JP2005073346A - System, method, and program for evaluating electric power quality - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric power quality evaluating system capable of evaluating, while taking the occurrence probability of quality degradation into account. <P>SOLUTION: The electric power quality evaluating system comprises an electric power quality calculating means which calculates the quality of each watthour obtained from a power grid whose quality is to be evaluated, a probability density function generating means which generates probability density function of power quality value from the power quality value acquired by the electric power quality calculating means, a decision value setting means for setting a decision value which is a reference for discriminating the quality of electric power, and an electric power quality evaluating means which evaluates the quality of electric power by using the probability density function of the electric power quality value and the set the decision value. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a power quality evaluation technique for evaluating power quality, and in particular, a highly accurate power quality evaluation that takes into consideration the occurrence probability of power quality deterioration, economic damage, and the needs of power consumers. The present invention relates to a system, a power quality evaluation method, and a power quality evaluation program.

  In recent years, deregulation has been promoted in the electric power business field, and not only the improvement of electric power quality but also the increase in quality is required. For this reason, the electric power consumer and electric power sales company who are engaged in the electric power field | area are pressed for the necessity to grasp electric power quality flexibly and multifacetedly. In general, as an item for determining the power quality, a phenomenon that deteriorates the power quality such as harmonics, voltage fluctuation, voltage imbalance, instantaneous voltage drop, and power failure is used. Therefore, an electric power quality measuring apparatus that calculates an index derived from each item (for example, an overall distortion rate in the case of a harmonic) from a predetermined formula and specifically measures the degree of electric power quality has been put into practical use.

Various conventional power quality measuring devices have been proposed. For example, there is a device that clearly describes a power quality index between a power consumer and a power sales company. Furthermore, a system for managing and operating power quality based on measured data, as well as simply measuring power quality, has been proposed. There exists patent document 1 as a prior art example of such a system. With this technology, it is possible to calculate the power quality required for a power consumer and obtain the reference value / optimum value of the power quality for that consumer. Thereby, it is said that it becomes possible to contribute to the consultation and system integration to the electric power consumer.
JP 2002-247780 A

  By the way, the occurrence of power quality deterioration phenomena such as harmonics, voltage fluctuations, voltage imbalances, and instantaneous voltage drops occurring in the power system has a large stochastic factor. Therefore, it is not sufficient to simply calculate the power quality level to evaluate the power quality of the power system. It is important to determine the probability of power quality deterioration and evaluate the quality using this as a decision factor. It is.

  However, the conventional power quality measuring device only shows a power quality index between the power consumer and the power selling company. In the system disclosed in Patent Document 1, the power quality reference value and the optimum value are determined for each power consumer, but the quality evaluation is not performed by incorporating the occurrence probability of the power quality deterioration phenomenon into the determination factor. It wasn't. That is, in the prior art, the deterioration of power quality was not caught from the viewpoint of occurrence probability. For this reason, development of the system which can evaluate electric power quality with higher precision was desired.

  Moreover, if power quality deteriorates, of course, economic loss will also occur. However, conventional power quality measuring devices only evaluate power quality from a physical aspect, and have not yet clearly shown the correlation between the degree of power quality deterioration and economic damage. It was. Therefore, it has been desired to develop a power quality evaluation system in consideration of economic loss.

  Furthermore, recently, in addition to deregulation in the electric power business field, the development of environmentally friendly small power generators such as fuel cells and wind power generators is also remarkable. Under such circumstances, power demand tends to be reduced. Along with this, the types of electric power consumers are subdivided, and the electric power quality level required for each electric power consumer is constantly diversifying. In addition, power consumers are expected to have a small-scale power supply and power storage device and use multiple types of power. Therefore, the level required by the electric power consumer varies depending on which of the facilities that the electric power consumer has to use. For this reason, there has been a tendency for the power quality to become multi-quality, and it has been desired to develop a system that can more flexibly evaluate the power quality.

The present invention has been proposed in order to solve the above-described problems of the prior art, and a first object of the present invention is to provide a power quality evaluation system and power that can be evaluated in consideration of the occurrence probability of quality deterioration. The object is to provide a quality evaluation method and a power quality evaluation program.
The second object is to provide a power quality evaluation system, a power quality evaluation method, and a power quality evaluation program that can be evaluated in consideration of economic loss.
A third object is to provide a power quality evaluation system, a power quality evaluation method, and a power quality evaluation program that can evaluate power quality according to the required levels of various power consumers.

  In order to achieve the above object, the present invention derives the probability of occurrence of a quality deterioration phenomenon from the result of calculating the degree of power quality, and evaluates the power quality based on this. In addition, the power quality is considered not only from a physical point of view but also from an economic point of view, and the power quality is evaluated in consideration of the degree of economic damage. Furthermore, an optimum determination criterion is set according to the needs of each power consumer, and the power quality is evaluated based on the criterion.

  In other words, the power quality evaluation system according to claim 1 includes a power quality calculation unit that calculates the degree of power quality of the amount of power to be evaluated, and a power quality value obtained from the power quality value obtained by the power quality calculation unit. A probability density function creating means for creating a probability density function of a value, a judgment value setting means for setting a judgment value serving as a reference for judging the degree of power quality, a probability density function of the power quality value, and a set judgment And power quality evaluation means for evaluating the degree of power quality using the value.

  The invention described in claim 10 is obtained from the viewpoint of the method according to the invention described in claim 1, and is obtained by calculating a power quality value indicating the degree of power quality of the amount of power to be evaluated. A probability density function of the power quality value is created from the measured power quality value, a determination value serving as a reference for determining the degree of power quality is set, and the probability density function of the power quality value and the set determination value are And to evaluate the degree of power quality.

  The invention according to claim 19 is an electric power quality evaluation program for evaluating the power quality by controlling the computer by capturing the invention according to claim 10 from the viewpoint of a computer program, The program calculates, in the computer, a power quality value indicating the degree of power quality of the amount of power to be evaluated, and creates a probability density function of the power quality value from the obtained power quality value; A step of setting a determination value serving as a reference for determining the degree of power quality, and a step of evaluating the degree of power quality using the probability density function of the power quality value and the set determination value are executed. It is characterized by being.

  According to the invention of claim 1, claim 10 and claim 19 having the above-described configuration, a probability density function is obtained from the power quality value, and the probability density function is compared with a determination value having a predetermined width. Thus, the occurrence probability of the power quality deterioration phenomenon can be used as a determination factor for power quality evaluation.

  According to a second aspect of the present invention, there is provided the power quality evaluation system according to the first aspect, wherein the power quality evaluation unit has a probability that a probability density function of the power quality value falls within a set judgment value range. The power quality is configured to be evaluated based on the size.

  The invention according to claim 11 captures the invention according to claim 2 from the viewpoint of the method, and in the power quality evaluation method according to claim 10, the probability density function of the power quality value is: It is characterized in that the power quality is evaluated based on the probability of falling within the set judgment value range.

  According to the invention of claim 2 or claim 11 having the above configuration, a probability density function is obtained from a power quality value, and the power quality is evaluated by comparing the probability density function with a determination value having a predetermined width. To do. That is, when the probability of the power quality value falling within the judgment value range is large, the power quality is evaluated as good, and conversely, when the probability of entering the judgment value range is small, the power quality deteriorates. Assess that you are doing. Thus, by using the occurrence probability of the power quality deterioration phenomenon as a determination factor for power quality evaluation, it becomes possible to evaluate the power quality with high accuracy, and the evaluation reliability is improved.

