Arc light high-resistance grounding fault modeling method, arc light high-resistance grounding fault analysis method, arc light high-resistance grounding fault analysis system and medium

Abstract

The invention relates to the field of electric power grounding fault detection, in particular to an arc light high-resistance grounding fault modeling method, an arc light high-resistance grounding fault analysis method, an arc light high-resistance grounding fault system and a medium, and the method comprises the steps: determining a dynamic arc model based on the combination of a Mayr arc model and a Cassie arc model; determining a grounding medium nonlinear resistance model; and connecting the dynamic arc model and the grounding medium nonlinear resistance model in series to obtain an arc light high-resistance grounding fault model. On the basis of considering the nonlinearity of the arc, the nonlinearity of the grounding medium resistance is increased, the nonlinearity characteristic of the arc light high-resistance fault can be accurately simulated, the defect that the nonlinearity characteristic of the grounding medium is not fully considered by the existing arc model is avoided, and the air gap breakdown process between the wire and the grounding medium is taken into consideration. The method can be used as a universal arc fault model covering all working conditions, and the technical defect that an existing single arc model cannot cover all working conditions is overcome.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of power grounding fault detection, in particular, to an arc high resistance grounding fault modeling method, an analysis method, a system and a medium. BACKGROUND

[0002] The resonant grounding distribution network has a complex branch structure, and the geographical environment is relatively poor, and non-metallic medium grounding faults through tree branches, grass, asphalt, etc. often occur, accompanied by air arc and solid medium breakdown induced nonlinear arc phenomenon, forming arc high resistance grounding fault. Due to the characteristics of weak fault electrical quantity and unstable arc breakdown voltage, the detection of such faults is difficult, and there is less recorded data obtained on site. Therefore, on the basis of limited measured data, accurate modeling and simulation analysis of arc high resistance fault is an important measure to identify arc high resistance grounding fault.

[0003] Considering that arc high resistance grounding fault is usually accompanied by nonlinear arc, arc models based on energy balance theory have been proposed, including Mayr arc model, Cassie arc model, Mayr and Cassie series combination arc model, "control theory" arc model and arc series resistance, etc. Among them, Mayr and Cassie arc model is a model based on thermal balance, thermal inertia and thermal ionization process of arc. The "control theory" arc model describes the relationship between various physical quantities of the arc by mathematical method, can control the arc length to reflect the change process of the arc, and reveal the internal phenomenon of the arc. The "control theory" arc model also proposes a nonlinear resistance model based on the principle of solid medium breakdown for arc high resistance grounding fault. The nonlinear resistance model is composed of a steady-state resistance and a transient-state resistance in series. The steady-state resistance is the resistance generated by the non-effective contact of the grounding medium and the ground. The transient-state resistance is the resistance of the grounding medium, and its nonlinear change is determined by the solid electric breakdown principle of the medium.

[0004] Although the existing arc fault models all have a clear scope of application, such as Mayr arc model is good at describing the dynamic characteristics of arc resistance under small current and high impedance conditions, but it does not include the influence mechanism of arc length on time constant and heat dissipation efficiency. Cassie arc model is more suitable for large current and low impedance fault scenarios, but it has significant deviation in simulating high impedance state.

[0005] The "cybernetics" arc model can improve the modeling accuracy of high-current systems by adjusting the arc length, but it is difficult to accurately reflect the fault characteristics of small-current grounding systems. The existing arc fault modeling method related to the "cybernetics" arc model usually simplifies the arc resistance as a series combination of the above-mentioned arc resistance and a fixed resistance, and does not fully consider the nonlinear characteristics of the grounding medium resistance. While the existing nonlinear resistance model establishes the current-field strength relationship curve through the piecewise linear fitting method, constructs the function relationship between the conductance and the voltage, and realizes the modeling of the nonlinear resistance characteristics of the high-resistance fault, it does not consider the air gap breakdown process between the conductor and the grounding medium, and the simulation of the high-impedance state also has significant deviation.

[0006] Due to the limitations of the above-mentioned existing arc models, they cannot meet market needs and are not accurate in detecting the arc light high-resistance grounding fault resistance. SUMMARY

[0007] The technical problem to be solved by the present disclosure is to provide an arc light high-resistance grounding fault modeling method, analysis method, system and medium to solve the technical problem that the existing arc model is not accurate in detecting the arc light high-resistance grounding fault resistance, and the present disclosure adopts the following technical solutions: In a first aspect, the present disclosure provides an arc light high-resistance grounding fault modeling method, comprising: determining a dynamic arc model based on the combination of Mayr arc model and Cassie arc model; determining a grounding medium nonlinear resistance model; connecting the dynamic arc model and the grounding medium nonlinear resistance model in series to obtain an arc light high-resistance grounding fault model.

