A method for inversion of physical parameters of GIS disconnectors guided by VFTO time-frequency characteristics

Abstract

The present invention provides a method for inverting the physical parameters of a GIS disconnector guided by VFTO time-frequency characteristics, comprising: obtaining the VFTO discrete time series of the entire process of the GIS disconnector opening and closing, and decomposing it into m A single breakdown VFTO discrete time series; extract m The measured breakdown characteristics of a single breakdown VFTO discrete time series are combined to form a measured breakdown characteristic set; a simulation model is established with GIS electrical parameters as input and single breakdown VFTO discrete time series as output; a simulation model is constructed with GIS electrical parameters as decision variables and minimizing the deviation between the simulated breakdown characteristics and the measured breakdown characteristics as the goal. m A multi-objective optimization problem; solving m A multi-objective optimization problem is obtained m The non-dominated solution set is used to calculate the average value of each GIS electrical parameter in all solution sets, and the optimal estimated value of the GIS bus length and distribution parameters is obtained. The present invention can realize the online and accurate estimation of GIS parameters, and provide reliable parameter support for conducting GIS related research.

Description

Technical Field

[0001] The present invention relates to the field of parameter estimation technology, and more specifically, to a very fast transient overvoltage (VeryFas tt ransien t Overvol t Inversion method of physical parameters of GIS disconnector guided by time-frequency characteristics of VFTO (age, VFTO). Background Art

[0002] As the scale and complexity of power systems increase, the reliability and safety requirements of power equipment are also increasing. t ed Swi t GIS is widely used in high-voltage and ultra-high-voltage substations due to its advantages of small footprint, stable operation and low maintenance. In GIS substations, the very fast transient overvoltage (VFS) generated by the disconnector operation tt ransien t Overvol t VFTO (VFTO) has the characteristics of high amplitude, steep wave front and high frequency, which has an important impact on the insulation of GIS and its equipment and the stable operation of the power system. Therefore, the study of VFTO has become a research hotspot. Due to the complexity of the transient characteristics of VFTO and its propagation characteristics in GIS, the study and analysis of the behavior of VFTO requires accurate grasp and description of the parameters of GIS equipment. Accurate GIS parameters can not only help better simulate and predict the generation and propagation process of VFTO, but also provide key data support for power system designers, so as to formulate effective protection measures to ensure the safe operation of equipment.

[0003] GIS parameters are divided into three categories: busbar distribution parameters, busbar length, and equipment electrical parameters. Traditional GIS parameter estimation methods are mainly obtained through on-site measurements, initial parameters provided by equipment manufacturers, or calculations using empirical formulas. The electrical parameters of GIS equipment obtained from the equipment nameplate are not easy to change during normal operation; the busbar distribution parameters are usually calculated using the empirical formula for the transmission line distribution parameters. However, the on-site busbar distribution parameters are affected by the complex electromagnetic environment and a large number of stray parameters during on-site operation and deviate from the empirical values, making it impossible to accurately calculate the busbar distribution parameters offline. The busbar length obtained from the manufacturer will change due to the on-site assembly of the GIS, the complex on-site electromagnetic environment, and the temperature and humidity environment. After the GIS is packaged, the busbar length cannot be measured offline from inside the GIS due to the airtightness of the equipment. Therefore, after the GIS is assembled, the technology for obtaining its electrical parameters online has broad application prospects. Summary of the invention

[0004] The present invention aims at solving the technical problems existing in the prior art and provides a very fast transient overvoltage (VeryFas tt ransien t Overvol t In this paper, a GIS disconnector physical parameter inversion method guided by the time-frequency characteristics of VFTO (age, VFTO) is proposed to solve the problem that it is difficult to obtain GIS electrical parameters online with the existing technology.

[0005] The technical solution of the present invention to solve the above technical problems is as follows: a VFTO time-frequency characteristic guided GIS disconnector physical parameter inversion method, comprising:

[0006] S100, obtain the VFTO discrete time series of the whole process of GIS disconnector opening and closing;

[0007] S200, decomposing the whole process VFTO discrete time series into m A single breakdown VFTO discrete time series is extracted m The measured breakdown characteristics of a single breakdown VFTO discrete time series are used to form a measured breakdown characteristic set;

[0008] S300, establishing a simulation model with GIS electrical parameters as input and single breakdown VFTO discrete time series as output; constructing a simulation model based on the measured breakdown feature set and with GIS electrical parameters as decision variables, with the goal of minimizing the deviation between the simulated breakdown feature and the measured breakdown feature. m A multi-objective optimization problem;

[0009] S400, solve the m A multi-objective optimization problem is obtained m non-dominated solution sets, calculate the average values ​​of GIS electrical parameters in all solution sets, and obtain the optimal estimated values ​​of GIS bus length and distribution parameters.

[0010] Based on the above technical solution, the present invention can also make the following improvements.

[0011] Further, in step S200, the VFTO discrete time series of the whole process is decomposed into m A single breakdown VFTO discrete time series, including:

[0012] The VFTO discrete time series of the whole process is recorded as ,Will Decompose into m A single breakdown VFTO discrete time series is obtained ,in, For the m The length of the single breakdown time series, mis the number of single breakdowns in the discrete time series of the whole VFTO process;

[0013] set up k for m One of the single breakdowns, , then k The single breakdown VFTO waveform time series is shown as follows:

[0014] .