  According to a third aspect of the present invention, in the power quality evaluation system according to the first aspect, the probability density function created for each of the plurality of power quality evaluation items is a determination value set for each of the evaluation items. It is configured to obtain a probability that falls within a range, and to evaluate power quality based on a product value of the probabilities obtained for two or more evaluation items to be comprehensively evaluated. .

  The invention according to claim 12 captures the invention according to claim 3 from the viewpoint of the method, and is created for each of a plurality of power quality evaluation items in the power quality evaluation method according to claim 10. The probability density function obtained is within the range of the judgment value set for each evaluation item, and the product of the probabilities obtained for two or more evaluation items to be comprehensively evaluated The power quality is evaluated based on the above.

  According to the invention of claim 3 or claim 12 having the above-described configuration, it is possible to perform power quality evaluation based on the occurrence probability over a plurality of power quality items, and for comprehensive quality evaluation and desired quality items. A narrow and selective evaluation can be performed.

  According to a fourth aspect of the present invention, there is provided a power quality evaluation system that calculates a power quality calculation unit that calculates a degree of power quality of an amount of power to be evaluated, and a power quality value obtained by the power quality calculation unit. Probability density function creation means for creating a probability density function, judgment value setting means for setting a judgment value as a reference for judging the degree of power quality, and damage for setting a damage curve indicating the relationship between the power quality value and damage It is characterized by comprising a curve setting means, a power quality evaluation means for evaluating the degree of power quality using the probability density function of the power quality value, and the set judgment value and damage curve.

  The invention described in claim 13 is obtained from the viewpoint of the method according to the invention described in claim 4, and is obtained by calculating a power quality value indicating the degree of power quality of the amount of power to be evaluated. From the power quality value, a probability density function of the power quality value is created, a determination value serving as a reference for determining the degree of power quality is set, and a damage curve indicating the relationship between the power quality value and the damage is set. The degree of power quality is evaluated using a probability density function of the power quality value and a set judgment value and damage curve.

  The invention according to claim 20 is an electric power quality evaluation program for evaluating the power quality by controlling the computer by capturing the invention according to claim 13 from the viewpoint of a computer program, The program calculates, in the computer, a power quality value indicating the degree of power quality of the amount of power to be evaluated, and creates a probability density function of the power quality value from the obtained power quality value; A step of setting a determination value serving as a reference for determining the degree of power quality, a step of setting a damage curve indicating a relationship between the power quality value and damage, a probability density function of the power quality value, and a set determination And a step of evaluating the degree of power quality using the value and the damage curve.

  According to the invention described in claim 4, claim 13, and claim 20 having the above-described configuration, the damage curve indicating the relationship between the power quality value and the damage is used as an evaluation element of the power quality. It becomes possible to evaluate power quality in consideration of economic loss.

  According to a fifth aspect of the present invention, in the power quality evaluation system according to the fourth aspect, the power quality evaluation unit evaluates the power quality based on a probability of deterioration of the power quality and a damage index indicating the damage at that time. It is comprised by these.

  The invention described in claim 14 captures the invention described in claim 5 from the viewpoint of the method. In the power quality evaluation method according to claim 13, the probability of power quality deterioration and the damage at that time are calculated. The power quality is evaluated based on the indicated damage index.

  According to the invention of claim 5 or claim 14 having the above-described configuration, the power quality is evaluated based on the damage index determined from the damage curve indicating the relationship between the power quality value and the damage and the probability density function of the power quality value. Therefore, it is possible to evaluate the power quality in consideration of both the occurrence probability of power quality deterioration and the economic loss.

  The invention described in claim 6 is the power quality evaluation system according to claim 4, wherein a damage index indicating the probability of power quality deterioration and the damage at that time is obtained for each of a plurality of power quality evaluation items. The power quality is evaluated on the basis of the sum of the damage indices obtained for two or more evaluation items as targets.

  The invention described in claim 15 captures the invention described in claim 6 from the viewpoint of the method, and in the power quality evaluation method according to claim 13, the power quality for each of a plurality of power quality evaluation items. It is characterized by obtaining a damage index indicating a probability of deterioration and damage at that time, and evaluating power quality based on a sum value of the damage indices obtained for two or more evaluation items to be comprehensively evaluated. To do.

  According to the invention of claim 6 or claim 15 having the above configuration, power quality can be evaluated over a plurality of power quality items, and comprehensive quality evaluation or selective focusing on desired quality items can be performed. Assessment can be carried out. In addition, since a damage curve can be set for each power quality item, it is possible to cope with the case where the economic damage level is different for each power quality item. Therefore, it is possible to perform highly reliable power quality evaluation from an economical viewpoint.

  According to a seventh aspect of the present invention, there is provided a power quality evaluation system that calculates a power quality calculation unit that calculates a degree of power quality of an amount of power to be evaluated, and a power quality value obtained by the power quality calculation unit. Using a power quality distribution map creating means for creating a distribution map, a judgment value setting means for setting a judgment value as a reference for judging the degree of power quality, the power quality distribution map, and a set judgment value And power quality evaluation means for evaluating the degree of power quality.

  The invention described in claim 16 is obtained from the viewpoint of the method according to the invention described in claim 7, and is obtained by calculating a power quality value indicating the degree of power quality of the amount of power to be evaluated. A distribution map of power quality values is created from the measured power quality values, a determination value serving as a reference for determining the degree of power quality is set, and power is calculated using the power quality distribution map and the set determination values. It is characterized by evaluating the degree of quality.

  The invention according to claim 21 is a power quality evaluation program for evaluating the power quality by controlling the computer by capturing the invention according to claim 16 from the viewpoint of a computer program, The program calculates, in the computer, a power quality value indicating the degree of power quality of the amount of power to be evaluated, a distribution map of power quality values from the obtained power quality values, A step of setting a determination value serving as a reference for determining the degree of quality, and a step of evaluating the degree of power quality using the power quality distribution map and the set determination value. It is characterized by.

  According to invention of Claim 7, Claim 16, and Claim 21 which has said structure, an electric power quality distribution map is created from an electric power quality value, and the determination value which has this power quality distribution map and predetermined width | variety, Thus, the probability of occurrence of a power quality deterioration phenomenon can be used as a determination factor for power quality evaluation.

  According to an eighth aspect of the present invention, in the power quality evaluation system according to the seventh aspect, the power quality evaluation unit determines the probability that the power quality distribution map falls within a set judgment value range. It is configured to evaluate the power quality based on it.

  The invention according to claim 17 captures the invention according to claim 8 from the viewpoint of the method, and in the power quality evaluation method according to claim 16, the power quality distribution map is set. It is characterized in that the power quality is evaluated based on the probability of falling within the range of the judgment value.

  According to the invention of claim 8 or claim 17 having the above-described configuration, the power quality distribution map is obtained from the power quality value, and the power quality distribution is compared with the determination value having a predetermined width. To evaluate. That is, when the probability of the power quality value falling within the judgment value range is large, the power quality is evaluated as good, and conversely, when the probability of entering the judgment value range is small, the power quality deteriorates. Assess that you are doing. Thus, by using the occurrence probability of the power quality deterioration phenomenon as a determination factor for power quality evaluation, it becomes possible to evaluate the power quality with high accuracy, and the evaluation reliability is improved.

  According to a ninth aspect of the present invention, in the power quality evaluation system according to any one of the first to eighth aspects, the determination value setting unit sets different determination values depending on a required level of power quality. It is characterized in that it can be set.