[0008] Preferably, the determination of the dynamic arc model based on the combination of Mayr arc model and Cassie arc model comprises: establishing a Mayr arc model, the expression of which is as follows: (1) In formula (1), g is the arc conductivity of the Mayr arc model, is the thermal inertia time constant of the arc, is the potential per unit length of the arc, is the arc current, is the arc energy loss constant; = R Mayr , R Mayr is the dynamic resistance of the Mayr arc model.

[0009] Preferably, the determination is based on a dynamic arc model combining Mayr arc model and Cassie arc model, including: The Cassie arc model is established, and the expression is as follows: (2) In formula (2) ，g is the conductivity of the Cassie arc model, is the arc time constant, is the constant arc voltage; = R Cassie , R Cassie is the dynamic resistance of the Cassie arc model.

[0010] Preferably, the S1 determination is based on a dynamic arc model combining Mayr arc model and Cassie arc model, including: The Mayr arc model and the Cassie arc model are connected to construct a dynamic arc model, and the expression is as follows: (3) In formula (3), R Mayr is the dynamic resistance of the Mayr arc model, R Cassie is the dynamic resistance of the Cassie arc model, is a Sigmoid transition function with current as a variable, R arc is the dynamic resistance of the dynamic arc model.

[0011] Preferably, the transition function The expression can be as follows: (4) In formula (4), the output range is between (0, 1), I represents the instantaneous value of the arc current, I 0 represents the transition current, k represents the rate coefficient for controlling the change of continuous function; wherein, k the larger, the faster the change rate when the arc current tends to zero, and the more obvious the transition boundary of the Mayr arc model and the Cassie arc model. Formula (4) can avoid the sudden change from small current to large current.

[0012] Preferably, the S2 determination is a nonlinear resistance model of grounding medium, and the expression is as follows: (5) In formula (5), R var R is the nonlinear resistance of the grounding medium, R R1 is the inherent resistance of the grounding medium, u u is the voltage of the grounding medium, u 1、 u K2 is a constant, k 1、 k K2 is a constant, The inherent resistance of the grounding medium refers to the resistance that exists in the grounding medium without considering external influences. The voltage u of the grounding medium refers to the voltage drop across the grounding medium. The nonlinear resistance of the grounding medium refers to the resistance value of the grounding medium, and the resistance value presents a nonlinear trend. R var The nonlinear resistance of the grounding medium refers to the resistance value of the grounding medium, and the resistance value presents a nonlinear trend.

[0013] Preferably, the arc high resistance grounding fault model is expressed as follows: (6) In formula (6), R f R is the arc high resistance grounding fault resistance, R arc R1 is the dynamic resistance of the dynamic arc model, R var R is the nonlinear resistance of the grounding medium.

[0014] The second aspect of the present disclosure provides an arc high resistance grounding fault analysis method, which comprises: Inputting the arc parameters into the arc high resistance grounding fault model to obtain the arc high resistance grounding fault resistance of the fault point, and simulating the voltage-current characteristic curve, voltage-current waveform and other characteristics of the fault point based on the arc high resistance grounding fault resistance.

[0015] Preferably, based on the arc high resistance grounding fault resistance of the fault point, the voltage-current characteristic curve, voltage-current waveform and other characteristics of the fault point can be simulated through a simulation system.

[0016] Preferably, the arc high resistance grounding fault model is obtained by the arc high resistance grounding fault modeling method provided in the first aspect or any one of the embodiments thereof.

[0017] Preferably, the arc parameters are corresponding values of the parameters included in the arc high resistance grounding fault model.

[0018] Preferably, the arc parameters include the parameters of the dynamic arc model (as shown in Table 1) and the parameters of the nonlinear resistance model of the grounding medium.R 1、 u 1、 u 2、 k 1、 k 2)。

[0019] Preferably, the parameters of the dynamic arc model include the parameters of the Mayr arc model, the parameters of the Cassie arc model and the parameters of the transition function .