[0015] Further, in step S200, the extraction m The measured breakdown characteristics of a single breakdown VFTO discrete time series are used to form a measured breakdown characteristic set, including:

[0016] for m For each single breakdown VFTO discrete time series in the single breakdown, the measured breakdown characteristics are extracted; m The first single breakdown k A single breakdown VFTO discrete time series, the measured breakdown characteristics include the source side bus voltage value at the breakdown time , Load side bus voltage value at breakdown time , voltage peak , Stabilization time , the first maximum value of the spectrum in the frequency domain and the second maximum value of the spectrum in the frequency domain , ;

[0017] merge m All the measured breakdown characteristics of a single breakdown VFTO discrete time series form a breakdown characteristic set ,in, For the m Measured breakdown characteristics of a single breakdown VFTO discrete time series.

[0018] Further, for the k A single breakdown VFTO discrete time series, the source side bus voltage value at the breakdown time And the load side bus voltage value at the breakdown time The extraction methods include:

[0019] The residual voltage of each single breakdown VFTO discrete time series is calculated according to the following formula:

[0020] , ,

[0021] in, To calculate the number of sampling points for the residual voltage, For thek The residual voltage value of the discrete time series of the sub-breakdown voltage;

[0022] According to the following formula, the source side bus voltage value of each single breakdown VFTO discrete time series is calculated: The bus voltage value at the load side :

[0023] .

[0024] Further, for the k In the discrete time series of a single breakdown VFTO, the voltage peak And stabilization time The extraction methods include:

[0025] The single breakdown VFTO time series after the whole process VFTO discrete time series is separated is: ,in, For the k The length of the sequence;

[0026] According to the following formula, calculate the voltage peak and stabilization time :

[0027] ,

[0028] in, is the time step of the time series, is the threshold value for a single VFTO to enter the stable error band; For the k Voltage discrete time series The element number that satisfies the given threshold condition in the formula.

[0029] Further, for the k The single breakdown VFTO discrete time series in the frequency domain has the first maximum value of the spectrum , the second maximum of the spectrum , the frequency corresponding to the first maximum value of the spectrum And the frequency corresponding to the second maximum of the spectrum The extraction methods include:

[0030] Fast Fourier transform is used to calculate the k Amplitude-frequency curve of a single breakdown VFTO discrete time series ， Amplitude-frequency curve The total number of points, the frequency number of the spectrum maximum It can be determined by the following formula:

[0031] ,

[0032] The frequency corresponding to the first maximum value of the spectrum is calculated according to the following formula: , the frequency corresponding to the second maximum of the spectrum :

[0033] ,

[0034] in, is the sampling frequency of the VFTO discrete time series of the whole process; For the k The total number of points of a single breakdown VFTO amplitude-frequency curve;

[0035] According to the following formula, calculate the k The first maximum of the spectrum of a single breakdown VFTO discrete time series The second maximum of the spectrum :

[0036] .

[0037] Further, in step S300, the establishment of a simulation model with GIS electrical parameters as input and single breakdown VFTO discrete time series as output includes:

[0038] Determine the GIS bus parameters to be evaluated based on the GIS topology, the GIS bus parameters include the source side bus length , Load side bus length , Distributed resistance , Distributed Inductance , distributed conductivity and distributed capacitance ;

[0039] Note the location in the GIS distribution parameter model x exist t The voltage at the moment is , the current is , combined with the arcing resistance of the disconnector gap breakdown Arcing Inductance , the voltage and current equations for single breakdown VFTO simulation are constructed based on transmission line theory as follows:

[0040] ,

[0041] in, is the simulation duration of single breakdown VFTO simulation;

[0042] The initial conditions of the source side bus and the load side bus of the GIS distributed parameter model are set according to the following formula:

[0043] ,

[0044] in, They represent the two ends of the disconnector at the connection between the source side bus and the load side bus. Indicates the source bus voltage value at the moment of single breakdown, Indicates the bus voltage value on the load side at the moment of single breakdown;

[0045] The boundary conditions of the source side bus head end, load side bus end, and disconnector arc position of the GIS distributed parameter model are set according to the following formula:

[0046] ,

[0047] The above equations are solved by numerical calculation method, and the GIS distributed parameter model is obtained, which takes the estimated GIS electrical parameters and the voltage value at the time of busbar breakdown as input and the single breakdown VFTO discrete time series as output, which is expressed as:

[0048] ，

[0049]

[0050] in, Represents the GIS distributed parameter model.

[0051] Further, in step S300, based on the measured breakdown feature set, the GIS electrical parameters are used as decision variables, and the deviation between the simulated breakdown feature and the measured breakdown feature is minimized to construct m A multi-objective optimization problem, including:

[0052] From the measured breakdown feature set, obtain the k Secondary breakdown characteristics The peak voltage in the time domain and stabilization time , the first maximum value of the spectrum in the frequency domain and its corresponding frequency , the second maximum of the spectrum and its corresponding frequency , the objective function is constructed by the relative error between the time-frequency characteristics of the simulated VFTO discrete time series and the measured VFTO discrete time series, as shown in the following formula:

[0053] ,

[0054] ,

[0055] ,

[0056] in, is the objective function; To simulate the time-frequency characteristics of the VFTO time series, To simulate the voltage peak in the time domain of the VFTO time series, To simulate the settling time of the VFTO time series in the time domain, To simulate the first maximum value of the spectrum in the frequency domain of the VFTO time series, It is the second maximum value of the spectrum in the frequency domain of the simulated VFTO time series; are the decision variables for the multi-objective optimization problem, Including GIS electrical parameters and arcing resistance of disconnector gap breakdown ;

[0057] According to the following formula, the multi-objective optimization problem of GIS parameter estimation is constructed as follows:

[0058] ,

[0059] in, is the objective function set, the decision variables and decision variables Satisfy the inequality constraints, c The speed of light.