  The invention described in claim 18 captures the invention described in claim 9 from the viewpoint of the method, and is required in the power quality evaluation method according to any one of claims 10 to 17. Different judgment values are set according to the degree of power quality.

  According to the invention of claim 9 or claim 18 having the above-described configuration, it is possible to perform flexible power quality evaluation according to the required power quality. The evaluation of the power quality differs depending on the setting of the determination value even if the occurrence probability of the quality deterioration phenomenon is the same. That is, if the range of the judgment value is set to be narrow and the judgment criterion is stricter, the probability of occurrence of the power quality value that falls within the range of the judgment value is reduced. For this reason, even if the occurrence probability itself of the quality deterioration phenomenon does not change, if the range of the determination value is set narrow, the occurrence probability that falls within the determination value becomes relatively small and the power quality is deteriorated. On the other hand, if the judgment value is set wider and the judgment criterion is relaxed, the probability of occurrence of the power quality value entering there increases, and the power quality is evaluated as good.

  Therefore, by changing the setting of the judgment value according to the power quality level desired by the power consumer, it is possible to evaluate the power quality with the optimum judgment value for the power consumer and subdivide the power consumer. It is possible to perform power quality evaluation that can accurately meet the needs of customers.

As described above, according to the present invention, it is possible to provide a power quality evaluation system, a power quality evaluation method, and a power quality evaluation program that can be evaluated in consideration of the occurrence probability of quality deterioration.
It is also possible to provide a power quality evaluation system, a power quality evaluation method, and a power quality evaluation program that can be evaluated in consideration of economic loss.
Furthermore, it is possible to provide a power quality evaluation system, a power quality evaluation method, and a power quality evaluation program that can evaluate power quality according to the required levels of various power consumers.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments relating to a power quality evaluation system and a power quality evaluation method according to the present invention will be specifically described with reference to the drawings.

(1) First Embodiment (1-1) Overall Configuration FIG. 1 shows the overall configuration of the power quality evaluation system of the present embodiment. Data acquisition means 1 for acquiring the power amount, data storage means 2 for storing the acquired power data, power quality calculation means 3 for calculating the degree of power quality of each acquired power amount, and this power quality calculation The power quality value storage means 5 for storing the degree of power quality obtained by the means 3 (hereinafter referred to as power quality value) in the power quality value database 4 and the power quality value stored in the power quality value database 4. From the probability density function creating means 6 for creating a probability density function of the power quality value, a judgment value database 7 storing a judgment value serving as a reference for judging the degree of power quality, and the judgment value database 7, A judgment value setting means 8 for selecting and setting a desired judgment value; a power quality evaluation means 9 for evaluating the degree of power quality using the probability density function of the power quality value and the set judgment value; It has.

  The probability density function creating unit 6 includes a power quality value totaling unit 61 and a probability density function applying unit 62. The power quality evaluating unit 9 calculates a σ value based on a calculation formula described later. Unit 91, σ value evaluation unit 92 that obtains a power quality evaluation value based on the σ value, and quality evaluation value output unit 93 that outputs the obtained power quality evaluation value.

  The determination value setting means 8 may be configured not only to select and set a desired determination value from the determination value database 7, but also to set a desired determination value independently. This determination value is a value for determining the power quality value, and is set with a predetermined width.

(1-1-1) Examples of Items Representing Power Quality Here, various power quality evaluation items to be evaluated by the power quality evaluation system according to the present invention will be described. FIG. 2 shows typical items representing power quality such as harmonics, voltage fluctuations, voltage imbalance, and instantaneous voltage drop, typical indexes representing the degree thereof, and calculation formulas thereof.

(A) Harmonics As a representative index of harmonics, there is an overall distortion rate obtained by dividing the effective value of only the harmonic component by the effective value. The calculation formula is expressed by Formula (1). The smaller the harmonic content, the smaller the overall distortion factor and the better the power quality. If there is no harmonic content, the total distortion will be zero. On the contrary, if the harmonic content increases, the total distortion rate increases and the power quality deteriorates.
Total distortion factor = RMS value only for harmonics ÷ RMS value (1)

(B) Voltage fluctuation As an indicator of voltage fluctuation, there is a voltage fluctuation rate indicating the magnitude of voltage fluctuation per reference voltage. The calculation formula is expressed by Formula (2). The smaller the voltage fluctuation, the smaller the absolute value of the voltage fluctuation rate and the better the power quality. When there is no voltage fluctuation, the voltage fluctuation rate becomes zero. On the other hand, if the voltage fluctuation is large, the absolute value of the voltage fluctuation rate is large, and the power quality is deteriorated. If the voltage fluctuation is on the positive side, the voltage fluctuation rate is positive. If the voltage fluctuation is on the negative side, the voltage fluctuation rate is negative.
Voltage fluctuation rate = Voltage fluctuation (magnitude) ÷ Reference voltage (2)

(C) Voltage imbalance As an indicator of voltage imbalance, there is a voltage imbalance ratio obtained by dividing the absolute value of the negative phase voltage by the absolute value of the positive phase voltage, and the calculation formula is expressed by the following equation (3). The smaller the negative phase voltage, the smaller the voltage imbalance rate and the better the power quality. If there is no reverse phase voltage, the voltage fluctuation rate is zero. On the other hand, if the reverse phase voltage is large, the voltage imbalance ratio is also large, and the power quality is deteriorated.
Voltage imbalance ratio = | Reverse phase voltage | ÷ | Normal phase voltage |

(D) Instantaneous voltage drop As indicators of instantaneous voltage drop (also referred to as instantaneous voltage drop), there are voltage drop rate and duration of instantaneous voltage drop. Here, the voltage drop rate per reference voltage is considered. The calculation formula is expressed by Formula (4). The smaller the amount of voltage drop, the smaller the voltage drop rate and the better the power quality. If there is no voltage drop amount, the voltage drop rate becomes zero. Conversely, the greater the amount of voltage drop, the greater the voltage drop rate and the worse the power quality.
Voltage drop rate = Voltage drop amount / Reference voltage (4)

(1-1-2) Calculation and Storage of Power Quality Value Subsequently, the power quality calculation unit 3 and the power quality value storage unit 5 illustrated in FIG. 1 will be described in more detail.
First, the amount of electric power such as voltage and current of the electric power system is input to the AD converter by an instrument transformer such as CT and PT installed in the electric power system to be evaluated. Since the electric energy input to the AD converter is an analog amount, the analog amount is converted into a digital amount by the AD converter. The electric energy converted into the digital quantity is input to the data acquisition means 1 of this system and stored in the data storage means 2 or read into the power quality calculation means 3 via the data acquisition means 1.
Then, the power quality calculation means 3 calculates a power quality value indicating the degree of power quality of the read power amount. The calculated power quality value is stored in the power quality value database 4 by the power quality value storage means 5.

  FIG. 3 shows an example of the power quality value database 4, and the power distortion value, the overall distortion rate, the voltage fluctuation rate, the voltage imbalance rate, and the voltage drop rate are compiled in a time series. Is. Referring to FIG. 3, the power quality value is a value obtained by calculating the index shown in FIG. 2 according to the formulas (1) to (4). That is, when the power quality evaluation item is harmonic, it is the total distortion rate, the voltage variation rate when the voltage is changed, the voltage unbalance rate when the voltage is unbalanced, and the voltage drop rate when the instantaneous voltage is lowered. is there.

