JP4802129B2 - Power quality evaluation system - Google Patents

Description

  The present invention relates to a power quality evaluation system capable of estimating the generation factor of harmonics generated in a power system.

 A power quality measuring apparatus or a power quality analyzing apparatus that measures or analyzes the degree of power quality such as voltage fluctuation, voltage imbalance, and instantaneous voltage drop occurring in a power system has been put into practical use. In addition, a power quality measuring apparatus or a power quality analyzing apparatus that measures or analyzes these through a transmission system has been put into practical use.

  Patent document 1 evaluates electric power quality from the generation | occurrence | production probability and damage degree of electric power quality deterioration.

  Patent Document 2 evaluates the power quality when a power quality assurance device is introduced in consideration of the occurrence probability and the degree of damage of power quality deterioration.

Patent Document 3 has a function of estimating the power quality deterioration factor in consideration of the occurrence probability and the degree of damage of power quality deterioration.
JP-A-2005-73346 JP 2005-287238 A JP 2006-217709 A

  The power quality evaluation systems of Patent Documents 1, 2, and 3 are connected to an electric power system, collect electrical physical quantities such as voltage and current of consumers who receive power supply using a transmission system, and measure the degree of power quality. Is to evaluate.

  However, it can be connected to the power grid, and the electrical and physical quantities such as voltage and current of consumers who receive power supply can be collected using the transmission system, etc., and the generation factor of harmonics, which is one of the power quality, can be estimated There is no power quality evaluation system.

  The present invention has been made in consideration of the above-described circumstances, and an object thereof is to provide a power quality evaluation system capable of estimating a factor of harmonics.

    In order to achieve the above object, the invention corresponding to claim 1 is based on an electrical physical quantity including at least one of a current and a voltage measured at at least one location of a power system, and a harmonic component of the electrical physical quantity. Calculated by the harmonic component calculating means, a database for storing the harmonic components of a plurality of harmonic generating devices estimated to generate the harmonic, and the harmonic component calculating means. Each harmonic component is approximated by a total value obtained by adding a weighting factor to the harmonic components of a plurality of harmonic generation devices stored in the database, and becomes a harmonic generation source based on the approximated weighting factor. It is an electric power quality evaluation system provided with the influence calculation means which can estimate the factor of the said harmonic generator.

 According to the present invention, a harmonic component is calculated based on the measured electrical physical quantity, and a weighting factor is added to the calculated harmonic component to the harmonic components of a plurality of harmonic generators stored in the database. By approximating with the total value thus obtained, it is possible to provide a power quality evaluation system capable of estimating the factor of the harmonic generation device.

  FIG. 1 is a schematic diagram showing an application example of a power quality evaluation system according to the present invention.

  The power quality evaluation system 1 is, for example, one of the qualities of power supplied to a load facility 28 that is electrically connected to a feeder 22 of a consumer 50 that uses electricity by receiving power from a power system (upper power system) 32. This is a system for analyzing the generation factors of harmonics.

  The power quality evaluation system 1 is realized, for example, by the cooperation of a computer as hardware and a program as software for analyzing factors that generate harmonics in terms of power quality.

  As shown in FIG. 1, a measuring device that acquires electrical physical quantity information (hereinafter referred to as electrical physical quantity information) 12 including at least current and voltage in a feeder 22 electrically connected to a bus 30 of a customer 50. 27 is installed. The power quality evaluation system 1 estimates the factor of the harmonic generation device based on the electrical physical quantity information 12 acquired from the measuring device 27 when the harmonic is superimposed on the current and voltage.

[First Embodiment]
FIG. 2 is a schematic diagram showing the configuration and function of the first power quality evaluation system 1 of the present invention.

  As shown in FIG. 2, the harmonics of the electrical physical quantity are based on the electrical physical quantity information 12 including at least one of the current and the voltage measured by at least one location of the power system 32 by the measuring device 27 shown in FIG. Harmonic component calculation means 2 for calculating components for each measurement location is provided.

  Furthermore, a measured harmonic component storage means 3 for storing a calculation result (hereinafter referred to as measured harmonic component calculation result 6) of the harmonic component obtained by the harmonic component calculation means 2 is provided.

  In addition, a database (hereinafter referred to as harmonic generation device database 11) storing harmonic components (hereinafter referred to as harmonic generation device harmonic components 7) of devices estimated to generate harmonics is provided. Then, a vector having the measured harmonic component result 6 stored by the measured harmonic component storage means 3 as a vector element (hereinafter, measured harmonic vector 60) and a vector having the harmonic generator harmonic component 7 as a vector element (hereinafter referred to as a vector element). The weighting coefficient (hereinafter referred to as harmonic influence degree 10) is calculated when expressed by an approximate expression of a vector sum to which a weighting coefficient (hereinafter referred to as generating equipment harmonic weighting coefficient 62) of harmonic generation equipment harmonic vector 61) is added. Harmonic influence degree calculation means 8 is provided.