[0060] Further, in step S400, the solution of m A multi-objective optimization problem is obtained m non-dominated solution sets, including:

[0061] For the k A multi-objective optimization problem, i The set of decision variables for the generation population for:

[0062]

[0063] In the formula, is the number of individuals in the population; is the number of population iterations;

[0064] According to the expression of the objective function, the i The target value of all individuals in the first generation population is i Generation population objective function set :

[0065]

[0066] ;

[0067] According to iThe set of decision variables for the generation population With the objective function set , using a multi-objective evolutionary algorithm to iteratively obtain the i +1 generation population decision variable set , and then calculate the i +1 generation population objective function set ; Repeat the iterative solution process until the Generation population decision variable set With the objective function set ;

[0068] According to the following formula, filter out k Non-dominated solution set for a multi-objective optimization problem :

[0069] ,

[0070] In the formula, and The decision variable set The decision variables are , ,but x and z The same element of the decision variable set will not be taken at the same time, that is, x ≠ z ;

[0071] The final non-dominated solution set for:

[0072] ,

[0073] For the k The number of solutions in the non-dominated solution set of a multi-objective optimization problem.

[0074] Further, in step S400, the average values ​​of the electrical parameters of the GIS in all solution sets are calculated to obtain the optimal estimated values ​​of the GIS bus length and distribution parameters, including:

[0075] Record k The last generation of non-dominated solutions of the single-breakdown VFTO multi-objective optimization problem is: , calculated according to the following formula m The average value of decision variables of non-dominated solution set of multi-objective optimization problem:

[0076] ,

[0077] In the formula, Indicates k The first non-dominated solution set aA solution;

[0078] Calculate the optimal estimate of GIS electrical parameters for:

[0079] .

[0080] The present invention provides a VFTO time-frequency feature guided GIS disconnector physical parameter inversion method, which obtains VFTO waveform data generated by the opening and closing of the GIS disconnector, calculates the key time-frequency domain features reflecting the GIS electrical parameters, and determines the GIS parameter values ​​through the parameter inversion optimization method, which can achieve accurate estimation of the GIS structure and electrical parameters of the field operation. The method of the present invention can achieve online and accurate estimation of GIS parameters after the GIS is assembled, overcomes the limitation that the traditional offline acquired GIS parameters cannot accurately reflect the actual parameters of the system under the online operation state, and provides reliable parameter support for conducting GIS related research. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Figure 1 A flow chart of a method for inverting physical parameters of a GIS disconnector guided by time-frequency characteristics of ultra-fast transient overvoltage provided by an embodiment of the present invention;

[0082] Figure 2 The VFTO waveform diagram of the whole process of repeated breakdown of the GIS gap provided by the embodiment of the present invention;

[0083] Figure 3 A schematic diagram of a distributed parameter simulation model for calculating a GIS single VFTO discrete time series provided by an embodiment of the present invention;

[0084] Figure 4 A single breakdown simulation waveform diagram provided by an embodiment of the present invention;

[0085] Figure 5 A schematic diagram of parameter estimation results provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0086] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0087] Figure 1 A flow chart of a method for inverting physical parameters of a GIS disconnector guided by VFTO time-frequency characteristics provided by an embodiment of the present invention is shown in FIG. Figure 1 As shown, the method includes steps S100 to S400:

[0088] S100, obtain the VFTO discrete time series of the whole process of GIS disconnector opening and closing;

[0089] Specifically, when the GIS disconnector performs the opening and closing operation, the low-voltage analog signal output of the VFTO sensor on the load-side busbar of the disconnector is synchronously collected and converted into a digital signal, and the digital signal is restored according to the sensor ratio to obtain the following: Figure 2 The restored full-process VFTO waveform shown in the figure is used to obtain the full-process VFTO waveform discrete time series ,in, n is the sequence length. To ensure that the collected signal is not distorted as much as possible, the sampling rate of the digital acquisition device should not be less than 500 M S / s, the preferred sampling rate is 625 M S / s.

[0090] S200, decomposing the whole process VFTO discrete time series into m A single breakdown VFTO discrete time series is extracted m The measured breakdown characteristics of a single breakdown VFTO discrete time series are used to form a measured breakdown characteristic set;

[0091] For example, after decomposing the measured whole process VFTO discrete time series into m single breakdown VFTO discrete time series, k A single breakdown VFTO discrete time series is extracted to extract the source side bus at the breakdown time and bus voltage value on no-load side , extract the voltage peak value of the single breakdown VFTO discrete time series , Stabilization time , the first maximum value of the spectrum in the frequency domain , the second maximum value of the spectrum in the frequency domain The measured breakdown characteristics are as follows. m The measured breakdown characteristics of a single breakdown VFTO discrete time series form a breakdown characteristic set .

[0092] S300, establishing a simulation model with GIS electrical parameters as input and single breakdown VFTO discrete time series as output; constructing a simulation model based on the measured breakdown feature set and with GIS electrical parameters as decision variables, with the goal of minimizing the deviation between the simulated breakdown feature and the measured breakdown feature. m A multi-objective optimization problem;

[0093] S400, solve the m A multi-objective optimization problem is obtained m non-dominated solution sets, calculate the average values ​​of GIS electrical parameters in all solution sets, and obtain the optimal estimated values ​​of GIS bus length and distribution parameters.

