00 to 18:00, basically, an event in which the value of active power slides horizontally due to stable solar power generation is observed, but this chart further shows that active power Events in which P and reactive power Q are fluctuating rapidly are measured. The present inventors paid attention to the rapid fluctuation of the active power P and the reactive power Q due to the sudden change of the weather in 13:00 to 18:00 among them.

  From this momentary fluctuation, the power factor of photovoltaic power generation can be estimated. Assuming that the values of active power P and reactive power Q immediately before the sudden change are P1 and Q1 and the values after the rapid change are P2 and Q2, the ratio of ΔP (= P1-P2) to ΔQ (= Q1-Q2) (ΔQ / The power factor characteristic of photovoltaic power generation can be calculated as ΔP).

  FIG. 7 shows the above findings and the processing procedure of the present invention on the fourth quadrant. Here, L1 is a characteristic line indicating the state of the load in the non-dispersive power supply state. On the other hand, an example of a straight line having a power factor (slope) m obtained from the values of the active power P and the reactive power Q before and after the sudden load change in FIG. 6 is L2. However, the straight line L2 assumes a straight line of a slope m passing through the coordinates (Pn, Qn) when the values measured at the A electrical station are the active power Pn and the reactive power Qn.

  Assuming that the power factor of the distributed power source is 1 with respect to the measured value (Pn, Qn), the load in the non-distributed power state moves the measured value (Pn, Qn) laterally. It can be represented by coordinate values (Pn1, Qn) intersecting the straight line L1. On the other hand, when the actual distributed power supply has a slope of power factor m, the load in the non-distributed power state moves the measured value (Pn, Qn) along the slope m of the characteristic line L2 It can be represented by coordinate values (Pnm, Qnm) intersecting the straight line L1.

  From this result, in the current state, the active power P by solar power generation can be obtained as the difference (Pnm−Pn) between the active power Pnm at the intersection of the straight lines L1 and L2 and the measured value Pn. Similarly, the reactive power Q by solar power generation can be obtained as the difference (Qnm−Qn) between the reactive power Qnm at the intersection of the straight lines L1 and L2 and the measured value Qn.

  The power generation amount estimation apparatus and method of the distributed power supply of the present invention configured based on the above examination results will be described in detail below. First, FIG. 8 shows an example of a distribution system to which the present invention is applied. In FIG. 8, the power transmitted from the substation 1 is supplied to a plurality of customers 4 via the distribution line 6. The customers 4 include large customers and general consumers, and some of them include the customers 4A equipped with a distributed power source 5A such as solar power. In addition, the distribution line 6 may be provided with a distributed power source 5B such as solar power generation owned by a power generation company. Moreover, the feeder circuit breaker 2 which installed the sensor S which can measure surface load, and the switch 3 are installed in the distribution system of FIG. In the power generation amount estimation device 10, data sent from sensors at various points of the distribution line are collected. As the aggregated data, active power P and reactive power Q obtained at the sensor installation site are stored and held in time series.

  FIG. 1 is a block diagram showing a functional configuration of the power generation amount estimation apparatus 10 of the present invention. The following will be described in order.

  In FIG. 1, the measuring device S is a device for measuring the active power P and the reactive power Q, or the apparent power and the power factor, and the demand in the substation 1, the feeder breaker 2, the switch 3 and the customer 4 in FIG. A power measuring device or the like corresponds to this.

  The measured value storage unit 12 in the power generation amount estimation device 10 stores and stores information of active power and reactive power obtained from the measuring device S or apparent power and power factor in time series for each measurement point. . The stored information is time-series information as shown in FIG.

  Next, in the PQ operation linear calculation unit 13, based on the information measured at the substation from the information of the measurement value stored and stored in the measurement value storage unit 12, the PQ operation when there is no generated power of the distributed power source Calculate straight line L1. In addition, although the following processing example demonstrates substation measurement information to an example, it is also possible to use the information of an arbitrary measurement point as this. In addition, it is also possible to obtain each from measurement values of a plurality of measurement points and compare the results.

  A specific calculation method here is shown in FIG. 4. In short, for example, the reactive power is divided into ranges by 25 kVar, and among them, only the top 5 data are plotted in descending order of the active power, The characteristic line L1 representing the state of the load in the non-dispersive power supply state is obtained by straight-line simulation from the plot tendency in the region of.

  The actual load estimation unit 14 is a device for estimating the actual load actually consumed from the measured value of the time to estimate the power generation amount, the power factor of the distributed power source, and the PQ operation line L1 obtained by the PQ operation linear calculation unit 13 . As a premise of this processing, it is assumed that information of the power factor (slope) m is appropriately obtained as the characteristics of the active power P and the reactive power Q of the distributed power supply in the actual load estimation unit 14. The method of calculating the power factor (slope) m is as described in FIG. In short, for example, ΔP (= P1-P2) and ΔQ (= Q1-Q2) are calculated as the difference between the active power P and the reactive power Q before and after the sudden change of the weather, and the ratio (ΔQ / ΔP) of the solar power generation is calculated. The power factor characteristics are obtained in advance.