[0020] It can be understood that the characteristics such as the voltage-current characteristic curve, the voltage and current waveform of the fault point obtained by simulation can reproduce or analyze the characteristics such as the current amplitude and phase of the actual arc high-resistance ground fault. The real fault point resistance is simulated and reproduced by the arc high-resistance ground fault resistance. The reproduction or analysis of the characteristics such as the current amplitude, phase and resistance by the characteristics such as the voltage-current characteristic curve, the voltage and current waveform is the prior art, which will not be described here.

[0021] In a third aspect, the present disclosure provides an arc high-resistance ground fault modeling system, comprising: an arc model module for determining a dynamic arc model based on the combination of the Mayr arc model and the Cassie arc model; a ground model module for determining a ground medium nonlinear resistance model; a fault resistance module for connecting the dynamic arc model and the ground medium nonlinear resistance model in series to obtain an arc high-resistance ground fault model.

[0022] In a fourth aspect, the present disclosure provides a computer readable storage medium storing a computer program, wherein the computer program is executed by a processor to implement the arc high-resistance ground fault modeling method of the first aspect and any optional implementation thereof, or to implement the ground fault analysis method of the second aspect, or to implement the arc high-resistance ground fault modeling system of the third aspect and any optional implementation thereof.

[0023] In a fifth aspect, the present disclosure provides an electronic device comprising a processor and a memory, wherein the processor is configured to execute a computer program stored in the memory to implement the arc high-resistance ground fault modeling method as described above.

[0024] Beneficial effects of the present disclosure: The present disclosure proposes an arc high resistance grounding fault modeling method, analysis method, system and medium. On the basis of considering the nonlinearity of arc, the nonlinearity of grounding medium resistance is also increased, which can accurately simulate the nonlinearity characteristics of arc high resistance fault, avoids the defects that the existing arc model does not fully consider the nonlinearity characteristics of grounding medium, and takes the air gap breakdown process between the conductor and the grounding medium into consideration, so as to cover the needs of all working conditions. The arc high resistance grounding fault model based on the non-linear dynamic resistance series provided by the present disclosure can serve as a general arc fault model covering all working conditions, and overcomes the technical defects that the existing single arc model cannot cover all working conditions.

[0025] The present disclosure is based on the field experiment of arc high resistance fault, and analyzes that the nonlinearity distortion of arc high resistance fault is mainly caused by arc and grounding medium. Therefore, an arc high resistance grounding fault modeling method is proposed. The arc high resistance grounding fault model provided by the method fully considers the non-linear resistance of grounding medium and the dynamic resistance of arc model in series. The Mayr arc model is more suitable for simulating the case of small arc current because the arc conductance is relatively small when the arc is started. The Cassie arc model simulates the case of stable large arc current when the arc is completely burned. The present disclosure establishes a complete dynamic arc model by combining Mayr and Cassie. The present disclosure simulates the non-linear change of grounding medium resistance by using the solid electrical breakdown principle of medium, so as to avoid the defects that the existing arc model does not fully consider the nonlinearity characteristics of grounding medium. The arc high resistance grounding fault model is obtained by connecting the dynamic arc model and the non-linear resistance of grounding medium in series. The nonlinearity characteristics of arc high resistance fault and the nonlinearity characteristics of grounding medium are considered, so the needs of all working conditions can be covered, and the current amplitude, phase and other characteristics of actual arc high resistance grounding fault can be more accurately reproduced, thereby facilitating the accurate modeling and simulation analysis of arc high resistance fault. BRIEF DESCRIPTION OF DRAWINGS

[0026] The drawings accompanying the specification of this application form a part thereof, serve to provide further understanding of the present disclosure, and together with the description of the exemplary embodiments of the present disclosure and their description serve the purpose of explaining the present disclosure. In the drawings: Figure 1 The flowchart of the arc high resistance grounding fault modeling method in the present disclosure embodiment 1.

[0027] Figure 2 The equivalent resistance schematic diagram of the arc high resistance grounding fault model in the present disclosure embodiment 1.

[0028] Figure 3A schematic diagram of the series connection of the dynamic arc model and the nonlinear resistance of the grounding medium in Embodiment 1 of the present disclosure.

[0029] Figure 4 A simulation schematic diagram of the dynamic arc model in Embodiment 1 of the present disclosure.

[0030] Figure 5 A volt-ampere characteristic curve of the dynamic arc model in Embodiment 1 of the present disclosure.

[0031] Figure 6 A nonlinear change diagram of the nonlinear resistance model of the grounding medium in Embodiment 1 of the present disclosure.