[0094] It is understandable that, based on the defects in the background technology, the embodiment of the present invention proposes a method for inverting the physical parameters of the GIS disconnector guided by the VFTO time-frequency characteristics. The method obtains the VFTO waveform data generated by the opening and closing of the GIS disconnector, calculates the key characteristics in the time-frequency domain that reflect the GIS electrical parameters, and determines the GIS parameter values ​​through the parameter inversion optimization method, which can achieve accurate estimation of the GIS structure and electrical parameters of the GIS running on site. The method provided in this embodiment can realize accurate online estimation of GIS parameters after the GIS is assembled, overcoming the limitation that the traditional offline acquired GIS parameters cannot accurately reflect the actual parameters of the system under the online operation state, and provides reliable parameter support for conducting GIS related research.

[0095] Based on the above technical solution, the present embodiment may also be improved as follows.

[0096] In a possible embodiment, in S200, the VFTO discrete time series of the whole process is decomposed into m A single breakdown VFTO discrete time series, including:

[0097] The VFTO discrete time series of the whole process measured is: ,like Figure 2 As shown in the point marked with an asterisk, the single breakdown time of the whole VFTO discrete time series is located according to the VFTO voltage change rate law. Decompose into m A single breakdown VFTO discrete time series, m is the number of single breakdowns in the discrete time series of the whole process VFTO. More specifically, the voltage change rate of the whole process VFTO waveform data is calculated according to the following formula :

[0098] (1),

[0099] In formula (1), The discrete time series of the whole process VFTO is i sampling points, For the i The voltage change rate of the voltage data, is the discrete time series step size.

[0100] Based on the rule that the voltage steepness is high when the gap breaks down, set the appropriate threshold Filter out those that are greater than the threshold is the time when a single breakdown occurs, that is The single breakdown time selected is recorded as .

[0101] Extract the voltage data between two adjacent moments as a single breakdown VFTO discrete time series , m is the number of single breakdowns in the discrete time series of the whole VFTO process, that is, m is the number of single breakdown voltage waveforms in the whole process VFTO waveform, For the m The length of the single breakdown time series, k for m One of the single breakdowns, Among them k Single breakdown VFTO discrete time series As follows:

[0102] (2).

[0103] In a possible embodiment, in step S200, the extraction m The measured breakdown characteristics of a single breakdown VFTO discrete time series are used to form a measured breakdown characteristic set, including:

[0104] for m For each single breakdown VFTO discrete time series in the single breakdown, the measured breakdown characteristics are extracted; m The first single breakdown k A single breakdown VFTO discrete time series, the measured breakdown characteristics include the source side bus voltage value at the breakdown time , Load side bus voltage value at breakdown time , voltage peak , Stabilization time , the first maximum value of the spectrum in the frequency domain and the second maximum value of the spectrum in the frequency domain , ;

[0105] merge m All the measured breakdown characteristics of a single breakdown VFTO discrete time series form a breakdown characteristic set ,in, For the m Measured breakdown characteristics of a single breakdown VFTO discrete time series.

[0106] In a possible embodiment, in step S200, for the k A single breakdown VFTO discrete time series, the source side bus voltage value at the breakdown time And the load side bus voltage value at the breakdown time The extraction method specifically includes:

[0107] 1. Calculate the residual voltage of each single breakdown VFTO discrete time series according to the following formula:

[0108] , (3),

[0109] In formula (3), To calculate the number of sampling points for the residual voltage, For the k The residual voltage value of the discrete time series of the sub-breakdown voltage. The value of is related to the duration of selecting the end data, which can be determined by the following formula (4):

[0110] (4),

[0111] In formula (4), The data length at the end of the waveform used to calculate the residual voltage ， is the sampling time of the data. Usually in Internal value, preferred Take 100 .

[0112] 2. Based on residual voltage , extract the bus voltage at the moment of single breakdown of GIS contact gap.

[0113] Source side bus voltage The voltage of the busbar on the source side is approximately constant during the duration of VFTO. After the gap arcing ends, the busbar voltage on the load side is consistent with the busbar voltage on the load side. k The source side bus voltage at the second breakdown It is approximately the residual voltage of the breakdown VFTO time series, that is:

[0114] (5),

[0115] After the gap arcing ends, the residual voltage of the busbar on the load side remains stable due to the extremely small distributed conductivity of the busbar. k Load side bus voltage at the time of the second breakdown for:

[0116] (6).

[0117] By sorting out formula (5) and formula (6), we can get:

[0118] .

[0119] It is worth noting that the single VFTO waveform of the load-side busbar is similar to a damped oscillation waveform. The VFTO can be uniquely determined by extracting the peak value and oscillation duration in the time domain and extracting the spectrum peak value and its frequency in the frequency domain. Therefore, the following sub-steps of step S200 record the voltage peak value in the time domain. And stabilization time The extraction method of the spectrum peak and its corresponding frequency in the frequency domain (such as the first maximum value of the spectrum , the second maximum of the spectrum , the frequency corresponding to the first maximum value of the spectrum And the frequency corresponding to the second maximum of the spectrum ) extraction method.

[0120] In a possible embodiment, in step S200, for the k In the discrete time series of a single breakdown VFTO, the voltage peak And stabilization time The extraction method specifically includes:

[0121] The single breakdown VFTO time series after the whole process VFTO discrete time series is separated is: ,in, For the k The length of the sequence, m is the number of single breakdowns in the discrete time series of the whole VFTO process;

[0122] According to the following formula, calculate the voltage peak and stabilization time :

[0123] (7),

[0124] In formula (7), is the time step of the time series, is the threshold value for a single VFTO to enter the stable error band, Usually the value is within 0.01-0.05, preferably Take 0.02; For the k Voltage discrete time series The element number that satisfies the given threshold condition in the formula.

