Novel electrical equipment insulation resistance value calculation method

Abstract

The invention discloses a novel electrical equipment insulation resistance value calculation method, and relates to the technical field of electrical equipment insulation resistance calculation. The novel electrical equipment insulation resistance value calculation method comprises the following steps of 1, building a fractional order equivalent circuit model; 2, performing fractional order on equivalent circuit model parameters by using a CVF algorithm; and step 3, calculating the insulation resistance value of the electrical equipment. The calculation method comprises the following steps: firstly, building a fractional order equivalent circuit model of the electrical equipment under the influence of alternating-current high voltage, determining a specific model structure of the electrical equipment under the alternating-current high voltage, proposing a CVF algorithm, and fitting parameters of the fractional order equivalent circuit model of the electrical equipment by using the fitting algorithm; setting a minimum objective function and an error evaluation function of the algorithm to fit the fractional order equivalent circuit model to obtain each parameter of the fractional order model of the electrical equipment, and finally calculating the insulation resistance value of the electrical equipment according to the fractional order equivalent circuit model of the electrical equipment.

Description

Technical Field

[0001] The invention relates to the technical field of electrical equipment insulation resistance calculation, in particular to a novel electrical equipment insulation resistance value calculation method. Background Art

[0002] Insulation resistance is a key parameter for measuring the insulation performance of electrical equipment and plays a vital role in ensuring the safe and stable operation of the power system. Accurately measuring insulation resistance is an indispensable part of daily maintenance and troubleshooting of power systems.

[0003] Traditional insulation resistance calculation methods mainly include direct measurement method and comparative measurement method. The direct measurement method uses Ohm's law to apply a certain DC voltage across the insulator to measure the current flowing through the insulator, thereby calculating the insulation resistance value. This method is simple in principle and easy to operate, but in practical applications, it is easily affected by factors such as ambient temperature, humidity, and the surface condition of the insulator being measured, resulting in certain errors in the measurement results. The comparative measurement method compares the insulation resistance of the insulator being measured with a known resistance to indirectly obtain the insulation resistance value of the insulator being measured.

[0004] This method can eliminate the influence of some environmental factors and improve the measurement accuracy, but the operation is relatively complicated and requires additional comparison resistors, which increases the measurement cost. However, both the direct measurement method and the comparison measurement method have obvious shortcomings when facing the complex electromagnetic environment near AC high-voltage transmission lines. In addition, the traditional method is also susceptible to interference from external factors such as ambient temperature and humidity, resulting in poor stability and repeatability of the measurement results. What is more serious is that the application of traditional insulation resistance calculation methods in AC high-voltage transmission lines has great safety risks.

[0005] Neither the direct measurement method nor the comparative measurement method can be directly applied to AC high voltage environments, because AC high voltage environments will cause great errors in Ohm's law during the measurement process, and may damage the measurement equipment or even threaten the life of the operator. Therefore, special safety measures must be taken when measuring insulation resistance in AC high voltage environments, which undoubtedly greatly increases the complexity and cost of the measurement.

[0006] Therefore, in order to reduce the cost of insulation resistance measurement under AC high voltage environment and improve the safety and reliability of the test environment, it is very important to develop a new method for calculating the insulation resistance value of electrical equipment.

[0007] The prior art CN109884394A discloses a method for measuring the impedance parameters of a supercapacitor fractional-order model. This method is suitable for measuring the impedance parameters of a supercapacitor fractional-order model, but cannot be used to measure the insulation resistance of electrical equipment. In addition, this method mainly focuses on the parameter measurement of two key components (equivalent series resistance and fractional-order capacitor) related to the characteristics of the supercapacitor itself.

[0008] The prior art CN119087046A discloses a DC loop resistance test system, test method and loop resistance tester. This technology tests the resistance of the DC loop and is not suitable for high-voltage AC insulation resistance measurement. In the resistance test, multiple functional modules (intelligent test module, temperature calibration module, data analysis module, etc.) are used to work together to achieve accurate measurement of the DC loop resistance.

[0009] The prior art CN115219911A is a SOC-SOH joint estimation method based on a lithium battery model and fractional order theory, which jointly estimates the state of charge (SOC) and state of health (SOH) of a lithium battery, and is not applicable to the measurement of insulation resistance of electrical equipment. Summary of the invention

[0010] 1. Technical issues to be resolved In view of the deficiencies in the prior art, the present invention provides a novel method for calculating the insulation resistance value of electrical equipment, which solves the technical problems mentioned in the background technology.

[0011] (II) Technical solution To achieve the above purpose, the present invention is implemented by the following technical scheme: a new method for calculating the insulation resistance value of electrical equipment, comprising the following steps: Step 1: Build a fractional-order equivalent circuit model of electrical equipment under the influence of AC high voltage; Step 2: Use the complex value fitting (CVF) algorithm to fit the fractional-order equivalent circuit model parameters of the electrical equipment; Step 3: Calculate the insulation resistance value of the electrical equipment based on the fractional-order equivalent circuit model of the electrical equipment.