  Harmonic factor estimation means 9 for estimating a harmonic influence factor of 10 as a main factor of the actually measured harmonic is provided, and the harmonic factor estimation means 9 converts the estimated main factor of the harmonic into a harmonic factor. Output as an estimation result 20.

    FIG. 3 is a diagram showing voltage waveforms for two phases between lines as an example of the waveform of the electrical physical quantity 12 actually measured by the measuring device 27 of FIG. For example, in the power quality evaluation system 1, information representing the waveform of the electrical physical quantity as shown in FIG. 3 is acquired, and the harmonic component calculation means 2 calculates the harmonic component based on the acquired waveform information. .

  Here, the horizontal axis of the graph shown in FIG. 3 is time, and the vertical axis is voltage. Vab is a line voltage between a phase and b phase of three phases (a phase, b phase and c phase), and Vbc is a line voltage between b phase and c phase.

  FIG. 4 shows an example of the harmonic component calculation means 2 of FIG. The electrical physical quantity information 12 is input, and a component for each harmonic order included in the electrical physical quantity information 12 is calculated. In this case, FFT (Fast Fourier Transform) is known as the most general method for calculating components for each harmonic order. In the embodiment, the FFT processing unit 02 calculates.

Here, the FFT processing unit 02 will be described. Harmonics are represented as a collection of sine waves with a constant period and different periods. Assuming that the fundamental wave is primary, the period is 1/2 of the fundamental wave (frequency is twice), the period is 1/3 of the fundamental wave (frequency is 3 times), the third order, and 1 / n (frequency is n Times) is called the nth order. When a harmonic enters the commercial frequency, the commercial frequency is called distorted, and the harmonic component can be obtained by Fourier transform or the like. When the observation data is a sampling value, a technique called discrete Fourier transform is used to obtain a harmonic component from this. A method improved so that the discrete Fourier transform can be solved at high speed is called fast Fourier transformation (FFT), and is the most general-purpose method in harmonic analysis. )
In this way, the FFT processing unit 02 outputs the actually measured harmonic component 6 obtained.

  FIG. 5 is an example of the measured harmonic component result 6 calculated by the harmonic component calculation means 2.

  This is an example in which the electrical physical quantity 12 shown in FIG. 3 is calculated for each harmonic order using the FFT in the harmonic component calculation means 2. In this example, the harmonic content of Vab and Vbc is shown. The vertical axis represents the harmonic content, and the horizontal axis represents the harmonic order. The harmonic content rate is calculated for each order of the harmonics, and is calculated using Equation (1).

Harmonic content (order) = Harmonic magnitude (order) ÷ Fundamental wave magnitude (1)
The harmonic generation device database 11 stores the harmonic generation device harmonic component 7 of the harmonic generation device 21.

  FIGS. 6 to 9 show examples of the harmonic generator harmonic component 7 stored in the harmonic generator database 11.

  6 shows an example of a power converter (6-phase), FIG. 7 shows an arc furnace, FIG. 8 shows an air conditioner, and FIG. 9 shows an example of general illumination. In FIGS. The axis indicates the harmonic order.

  FIG. 10 is a schematic diagram for explaining the harmonic component influence calculation means 8 of FIG.

The harmonic component influence degree calculation means 8 includes a normalization calculation means 13 and an influence degree calculation means 14. The normalization calculation means 13 performs normalization so that the sum of the harmonic components of the actually measured harmonic component calculation result 6 is 1. Equation (2) represents the j-th order component after normalization.

  Standardize the value after normalization of the measured harmonic component calculation result 6 Normalize the measured harmonic component calculation result 19 and the normalized value of the harmonic generation device harmonic component 7 in the harmonic generation device database 11 A harmonic generation device harmonic component 15 is assumed.

  When the influence level calculation means 14 is represented by the real side harmonic vector 60 having the real side harmonic component as a vector element, the influence degree calculating means 14 is a vector 61 to which a weighting coefficient 62 having the harmonic component of the equipment in the equipment database as a vector element is added. When the harmonic vector of the actually measured harmonic is represented by an approximate expression using a vector sum, a weighting coefficient (harmonic influence degree) 62 is calculated.

  FIG. 11 is a diagram for explaining the harmonic component normalization. Here, the harmonic generation device harmonic component 7 in the harmonic generation device database 11 of FIG. 10 may not match the harmonic calculation maximum order of the actually measured harmonic component calculation result 6. For example, when the maximum order of the harmonic generation device harmonic component 7 is 25th order and the maximum order of the harmonic generation device harmonic component 7 is only 20th order, the standardized maximum order is matched, Both are performed up to the 20th order. In this case, the denominator of Equation (2) is the total value up to the 20th order of the harmonic components before normalization.

