A method for evaluating power quality based on photovoltaic grid-connected power generation

Abstract

The present invention specifically relates to a method for evaluating power quality based on photovoltaic grid-connected power generation, and the method comprises the steps of: obtaining a historical power-related data group; establishing a functional relationship (y, z) between any two power quality evaluation indicators and a power quality evaluation customer satisfaction value x, establishing a comprehensive differential equation group between a first power quality evaluation indicator function, a second power quality evaluation indicator function and a power quality evaluation customer satisfaction value through a historical power quality evaluation indicator and a power quality evaluation customer satisfaction value statistical data group, calculating a particular solution of the comprehensive differential equation group, and then determining a relative weight of each power quality evaluation indicator, and then uniformly normalizing the relative weights of all the power quality evaluation indicators to obtain a weight of each power quality evaluation indicator, and inputting a numerical value of each power quality evaluation indicator according to the weight of each power quality evaluation indicator to obtain a power quality evaluation customer satisfaction value.

Description

Technical Field

[0001] The present invention belongs to the field of electric power, and in particular relates to a method for evaluating power quality based on photovoltaic grid-connected power generation. Background Art

[0002] There are few related prior arts for the quality assessment of photovoltaic grid-connected power generation. For example, the patent document CN113361946A discloses a photovoltaic grid-connected power quality assessment technology. This type of technology mainly obtains the voltage value of the target grid-connected point, then determines the quality assessment index, and then assigns corresponding weights to the quality assessment index, and finally determines the corresponding assessment value. The core problem of this technology lies in the determination of the weights of different evaluation indicators. The specific technical solution for the weight determination of this type of technology is to establish a system and divide the quality assessment indicators of electricity into levels, and then determine the weights of different quality assessment indicators through a series of calculation methods such as intuitive fuzzy numbers and intuitive fuzzy judgment matrices.

[0003] The existing technology is not effective in operation because it uses a subjective and artificial method to establish an indicator system and divide grades, and adopts a relatively complex calculation method. Its evaluation weights cannot truly represent the opinions of customers. This method is not only subjective, but also cumbersome in calculation and ineffective. Therefore, the determined weight values ​​and quality assessment values ​​are not accurate enough. Summary of the invention

[0004] The purpose of the present invention is to provide a method for evaluating power quality based on photovoltaic grid-connected power generation to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] The power quality assessment method based on photovoltaic grid-connected power generation includes the following steps:

[0007] Obtain historical power quality assessment indicators and power quality assessment customer satisfaction value statistical data group;

[0008] Establish a functional relationship (y, z) between any two power quality assessment indicators and the power quality assessment customer satisfaction value x, where y is the first power quality assessment indicator function value corresponding to the power quality assessment customer satisfaction value x, and z is the second power quality assessment indicator function value corresponding to the power quality assessment customer satisfaction value x;

[0009] A comprehensive differential equation group between the first power quality assessment index function, the second power quality assessment index function and the power quality assessment customer satisfaction value is established through the historical power quality assessment index and power quality assessment customer satisfaction value statistical data group, and the specific solution of the comprehensive differential equation group is calculated, and then the relative weight of each power quality assessment index is determined, and then the relative weights of all the power quality assessment indicators are uniformly normalized to obtain the weight of each power quality assessment indicator, and each power quality assessment indicator value is input according to the weight of each power quality assessment indicator to obtain the power quality assessment customer satisfaction value.

[0010] Furthermore, a group of comprehensive differential equations between the first power quality assessment index function, the second power quality assessment index function and the power quality assessment customer satisfaction value is established, specifically including the establishment of a group of comprehensive differential equations: dy / dx=ay+bz, dz / dx=cy+ez; wherein a, b, c, and e are all determined constants, x is the power quality assessment customer satisfaction value, y is the first power quality assessment index function value corresponding to the power quality assessment customer satisfaction value x, wherein z is the second power quality assessment index function value corresponding to the power quality assessment customer satisfaction value x, and dy, dx, and dz are all differentials of corresponding variables.

[0011] Furthermore, a particular solution of the comprehensive differential equation group is calculated, specifically including eliminating the comprehensive differential equation group to obtain a linear differential equation with a constant coefficient, then calculating the general solution of the linear differential equation with a constant coefficient, and then calculating the general solution of the entire system of equations, and then obtaining at least one set of conditional values ​​from historical power quality assessment indicators and power quality assessment customer satisfaction value statistical data groups and substituting them into the general solution of the entire system of equations to obtain the corresponding particular solution.

[0012] Furthermore, the determination of the relative weight of each power quality assessment indicator specifically includes calculating the particular solution of each power quality assessment indicator function to the power quality assessment customer satisfaction value, setting the power quality assessment customer satisfaction value to a standard value (for example, 1), and calculating the corresponding power quality assessment indicator function value, which is the relative weight of the power quality assessment indicator.