[0032] Figure 7 A simulation schematic diagram of the nonlinear resistance model of the grounding medium in Embodiment 1 of the present disclosure.

[0033] Figure 8 A volt-ampere characteristic curve of the nonlinear resistance model of the grounding medium in Embodiment 1 of the present disclosure.

[0034] Figure 9 A volt-ampere characteristic curve of the arc light high resistance grounding fault model in Embodiment 1 of the present disclosure.

[0035] Figure 10 A comparison diagram of the arc waveform and the effect of the zero rest process of the dynamic arc model (a), the nonlinear resistance model of the grounding medium (b) and the arc light high resistance grounding fault model (c) in Embodiment 1 of the present disclosure.

[0036] Figure 11 A flowchart of the grounding fault analysis method based on the arc light high resistance grounding fault modeling method in Embodiment 2 of the present disclosure.

[0037] Figure 12 A comparison diagram of the volt-ampere characteristic curve of the arc light high resistance grounding fault model (a) and the arc light high resistance grounding experiment of the Wroclaw University of Technology (b) in Embodiment 2 of the present disclosure.

[0038] Figure 13 A comparison diagram of the voltage and current waveforms of the arc light high resistance grounding fault model (a) and the arc light high resistance grounding experiment of the Wroclaw University of Technology (b) in Embodiment 2 of the present disclosure.

[0039] Figure 14 A structural diagram of the arc light high resistance grounding fault modeling system in Embodiment 3 of the present disclosure. DETAILED DESCRIPTION

[0040] The present disclosure will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0041] The following detailed descriptions are exemplary and intended to provide further detailed explanation of this disclosure. Unless otherwise specified, all technical terms used in this disclosure have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this disclosure.

[0042] Example 1: like Figure 1 As shown, this disclosure provides a method for modeling arc flash high-resistivity grounding faults, the method comprising: S1 determines a dynamic arc model based on a combination of the Mayr arc model and the Cassie arc model; S2 determines the nonlinear resistance model of the grounding medium; S3 connects the dynamic arc model and the nonlinear resistance model of the grounding medium in series to obtain the arc high resistance grounding fault model.

[0043] It is understandable that the dynamic arc model is a Cassie-Mayr dynamic arc simulation model. Because after a fault occurs, regardless of whether the power distribution line is in direct contact with the grounding medium, as long as the power supply voltage is greater than the air gap breakdown voltage, an arc resistance will be formed. Its resistance value is related to the state of the electric arc, whether it is burning or extinguished. After the fault arc is generated, the arc channel connects the conductor and the grounding medium together, and the fault current flows into the ground through the arc channel. During this process, the nonlinear resistance of the grounding medium... R var The nonlinear characteristics of the dielectric are simulated using the solid-state electrical breakdown principle. Its equivalent time-varying resistance changes with the arc voltage, and the dynamic resistance... and grounding dielectric resistance Essentially, they are all nonlinear dynamic resistors. Therefore, the arc-induced high-resistance grounding fault resistance of high-resistance arc-induced grounding faults... From dynamic resistance R arc and nonlinear resistance of grounding medium R var It is connected in series and its equivalent resistance changes dynamically with the arc current and arc voltage. A schematic diagram of its equivalent resistance is shown below. Figure 2 As shown. The dynamic resistance... R arc and nonlinear resistance of grounding medium R var These correspond to the air gap breakdown process and the fault current breakdown process in the solid dielectric of a high-resistivity arc grounding fault, respectively, and have clear physical significance.

[0044] In one embodiment, the S1 determines a dynamic arc model based on a combination of Mayr arc model and Cassie arc model, comprising: S11 establishes a Mayr arc model, the expression is as follows: (1) In formula (1), g is the arc conductivity of Mayr arc model, is the thermal inertia time constant of the arc, is the potential per unit length of the arc, is the arc current, is the arc energy loss constant; = R Mayr , R Mayr is the dynamic resistance of Mayr arc model.

[0045] In one embodiment, the S1 determines a dynamic arc model based on a combination of Mayr arc model and Cassie arc model, comprising: S12 establishes a Cassie arc model, the expression is as follows: (2) In formula (2), ，g is the conductivity of Cassie arc model, is the arc time constant, is the constant arc voltage; = R Cassie , R Cassie is the dynamic resistance of Cassie arc model.