  Next, the function of the influence calculation means 14 will be described with reference to FIG.

  The influence degree calculation means 14 calculates a generator harmonic weight coefficient 62 for approximating the measured harmonic vector 60 with the vector sum of the harmonic generator harmonic vector 61 to which the generator harmonic weight coefficient 62 is added. To do.

  The measured harmonic vector 60 having the normalized value of the measured harmonic component calculation result 6 (hereinafter referred to as the normalized measured harmonic component calculation result 19) as a vector element is used as a harmonic generator harmonic in the harmonic generator database 11. The harmonic component 61 is approximated by a vector sum obtained by adding the generating device harmonic weight coefficient 62 to the harmonic generating device harmonic vector 61 having the normalized value of the wave component 7 (hereinafter referred to as the normalized harmonic generating device harmonic component 15) as an element. A generator harmonic weighting factor 62 is calculated for this purpose.

Expression (3) is an example of an approximate expression of the actually measured harmonic vector 60. In this example, the actually measured harmonic vector 60 is approximated by a linear sum of n harmonic generator harmonic vectors.

  In Expression (3), Aj is the generator harmonic weight coefficient 62 of the j-th harmonic generator harmonic vector 61 (harmonic generator harmonic vector 61-j).

Normalization of the measured harmonic vector 60 from the second to twentieth standardized harmonic component calculation result 19, and generation of the harmonic element 61 from the second harmonic to the twentieth standardized harmonic generation When the device harmonic component 15 is represented in a vector format, the equation (3) is represented by the equation (4).

Next, how to determine the generator harmonic weight coefficient 62 will be described. Assuming that the i-order component of the measured harmonic vector 60 is HMi and the i-order component of the approximate expression represented by the right side of Expression (4) is hmi, the approximate expression represented by the right side of Expression (4) is the expression ( 5).

  The generator harmonic weighting coefficient 62 is set so that the error between the actual measurement value represented by the actual harmonic vector 60 and the approximate value represented by the equation (5) (hereinafter, the actual harmonic approximation vector 63) is minimized. The generator harmonic weighting coefficient 62 is obtained.

  The generator harmonic weighting coefficient 62 that minimizes the sum of the squares of the differences between the elements of the measured harmonic vector 60 and the elements of the measured harmonic approximate value vector 63 is obtained. This method is called a least square method, and is a general method for obtaining an approximate expression with the smallest error.

Assuming that the sum of the squares of the differences between the elements of the measured harmonic vector 60 and the elements of the measured harmonic approximate value vector 63 is S, S is expressed by Expression (6).

  In order to minimize the error by the least square method, it is necessary to partially differentiate Equation (6) with each generator harmonic weight coefficient 62 to obtain the generator harmonic weight coefficient 62 at which these become zero. .

When partial differentiation is performed with the j-th generator harmonic weighting coefficient 62, Equation (7) is obtained.

When formula (7) is expanded, formula (8) is obtained.

When equation (8) is set to zero, equation (8) is calculated with each generator harmonic weighting coefficient 62 and expressed in matrix form, equation (9) is obtained.

  The right-side matrix of the equation (9) is a symmetric matrix of ΣHSki × HSji (k columns j rows or j columns k rows) and ΣHSji × HSji (diagonal components of j columns j rows).

  The right side matrix of Equation (9) is a regular matrix (Non-Singular Matrix) if the number of harmonic orders ≥ the number of harmonic generators, and the inverse matrix can be calculated, that is, each generator harmonic weight coefficient 62 is calculated. it can.

  FIG. 12 is a schematic diagram for explaining the influence degree calculation means 14. The influence degree calculation means 14 includes a harmonic generation equipment selection means 65, a generation equipment harmonic weight coefficient calculation means 66, and a significance determination means 67. I have.

  The harmonic generator selection unit 65 selects a harmonic generator to be used as a sample.

In the generator harmonic weight coefficient calculation means 66, the procedure described in the equations (3) to (9)
A generator harmonic weighting coefficient 62 is calculated.

  Next, the significance determination means 67 determines the significance of the generated equipment harmonic weighting coefficient 62.

  Significance is the degree to which the physical meaning of the generator harmonic weighting coefficient 62 is high.

  Here, the significant residence is performed as follows.

(1) Significance judgment 1
As one of the significance determinations, there is an error determination using Expression (6).

  An error determination criterion ε is created and used for error determination as shown in equation (10).