[0013] Furthermore, the relative weights of all power quality assessment indicators are normalized to obtain the weight of each power quality assessment indicator, specifically including: assuming that the relative weight of the i-th power quality assessment indicator is n i , there are m power quality evaluation indicators in total, then the weight of the i-th power quality evaluation indicator after normalization is n i / (n1+n2+......+n m ).

[0014] Furthermore, the power quality assessment index includes voltage deviation parameter, voltage fluctuation parameter, harmonic content parameter, and imbalance parameter.

[0015] A machine-readable medium is used to store program codes for implementing a method for evaluating power quality based on photovoltaic grid-connected power generation.

[0016] Beneficial Effects

[0017] The present application provides a more accurate, simple and efficient method to determine weight values ​​and quality assessment values, and the differential variables used in the comprehensive differential equation group established in the initial calculation of the present application can more objectively represent the objective relationship between the changes in variables, so there is no need to use subjective division evaluation system, which is more scientific. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The overall flow chart of this application method. DETAILED DESCRIPTION

[0019] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0020] In the specific implementation, Figure 1 In a specific implementation, the present application discloses a method for evaluating power quality based on photovoltaic grid-connected power generation, which includes the steps of obtaining historical power quality evaluation indicators and power quality evaluation customer satisfaction value statistical data groups; establishing a functional relationship (y, z) between any two power quality evaluation indicators and the power quality evaluation customer satisfaction value x, wherein y is the first power quality evaluation indicator function value corresponding to the power quality evaluation customer satisfaction value x, and z is the second power quality evaluation indicator function value corresponding to the power quality evaluation customer satisfaction value x; the power quality evaluation indicators include voltage deviation parameters, voltage fluctuation parameters, harmonic content parameters, and unbalance parameters, and the specific calculation of voltage deviation parameters, voltage fluctuation parameters, harmonic content parameters, and unbalance parameters can apply the calculation methods of voltage deviation parameters, voltage fluctuation parameters, harmonic content parameters, and unbalance parameters in the prior art;

[0021] A comprehensive differential equation group between the first power quality assessment index function, the second power quality assessment index function and the power quality assessment customer satisfaction value is established through a historical power quality assessment index and a power quality assessment customer satisfaction value statistical data group, specifically including the establishment of a comprehensive differential equation group: dy / dx=ay+bz, dz / dx=cy+ez; wherein a, b, c, and e are all determined constants, x is the power quality assessment customer satisfaction value, y is the first power quality assessment index function value corresponding to the power quality assessment customer satisfaction value x, wherein z is the second power quality assessment index function value corresponding to the power quality assessment customer satisfaction value x, and dy, dx, and dz are all differentials of corresponding variables; for example, in the embodiment, dy / dx=ay+bz, dz / dx=cy+ez, specifically dy / dx=3y-2z, dz / dx=2y-z, and a, b, c, and e are 3, -2, 2, and -1, respectively;

[0022] Calculating a special solution of the comprehensive differential equation group specifically includes eliminating the comprehensive differential equation group to obtain a constant coefficient linear differential equation, then calculating the general solution of the constant coefficient linear differential equation, then calculating the general solution of the entire equation group, and then obtaining at least one set of conditional values ​​from historical power quality assessment indicators and power quality assessment customer satisfaction value statistical data groups and substituting them into the general solution of the entire equation group to obtain a corresponding special solution; for example, in the embodiment, when dy / dx=ay+bz, dz / dx=cy+ez, specifically dy / dx=3y-2z, dz / dx=2y-z, a, b, c, e are 3, -2, 2, -1 respectively, then eliminating the comprehensive differential equation group to obtain a constant coefficient linear differential equation includes, from dy / dx=3y-2z, dz / dx=2y-z, calculating y=1 / 2(dz / dx+z), taking the derivative on both sides of the equal sign to obtain dy / dx=1 / 2(d 2 z / dx 2 +dz / dx), set y=1 / 2(dz / dx+z), dy / dx=1 / 2(d 2 z / dx 2 +dz / dx) into dy / dx=3y-2z, dz / dx=2y-z and simplify to get d 2 z / dx 2-2dz / dx+z=0, calculate the general solution of the constant coefficient linear differential equation, that is, z=(p1+p2*x)*exp(x), and substitute it into y=1 / 2(dz / dx+z) to obtain y=(2*p1+p2+2*p2*x)*exp(x), where p1 and p2 are both undetermined constants of the general solution. From the historical power quality assessment indicators and power quality assessment customer satisfaction value statistical data group, at least one set of conditional values ​​is obtained (only for example and may not be true) Real value): When x=0, y=1, when x=0, z=0, then substitute into y=1 / 2*(2*p1+p2+2*p2*x)*exp(x), z=(p1+p2*x)*exp(x), it can be calculated that p1=0, p2=2, that is, the corresponding special solution is y=(1+2*x)*exp(x), z=2*x*exp(x), this special solution is the special solution of the power quality assessment index function to the power quality assessment customer satisfaction value;