  Further, the actual load can be obtained as the value of PQ at the point where the straight line L2 of the slope m passing the measured value of PQ intersects the straight line L1, as described in FIG.

  The power generation amount estimation unit 15 estimates the power generation amount of the distributed power source from the actual load estimated by the actual load estimation unit 14 and the measurement value measured by the measuring device S.

  Although the present invention has been described above, among the dispersed power sources, the main effect of applying the present invention is solar power generation, and therefore, the above description has been mainly focused on solar power generation. Wind power generation can be estimated as well, but PQ measurement is possible at most installation points because it is a large facility. Further, since the number of installed devices is small, direct measurement is possible without introducing the estimation method as in the present invention.

  In the embodiment, an example has been described in which the power factor calculation of photovoltaic power generation is obtained from data before and after sudden weather change, but this obtains inclination information from statistical data during normal operation of photovoltaic power generation in the upper right of FIG. It is also possible. This is a method of obtaining the inclination from the change tendency of the data group of about 7 o'clock to 12 o'clock.

  Moreover, although the example demonstrated the example which measures the active power P and the reactive power Q, this can also be measured by measuring the apparent power and the power factor and calculating the active power P and the reactive power Q secondarily is there. In the present invention, active power P and reactive power Q are used as a concept including any of them.

1: substation 2: feeder breaker S: sensor 3: switch 4: customer 5: distributed power supply 10: power generation amount estimation device 12: measured value storage unit 13: PQ operation straight line calculation unit 14: actual load estimation unit 15: Power generation amount estimation unit

Claims (6)

A distributed power generation amount estimation device for a distributed power supply, which obtains active power P and reactive power Q at a predetermined location of a distribution line to which the distributed power supply is connected, and estimates the power generation amount of the distributed power supply,
A measurement value storage unit that stores active power P and reactive power Q at predetermined locations of the distribution line as time-series data;
A PQ operation line estimation unit for estimating a first PQ operation line indicating a relationship between active power P and reactive power Q when there is no generated power of the dispersed power source from data of the measurement value storage unit;
The power factor of the dispersed power source is calculated from the data of the measured value storage unit, and the measured value of the active power P and reactive power Q at the time when the power generation amount is to be estimated Estimates a second PQ operation line indicating the relationship between active power P and reactive power Q at the time of power generation, active power P, reactive power Q at the intersection of the first PQ operation line and the second PQ operation line. An actual load estimating unit that sets the actual load estimated value,
A measurement value of the active power P and reactive power Q at a time when it is desired to estimate the power generation amount, and a power generation amount estimation unit that calculates an estimated power generation amount of the distributed power source from the actual load estimated value Distributed power generation amount estimation device. The power generation amount estimation apparatus for distributed power source according to claim 1, wherein
The first PQ operation line is obtained by dividing the range of the reactive power Q with respect to magnitudes of a plurality of data in the measurement value storage unit, and extracting data indicating a large value of the active power within the range A power generation amount estimation device of a distributed power supply characterized by being obtained by simulation from a plurality of data groups. The power generation amount estimation apparatus for distributed power source according to claim 1 or 2, wherein
The power factor of the distributed power source is obtained from the values of the active power P and the reactive power Q before and after sudden weather change among the data in the daytime of the measured value storage unit. . The power generation amount estimation apparatus for distributed power source according to claim 1 or 2, wherein
The power factor of the dispersed power source simulates the change direction from the values of a plurality of active powers P and reactive powers Q in the state where power generation is stably performed among the data in the daytime of the measurement value storage unit. An apparatus for estimating the amount of power generation of a distributed power supply characterized by: The power generation amount estimation device for distributed power source according to any one of claims 1 to 4,
The power generation amount estimation unit includes active power P and reactive power Q at the intersection of the first PQ operation straight line and the second PQ operation straight line, and the active power P and reactive power Q at a time when the power generation amount is to be estimated. A power generation amount estimation apparatus of a distributed power supply, wherein the power generation amount of the distributed power supply is obtained as a difference between measurement values of A method for estimating the amount of power generation of a distributed power source, which obtains active power P and reactive power Q at predetermined positions of a distribution line to which the distributed power source is connected, and estimates the power generation amount of the distributed power source,
Storing active power P and reactive power Q at predetermined locations of the distribution line as time-series data;
From the stored data, a first PQ operation line indicating the relationship between the active power P and the reactive power Q when there is no power generation amount of the distributed power source is estimated;
Power factor of the distributed power source is calculated from the stored data, and the distributed power source generates power from the measured value of the active power P and reactive power Q at the time when it is desired to estimate the power generation amount and the power factor of the distributed power source The second PQ operation line indicating the relationship between the active power P and the reactive power Q of the second power source is estimated, and the active power P and reactive power Q at the intersection of the first PQ operation straight line and the second PQ operation straight line are Load estimate,
Power generation of a distributed power supply characterized by calculating an estimated power generation amount of the distributed power source from a difference between the measured value of the active power P and reactive power Q at a time when the power generation amount is to be estimated and the actual load estimated value. Quantity estimation method.

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