S = Σ (HMi−hmi) ² <ε (10)
(2) Significance determination 2
As another significance determination, there is a positive / negative determination of the generator harmonic weighting coefficient 62. When the generator harmonic weighting coefficient 62 is negative, it has little physical meaning and needs to be omitted.
The influence degree calculation means 14 finds a generator harmonic weighting coefficient 62 that satisfies significance determination 1 and significance determination 2.

   When the significance is 1 in the significance determination 1, the harmonic generator to be sampled is selected by the harmonic generator selection means 65 so as to exclude the harmonic generator having the smallest generator harmonic weight coefficient 62. .

   If the significance is 2 in the significance determination 2, harmonic generators that are sampled by the harmonic generator selection means 65 are excluded so as to exclude harmonic generators for which the generator harmonic weight coefficient 62 is negative. elect.

  When the significance is determined as Yes in the significance determination 68, the harmonic influence degree 10 is output.

  The harmonic influence degree 10 is the generated equipment harmonic weight coefficient 62 when the significance is determined to be Yes in the significance determination 68.

    FIG. 13 is a schematic diagram for explaining the harmonic factor estimating means 9 of FIG. 2, which comprises an influence degree rearranging means 17 and a harmonic factor extracting means 03. The influence degree rearranging means 17 is means for rearranging the harmonic generation equipment based on the harmonic influence degree 10, for example, the generation equipment harmonic weighting coefficient 62. For example, the components are rearranged in order from the highest in the generator harmonic weight coefficient 62, specifically, in the highest harmonic generator harmonic component 7.

    The harmonic factor extraction means 03 extracts the harmonic generators rearranged in descending order of the generator harmonic weight coefficient 62, specifically, the generator harmonic component 7 that seems to be a harmonic factor. What is estimated to be a harmonic factor from among them is output as a harmonic factor estimation result 20.

    FIG. 14 is a diagram for explaining the relationship between the generator harmonic weighting coefficient 62 and the harmonic generator 21. As shown in the equation (11), the generator harmonic weight coefficient ratio 69 is the ratio of the generator harmonic weight coefficient 62 to the sum of the generator harmonic weight coefficients 62.

Generator harmonic weighting factor ratio 69 =
Generating equipment harmonic weighting coefficient 62 ÷ Total sum of generating equipment harmonic weighting coefficient 62
(11)
When the generator harmonic weight coefficient ratio 69 is arranged from the left in order from the left, it can be seen that the generator harmonic weight coefficient 62 falls between 100% and 0% as shown in FIG.

  Therefore, as shown in FIG. 14, it is possible to provide a harmonic factor extraction threshold 18 and extract a harmonic generator 21 having a higher generation device harmonic weight coefficient ratio 69 than the harmonic factor extraction threshold 18 as a harmonic factor. is there.

    As the harmonic factor estimation result 20, the harmonic generation device harmonic component 7 or the harmonic generation device 21 that is above the harmonic factor extraction threshold 18 in FIG. 14 is output. Note that when the harmonic factor extraction threshold 18 is set to zero, the harmonic generators 21 of all factors are output.

According to the power quality evaluation system of the first embodiment described above, the electrical physical quantities such as the voltage and current of the consumer who is connected to the power system and receives power supply are collected using the transmission system and the like, A factor of generation of harmonics, which is one of power quality, can be estimated [second embodiment]
FIG. 15 is a schematic diagram for explaining the configuration and functions of the power quality evaluation system 1 according to the second embodiment of the present invention. 2 except that the high frequency factor estimating means 9 provided on the output side of the harmonic influence degree calculating means 8 of the embodiment of FIG. 2 is not provided and a result display means 23 is provided instead. is there.

The result display means 23 is a means for visually displaying an evaluation result to a user such as a CRT (Cathode Ray Tube), an LCD (Liquid Crystal Display), or a PDP (Plasma Display Panel). When receiving the harmonic factor estimation result 17, the display unit 12 displays the content of the harmonic factor estimation result 17 as an image.

  The power quality evaluation system 1 shown in FIG. 15 includes a display unit 23 as an output unit that outputs a harmonic factor estimation result in a format that can be recognized by the user. Instead of the display unit 23, for example, Other output means such as printing means may be provided.

 In the power quality evaluation system 1 having such a configuration, the following effects can be obtained. That is, the actual harmonic component calculation result 6 is calculated in the harmonic component calculation means 2, the harmonic influence degree 10 for each harmonic generation device 21 is calculated in the harmonic influence calculation means 8, and then the result display means 23. The harmonic influence degree 10 for each harmonic generation device 21 is displayed. This is repeated at regular intervals.