[0023] Then determine the relative weight of each power quality assessment indicator, and determine the relative weight of each power quality assessment indicator, specifically including calculating each power quality assessment indicator function to obtain a special solution of the power quality assessment customer satisfaction value, setting the power quality assessment customer satisfaction value to a standard value (for example, 1), and calculating the corresponding power quality assessment indicator function value, the corresponding power quality assessment indicator function value is the relative weight of the power quality assessment indicator; for example, in the embodiment, when the corresponding special solution is y=(1+2*x)*exp(x), z=2*x*exp(x), x is the power quality assessment customer satisfaction value, y is the first power quality corresponding to the power quality assessment customer satisfaction value x Evaluation index function value, where z is the second power quality evaluation index function value corresponding to the power quality evaluation customer satisfaction value x, and the power quality evaluation customer satisfaction value is set to a standard value of 1, and y is approximately equal to 8.15, and z is approximately equal to 5.44. Then the relative weight of the first power quality evaluation index is 8.15, and the relative weight of the second power quality evaluation index is 5.44. Then the relative weights of all power quality evaluation indicators are uniformly normalized to obtain the weight of each power quality evaluation indicator. The relative weights of all power quality evaluation indicators are uniformly normalized to obtain the weight of each power quality evaluation indicator, specifically including, assuming that the relative weight of the i-th power quality evaluation indicator is n i , there are m power quality evaluation indicators in total, then the weight of the i-th power quality evaluation indicator after normalization is n i / (n1+n2+......+n m ); input each power quality assessment indicator value according to the weight of each power quality assessment indicator to obtain the power quality assessment customer satisfaction value.

[0024] It can be seen that the present application provides a more accurate, simple and efficient method to determine weight values ​​and quality assessment values, and the differential variables used in the comprehensive differential equation group established in the initial calculation of the present application can more objectively represent the objective relationship between the changes in variables, so there is no need to use subjective division evaluation system, which is more scientific.

[0025] In an embodiment to be protected, the present application discloses a method for evaluating power quality based on photovoltaic grid-connected power generation, comprising the steps of:

[0026] Obtain historical power quality assessment indicators and power quality assessment customer satisfaction value statistical data group;

[0027] Establish a functional relationship (y, z) between any two power quality evaluation indicators and the power quality evaluation customer satisfaction value x.

[0028] Wherein y is the first power quality assessment index function value corresponding to the power quality assessment customer satisfaction value x, and z is the second power quality assessment index function value corresponding to the power quality assessment customer satisfaction value x;

[0029] Through the historical power quality evaluation index and the power quality evaluation customer satisfaction value statistical data group, a comprehensive differential equation group between the first power quality evaluation index function, the second power quality evaluation index function and the power quality evaluation customer satisfaction value is established, and the special solution of the comprehensive differential equation group is calculated, and then the relative weight of each power quality evaluation index is determined, and then

[0030] The relative weights of all power quality assessment indicators are uniformly normalized to obtain the weight of each power quality assessment indicator, and the value of each power quality assessment indicator is input according to the weight of each power quality assessment indicator to obtain the power quality assessment customer satisfaction value.

[0031] Preferably, a comprehensive differential equation group is established between the first power quality assessment index function, the second power quality assessment index function and the power quality assessment customer satisfaction value, specifically including the establishment of a comprehensive differential equation group: dy / dx=ay+bz, dz / dx=cy+ez; wherein a, b, c, e are all determined constants, x is the power quality assessment customer satisfaction value, y is the first power quality assessment index function value corresponding to the power quality assessment customer satisfaction value x, wherein z is the second power quality assessment index function value corresponding to the power quality assessment customer satisfaction value x, and dy, dx, dz are all differentials of corresponding variables.

[0032] The preferred calculation of the special solution of the comprehensive differential equation group specifically includes eliminating the comprehensive differential equation group to obtain a linear differential equation with constant coefficients, then calculating the general solution of the linear differential equation with constant coefficients, and then calculating the general solution of the entire system of equations, and then obtaining at least one set of conditional values ​​from historical power quality assessment indicators and power quality assessment customer satisfaction value statistical data groups and substituting them into the general solution of the entire system of equations to obtain the corresponding special solution.