(1-1-3) Creation of Probability Density Function As described above, the probability density function creation means 6 includes the power quality value totaling unit 61 and the probability density function application unit 62. The power quality value totaling unit 61 totals the power quality values stored in the power quality value database 4 and displays the total result in a histogram or the like. In addition, the probability density function application unit 62 creates a probability density function using the total result of the power quality value.

  FIG. 4 is a diagram showing an example of the power quality value tabulation results. The power quality values within a certain period of time t are tabulated from the power quality value database 4 shown in FIG. It is a representation. In FIG. 4, the vertical axis represents the frequency, and the horizontal axis represents the power quality value.

  As shown in the examples of the above formulas (1) to (4), the power quality is the best when the power quality value is zero, and the power quality becomes worse as the distance from zero increases in the plus or minus direction. In the example of FIG. 4, the power quality value has values in both the positive and negative directions, and the case where the power quality value is the voltage fluctuation rate is applicable.

  Usually, when the power quality value is zero, that is, when the power quality is the best, the frequency is large, and as the power quality deteriorates, the frequency decreases, so that the central portion as shown in FIG. 4 is high and the peripheral portion is low. It has a shape. Such a frequency distribution can be expressed as a probability distribution. Accordingly, the probability density function application unit 62 creates a probability density function using the total result of the power quality values. FIG. 5 shows an example in which a histogram of the aggregated power quality values is applied to a normal distribution as a probability density function.

Here, the probability density function of the normal distribution is expressed by the following equation (7). In Expression (7), x is a power quality value, and σ is a standard deviation. Expression (5) is an expression for obtaining an average value of power quality values. Further, the standard deviation σ can be obtained from the equation (6). In these equations, w represents the frequency.

  FIG. 6 shows the relationship between the normal distribution and the standard deviation σ. That is, the probability that the normal distribution will be within the standard deviation ± 1 (hereinafter, 1σ) is 68%, the probability that the normal deviation will be within ± 2 (hereinafter, 2σ) is 95%, and the probability that the standard deviation will be within ± 3 (hereinafter, 3σ) is 99.73%.

(1-1-4) Determination Value Setting The determination value setting means 8 reads a desired determination value from the determination value database 7 or sets a determination value independently. Due to the difference in the determination value, the power quality evaluation value varies greatly. The determination value and the σ value used for power quality evaluation in this embodiment are related as follows.

First, the σ value is defined by equation (8). This σ value is a value calculated by the power quality evaluation means 9 described later.

  FIG. 7 is a diagram showing the relationship between the determination value and the normal distribution. When the determination value H set by the determination value setting unit 8 is “standard deviation ± 3 (3σ)”, in other words, The determination of power quality is gradual, and the variation of the power quality value is smaller than the region between the positive and negative determination values H, and the distribution falls between the positive and negative determination values H. In this case, the σ value is a large value “3”.

  On the other hand, as shown in FIG. 8, when the determination value H set by the determination value setting means 8 is “standard deviation ± 1 (1σ)”, in other words, the determination of power quality is strict and the positive side When the distribution of the power quality value is larger than the region sandwiched between the negative and negative determination values H and the distribution protrudes outside the positive and negative determination values H, the σ value is “1”. And a small value.

  Thus, the larger the σ value, the smaller the variation of the power quality value with respect to the determination value H, and it can be said that the evaluation of the power quality is good. On the other hand, if the σ value decreases, the variation of the power quality value with respect to the determination value H increases, and it can be said that the evaluation of the power quality is bad. Therefore, the σ value is a scale indicating the good power quality.

(1-1-5) Evaluation of Power Quality Next, the power quality evaluation means 9 will be described. As described above, the power quality evaluation unit 9 calculates the σ value based on the formula (8) from the determination value and the standard deviation σ (σ value calculation unit), and evaluates the power quality based on the magnitude ( (sigma value evaluation part) and the electric power quality evaluation value are output (quality evaluation value output part).

  The table in FIG. 9 shows an example of the power quality evaluation value based on the σ value. Here, the power quality is evaluated in five levels from the highest quality according to the magnitude of the σ value. That is, if the σ value is less than 1, the power quality evaluation value is “1”, if the σ value is 1 or more and less than 2, the power quality evaluation value is “2”, and if the σ value is 2 or more and less than 3, the power quality evaluation value. If the evaluation value is “3”, the σ value is 3 or more and less than 4, the power quality evaluation value is “4”, and if the σ value is 4 or more, the power quality evaluation value is “5”.

(1-2) Overall Process Flow The process flow in the power quality evaluation system of the present embodiment having the above-described configuration will be described with reference to the flowchart shown in FIG.
First, the data acquisition means 1 reads various amounts of power of the power system to be evaluated (S1001). Subsequently, the power quality calculation means 3 calculates the degree of power quality at each power amount, and calculates a power quality value (S1002).

  Subsequently, the power quality value storage unit 5 stores the power quality value obtained by the power quality calculation unit 3 in the power quality value database 4 (S1003), and stores it in the power quality value totaling unit 61 of the probability density function creating unit 6. Then, the power quality values are tabulated (S1004), and the probability density function application unit 62 creates a probability density function 7 from the tabulated power quality values (S1005). At this time, the standard deviation σ is derived (S1006).

  Next, a desired determination value is read from the determination value database 7 by the determination value setting means 8 and set as a determination reference value (S1007). Further, in the power quality evaluation means 9, the σ value calculation unit 91 inputs the judgment value and the standard deviation σ to obtain the σ value (S 1008), and the σ value evaluation unit 92 evaluates the σ value to evaluate the power. A quality evaluation value is obtained (S1009). In step S1010, the power quality evaluation value is output.

(1-3) Effect As described above, in the first embodiment, the probability density function creating unit 6 obtains the probability density function and the standard deviation σ from the power quality value, and uses the preset determination value and the standard deviation σ. The σ value is determined and the power quality is evaluated based on the magnitude. That is, if the σ value increases, the power quality is good, and conversely, if the σ value decreases, the power quality is deteriorated.

  As described above, according to the present embodiment, the power quality can be evaluated by obtaining the probability density function from the power quality value and comparing the probability density function with a determination value having a predetermined width. It is possible to provide a power quality evaluation system in consideration of the occurrence probability of deterioration.

(2) Second Embodiment This embodiment is a modification of the first embodiment, and includes all items of a plurality of power quality evaluation items such as harmonics, voltage fluctuations, voltage imbalances, or two or more items. The items can be evaluated comprehensively.

(2-1) Configuration The basic configuration of the present embodiment is the same as that of FIG. 1 of the first embodiment, but the power quality evaluation method performed by the power quality evaluation means 9 is different from that of the first embodiment. ing.

  That is, in the present embodiment, among the power quality evaluation items, the four items of harmonics, voltage fluctuation, voltage imbalance, and instantaneous voltage drop are classified into power quality A, power quality B, power quality C, and power quality D, respectively. And Then, according to the procedure described in the first embodiment, for each power quality A to D, the power quality level is calculated by the power quality calculation means 3, and each power quality A to D is calculated by the power quality value storage means 5. The power quality value for each power quality is stored, and the probability density function creating means 6 creates the power quality probability density function for each power quality A to D. Further, the determination value setting means 8 sets a determination value for each power quality A to D.

  Then, the power quality evaluation means 9 evaluates the power quality for each power quality A to D using the probability density function and determination value for each power quality A to D. Furthermore, in the power quality evaluation means 9 of this embodiment, it evaluates comprehensively combining the evaluation about at least 2 or more power quality item among the evaluation with respect to power quality AD as follows. It is configured to be able to.