  FIG. 16 is a display example of the harmonic influence degree 10 for each harmonic generation device 21 in the result display means 23 shown in FIG. 15, where the vertical axis indicates the harmonic influence degree 10 and the horizontal axis indicates time. The example of FIG. 16 is a display example for 24 hours a day. In the example of FIG. 16, the harmonic influence degree 10 of the motor A with inverter, the motor B with inverter, the air conditioner, or the illumination is plotted for 24 hours a day as the harmonic generator 21.

[Third Embodiment]
FIG. 17 is a schematic diagram for explaining the configuration and functions of a power quality evaluation system 1A according to the third embodiment of the present invention. In the embodiment of FIG. 2, the harmonic component calculation means 2 is replaced with the harmonic component calculation means 2A, and the high frequency factor estimation means 9 provided on the output side of the harmonic influence calculation means 8 is not provided. 2 except that a high-frequency factor estimating means 9A is provided and an alarm generating means 37 is provided on the output side of the high-frequency factor estimating means 9A.

  The harmonic component calculation unit 2A includes an FFT processing unit 02 and a current direction calculation unit 24 as shown in FIG. Further, a harmonic generation source specifying logic 36 shown in FIG. 22 is provided in the harmonic factor estimating means 9A.

  Since the harmonic generation source 40 is specified by the harmonic factor estimating means 9A and the harmonic generation device 21 is specified, when the degree of harmonics is large, the harmonic generation source 40 that causes the harmonic generation and the harmonic generation An alarm 38 is output to the device 21 by the alarm generation means 37. In the case of FIG. 17, an example is shown in which an alarm 38 is issued to the central monitoring control center 39 that centrally manages the energy system.

  FIG. 18 is an explanatory diagram of the current direction calculation means 24 according to the present invention. The current direction calculation means 24 calculates the direction of current. The measured harmonic component calculation result 6 also records the direction of the harmonic current. In the harmonic factor estimation result 20 of FIG. 17, the current direction from the high-frequency generator 21 that is a harmonic factor is displayed.

  FIG. 19 is a diagram for explaining the function of the current direction calculation means 24 according to FIG. The voltage vector 25 is a harmonic voltage vector of a certain order n. Assuming that a vector of a harmonic current of a certain order n is a current vector 26, if the delay and advance of the current vector 26 with respect to the voltage vector 25 are within 90 degrees, the current vector 26 has the same direction as the voltage vector 25. To do. Conversely, if the delay and advance exceed 90 degrees, the direction of the current vector 26 is opposite to that of the voltage vector 25. In the example of FIG. 19, with respect to the voltage vector 25, the current vector 26A and the current vector 26B are in the same direction, and the current vector 26C and the current vector 26D are in the opposite direction.

  FIG. 20 is a system diagram for explaining a harmonic generation source specifying method according to the embodiment of FIG. As shown in FIG. 20, a system is considered in which power is supplied from the host system 32 and is composed of a power transmission line 29A, a bus 30, a power transmission line 29B, a power transmission line 29C, a load facility 28B, and a load facility 28C.

A measuring device 27A is installed in the power transmission line 29A, and the electrical physical quantity 12 (voltage, current) of the power transmission line 29A is taken into the power quality evaluation system 1 through the transmission system 31A. Similarly, a measuring device 27B is installed in the power transmission line 29B, and the electrical physical quantity 12 (voltage, current) of the power transmission line 29B is taken into the power quality evaluation system 1 through the transmission system 31B. Further, a measuring device 27C is installed on the transmission line 29C, and the electrical physical quantity 12 (voltage, current) of the transmission line 29C is taken into the power quality evaluation system 1 through the transmission system 31C.

  In the power quality evaluation system 1, harmonic factor estimation of current flowing through the transmission line 29A, the transmission line 29B, and the transmission line 29C is performed based on the electrical physical quantity 12 obtained from the measurement apparatus 27A, the measurement apparatus 27B, and the measurement apparatus 27C. The result 20 (see FIG. 15) is output. The harmonic factor estimation result 20 of the current flowing through the transmission line 29A, the transmission line 29B, and the transmission line 29C is set as a harmonic factor estimation result 20A, a harmonic factor estimation result 20B, and a harmonic factor estimation result 20C, respectively. The harmonic factor estimation result 20A is directed to the harmonic generation device 21 that causes a harmonic flowing in the transmission line 29A, and the harmonic factor estimation result 20B is a harmonic generation device that causes a harmonic flowing in the transmission line 29B. 21, and the harmonic factor estimation result 20 </ b> C is output with the harmonic generation device 21 and the direction that cause the harmonic flowing through the transmission line 29 </ b> C.