[0033] Preferably, the relative weight of each power quality assessment indicator is determined, specifically including calculating the particular solution of each power quality assessment indicator function to the power quality assessment customer satisfaction value, setting the power quality assessment customer satisfaction value to a standard value (for example, 1), and calculating the corresponding power quality assessment indicator function value, which is the relative weight of the power quality assessment indicator.

[0034] Preferably, the relative weights of all power quality evaluation indicators are uniformly normalized to obtain the weight of each power quality evaluation indicator, specifically including: assuming that the relative weight of the i-th power quality evaluation indicator is n i , there are m power quality evaluation indicators in total, then the weight of the i-th power quality evaluation indicator after normalization is n i / (n1+n2+......+n m ).

[0035] The preferred power quality assessment indicators include voltage deviation parameters, voltage fluctuation parameters, harmonic content parameters, and unbalance parameters.

[0036] It can be understood that the power quality assessment method based on photovoltaic grid-connected power generation in this application can be implemented by a host computer, and the functions of the host computer here can be implemented by program codes, and the corresponding program codes are stored in a machine-readable medium, which can be a tangible medium that can contain or store a program for use by an instruction execution system, device or equipment or used in combination with an instruction execution system, device or equipment. The machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium.

[0037] Machine-readable media may include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or apparatuses, or any suitable combination of the foregoing. More specific examples of machine-readable storage media would include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing. In order to provide interaction with a user, the host computer described herein may be implemented on a computer having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to a user; and a keyboard and pointing device (e.g., a mouse or trackball) through which a user can provide input to the computer. Other types of devices may also be used to provide interaction with a user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

Claims

1. A method for evaluating power quality based on photovoltaic grid-connected power generation, characterized in that: The steps include: Obtain historical power quality assessment indicators and power quality assessment customer satisfaction value statistical data group; Establish a functional relationship y, z between any two power quality assessment indicators and the power quality assessment customer satisfaction value x, where y is the first power quality assessment indicator function value corresponding to the power quality assessment customer satisfaction value x, and z is the second power quality assessment indicator function value corresponding to the power quality assessment customer satisfaction value x; A comprehensive differential equation group between the first power quality assessment index function, the second power quality assessment index function and the power quality assessment customer satisfaction value is established through the historical power quality assessment index and the power quality assessment customer satisfaction value statistical data group, and the specific solution of the comprehensive differential equation group is calculated, and then the relative weight of each power quality assessment index is determined, and then the relative weights of all the power quality assessment indicators are uniformly normalized to obtain the weight of each power quality assessment indicator, and each power quality assessment indicator value is input according to the weight of each power quality assessment indicator to obtain the power quality assessment customer satisfaction value; establish The comprehensive differential equation group between the first power quality assessment index function, the second power quality assessment index function and the power quality assessment customer satisfaction value specifically includes establishing the comprehensive differential equation group: dy / dx=ay+bz, dz / dx=cy+ez; wherein a, b, c, and e are all determined constants, x is the power quality assessment customer satisfaction value, y is the first power quality assessment index function value corresponding to the power quality assessment customer satisfaction value x, wherein z is the second power quality assessment index function value corresponding to the power quality assessment customer satisfaction value x, and dy, dx, and dz are all differentials of corresponding variables; Calculating the special solution of the comprehensive differential equation group specifically includes eliminating the comprehensive differential equation group to obtain a linear differential equation with constant coefficients, then calculating the general solution of the linear differential equation with constant coefficients, then calculating the general solution of the entire equation group, and then obtaining at least one set of conditional values ​​from historical power quality assessment indicators and power quality assessment customer satisfaction value statistical data groups and substituting them into the general solution of the entire equation group to obtain the corresponding special solution; determining the relative weight of each power quality assessment indicator specifically includes calculating each power quality assessment indicator function to obtain the special solution of the power quality assessment customer satisfaction value, setting the power quality assessment customer satisfaction value as a standard value, and calculating the corresponding power quality assessment indicator function value, and the corresponding power quality assessment indicator function value is the relative weight of the power quality assessment indicator.

2. The power quality assessment method based on photovoltaic grid-connected power generation according to claim 1 is characterized in that: The relative weights of all power quality assessment indicators are normalized to obtain the weight of each power quality assessment indicator, specifically including: assuming that the relative weight of the i-th power quality assessment indicator is n i , there are m power quality evaluation indicators in total, then the weight of the i-th power quality evaluation indicator after normalization is n i / (n1+n2+......+n m ).

3. The power quality assessment method based on photovoltaic grid-connected power generation according to claim 1 is characterized in that: The power quality assessment indicators include voltage deviation parameters, voltage fluctuation parameters, harmonic content parameters, and unbalance parameters.

4. A machine-readable medium, characterized in that it is used to store program codes for implementing the power quality assessment method based on photovoltaic grid-connected power generation in claim 1.

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