[0012] Preferably, the specific model structure of the fractional-order equivalent circuit model of the electrical equipment under the influence of AC high voltage in step 1 is: is the internal resistance of the electrical equipment, is the first set of pseudo capacitors, is the first group of fractional-order capacitor impedance, is the first set of parallel resistors, is the second set of pseudo capacitors, is the impedance of the second group of fractional-order capacitors, is the second set of parallel resistors, is the second set of pseudo capacitors, is the impedance of the second group of fractional-order capacitors, is the second set of parallel resistors, is the second set of pseudo capacitors, is the impedance of the second group of fractional-order capacitors, is the second set of parallel resistors, and After being connected in parallel, they form the first group of constant phase elements. and After being connected in parallel, they form the second set of constant phase elements. and After being connected in parallel, they form the third set of constant phase elements. and After being connected in parallel, a fourth group of constant phase elements is formed. The first group of constant phase elements is connected in series with the second group of constant phase elements, the second group of constant phase elements is connected in series with the third group of constant phase elements, the third group of constant phase elements is connected in series with the fourth group of constant phase elements, and the fourth group of constant phase elements is connected in series with the internal resistance value of the electrical equipment. Series connection, is the order of the fraction.

[0013] Preferably, in the specific model structure, the first group of fractional-order capacitor impedance , the second group of fractional capacitor impedance 、The third group of fractional capacitor impedance 、The fourth group of fractional capacitor impedance , order , , , The values ​​are all 0.4.

[0014] Preferably, in step 2, the CVF algorithm is used to fit the fractional-order equivalent circuit model parameters of the electrical equipment, and the specific steps are as follows: Step 2.1: Set the minimum objective function of the CVF algorithm : In the formula, is the optimal parameter vector, is the number of frequency points, is the weighting coefficient of the real part of impedance, is the weighting coefficient of the imaginary part of impedance, is the angular frequency, is the test impedance, is the theoretical impedance, is the real part function, is the imaginary part function; Step 2.2: Calculate the amplitude fitting error evaluation function : Step 2.3: Calculate the phase fitting error evaluation function : In the formula, To obtain the argument function, is the optimal parameter vector, is the angular frequency, is the test impedance, is the theoretical impedance; Step 2.4: According to the minimum objective function and error evaluation function , Fit the fractional-order equivalent circuit model to obtain the parameters of the fractional-order model of the electrical equipment.

[0015] Preferably, in step 3, the insulation resistance value of the electrical equipment is calculated according to the fractional-order equivalent circuit model of the electrical equipment, and the calculation formula is as follows: .

[0016] (III) Beneficial effects The present invention provides a novel method for calculating the insulation resistance value of electrical equipment. It has the following beneficial effects: This calculation method first builds a fractional-order equivalent circuit model of electrical equipment under the influence of AC high voltage, determines the specific model structure of the electrical equipment under AC high voltage, proposes a CVF algorithm, uses the fitting algorithm to fit the fractional-order equivalent circuit model parameters of the electrical equipment, sets the algorithm's minimum objective function and error evaluation function to fit the fractional-order equivalent circuit model, and obtains the fractional-order model parameters of the electrical equipment. Finally, the insulation resistance value of the electrical equipment is calculated based on the fractional-order equivalent circuit model of the electrical equipment. The fractional-order equivalent circuit model of the electrical equipment, combined with the CVF algorithm, can show good model accuracy and reliability under AC high voltage environment, reducing the complexity and cost of insulation resistance measurement under AC high voltage environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The figure is a flow chart of the calculation method of the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in 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 creative work are within the scope of protection of the present invention.

[0019] The present invention provides a technical solution: a novel method for calculating the insulation resistance value of electrical equipment.