[0125] In a possible embodiment, in step S200, for the k The single breakdown VFTO discrete time series in the frequency domain has the first maximum value of the spectrum , the second maximum of the spectrum , the frequency corresponding to the first maximum value of the spectrum And the frequency corresponding to the second maximum of the spectrum The extraction methods include:

[0126] 1. Use fast Fourier transform to calculate k Amplitude-frequency curve of a single breakdown VFTO discrete time series ， Amplitude-frequency curve The total number of points, the frequency number of the spectrum maximum It can be determined by the following formula:

[0127] (8),

[0128] Formula (8) is the index for finding the local maximum value of the spectrum.

[0129] 2. Calculate the frequency corresponding to the first maximum value of the spectrum according to the following formula: , the frequency corresponding to the second maximum of the spectrum :

[0130] (9),

[0131] In formula (9), is the sampling frequency of the whole process VFTO discrete time series, preferably, ; For the k The total number of points of a single breakdown VFTO amplitude-frequency curve;

[0132] 3. Calculate the k The first maximum of the spectrum of a single breakdown VFTO discrete time series The second maximum of the spectrum :

[0133] (10).

[0134] It is understandable that all the above examples are extracted. m The measured breakdown characteristics of the single-breakdown VFTO discrete time series can be combined to form a breakdown characteristic set .

[0135] In a possible embodiment, in step S300, the establishment of a simulation model with GIS electrical parameters as input and single breakdown VFTO discrete time series as output includes:

[0136] 1. Basis Figure 3 The GIS topology shown determines the GIS bus parameters to be evaluated, which include the source side bus length , Load side bus length , Distributed resistance , Distributed Inductance , distributed conductivity and distributed capacitance ;

[0137] 2. Remember the location in the GIS distribution parameter model x exist t The voltage at the moment is , the current is , combined with the arcing resistance of the disconnector gap breakdown Arcing Inductance , the voltage and current equations for single breakdown VFTO simulation are constructed based on transmission line theory as follows:

[0138] (11),

[0139] In formula (11), is the simulation duration of single breakdown VFTO simulation;

[0140] According to formula (11), the initial conditions of the source-side bus and the load-side bus of the GIS distributed parameter model are obtained as follows:

[0141] (12),

[0142] in, They represent the two ends of the disconnector at the connection between the source side bus and the load side bus. Indicates the source bus voltage value at the moment of single breakdown, Indicates the bus voltage value on the load side at the moment of single breakdown;

[0143] According to formula (11), the boundary conditions of the source side bus head end, load side bus end, and disconnector arc position of the GIS distributed parameter model are obtained as follows:

[0144] (13),

[0145] In formula (13), is the arcing resistance, is the arcing inductance. It changes with the opening distance of the disconnector and is a parameter to be estimated. The preferred value is .

[0146] 3. Solve the GIS distributed parameter model composed of equations (11) to (13). Preferably, the numerical calculation method is the time domain finite element method.

[0147] The numerical calculation method is used to solve the above equations (11) to (13), and the GIS distributed parameter model is obtained, which takes the estimated GIS electrical parameters and the busbar breakdown voltage value as input and the single breakdown VFTO discrete time series as output, which is expressed as:

[0148] ，

[0149] .

[0150] in, Represents the GIS distributed parameter model.

[0151] In a possible embodiment, in step S300, based on the measured breakdown feature set, the GIS electrical parameters are used as decision variables, and the deviation between the simulated breakdown feature and the measured breakdown feature is minimized. m A multi-objective optimization problem, including:

[0152] 1. Obtain the first k Secondary breakdown characteristics The peak voltage in the time domain and stabilization time , the first maximum value of the spectrum in the frequency domain and its corresponding frequency , the second maximum of the spectrum and its corresponding frequency , the objective function is constructed by the relative error between the time-frequency characteristics of the simulated VFTO discrete time series and the measured VFTO discrete time series, as shown in the following formula:

[0153] (14),

[0154] ,

[0155] In formula (14), is the objective function; To simulate the time-frequency characteristics of the VFTO time series, To simulate the voltage peak in the time domain of the VFTO time series, To simulate the settling time of the VFTO time series in the time domain, To simulate the first maximum value of the spectrum in the frequency domain of the VFTO time series, It is the second maximum value of the spectrum in the frequency domain of the simulated VFTO time series; are the decision variables for the multi-objective optimization problem, Including GIS electrical parameters and arcing resistance of disconnector gap breakdown ,Right now ;

[0156] 2 According to the fact that the propagation speed of the traveling wave in the transmission line is less than the speed of light, the decision variables satisfy the following inequality constraints:

[0157] (15),

[0158] In formula (15), is the propagation speed of the traveling wave on the busbar; c is the speed of light, .

[0159] Combining the above equations (14) to (15), the multi-objective optimization problem of GIS parameters can be expressed as:

[0160] (16),

[0161] in, is the objective function set, the decision variables and decision variables Satisfy the inequality constraints.