[0046] In one embodiment, the S1 determines a dynamic arc model based on a combination of Mayr arc model and Cassie arc model, comprising: S13 connects the Mayr arc model and Cassie arc model to build a dynamic arc model, the expression is as follows: (3) In formula (3), R Mayr is the dynamic resistance of Mayr arc model, R Cassie is the dynamic resistance of Cassie arc model, is the Sigmoid transition function with current as variable, R arcis the dynamic resistance of the dynamic arc model. Since the Mayr model and the Cassie model describe the arc characteristics in two different current ranges, respectively, the smooth connection of the arc characteristics in the two different current ranges can be made through a Sigmoid transition function.

[0047] In one embodiment, the transition function has an expression as follows: (4) In formula (4), the output range is between (0, 1), I represents the instantaneous value of the arc current, I 0 represents the transition current, and k represents the rate coefficient for controlling the change of the continuous function; wherein, k the larger the k is, the faster the change rate is when the arc current tends to zero, and the more obvious the transition boundary of the Mayr arc model and the Cassie arc model is. Formula (4) can avoid the sudden change from small current to large current.

[0048] It can be understood that the dynamic arc model is a Cassie-Mayr dynamic arc simulation model connected by the Mayr arc model and the Cassie arc model. The specific parameters of the dynamic arc model can be as shown in Table 1, and the volt-ampere characteristic curve is as shown in Figure 5 .

[0049] Table 1 Reference values of parameters of the dynamic arc model

[0050] In one embodiment, the S2 determines a grounding medium nonlinear resistance model, and the expression is as follows: (5) In formula (5), R var is the grounding medium nonlinear resistance, R 1 is the inherent resistance of the grounding medium, u is the voltage of the grounding medium, u 1、 u 2 is a constant, k 1、 k 2 is a to-be-determined coefficient. The inherent resistance of the grounding medium refers to the resistance that originally exists before the grounding medium is affected by the outside world. The voltage u of the grounding medium refers to the voltage drop between the two ends of the grounding medium; the grounding medium nonlinear resistance R var is the resistance value of the grounding medium, and the resistance value presents a nonlinear trend.

[0051] As shown in Figure 6 , when u is small (less than ), the R var is directly taken as R 1, that is, only the inherent resistance of the grounding medium is considered. When u increases, the grounding medium is ionized, R var decreases with the increase of the voltage, and the fault point resistance also decreases with the increase of the voltage; the greater 1 is and the smaller 2 is, the more obvious the nonlinear characteristics of the fault point resistance are. However, when the external electric field continues to increase and exceeds a certain limit (u2 ), the grounding medium is "broken down", and the equivalent resistance value of the grounding medium becomes very small and can be approximated as 0, so R var is taken as 0. Therefore, the voltage u of the grounding medium has different values in different ranges, and the resistance R var correspondingly has different trends, R var and thus presents obvious nonlinear changes.

[0052] The nonlinear changes of the resistance R var of the grounding medium are determined by the solid breakdown principle of the medium. The conductance of the solid medium mainly includes ion conductance and electronic conductance. When the external electric field is low, the ion conductance mainly works, and the voltage and the current are in a linear relationship, R var , that is, the linear resistance; when the external electric field gradually increases, the medium is ionized, R var decreases with the increase of the voltage, and the fault point resistance also decreases with the increase of the voltage, k 1 is greater and k 2 is smaller, the more obvious the nonlinear characteristics of the fault resistance are; when the external electric field continues to increase and exceeds a certain limit, the medium is "broken down", and the conductance value is already very large and the equivalent resistance value is very small, which can be approximated as 0.

[0053] In order to more intuitively display, the equivalent simulation model and the voltage-current characteristics of the nonlinear resistance model of the grounding medium are displayed below through Figure 7 , Figure 8 . Figure 7 An equivalent simulation model for displaying the nonlinear resistance model of the grounding medium, wherein R 1 is set to 1000Ω, u 1 is set to 100V, u2 is set to 400V, thus the simulated volt-ampere characteristic curve is shown in Figure 8 As shown in the above declaration, R 1、 u 1、 u 2 are all example values, not limiting R 1、 u 1、 u 2.