First, using the probability density function and determination value of each power quality A to D, the probability that the probability density function of each power quality A to D falls within the range of the determination value on the plus side and the minus side is obtained. For example, if the probability that the probability density function in the power quality A falls within the range of the determination value is PA (x) (−a ≦ x ≦ a), the probability can be obtained by Expression (9).

  Here, fa (x) is a probability density function in the power quality A, and is given by the above equation (7). Further, a in the equation is a determination value of the power quality A set by the determination value setting means 8. Similarly, regarding the power quality B, power quality C, and power quality D, the determination value is set for each of the power qualities B to D by the determination value setting means 8, and the probability density functions of the power qualities B to D are respectively set. Probability of falling within the judgment value range, PB (x), PC (x), PD (x) can be obtained.

Next, assuming that the probability that all probability density functions in the power qualities A to D fall within the range of the respective determination values is P (x), P (x) is expressed by Expression (10).
P (x) = PA (x) × PB (x) × PC (x) × PD (x) (10)

Further, if any one of the probability density functions in the power qualities A to D is out of the range of the respective determination values, Pnot (x) is expressed by Expression (11).
Pnot (x) = 1−P (x)
= 1−PA (x) × PB (x) × PC (x) × PD (x) (11)

  At this time, the smaller Pnot (x), that is, the larger P (x), the better the power quality. Here, the probabilities are examined for all of the power qualities A to D, but it is also possible to perform probability calculation by freely combining two or more desired power quality items.

  FIG. 11 shows the relationship between the P (x) and the standard deviation σ, and the table in FIG. 12 shows an example of the relationship between the P (x) and σ values and the power quality evaluation value. Is. Since it can be said that the power quality is better as P (x) is larger, the power quality can be evaluated in five stages based on the magnitude of P (x) as shown in the table of FIG. That is, in the example shown in FIG. 12, the quality evaluation is “1” if P (x) is less than 68%, and the quality evaluation is “2” if P (x) is 68% or more and less than 95%. If x) is 95% or more and less than 99.73%, the quality evaluation is “3”, and if P (x) is 99.73% or more and less than 99.994%, the quality evaluation is “4”, P (x) Is 99.994% or more, the quality evaluation is “5”.

(2-2) Operational Effects According to the second embodiment as described above, not only can the power quality be individually evaluated for the four power qualities A to D to be evaluated, but also two or more power qualities. Along with the evaluation, the power quality of the entire power system can be comprehensively evaluated.

(3) Third Embodiment In the present embodiment, different determination values are set according to the needs of each power consumer, and the power quality is evaluated based on the determination values. FIG. 13 is a diagram showing the relationship between the probability density function and each judgment value when different judgment values are used. Even if the probability density function is the same, the magnitude of the judgment value is different. It shows that the evaluation of power quality is different.

(3-1) Configuration In the third embodiment, the determination value database 7 and the determination value setting means 8 are provided as in the first embodiment. However, these configurations and their functions are different from those in the first embodiment. ing.

  That is, the determination value database 7 of the present embodiment stores determination values according to each power consumer so as to flexibly cope with the power quality requirement degree desired by each power consumer. Moreover, the judgment value setting means 8 can take out and set the judgment value according to the power quality requirement degree desired by the power consumer from the judgment value database 7.

  That is, in FIG. 13, the determination value Ha is an example when the power quality criterion is strict, and the determination value Hb is an example when the power quality criterion is moderate. The power quality evaluation unit 9 according to the present embodiment calculates the σ value based on the equation (8) using the determination values Ha and Hb and the standard deviation σ calculated by the equation (6). 9 or the power quality evaluation value according to the table of FIG.

(3-2) Operational Effects The operational effects of the third embodiment having the above-described configuration are as follows. That is, when the criterion is a strict criterion Ha, since the σ value is 2> σ value ≧ 1, the power quality evaluation value is “2” from FIG. Further, when the determination criterion is a moderate determination value Hb, since the σ value is 4> σ value ≧ 3, the power quality evaluation value is “4” from FIG.

  In this way, even if the probability density function is the same, the evaluation of the power quality is different if the magnitudes of the determination values are different. That is, when the judgment value Ha is set with strict criteria for judging the power quality, the power quality evaluation value becomes small, and the power quality is judged as bad. On the other hand, when the judgment value Hb is set with a gentle judgment criterion for power quality, the power quality evaluation value increases and the power quality is judged good.

  Therefore, consumers who want high-quality power, such as precision machinery factories and factories that use computers, need to tighten the judgment value.For general consumers who do not need such high-quality power, the judgment value May be moderate. In this way, since it is possible to change and set the determination value according to the level requested by the target electric power consumer, the power quality is evaluated using the optimal determination value for each electric power consumer. Can do. As a result, it is possible to execute a flexible and accurate power quality evaluation with respect to the needs of power consumers who are being segmented.

(4) Fourth Embodiment The fourth embodiment incorporates an economical viewpoint in power quality evaluation.
That is, as described in the section of the prior art, if power quality deteriorates, an economic loss naturally occurs. In this embodiment, paying attention to this point, the degree of power quality is evaluated using a damage curve as shown in FIG.

(4-1) Damage Curve First, the damage curve will be described with reference to FIG. The damage curve indicates the relationship between the power quality value indicating the degree of power quality and the damage, and as shown in the upper diagram of FIG. 14, the power quality value rapidly deteriorates when the power quality value exceeds a certain value. Therefore, by setting a value at which the damage curve rapidly deteriorates as the determination value, it is possible to maintain power quality that minimizes the damage. For example, as shown in the lower diagram of FIG. 14, if the power quality is “3” and the power quality evaluation value is “4”, the probability that the damage is almost 0 is 99. 73%.

(4-2) Configuration FIG. 15 shows the overall configuration of the power quality evaluation system of the present embodiment, in which a part of the configuration of the power quality evaluation system of the first embodiment is changed.
That is, in the power quality evaluation system of the present embodiment, for various power quality items to be evaluated, a damage curve database 11 storing a power curve indicating the degree of power quality and a damage curve indicating the relationship between the damage and The damage curve setting means 12 for selecting and setting the damage curve corresponding to the power quality item to be evaluated from the damage curve database 11, the probability density function of the power quality value, the set damage curve, and the setting Power quality evaluation means 9 for evaluating the degree of power quality using the determined determination value is provided.

  Further, the power quality evaluation means 9 is based on a calculation formula to be described later, a damage index calculation unit 94 for obtaining a “power quality loss index” that is an index indicating the probability of power quality deterioration and damage at that time, and the power quality It comprises a damage index evaluation unit 95 that obtains a power quality evaluation value based on the damage index, and a quality evaluation value output unit 96 that outputs the obtained power quality evaluation value. Since other configurations are the same as those of the first embodiment, description thereof will be omitted.

(4-2-1) Power Quality Damage Index Calculation Method Next, a power quality loss index calculation method in the damage index calculation unit 94 of the power quality evaluation unit 9 will be described.
First, let the damage curve be a function of the power quality value shown in equation (12). In addition, x in Formula (12) is a power quality value.
Damage curve = l (x) (12)

Next, from the probability density function defined by Equation (7) and the damage curve defined by Equation (12), the “power quality probability / damage curve” is defined by Equation (13). The power quality probability / damage curve is a curve as shown in FIG.
Electric power quality probability / damage curve = l (x) · f (x) (13)

Further, the power quality loss index is defined by the equation (14). Here, uj is a value on the plus side of the judgment value, and lj is a value on the minus side of the judgment value.