[0162] In a possible embodiment, in step S400, an optimization algorithm is used to solve the m A multi-objective optimization problem is obtained m The optimization algorithm adopts a multi-objective evolutionary algorithm, preferably a RSEA algorithm. Specifically, it includes:

[0163] 1. For k A multi-objective optimization problem, i The set of decision variables for the generation population for:

[0164] (17),

[0165] In formula (17), is the number of individuals in the population; is the number of population iterations;

[0166] According to the expression of the objective function described in formula (14), the first i The target value of all individuals in the first generation population is i Generation population objective function set :

[0167] (18),

[0168]

[0169] According to i The set of decision variables for the generation population With the objective function set , using a multi-objective evolutionary algorithm to iteratively obtain the i+1 The set of decision variables for the generation population , and then calculate the i+1 The objective function set of the generation population ; Repeat the iterative solution process until the Generation population decision variable set With the objective function set .

[0170] It can be understood that, in this embodiment, k A GIS parameter multi-objective optimization problem is firstly to randomly initialize the GIS parameter population in the GIS parameter search space, and then compare the GIS parameters of all individuals in the population with the first k Measured single-breakdown VFTO breakdown characteristics The bus voltage at the breakdown moment Substitute the VFTO simulation model to calculate and generate a single breakdown VFTO discrete time series. Secondly, calculate the single breakdown VFTO discrete time series characteristics according to equations (7) to (10). Then calculate the optimization target value of all individuals in the population according to equation (14), and use the multi-objective evolutionary algorithm to find the population decision variable distribution of the next iteration in the search space. Repeat the iterative process of generating the simulated VFTO waveform corresponding to the individuals in the population, calculating the optimization target value, and updating the population distribution until the total number of evaluations reaches the preset value. The total number of evaluations is the product of the population size and the number of iterations. The value is determined by factors such as the problem scale and the complexity of the objective function. The preferred total number of evaluations is 50,000.

[0171] 2. According to the following formula (19), filter out k Non-dominated solution set for a multi-objective optimization problem :

[0172] (19),

[0173] In formula (19), and The decision variable set The decision variables are , ,but x and z The same element of the decision variable set will not be taken at the same time, that is, x ≠ z ;

[0174] The final non-dominated solution set for:

[0175] (20),

[0176] In formula (20), For the k The number of solutions in the non-dominated solution set of a multi-objective optimization problem.

[0177] In a possible implementation manner, in step S400, calculating the average values ​​of the electrical parameters of the GIS in all solution sets to obtain the optimal estimated values ​​of the GIS bus length and the distribution parameters includes:

[0178] Record k The last generation of non-dominated solutions of the single-breakdown VFTO multi-objective optimization problem is: , calculated according to the following formula m The average value of decision variables of non-dominated solution set of multi-objective optimization problem:

[0179] (twenty one),

[0180] In formula (21), Indicates k The first non-dominated solution set a A solution;

[0181] Calculate the optimal estimate of GIS electrical parameters for:

[0182] (twenty two).

[0183] The technical solution of the present invention is now illustrated by taking a specific implementation scenario.

[0184] On a 220kV GIS test platform, a GIS disconnector physical parameter inversion method guided by the time-frequency characteristics of ultra-fast transient overvoltage proposed in the present invention is implemented. Figure 1 As shown, this implementation scenario is illustrated with steps 1 to 5.

[0185] Step 1: Obtain the VFTO discrete time series of multiple breakdowns of the gap between the moving and static contacts of the GIS disconnector during opening and closing.

[0186] First, when the isolating switch is performing the opening and closing operation, the low-voltage analog signal output of the VFTO sensor on the load-side busbar of the isolating switch is synchronously collected and converted into a digital signal. The sampled signal is restored to the digital signal according to the sensor ratio to obtain the VFTO waveform data of the whole process. The VFTO waveform of the whole process after restoration is as follows: Figure 2 shown.

[0187] Step 2: According to formula (1), the single breakdown time of the whole process VFTO waveform is extracted. Figure 2The asterisk is used in the Figure 2 As shown, there are 10 separated single breakdown VFTO waveforms in total. The residual voltage values ​​of the 10 single breakdown VFTO waveforms are extracted, and the bus voltage at the time of single breakdown is calculated as shown in Table 1 below.

[0188] Table 1 Bus voltage at the moment of single breakdown

[0189]

[0190] Calculate the voltage peak of the single breakdown VFTO waveform according to equations (6), (7), and (8): , Stabilization time , the first maximum value of the spectrum and its frequency , the second maximum of the spectrum and its frequency , as shown in Table 2 below.

[0191] Table 2 Time-frequency characteristics of each single breakdown VFTO waveform

[0192]

[0193] Step 3: Establish a distributed parameter model of the GIS circuit based on the GIS electrical topology. In this embodiment, the source side busbar-disconnector-load side busbar topology is considered, and its distributed parameter model is as follows: Figure 3 As shown;

[0194] Combined with the initial conditions of voltage and current of single breakdown, the time-domain finite element method is used to solve the voltage and current of all points on the busbar of the single breakdown VFTO model. The time-domain finite element method is the preferred numerical calculation method. The single breakdown VFTO waveform generated by the simulation model is as follows: Figure 4 shown.

[0195] Step 4: Based on the time-frequency characteristics of 10 single-breakdown VFTO discrete time series, the corresponding GIS parameter optimization problem is constructed according to formula (11). In this embodiment, the total length of the source side bus and the load side bus is fixed to 13m, and the length of the load side bus is The source side bus Indicates that =13- ; Distributed conductance of busbar is 0; Distributed resistance of the stage The influence on the features is negligible. The decision variables after combination are .

[0196] Step 5, solve 10 GIS parameter optimization problems, select the non-dominated solution set according to step S400 in the above embodiment, and calculate the optimal parameter estimation value of each multi-objective optimization problem as follows: Figure 5 As shown, the average value of the decision variables of the 10 solutions is:

[0197]

[0198] ,

[0199] The optimal estimation of GIS parameters in this implementation scenario is shown in Table 3 below.