[0054] In one embodiment, the arc high resistance grounding fault model is expressed as follows: (6) In formula (6), R f is the arc high resistance grounding fault resistance, R arc is the dynamic resistance of the dynamic arc model, R var is the nonlinear resistance of the grounding medium. Formula (6) is obtained by connecting the dynamic arc model shown in formula (3) and the nonlinear resistance model of the grounding medium shown in formula (5) in series, so as to construct the arc high resistance grounding fault model based on the series connection of nonlinear dynamic resistance, and the equivalent model is shown in Figure 3 . The arc resistance changes following the dynamic change of the arc current, and the grounding medium resistance changes following the dynamic change of the arc voltage.

[0055] The volt-ampere characteristic curve of the arc high resistance grounding fault model is shown in Figure 9 As shown in Figure 10 , for the dynamic arc model, the nonlinear resistance model of the grounding medium, and the arc high resistance grounding fault model, the effects of the arc waveforms and the zero process under the three models are compared.

[0056] Through Figure 9 , Figure 10As can be seen from the waveforms, the three arc light high resistance grounding fault models can all reflect the non-linear distortion of arc current to some extent, but there are still obvious differences in the shape of non-linear distortion, zero period length, symmetry and other factors. Compared with the dynamic arc model and the grounding medium nonlinear resistance model, the arc light high resistance grounding fault model has a significant zero-hibernation phenomenon at the zero-crossing point, which corresponds to the extinction and reignition characteristics of the arc. At the same time, considering the influence of the grounding medium, the arc resistance decays to a relatively stable value with the increase of voltage and current after the zero-crossing point. Through comparison, it can be seen that compared with the dynamic arc model and the grounding medium nonlinear resistance model, the arc light high resistance grounding fault model can more accurately reproduce the current amplitude, phase and other characteristics of the actual arc light high resistance grounding fault.

[0057] Embodiment 2 As Figure 11 shown, the embodiment 2 of the present disclosure provides an arc light high resistance grounding fault analysis method based on the arc light high resistance grounding fault analysis method provided in embodiment 1, the method comprising: A1 inputting arc parameters into the arc light high resistance grounding fault model to obtain arc light high resistance grounding fault resistance at the fault point, and simulating to obtain voltage-current characteristic curve, voltage and current waveform and other characteristics at the fault point based on the arc light high resistance grounding fault resistance.

[0058] In one embodiment, the arc light high resistance grounding fault model is obtained by the arc light high resistance grounding fault modeling method provided in embodiment 1 or any one of the embodiments.

[0059] In one embodiment, the arc parameters are corresponding values of the parameters included in the arc light high resistance grounding fault model.

[0060] In one embodiment, the arc parameters include the parameters of the dynamic arc model (as shown in Table 1) and the parameters of the grounding medium nonlinear resistance model (as shown in Table 2). R 1、 u 1、 u 2、 k 1、 k 2).

[0061] In one embodiment, the parameters of the dynamic arc model include the parameters of the Mayr arc model, the parameters of the Cassie arc model and the parameters of the transition function.

[0062] ​It can be understood that the characteristics such as the voltage-current characteristic curve, the voltage-current waveform and the like of the fault point obtained by means of simulation can reproduce or analyze the current amplitude, phase and the like of the actual arc high resistance grounding fault. The real fault point resistance is simulated and reproduced by the arc high resistance grounding fault resistance. The reproduction or analysis of the current amplitude, phase, resistance and the like by the characteristics such as the voltage-current characteristic curve, the voltage-current waveform and the like is the prior art, and will not be described here.

[0063] As shown in Figure 12 To further verify whether the arc high resistance grounding fault model can accurately reproduce the actual arc high resistance grounding fault characteristics, the voltage-current characteristic curve of the arc high resistance grounding fault model is compared with the arc high resistance grounding experiment of the Poland Wroclaw University of Technology. It can be seen that the voltage-current characteristic curves of the two are basically consistent, and the waveforms are basically symmetrical near the zero-crossing point.

[0064] As shown in Figure 13 The voltage-current waveform of the arc high resistance grounding fault model is compared with the arc high resistance grounding experiment of the Poland Wroclaw University of Technology. It can be seen that the voltage-current waveforms of the two are basically consistent.