  FIG. 21 is an explanatory diagram of the relationship between the harmonic generation source and the harmonic current for explaining the harmonic generation source specifying method according to the embodiment of FIG. 17 of the present invention. For example, when there is a harmonic generation source in the load facility 28B, the harmonic generation current 33 flows through the power transmission line 29B and the bus 30 and flows into the upper system 32 through the power transmission line 29A. It flows into the load facility 28C through 29C. At this time, the power quality evaluation system 1 knows the direction of the harmonic current 33 flowing through the transmission line 29A, the transmission line 29B, and the transmission line 29C through the measurement apparatus 27A, the measurement apparatus 27B, and the measurement apparatus 27C. From the direction of the harmonic current 33 of the electric wire 29B and the transmission line 29C, it can be estimated that the harmonic generation source is the load facility 28B.

  Therefore, the harmonic component pattern of the harmonic current 33 flowing from the harmonic generation source can be analyzed by the harmonic component calculation means 2 of the power quality evaluation system 1, and the harmonic influence calculation means 8 and the harmonic factor estimation means. 9 indicates the harmonic generation device 21 that causes the harmonic, and thus the harmonic generation source and the harmonic generation device 21 that causes the harmonic can be identified.

    For example, when the harmonic generation device 21 that causes the harmonic current 33 is a motor with an inverter, harmonics generated from the motor with an inverter pass through the power transmission line 29B and the bus 30 and pass through the power transmission line 29A. It can be seen that it flows into the host system 32 and also flows into the load facility 28C through the power transmission line 29C.

  In this manner, the harmonic generation source and the harmonic generation device 21 that causes the harmonic can be identified from the direction of the harmonic current 33 passing through the plurality of measuring devices 27A, 27B, and 27C.

  In the harmonic factor estimating means 9A of the embodiment of FIG. 17, the harmonic generation source and the harmonic generation device 21 that causes the harmonic are specified. Since the method for specifying the harmonic generation device 21 that causes harmonics has been described in the description of the first embodiment, an example of a method for specifying the harmonic generation source 40 will be described with reference to the logic of FIG.

  FIG. 22 is a diagram illustrating the harmonic generation source specifying logic 36 in the harmonic factor estimating means 9, and an example in which the measurement device 27 is installed at three locations as shown in FIG. 20 and FIG. is there. As shown in FIG. 22, the harmonic generation source specifying logic 36 includes a harmonic generation source specifying logic 36 </ b> A in the case where there is one harmonic generation source 40, and harmonic generation in the case where there are a plurality of harmonic generation sources 40. It can also be divided into the source identification logic 36B, and the harmonic generation source 40 is identified by each logic.

  FIG. 23 is a system diagram for explaining the alarm generation means 37 according to the embodiment of FIG. The power quality evaluation system 1 has an alarm transmission system 42 for alarm transmission. When the degree of harmonics is large, the harmonic generation source 40 and the harmonic generation device 21 are connected via the alarm transmission system 42. Alarm 38.

  FIG. 23 shows an example in which the harmonic generation source 40 is the load facility 28B and the harmonic generation device 21 is specified by the power quality evaluation system 1. The power quality evaluation system 1 issues an alarm 38 to the load facility 28B or the harmonic generation device 21 via the alarm transmission system 42B. Further, an alarm 38 is issued via the alarm transmission system 42D to the central monitoring control center 39 to inform that the harmonic generation source 40 is the load facility 28B and the harmonic generation device 21 has been specified.

  For the degree of harmonics, an overall distortion 43 shown in the equation (12) is often used.

Total distortion 43 = RMS value only for harmonics ÷ RMS value (12)
When the overall distortion 43 exceeds a harmonic warning level threshold value 44 indicating a harmonic warning level for a certain time (hereinafter referred to as an alarm generation time limit value 45), an alarm 38 is generated.

  FIG. 24 is an explanatory diagram from when the total distortion rate 43 exceeds the harmonic warning level threshold 44 to when the alarm 38 is generated, and the vertical axis indicates the total distortion rate 43 and the horizontal axis indicates time.

  As shown in FIG. 24, when the harmonic total distortion rate 43 exceeds the harmonic warning level threshold 44 and the alarm generation time limit 45 or more has elapsed, an alarm 38 is generated.

  In the power quality evaluation system of the third embodiment described above, in addition to the effects of the first embodiment described above, the generation factor of harmonics and the location where the harmonics are generated are estimated, and an alarm is issued. It becomes possible to warn of the occurrence of

[Fourth Embodiment]
FIG. 25 is a schematic diagram for explaining the configuration and functions of a power quality evaluation system 1B according to the fourth embodiment of the present invention. As shown in FIG. 17, a control command generation means 47 is newly provided on the output side of the harmonic estimation factor means 9A in the configuration in which the alarm generation means 37 is provided on the output side of the harmonic estimation means 9A. The outputs of the generating means 47 and the alarm generating means 37 are configured to be given to the load facility 28.