  That is, since the power quality loss index is an integral value of the power quality probability / damage curve sandwiched between the positive and negative determination values, the power quality loss index changes when the determination value changes.

  Subsequently, the relationship between the range of the determination value and the power quality loss index will be described with reference to FIGS. FIG. 16 is a diagram illustrating the relationship between the power quality probability / damage curve, the power quality loss index, and the determination value.

  FIG. 17 shows an example in which the power quality probability / damage curve is inward with respect to the range of the positive and negative determination values as compared to FIG. In other words, if the range of judgment values becomes wider, in other words, if the judgment criteria become milder, the power quality probability / damage curve will go deep inside the range of judgment values on the plus side and minus side, and the integrated value The power quality loss index is large.

  FIG. 18 shows an example in which the graph of the power quality probability / damage curve appears outside the range of the judgment value on the plus side and the minus side as compared to FIG. Yes. In other words, if the range of judgment values becomes narrow, in other words, if judgment criteria become stricter, the power quality probability / damage curve will increase in the part that goes outside the range of judgment values on the plus side and minus side. The damage indicator is smaller.

  In this way, the power quality loss index becomes smaller as the power quality is better and the power quality probability / damage curve goes out of the judgment value range, while the power quality is worse and the power quality probability / damage curve is the judgment value. The power quality loss index increases as it goes inside the range. Therefore, it can be seen that the power quality loss index is an index for evaluating the power quality.

  FIG. 19 is a diagram showing the relationship between the power quality evaluation value and the power quality loss index. The power quality evaluation value is better as the power quality loss index is smaller, and worse as the power quality loss index is larger. The damage index evaluation unit 95 obtains a power quality evaluation value from the power quality damage index with reference to FIG.

(4-3) Overall Process Flow The process flow in the power quality evaluation system of the present embodiment having the above-described configuration will be described with reference to the flowchart shown in FIG.
First, the data acquisition unit 1 reads various amounts of power of the power system to be evaluated (S2001). Subsequently, the power quality calculation means 3 calculates the degree of power quality in each power amount, and calculates a power quality value (S2002).

  Subsequently, the power quality value storage unit 5 stores the power quality value obtained by the power quality calculation unit 3 in the power quality value database 4 (S2003), and stores it in the power quality value totaling unit 61 of the probability density function creating unit 6. Then, the power quality values are tabulated (S2004), and the probability density function application unit 62 creates a probability density function from the tabulated power quality values (S2005).

  Next, a desired determination value is read from the determination value database 7 by the determination value setting means 8 and set as a determination reference value (S2006). The damage curve setting means 12 makes an evaluation object from the damage curve database 11. The damage curve corresponding to the power quality item is read and set (S2007).

  Next, in the power quality evaluation means 9, the damage index calculation unit 94 obtains a power quality damage index (S2008), and the damage index evaluation unit 95 obtains a power quality evaluation value (S2009). In step S2010, the power quality evaluation value is output.

(4-4) Effect As described above, in this embodiment, the damage index calculation unit 94 calculates the power quality damage index from the probability density function, the damage curve, and the determination value, and the power quality is calculated based on the damage index. Evaluating. In this way, when evaluating power quality, the power quality loss index, which is an index indicating the probability of power quality deterioration and the damage at that time, is used. It is possible to obtain a power quality evaluation system that can evaluate power quality in consideration of

(5) Fifth Embodiment This embodiment is a modification of the fourth embodiment, and includes all items of a plurality of power quality evaluation items such as harmonics, voltage fluctuations, voltage imbalances, or two or more items. The items can be evaluated comprehensively.

(5-1) Configuration The basic configuration of the present embodiment is the same as that of FIG. 15 of the fourth embodiment, but the power quality evaluation method performed in the power quality evaluation means 9 is different from that of the fourth embodiment. ing.

  That is, in the present embodiment, among the power quality evaluation items, the four items of harmonics, voltage fluctuation, voltage imbalance, and instantaneous voltage drop are classified into power quality A, power quality B, power quality C, and power quality D, respectively. And Then, in the procedure described in the fourth embodiment, for each power quality A to D, the level of the power quality is calculated by the power quality calculation means 3, and each power quality A to D is calculated by the power quality value storage means 5. The power quality value for each power quality is stored, and the probability density function creating means 6 creates the power quality probability density function for each power quality A to D.

The determination value setting means 8 sets determination values for each power quality A to D, and the damage curve setting means 12 reads and sets a damage curve corresponding to the power quality item to be evaluated.
And the power quality evaluation means 9 calculates | requires a power quality damage index using the probability density function for every power quality A-D, a judgment value, and a damage curve, and based on this power quality damage index, each power quality AD Evaluate each power quality. Furthermore, in the power quality evaluation means 9 of this embodiment, it evaluates comprehensively combining the evaluation about at least 2 or more power quality item among the evaluation with respect to power quality AD as follows. It is configured to be able to.

(5-2) Calculation of Power Quality Damage Index The power quality probability / damage curves of power quality A, power quality B, power quality C, and power quality D are expressed by equations (15) to (18). In the following equation, la (x), lb (x), lc (x), and ld (x) are loss curves of power quality A, power quality B, power quality C, and power quality D, respectively. Further, fa (x), fb (x), fc (x), and fd (x) are probability density functions of power quality A, power quality B, power quality C, and power quality D, respectively.
Power quality probability / damage curve of power quality A = la (x) · fa (x) (15)
Power quality probability / damage curve of power quality B = lb (x) · fb (x) (16)
Power quality probability / damage curve of power quality C = lc (x) · fc (x) (17)
Power quality probability / damage curve of power quality D = ld (x) · fd (x) (18)

ここで、ｕａｊ：電力品質Ａの判定値のプラス側の値
ｌａｊ：電力品質Ａの判定値のマイナス側の値

ここで、ｕｂｊ：電力品質Ｂの判定値のプラス側の値
ｌｂｊ：電力品質Ｂの判定値のマイナス側の値

ここで、ｕｃｊ：電力品質Ｃの判定値のプラス側の値
ｌｃｊ：電力品質Ｃの判定値のマイナス側の値

ここで、ｕｄｊ：電力品質Ｄの判定値のプラス側の値
ｌｄｊ：電力品質Ｄの判定値のマイナス側の値 For the power quality loss indexes of power quality A, power quality B, power quality C, and power quality D, the power quality probability / damage curves of the above equations (15) to (18) are substituted into equation (14). Can be obtained. This is shown by Formula (19), Formula (20), Formula (21), and Formula (22), respectively.

Where uaj is the positive value of the judgment value of power quality A
laj: negative value of the judgment value of power quality A

Where ubj: value on the positive side of the judgment value of power quality B
lbj: negative value of the judgment value of power quality B

Here, ucj: value on the positive side of the judgment value of power quality C
lcj: Negative value of the judgment value of power quality C

Here, udj: a value on the positive side of the judgment value of power quality D
ldj: Negative value of the judgment value of power quality D

Since the degree of the total power quality of these power qualities A to D is considered to be the sum of Formula (19) to Formula (22), the overall power quality loss index is expressed by Formula (23).

  FIG. 21 is a diagram illustrating the relationship between the power quality evaluation value and the overall power quality loss index. The smaller the overall power quality loss index, the better the power quality evaluation value, and the greater the overall power quality loss index. Deteriorate. The damage index evaluation unit 95 obtains a power quality evaluation value from the overall power quality damage index with reference to FIG.