[0020] The steps include: Step 1: Build a fractional-order equivalent circuit model of electrical equipment under the influence of AC high voltage; The specific model structure of the fractional-order equivalent circuit model of electrical equipment under the influence of AC high voltage in step 1 is: is the internal resistance of the electrical equipment, is the first set of pseudo capacitors, is the first group of fractional-order capacitor impedance, is the first set of parallel resistors, is the second set of pseudo capacitors, is the impedance of the second group of fractional-order capacitors, is the second set of parallel resistors, is the second set of pseudo capacitors, is the impedance of the second group of fractional-order capacitors, is the second set of parallel resistors, is the second set of pseudo capacitors, is the impedance of the second group of fractional-order capacitors, is the second set of parallel resistors, and After being connected in parallel, they form the first group of constant phase elements. and After being connected in parallel, they form the second set of constant phase elements. and After being connected in parallel, they form the third set of constant phase elements. and After being connected in parallel, a fourth group of constant phase elements is formed. The first group of constant phase elements is connected in series with the second group of constant phase elements, the second group of constant phase elements is connected in series with the third group of constant phase elements, the third group of constant phase elements is connected in series with the fourth group of constant phase elements, and the fourth group of constant phase elements is connected in series with the internal resistance value of the electrical equipment. Series connection, is the order of the fractional order; Where: The first group of fractional capacitor impedance , the second group of fractional capacitor impedance 、The third group of fractional capacitor impedance 、The fourth group of fractional capacitor impedance , order , , , The value is 0.4 Step 2: Use the CVF algorithm to fit the fractional-order equivalent circuit model parameters of the electrical equipment; In step 2, the CVF algorithm is used to fit the fractional-order equivalent circuit model parameters of the electrical equipment. The specific steps are as follows: Step 2.1: Set the minimum objective function of the CVF algorithm : In the formula, is the optimal parameter vector, is the number of frequency points, is the weighting coefficient of the real part of impedance, is the weighting coefficient of the imaginary part of impedance, is the angular frequency, is the test impedance, is the theoretical impedance, is the real part function, is the imaginary part function; Step 2.2: Calculate the amplitude fitting error evaluation function : Step 2.3: Calculate the phase fitting error evaluation function : In the formula, To obtain the argument function, is the optimal parameter vector, is the angular frequency, is the test impedance, is the theoretical impedance; Step 2.4: According to the minimum objective function and error evaluation function , Fit the fractional-order equivalent circuit model to obtain the parameters of the fractional-order model of the electrical equipment; Step 3: Calculate the insulation resistance of electrical equipment based on the fractional equivalent circuit model of electrical equipment The calculation formula is as follows: .

[0021] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0022] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A new method for calculating the insulation resistance value of electrical equipment, characterized in that: The steps include: Step 1: Build a fractional-order equivalent circuit model of electrical equipment under the influence of AC high voltage; Step 2: Use a complex value fitting algorithm to fit the fractional-order equivalent circuit model parameters of the electrical equipment; Step 3: Calculate the insulation resistance value of the electrical equipment based on the fractional-order equivalent circuit model of the electrical equipment.

2. A novel method for calculating insulation resistance of electrical equipment according to claim 1, characterized in that: The specific model structure of the fractional-order equivalent circuit model of the electrical equipment under the influence of AC high voltage in step 1 is: is the internal resistance of the electrical equipment, is the first set of pseudo capacitors, is the first group of fractional-order capacitor impedance, is the first set of parallel resistors, is the second set of pseudo capacitors, is the impedance of the second group of fractional-order capacitors, is the second set of parallel resistors, is the second set of pseudo capacitors, is the impedance of the second group of fractional-order capacitors, is the second set of parallel resistors, is the second set of pseudo capacitors, is the impedance of the second group of fractional-order capacitors, is the second set of parallel resistors, and After being connected in parallel, they form the first group of constant phase elements. and After being connected in parallel, they form the second set of constant phase elements. and After being connected in parallel, they form the third set of constant phase elements. and After being connected in parallel, a fourth group of constant phase elements is formed. The first group of constant phase elements is connected in series with the second group of constant phase elements, the second group of constant phase elements is connected in series with the third group of constant phase elements, the third group of constant phase elements is connected in series with the fourth group of constant phase elements, and the fourth group of constant phase elements is connected in series with the internal resistance value of the electrical equipment. Series connection, is the order of the fraction.

3. A novel method for calculating insulation resistance of electrical equipment according to claim 2, characterized in that: In the specific model structure, the first group of fractional-order capacitor impedance , the second group of fractional capacitor impedance 、The third group of fractional capacitor impedance 、The fourth group of fractional capacitor impedance , order , , , The values ​​are all 0.

4.

4. A novel method for calculating insulation resistance of electrical equipment according to claim 1, characterized in that: In step 2, a complex value fitting algorithm is used to fit the fractional-order equivalent circuit model parameters of the electrical device. The specific steps are as follows: Step 2.1: Set the minimum objective function of the complex-valued fitting algorithm : In the formula, is the optimal parameter vector, is the number of frequency points, is the weighting coefficient of the real part of impedance, is the weighting coefficient of the imaginary part of impedance, is the angular frequency, is the test impedance, is the theoretical impedance, To take the real part function, is the imaginary part function; Step 2.2: Calculate the amplitude fitting error evaluation function : Step 2.3: Calculate the phase fitting error evaluation function : In the formula, To obtain the argument function, is the optimal parameter vector, is the angular frequency, is the test impedance, is the theoretical impedance; Step 2.4: According to the minimum objective function and error evaluation function , Fit the fractional-order equivalent circuit model to obtain the parameters of the fractional-order model of the electrical equipment.

5. The method for calculating the insulation resistance value of a novel electrical equipment according to claim 1 is characterized in that: In step 3, the insulation resistance value of the electrical equipment is calculated according to the fractional-order equivalent circuit model of the electrical equipment. The calculation formula is as follows: 。

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