[0065] The above-mentioned arc high resistance grounding experiment of the Poland Wroclaw University of Technology, the reference source: China Electrical Engineering Journal, Vol. 34, No. 22, article number—“0258-8013(2014)22-3815-09”, article name—“Analysis and detection of high resistance grounding fault voltage-current characteristics of distribution network”, author: Wang Bin, Geng Jianzhao, Dong Xinzhou (National Key Laboratory of Power System and Power Generation Equipment Control and Simulation (Department of Electrical Engineering and Applied Electronics Technology, Tsinghua University), the relevant website is: https: / / kns.cnki.net / kcms2 / article / abstract?v=5ykJdPmCibL1lhbfhWJ3XrqJRzn_qKU_qIEn3qepjYMuBhltgT_humgVwEipZh9udcYP90jG75bab2Sh4nmJVfjTbinzPTGq9aRdB0mYz-uuj-x50zzMiPGhpQYJMWNe9HAVIkAmfB1_MdcbRE2LbnvQyMbIOrvtjNX2F4T__5ND557D5oWk-A==&uniplatform=NZKPT&language=CHS.

[0066] Embodiment 3 As shown in Figure 14 Embodiment 3 of the present disclosure provides an arc high resistance grounding fault modeling system, the system comprises: Arc model module 100: used for S1 to determine a dynamic arc model based on a combination of Mayr arc model and Cassie arc model; Ground model module 200: used for S2 to determine a ground medium nonlinear resistance model; Fault resistance model 300: used for S3 to connect the dynamic arc model and the ground medium nonlinear resistance model in series to obtain an arc high resistance grounding fault model.

[0067] In implementation, the arc model module 100, the ground model module 200, and the fault resistance model 300 can be respectively used to perform S1, S2, and S3 in Embodiment 1. It is worth noting that the system described in Embodiment 3 is only a system implementation of the arc high resistance grounding fault modeling method, and does not limit the arc high resistance grounding fault modeling method to rely on the system described in Embodiment 3.

[0068] Embodiment 4: In Embodiment 4 of the present disclosure, a computer readable storage medium is provided, which stores a computer program. When the computer program is executed by a processor, the arc high resistance grounding fault modeling method described in Embodiment 1 is implemented, or the ground fault analysis method described in Embodiment 2 is implemented, or the arc high resistance grounding fault modeling system described in Embodiment 3 is implemented.

[0069] The computer readable storage medium includes volatile or non-volatile, removable or non-removable media implemented in any method or technology for storing information such as computer readable instructions, data structures, computer program modules, or other data. Computer readable storage media include, but are not limited to, RAM (Random Access Memory), ROM (Read-Only Memory), EEPROM (Electrically Erasable Programmable read only memory), flash memory or other memory technology, CD-ROM (Compact Disc Read-Only Memory), digital versatile disc (DVD) or other optical disc storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and can be accessed by a computer.

[0070] Embodiment 5: In Embodiment 5 of the present disclosure, an electronic device is provided, which includes a processor and a memory. The processor is configured to execute a computer program stored in the memory to implement the arc high resistance grounding fault modeling method described in Embodiment 1.

[0071] Based on such understanding, the disclosure implements all or part of the processes in the above-mentioned embodiment methods, and can also be completed by instructing related hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and when the computer program is executed by a processor, the steps of each method embodiment described above can be implemented. The computer program includes computer program code, which can be in the form of source code, object code, an executable file, or some intermediate form. The computer-readable medium can include any entity or device capable of carrying computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, and read-only memory (ROM).

[0072] Those skilled in the art should understand that the embodiments of the disclosure can be provided as a method, a system, or a computer program product. Therefore, the disclosure can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the disclosure can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0073] The disclosure is described with reference to flowcharts and / or block diagrams of methods, devices (systems) and computer program products according to embodiments of the disclosure. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to produce a machine, so that the instructions executed by the computer or other programmable data processing devices produce a device that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks Figure 1 The functions specified in one or more flows and / or blocks

[0074] These computer program instructions can also be stored in a computer-readable memory that can guide the computer or other programmable data processing devices to work in a specific way, so that the instructions stored in the computer-readable memory produce a manufactured product including instruction devices that implement the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks Figure 1 The functions specified in one or more flows and / or blocks

[0075] These computer program instructions can also be loaded into a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks Figure 1 one or more flowcharts and / or blocks

[0076] In the description of the present specification, the description of the terms "one embodiment", "an example", "a specific example" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0077] In summary, the arc high resistance grounding fault modeling method, analysis method, system and medium provided by embodiments 1-5 of the present disclosure can accurately simulate the nonlinear characteristics of arc high resistance fault by considering the nonlinearity of arc and increasing the nonlinearity of grounding medium resistance, avoiding the defects of existing arc models that do not fully consider the nonlinearity of grounding medium, and taking into account the air gap breakdown process between the conductor and the grounding medium, so as to meet the needs of full working conditions. The arc high resistance grounding fault model based on nonlinear dynamic resistance series provided by the present disclosure can serve as a universal arc fault model covering full working conditions, overcoming the technical defects that existing single arc models cannot cover full working conditions.