(5-3) Operational Effects According to the present embodiment as described above, the same operational effects as those of the second and fourth embodiments can be obtained. That is, regarding the four power quality items A to D, the power quality can be evaluated using the probability of power quality deterioration and the damage at that time as the determination factors. In addition, comprehensive or selective power quality evaluation is possible. Further, since the setting of the damage curve can be changed for each power quality item, it is possible to flexibly cope with the case where the economic damage level is different for each power quality item. Therefore, it is possible to perform power quality evaluation with excellent reliability from an economical viewpoint.

(6) Sixth Embodiment The sixth embodiment is a modification of the fourth embodiment, in which a determination value is set according to the needs of each power consumer, and the power quality is evaluated based on the determination value. It is a thing.

  In the sixth embodiment, similarly to the third embodiment, the determination value database 7 sets the determination value according to each power consumer so that the power demands desired by each power consumer can be flexibly handled. Storing. Moreover, the judgment value setting means 8 can take out and set the judgment value according to the power quality requirement degree desired by the power consumer from the judgment value database 7.

  Further, the damage curve database 11 stores a damage curve corresponding to each electric power consumer. Moreover, the damage curve setting means 12 can take out the damage curve according to the electric power consumer from the damage curve database 11, and can set it now.

  Here, the damage curve according to an electric power consumer is demonstrated. For example, in the case of a consumer who desires high-quality electric power such as a precision machine factory or a computer use factory, even if the electric power quality is slightly deteriorated, the economic damage is increased. On the other hand, economic damage caused by changes in power quality is small for general consumers who do not require such high-quality power. For this reason, more accurate power quality evaluation can be performed by providing an individual damage curve according to a power consumer.

  Thus, in this embodiment, since a separate judgment value and damage curve can be set for each consumer, it is possible to flexibly and accurately respond to the needs of power consumers who are being segmented. It is possible to evaluate the power quality that can be achieved.

(7) Seventh Embodiment The present embodiment is a modification of the first embodiment, and uses a power quality distribution map instead of a probability density function.
In the present embodiment, as shown in FIG. 22, instead of the probability density function creating means 6 used in each of the above embodiments, a power quality distribution map creating means 20 is provided to output a power quality distribution map. It has become.

  The power quality distribution map creating means 20 includes a power quality value totaling unit 21, a totaling result normalizing unit 22, and a distribution map creating unit 23. In addition, the power quality evaluation means 9 includes a normalized power calculator 97 for obtaining a normalized power magnitude P sandwiched between positive and negative determination values in the power quality distribution map, and the power shown in FIG. The standardization frequency evaluation unit 98 that obtains a power quality evaluation value based on a table showing the relationship between the quality evaluation value and P, and a quality evaluation value output unit 99 that outputs the power quality evaluation value. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

(7-1) Creation of Power Quality Distribution Map The power quality value totaling unit 21 of the power quality distribution map creating unit 20 totals the power quality values stored in the power quality value database 4, and the result is the power quality value. Assume the total result. The tabulation result normalization unit 22 normalizes the tabulation result, and the normalized result is used as the tabulation result standard for the power quality value. Then, the distribution map creation unit 23 sets the power quality value aggregation result standard or the aggregation result as the power quality distribution map.

  The processing in the tabulation result normalization unit 22 normalizes the tabulation result of the power quality value. Taking FIG. 4 in the first embodiment as an example, the frequency for each power quality value in FIG. This is equivalent to dividing by the total frequency. If this is a normalized frequency, the total value of all the normalized powers for all power quality values is 1.

  FIG. 23 is a diagram illustrating the relationship between the normalized frequency and the power quality value, and FIG. 24 is a diagram illustrating the evaluation of power quality based on the determination value and the power quality value aggregation result standard. As is clear from FIG. 24, it can be seen that the higher the normalized frequency sandwiched between the positive and negative determination values, the better the power quality.

  Here, FIG. 25 shows an example of the relationship between P and the power quality evaluation value, where P is the magnitude of the normalized frequency sandwiched between the positive and negative determination values. That is, as in the example of FIG. 12, the power quality evaluation means 9 represents the power quality evaluation value as a numerical value in five stages. If it is less than%, the quality evaluation is “2”, if P is 95% or more and less than 99.73%, the quality evaluation is “3”, and if P is 99.73% or more and less than 99.994%, the quality evaluation is If “4” and P are 99.994% or more, the quality evaluation is “5”.

(7-2) Operational Effects As described above, in the present embodiment, the power quality distribution map creating unit 20 obtains a power quality distribution map from the power quality values, and the power quality evaluation unit 9 has the positive side and the negative side. The power quality evaluation value is output based on the normalized frequency that falls within the range of the determination value. Thus, according to the present embodiment, it is possible to provide a power quality evaluation system that can evaluate power quality in consideration of the occurrence probability of a power quality deterioration phenomenon.

(8) Other Embodiments The present invention is not limited to the above embodiment. For example, in the second to sixth embodiments, the power quality distribution map creating means 20 is used instead of the probability density function creating means 6. May be used. However, in the fourth to sixth embodiments having the damage index calculation unit 94, regarding the power quality probability / damage curve used when deriving the power quality damage index, the probability density function is not multiplied by the damage curve. Use an amount obtained by multiplying the conversion frequency by the damage curve.

  Further, as a modification of the seventh embodiment, when a plurality of power quality evaluation items are power quality A, power quality B, power quality C, and power quality D, respectively, determination of the positive side and the negative side of each power quality Assuming that the standardized frequency sandwiched between values is Pa, Pb, Pc, and Pd, the power quality evaluation may be performed using these average values.

  Further, stage evaluation in the power quality evaluation means, types of power quality items, combinations thereof, and the like can be selected as appropriate. Furthermore, a wide variety of other forms can be implemented within the scope of the present invention, and when the configurations according to each of the above embodiments are used in appropriate combination, the same or a synergistic effect by the combination depending on the combination It goes without saying that can be obtained.

The block diagram which shows the structure of 1st Embodiment of the power quality evaluation system which concerns on this invention. The figure which shows the representative parameter | index showing the electric power quality evaluation item and its grade, and its calculation formula. The figure which shows an example of an electric power quality value database. The histogram which shows an example of the total result of an electric power quality value. The figure which showed the example which applied the histogram of the total electric power quality value to normal distribution as a probability density function. The figure which showed the relationship between normal distribution and standard deviation (sigma). It is a figure which shows the relationship between a judgment value and normal distribution, Comprising: When judgment value H is "standard deviation +/- 3 (3 (sigma))". It is a figure which shows the relationship between a judgment value and normal distribution, Comprising: When judgment value H is "standard deviation +/- 1 (1 (sigma))". The figure which showed an example of the electric power quality evaluation value based on (sigma) value. The flowchart which shows the flow of the process in the electric power quality evaluation system of 1st Embodiment. The figure which showed the relationship between P (x) and standard deviation (sigma). The figure which shows an example of the relationship between P (x) and (sigma) value, and a power quality evaluation value. The figure which showed the relationship between a probability density function and each determination value at the time of using a different determination value. The figure which shows the relationship between a power quality value, a damage curve, and a probability density function. The block diagram which shows the structure of 4th Embodiment of the power quality evaluation system which concerns on this invention. The figure which shows the relationship between a power quality probability and damage curve, a power quality damage index, and a judgment value. The figure which shows the relationship between a power quality probability and damage curve, a power quality damage index, and a judgment value. The figure which shows the relationship between a power quality probability and damage curve, a power quality damage index, and a judgment value. The figure which shows the relationship between an electric power quality evaluation value and an electric power quality damage index. The flowchart which shows the flow of a process in the electric power quality evaluation system of 4th Embodiment. The figure which shows the relationship between an electric power quality evaluation value and the whole electric power quality damage parameter | index. The block diagram which shows the structure of 7th Embodiment of the power quality evaluation system which concerns on this invention. The figure which shows the relationship between a normalization frequency and an electric power quality value. The figure explaining evaluation of electric power quality by a judgment value and a total result standard. The figure which shows the relationship between the magnitude | size P of the normalization frequency pinched | interposed into the judgment value, and an electric power quality evaluation value.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Data acquisition means 2 ... Data storage means 3 ... Electric power quality calculation means 4 ... Electric power quality value database 5 ... Electric power quality value storage means 6 ... Probability density function creation means 61 ... Electric power quality value totaling part 62 ... Probability density function application part 7 ... Determination value database 8 ... Determination value setting means 9 ... Power quality evaluation means 91 ... σ value calculation section 92 ... σ value evaluation section 93 ... Quality evaluation value output section 94 ... Damage index calculation section 95 ... Damage index evaluation section 96 ... Quality evaluation value output unit 97 ... Normalized frequency calculation unit 98 ... Standardized frequency evaluation unit 99 ... Quality evaluation value output unit 11 ... Damage curve database 12 ... Damage curve setting means 20 ... Power quality distribution map creation means 21 ... Power quality value Total part 22 ... Total result standard part 23 ... Distribution map creation part