[0200] Table 3 Optimal estimated values ​​of GIS parameters obtained in Example

[0201]

[0202] It has been verified that the optimal estimated values ​​of GIS parameters finally obtained in this implementation scenario can achieve accurate estimation of the operating GIS structure and electrical parameters.

[0203] An embodiment of the present invention provides a GIS disconnector physical parameter inversion method guided by the time-frequency characteristics of very fast transient overvoltage (VFTO). First, the whole process VFTO discrete time series generated during the opening and closing process of the GIS disconnector is collected and obtained; the single breakdown occurrence time of the whole process VFTO discrete time series is located according to the VFTO voltage change rate law, the whole process VFTO discrete time series is decomposed into m single breakdown VFTO discrete time series, the time domain and frequency domain characteristics of the single breakdown VFTO are extracted, the characteristics of all single breakdown VFTO discrete time series are merged, and a feature set is constructed; based on the transmission line theory and feature extraction method, a GIS distributed parameter model from GIS parameters to single VFTO discrete time series is established; for m The characteristics of a single breakdown VFTO discrete time series are constructed based on the deviation between the simulated and measured waveform characteristics. m A multi-objective estimation optimization problem of parameters is proposed; each problem is iteratively solved until the maximum number of evaluations is reached using a multi-objective optimization algorithm, the non-dominated solutions of the last generation of population for each optimization problem are extracted, and the average value of the non-dominated solutions is calculated as the optimal estimate of the GIS parameters.

[0204] The method of the present invention obtains the VFTO waveform data generated by the opening and closing of the GIS disconnector, calculates the key characteristics of the time-frequency domain reflecting the GIS electrical parameters, and determines the GIS parameter values ​​through the parameter inversion optimization method, which can realize the accurate estimation of the GIS structure and electrical parameters of the field operation. This method can realize the online and accurate estimation of GIS parameters after the GIS is assembled, overcomes the limitation that the traditional offline GIS parameters cannot accurately reflect the actual parameters of the system under the online operation state, and provides reliable parameter support for conducting GIS related research.

[0205] It should be noted that in the above embodiments, the description of each embodiment has its own emphasis, and for parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0206] It should be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, etc.) containing computer-usable program code. M , optical storage, etc.).

[0207] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded computer, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0208] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0209] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0210] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0211] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A VFTO time-frequency characteristic guided GIS disconnector physical parameter inversion method, characterized in that: include: S100, obtain the VFTO discrete time series of the whole process of GIS disconnector opening and closing; S200, decomposing the whole process VFTO discrete time series into m A single breakdown VFTO discrete time series, including: The VFTO discrete time series of the whole process is recorded as ,Will Decompose into m A single breakdown VFTO discrete time series is obtained ,in, For the m The length of the single breakdown time series, m is the number of single breakdowns in the discrete time series of the whole VFTO process; set up k for m One of the single breakdowns, , then k The single breakdown VFTO waveform time series is shown as follows: ； extract m The measured breakdown characteristics of a single breakdown VFTO discrete time series are used to form a measured breakdown characteristic set; including: for m For each single breakdown VFTO discrete time series in the single breakdown, the measured breakdown characteristics are extracted; m The first single breakdown k A single breakdown VFTO discrete time series, the measured breakdown characteristics include the source side bus voltage value at the breakdown time , Load side bus voltage value at breakdown time , voltage peak , Stabilization time , the first maximum value of the spectrum in the frequency domain and the second maximum value of the spectrum in the frequency domain , ; merge m All the measured breakdown characteristics of a single breakdown VFTO discrete time series form a breakdown characteristic set ,in, For the m The measured breakdown characteristics of the single-breakdown VFTO discrete time series; S300, establishing a simulation model with GIS electrical parameters as input and single breakdown VFTO discrete time series as output; constructing a simulation model based on the measured breakdown feature set and with GIS electrical parameters as decision variables, with the goal of minimizing the deviation between the simulated breakdown feature and the measured breakdown feature. m A multi-objective optimization problem; S400, solve the m A multi-objective optimization problem is obtained m non-dominated solution sets, calculate the average values ​​of GIS electrical parameters in all solution sets, and obtain the optimal estimated values ​​of GIS bus length and distribution parameters.

2. According to claim 1, a VFTO time-frequency characteristic guided GIS disconnector physical parameter inversion method is characterized in that: For k A single breakdown VFTO discrete time series, the source side bus voltage value at the breakdown time And the load side bus voltage value at the breakdown time The extraction methods include: The residual voltage of each single breakdown VFTO discrete time series is calculated according to the following formula: , in, To calculate the number of sampling points for the residual voltage, For the k The residual voltage value of the discrete time series of the sub-breakdown voltage; According to the following formula, the source side bus voltage value of each single breakdown VFTO discrete time series is calculated: The bus voltage value at the load side : 。 3. According to claim 2, a VFTO time-frequency characteristic guided GIS disconnector physical parameter inversion method is characterized in that: For k In the discrete time series of a single breakdown VFTO, the voltage peak And stabilization time The extraction methods include: The single breakdown VFTO time series after the whole process VFTO discrete time series is separated is: ,in, For the k The length of the sequence; According to the following formula, calculate the voltage peak and stabilization time : ， in, is the time step of the time series, is the threshold value for a single VFTO to enter the stable error band; For the k Voltage discrete time series The element number that satisfies the given threshold condition in the formula.