[0078] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present disclosure and not to limit them, although the present disclosure has been described in detail with reference to the above embodiments, those skilled in the art should understand that: the specific embodiments of the present disclosure can still be modified or replaced, without departing from the spirit and scope of the present disclosure. Any modification or equivalent replacement thereof should be covered within the protection scope of the claims of the present disclosure.

Claims

1. A method of modeling arc high resistance ground faults, the method comprising: The method comprises: determining a dynamic arc model based on combination of Mayr arc model and Cassie arc model; determining a grounding medium nonlinear resistance model; connecting the dynamic arc model and the grounding medium nonlinear resistance model in series to obtain an arc high resistance grounding fault model.

2. The arc high resistance ground fault modeling method of claim 1, wherein, The determination of the dynamic arc model based on combination of Mayr arc model and Cassie arc model comprises: establishing a Mayr arc model, the expression of which is as follows: (1) in formula (1), g is the arc conductivity of the Mayr arc model, is the thermal inertia time constant of the arc, is the arc potential per unit length, is the arc current, is the arc energy loss constant; = R Mayr , R Mayr is the dynamic resistance of the Mayr arc model.

3. The arc high resistance ground fault modeling method of claim 1, wherein, The determination of the dynamic arc model based on combination of Mayr arc model and Cassie arc model comprises: establishing a Cassie arc model, the expression of which is as follows: (2) In formula (2) ，g is the conductivity of the Cassie arc model, is the arc time constant, is the constant arc voltage; = R Cassie , R Cassie is the dynamic resistance of the Cassie arc model.

4. The arc high resistance ground fault modeling method of claim 1, wherein, The determination of the dynamic arc model based on combination of Mayr arc model and Cassie arc model comprises: connecting the Mayr arc model and the Cassie arc model to construct a dynamic arc model, the expression of which is as follows: (3) in formula (3), R Mayr is a dynamic resistance for the Mayr arc model, R Cassie is a dynamic resistance for the Cassie arc model, is a Sigmoid transition function with current as variable, R arc is a dynamic resistance for the dynamic arc model.

5. The arc high resistance grounding fault modeling method of claim 4, wherein, Transition function The expression of the transition function is as follows: (4) In formula (4), The output range is between (0, 1), I denotes the instantaneous value of the arc current, I 0 represents the transition current, k denotes the rate coefficient that controls the rate of change of the continuous function; wherein, k the greater, the faster the rate of change when the arc current tends to zero, the more pronounced the transition limit of the Mayr arc model and the Cassie arc model.

6. The arc high resistance ground fault modeling method of claim 1, wherein, The determination of the grounding medium nonlinear resistance model has the expression as follows: (5) In formula (5), R var R is the inherent resistance of the grounding medium, u is the voltage of the grounding medium, R 1 is the inherent resistance of the grounding medium, u is the voltage of the grounding medium, u 1、 u 2 is a constant, k 1、 k 2 is a constant.

7. The arc high resistance ground fault modeling method of claim 1, wherein, The arc high resistance grounding fault model has the expression as follows: (6) in formula (6), R f is an arc high resistance grounding fault resistance, R arc is a dynamic resistance of the dynamic arc model, R var is a grounding medium nonlinear resistance.

8. An arc high resistance ground fault analysis method characterized by, The method comprises: inputting arc parameters into the arc high resistance grounding fault model to obtain an arc high resistance grounding fault resistance of a fault point, and simulating to obtain a voltage-current characteristic curve and voltage and current waveforms of the fault point based on the arc high resistance grounding fault resistance; The arc high resistance grounding fault model is obtained by the arc high resistance grounding fault modeling method of any one of claims 1-7. The arc parameters are corresponding values of parameters included in the arc high resistance grounding fault model.

9. An arc high resistance ground fault modeling system, characterized by, The system comprises: an arc model module for determining a dynamic arc model based on combination of Mayr arc model and Cassie arc model; a grounding model module for determining a grounding medium nonlinear resistance model; a fault resistance module for connecting the dynamic arc model and the grounding medium nonlinear resistance model in series to obtain an arc high resistance grounding fault model.

10. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, and the computer program is executed by the processor to implement the method of any one of claims 1-8.

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