Claims (21)

Power quality calculation means for calculating the degree of power quality of the amount of power to be evaluated;
A probability density function creating means for creating a probability density function of the power quality value from the power quality value obtained by the power quality calculating means;
Determination value setting means for setting a determination value serving as a reference for determining the degree of power quality;
A power quality evaluation system comprising: a power quality evaluation unit that evaluates the degree of power quality using a probability density function of the power quality value and a set determination value.   The power quality evaluation means is configured to evaluate the power quality based on the probability that the probability density function of the power quality value falls within a set judgment value range. The power quality evaluation system according to claim 1.   The probability density function created for each of the plurality of power quality evaluation items obtains the probability that each of the probability density functions falls within the range of the judgment value set for each evaluation item, and two or more evaluation items to be subjected to comprehensive evaluation 2. The power quality evaluation system according to claim 1, wherein the power quality evaluation system is configured to evaluate a power quality based on a value of the product of the probabilities obtained for. Power quality calculation means for calculating the degree of power quality of the amount of power to be evaluated;
A probability density function creating means for creating a probability density function of the power quality value from the power quality value obtained by the power quality calculating means;
Determination value setting means for setting a determination value serving as a reference for determining the degree of power quality;
A damage curve setting means for setting a damage curve indicating a relationship between the power quality value and the damage;
A power quality evaluation system, comprising: a power quality evaluation unit that evaluates the degree of power quality using a probability density function of the power quality value and a set judgment value and damage curve.   5. The power quality evaluation system according to claim 4, wherein the power quality evaluation unit is configured to evaluate the power quality based on a probability of power quality deterioration and a damage index indicating damage at that time.   A damage index indicating the probability of power quality deterioration and the damage at that time is obtained for each of a plurality of power quality evaluation items, and based on the sum of the damage indexes obtained for two or more evaluation items to be comprehensively evaluated. The power quality evaluation system according to claim 4, wherein the power quality evaluation system is configured to evaluate power quality. Power quality calculation means for calculating the degree of power quality of the amount of power to be evaluated;
A power quality distribution map creating means for creating a power quality value distribution map from the power quality value obtained by the power quality calculating means;
Determination value setting means for setting a determination value serving as a reference for determining the degree of power quality;
A power quality evaluation system comprising: a power quality evaluation unit that evaluates the degree of power quality using the power quality distribution map and a set determination value.   8. The power quality evaluation unit is configured to evaluate power quality based on a probability that the power quality distribution map falls within a set judgment value range. The power quality evaluation system described in 1.   The determination value setting unit is configured to be able to set a different determination value according to a required level of power quality. Power quality evaluation system. Calculate a power quality value that indicates the degree of power quality of the amount of power to be evaluated,
Create a probability density function of the power quality value from the obtained power quality value,
Set a criterion value to determine the level of power quality,
A power quality evaluation method characterized in that the degree of power quality is evaluated using a probability density function of the power quality value and a set determination value.   The power quality evaluation method according to claim 10, wherein the power quality is evaluated based on a probability that the probability density function of the power quality value falls within a set determination value range.   The probability density function created for each of the plurality of power quality evaluation items obtains the probability that each of the probability density functions falls within the range of the judgment value set for each evaluation item, and two or more evaluation items to be subjected to comprehensive evaluation The power quality evaluation method according to claim 10, wherein power quality is evaluated based on a product value of the probabilities obtained with respect to. Calculate a power quality value that indicates the degree of power quality of the amount of power to be evaluated,
Create a probability density function of the power quality value from the obtained power quality value,
In addition to setting a criterion value to determine the level of power quality,
Set a damage curve showing the relationship between the power quality value and damage,
A power quality evaluation method, wherein the degree of power quality is evaluated using a probability density function of the power quality value and a set judgment value and damage curve.   The power quality evaluation method according to claim 13, wherein power quality is evaluated based on a probability of power quality deterioration and a damage index indicating damage at that time.   A damage index indicating the probability of power quality deterioration and the damage at that time is obtained for each of a plurality of power quality evaluation items, and based on the sum of the damage indexes obtained for two or more evaluation items to be comprehensively evaluated. The power quality evaluation method according to claim 13, wherein the power quality is evaluated. Calculate a power quality value that indicates the degree of power quality of the amount of power to be evaluated,
Create a distribution map of power quality values from the calculated power quality values,
Set a criterion value to determine the level of power quality,
A power quality evaluation method characterized by evaluating the degree of power quality using the power quality distribution map and a set determination value.   The power quality evaluation method according to claim 16, wherein the power quality is evaluated based on a probability that the power quality distribution map falls within a set determination value range.   The power quality evaluation method according to any one of claims 10 to 17, wherein different determination values are set according to a required level of power quality. A power quality evaluation program for evaluating power quality by controlling a computer,
The program is stored in the computer,
Calculating a power quality value indicating the degree of power quality of the amount of power to be evaluated;
Creating a probability density function of the power quality value from the determined power quality value;
Setting a determination value as a reference for determining the degree of power quality;
Using the probability density function of the power quality value and the set determination value to evaluate the degree of power quality;
A program for evaluating power quality, characterized in that A power quality evaluation program for evaluating power quality by controlling a computer,
The program is stored in the computer,
Calculating a power quality value indicating the degree of power quality of the amount of power to be evaluated;
Creating a probability density function of the power quality value from the determined power quality value;
Setting a determination value as a reference for determining the degree of power quality;
Setting a damage curve indicating a relationship between the power quality value and damage;
Using the probability density function of the power quality value and the set judgment value and damage curve to evaluate the degree of power quality;
A program for evaluating power quality, characterized in that A power quality evaluation program for evaluating power quality by controlling a computer,
The program is stored in the computer,
Calculating a power quality value indicating the degree of power quality of the amount of power to be evaluated;
Creating a distribution map of power quality values from the determined power quality values;
Setting a determination value as a reference for determining the degree of power quality;
Using the power quality distribution map and the set determination value to evaluate the degree of power quality;
A program for evaluating power quality, characterized in that

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