4. The method for inversion of physical parameters of GIS disconnector guided by VFTO time-frequency characteristics according to claim 1 is characterized in that: For k The single breakdown VFTO discrete time series in the frequency domain has the first maximum value of the spectrum , the second maximum of the spectrum , the frequency corresponding to the first maximum value of the spectrum And the frequency corresponding to the second maximum of the spectrum The extraction methods include: Fast Fourier transform is used to calculate the k Amplitude-frequency curve of a single breakdown VFTO discrete time series , Amplitude-frequency curve The total number of points, the frequency number of the spectrum maximum It can be determined by the following formula: ， The frequency corresponding to the first maximum value of the spectrum is calculated according to the following formula: , the frequency corresponding to the second maximum of the spectrum : ， in, is the sampling frequency of the VFTO discrete time series of the whole process; For the k The total number of points of a single breakdown VFTO amplitude-frequency curve; According to the following formula, calculate the k The first maximum of the spectrum of a single breakdown VFTO discrete time series The second maximum of the spectrum : 。 5. The method for inversion of physical parameters of GIS disconnector guided by VFTO time-frequency characteristics according to claim 4 is characterized in that: In step S300, the establishment of a simulation model with GIS electrical parameters as input and single breakdown VFTO discrete time series as output includes: Determine the GIS bus parameters to be evaluated based on the GIS topology, the GIS bus parameters include the source side bus length , Load side bus length , Distributed resistance , Distributed Inductance , distributed conductivity and distributed capacitance ; Note the location in the GIS distribution parameter model x exist t The voltage at the moment is , the current is , combined with the arcing resistance of the disconnector gap breakdown Arcing Inductance , the voltage and current equations for single breakdown VFTO simulation are constructed based on transmission line theory as follows: ， in, is the simulation duration of single breakdown VFTO simulation; The initial conditions of the source side bus and the load side bus of the GIS distributed parameter model are set according to the following formula: ， in, They represent the two ends of the disconnector at the connection between the source side bus and the load side bus. Indicates the source bus voltage value at the moment of single breakdown, Indicates the bus voltage value on the load side at the moment of single breakdown; The boundary conditions of the source side bus head end, load side bus end, and disconnector arc position of the GIS distributed parameter model are set according to the following formula: ， The above equations are solved by numerical calculation method, and the GIS distributed parameter model is obtained, which takes the estimated GIS electrical parameters and the voltage value at the time of busbar breakdown as input and the single breakdown VFTO discrete time series as output, which is expressed as: ， in, Represents the GIS distributed parameter model.

6. A VFTO time-frequency characteristic guided GIS disconnector physical parameter inversion method according to claim 5, characterized in that: In step S300, based on the measured breakdown feature set, the GIS electrical parameters are used as decision variables, and the deviation between the simulated breakdown feature and the measured breakdown feature is minimized. m A multi-objective optimization problem, including: From the measured breakdown feature set, obtain the k Secondary breakdown characteristics The peak voltage in the time domain and stabilization time , the first maximum value of the spectrum in the frequency domain and its corresponding frequency , the second maximum of the spectrum and its corresponding frequency , the objective function is constructed by the relative error between the time-frequency characteristics of the simulated VFTO discrete time series and the measured VFTO discrete time series, as shown in the following formula: ， ， in, is the objective function; To simulate the time-frequency characteristics of the VFTO time series, To simulate the voltage peak in the time domain of the VFTO time series, To simulate the settling time of the VFTO time series in the time domain, To simulate the first maximum value of the spectrum in the frequency domain of the VFTO time series, It is the second maximum value of the spectrum in the frequency domain of the simulated VFTO time series; are the decision variables for the multi-objective optimization problem, Including GIS electrical parameters and arcing resistance of disconnector gap breakdown ; According to the following formula, the multi-objective optimization problem of GIS parameter estimation is constructed as follows: in, is the objective function set, the decision variables and decision variables Satisfy the inequality constraints, c The speed of light.

7. A VFTO time-frequency characteristic guided GIS disconnector physical parameter inversion method according to claim 6, characterized in that: In step S400, the solution m A multi-objective optimization problem is obtained m non-dominated solution sets, including: For the k A multi-objective optimization problem, i The set of decision variables for the generation population for: In the formula, is the number of individuals in the population; is the number of population iterations; According to the expression of the objective function, the i The target value of all individuals in the first generation population is i Generation population objective function set : ； According to i The set of decision variables for the generation population With the objective function set , using a multi-objective evolutionary algorithm to iteratively obtain the i +1 generation population decision variable set , and then calculate the i +1 generation population objective function set ; Repeat the iterative solution process until the Generation population decision variable set With the objective function set ; According to the following formula, filter out k Non-dominated solution set for a multi-objective optimization problem : ， The final non-dominated solution set for: ， For the k The number of solutions in the non-dominated solution set of a multi-objective optimization problem.

8. The method for inversion of physical parameters of GIS disconnector guided by VFTO time-frequency characteristics according to claim 7 is characterized in that: In step S400, the calculation of the average values ​​of the electrical parameters of the GIS in all solution sets to obtain the optimal estimated values ​​of the GIS bus length and distribution parameters includes: Record k The last generation of non-dominated solutions of the single-breakdown VFTO multi-objective optimization problem is: , calculated according to the following formula m The average value of decision variables of non-dominated solution set of multi-objective optimization problem: In the formula, Indicates k The first non-dominated solution set a A solution; Calculate the optimal estimate of GIS electrical parameters for: 。

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