  Since the harmonic generation source 40 is specified by the harmonic estimation factor means 9A and the harmonic generation device 21 is specified, when the degree of the harmonic is very large, The alarm generation unit 37 issues an alarm 38 to the wave generation device 21, and the control command generation unit 47 issues a control command 46 such as a stop to the harmonic generation device 21. Also, an alarm 38 is issued to the central supervisory control center 39 that centrally manages the energy system.

  FIG. 26 is an example in which the harmonic generation source 40 is the load facility 28B and the harmonic generation device 21 is specified by the power quality evaluation system 1B. The power quality evaluation system 1 issues an alarm 38 to the load equipment 28B or the harmonic generation device 21 via the alarm transmission system 42B, and also stops the harmonic generation device 21 via the control command transmission system 47B. A control command 46 is issued. Further, an alarm 38 is output to the central monitoring control center 39 via the alarm transmission system 42D, the harmonic generation source 40 is the load facility 28B, the harmonic generation device 21 is specified, and a control command such as a stop is issued. 46 is transmitted to the harmonic generator 21.

  When the overall distortion 43 exceeds the harmonic warning level threshold 44 indicating the warning level of the harmonics, the alarm 38 is generated when the alarm generation time limit 45 is exceeded. Furthermore, the total distortion 43 indicates the harmonics indicating the danger level of the harmonics. When the wave danger level threshold 48 exceeds a certain time (hereinafter, control command generation time limit value 49), a control command 46 such as a stop is issued.

  FIG. 27 is an explanatory diagram from when the total distortion rate 43 exceeds the harmonic danger level threshold 48 to when a control command 46 such as a stop is generated. The vertical axis represents the overall strain rate 43, and the horizontal axis represents time. As shown in FIG. 27, when the harmonic total distortion rate 43 exceeds the harmonic danger level threshold 48 and the control command generation time limit value 49 or more has elapsed, a control command 46 for stopping or the like is issued.

  In the power quality evaluation system of the fourth embodiment described above, in addition to the effects of the first embodiment described above, the generation factor of the harmonic and the place where the harmonic is generated are estimated, and the influence of the harmonic is dangerous. By controlling the harmonic generation device, it is possible to prevent disasters due to harmonics.

Schematic which shows the example of application of the electric power quality evaluation system of this invention. Schematic for demonstrating the structure and function of the electric power quality evaluation system which concern on the 1st Embodiment of this invention. The figure which shows the voltage waveform for two phases between lines as an example of the waveform of the electrical physical quantity which the measurement apparatus of FIG. 1 measured. Schematic which shows an example of the harmonic component calculation means of FIG. The figure for demonstrating an example of the measurement harmonic component calculation result which calculated the harmonic component about Vab and Vbc shown by FIG. Explanatory drawing showing the relationship between the harmonic order of the power converter device (6 phases) which is an example of a harmonic generator, and its component (content rate). Explanatory drawing showing the relationship between the harmonic order of the arc furnace which is an example of a harmonic generator, and its component (content rate). Explanatory drawing showing the relationship between the harmonic order of the air-conditioner which is an example of a harmonic generator, and its component (content rate). Explanatory drawing showing the relationship between the harmonic order of the general illumination which is an example of a harmonic generator, and its component (content rate). The figure for demonstrating the function and processing content of the harmonic influence calculation means of FIG. The figure for demonstrating the function of the normalization calculation means of FIG. The figure for demonstrating the function and process content of the influence degree calculation means of FIG. The figure for demonstrating the function and processing content of the harmonic factor estimation means of FIG. The figure for demonstrating the relationship between the generator harmonic weighting coefficient of FIG. 12, and a harmonic generator. Schematic for demonstrating the structure and function of the electric power quality evaluation system which concern on the 2nd Embodiment of this invention. The figure which shows the example of a display of the harmonic influence degree for every harmonic generator in the result display means of FIG. Schematic for demonstrating the structure and function of the electric power quality evaluation system which concern on the 3rd Embodiment of this invention. The figure for demonstrating the harmonic component calculation means of FIG. The figure for demonstrating the function of the current direction calculation means which concerns on FIG. FIG. 18 is a system diagram for explaining a harmonic generation source specifying method according to FIG. 17. Explanatory drawing of the relationship between the harmonic generation source and harmonic current for description of the harmonic generation source specific method which concerns on FIG. The figure for demonstrating an example of a harmonic generation source specific logic in the harmonic factor estimation means of FIG. FIG. 18 is a system diagram for explaining an alarm generation unit according to FIG. 17. FIG. 18 is a diagram for explaining the alarm generation means according to FIG. 17, for explaining a period from when the total distortion rate exceeds a harmonic warning level threshold to when an alarm is generated. Schematic for demonstrating the structure and function of the electric power quality evaluation system which concern on the 4th Embodiment of this invention. The figure for demonstrating the example in which the harmonic generation apparatus was identified when the harmonic generation source in FIG. 25 is load equipment. The figure for demonstrating until it produces | generates control commands, such as a stop, after the total distortion rate in the control command generation means of FIG. 25 exceeds a harmonic danger level threshold value.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electric power quality evaluation system, 2 ... Harmonic component calculation means, 02 ... FFT processing part, 03 ... Harmonic factor extraction means, 3 ... Actual harmonic component preservation | save means, 6 ... Actual harmonic component calculation result, 7 ... Harmonic Harmonic component of wave generator, 8 ... Harmonic influence calculation means, 9 ... Harmonic factor estimation means, 10 ... Harmonic influence degree, 11 ... Harmonic generator database, 12 ... Electrical physical quantity, 13 ... Normalization calculation Means, 14 ... Influence degree calculating means, 15 ... Normalized harmonic generation equipment harmonic component, 17 ... Influence degree rearranging means, 18 ... Harmonic factor extraction threshold, 19 ... Normalized actual measurement harmonic component calculation result, 20 ... Harmonic factor estimation result, 21 ... harmonic generator, 22 ... feeder, 23 ... result display means, 24 ... current direction calculating means, 25 ... voltage vector, 26 ... current vector, 27 ... measuring device, 28 ... load equipment, 29 ... Power transmission , 30 ... bus, 31 ... transmission system, 32 ... host system, 33 ... harmonic current, 35 ... harmonic generation source estimation result, 36 ... harmonic generation source identification logic, 37 ... alarm generation means, 38 ... alarm, 39 ... central monitoring and control center, 40 ... harmonic generation source, 42 ... alarm transmission system, 43 ... total distortion, 44 ... harmonic warning level threshold, 45 ... alarm occurrence time limit, 46 ... control command, 47 ... control command transmission 48: Harmonic danger level threshold value 49: Control command generation time limit value 60: Measured harmonic vector 61: Harmonic generator harmonic vector 62: Generated harmonic weight coefficient 63: Measured harmonic approximation Value vector, 65... Harmonic generator selection means, 66... Generation equipment harmonic weight coefficient calculation means, 67... Significance judgment means, 68.

Claims (5)

Harmonic component calculation means for calculating a harmonic component of the electrical physical quantity for each measurement location based on an electrical physical quantity including at least one of current and voltage measured at least at one location of the power system;
A database for storing harmonic components of a plurality of harmonic generation devices estimated to generate the harmonics;
Each harmonic component calculated by the harmonic component calculating means is approximated by a total value obtained by adding a weighting factor to the harmonic components of a plurality of harmonic generating devices stored in the database, and the approximated weighting factor An influence degree calculation means capable of estimating the factor of the harmonic generation device to be a harmonic generation source based on
A power quality evaluation system characterized by comprising:   2. The power quality evaluation system according to claim 1, further comprising display means for displaying in order from a harmonic generator having a harmonic component having a higher harmonic influence from the influence calculation means. .   The power quality evaluation system according to claim 1, further comprising display means for displaying the degree of influence of harmonics and the harmonic generation device at a predetermined time interval. Means for calculating the direction of the harmonic current for each harmonic order;
Means for calculating the direction of the harmonic generation device to be a harmonic generation source from the direction of each harmonic current;
Based on an electrical physical quantity that includes at least one of current and voltage measured at at least one location of the power system, calculate a harmonic component of the measured electrical physical quantity for each measurement location, Further, means for identifying the position of the harmonic generation source from the direction of the harmonic generation equipment for each observation point,
Calculate the degree of harmonics for each observation point, and if the degree of harmonics is greater than a predetermined value, information that alerts the harmonic generating device, etc., which is the harmonic generation source, Means to put out,
The power quality evaluation system according to claim 1, further comprising: Means for calculating the direction of the harmonic current for each harmonic order;
Means for calculating the direction of the harmonic generation device as a harmonic generation source from the direction of these harmonic currents;
Based on the electrical physical quantity including at least one of current and voltage measured at at least one location of the power system, the direction of the harmonic generating device at each measurement location is calculated from the measured electrical physical quantity. And means for identifying the position of the harmonic generation source from the direction of the harmonic generation device for each observation point;
Calculates the degree of harmonics at each observation point, and when the degree of harmonics is greater than a predetermined value, issues a control command such as shut-off or output adjustment to the harmonic generation device that is the harmonic generation source. Means,
The power quality evaluation system according to claim 1, further comprising:

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