CN103400019B - AC fault electric arc emulation mode based on Matlab/Simulink - Google Patents

Abstract

The present invention relates to a kind of AC fault arc simulation method based on Matlab/Simulink, comprising the following steps: 1) Based on the mathematical model of DC arc, according to the relationship between the static characteristics and dynamic characteristics of the arc, the mathematical model of the dynamic volt-ampere characteristic of the arc is proposed Assumption, thereby establishing the dynamic mathematical model of the low-voltage series AC fault arc in the resistive system and the resistive-inductive system; 2) Through the analysis of the dynamic mathematical model of the AC fault arc, determine the combustion process of the AC fault arc; 3) According to the AC fault arc 4) Run the simulation model of AC fault arc in the resistive system and resistive-inductive system, and output the simulation results of the simulation model. Compared with the prior art, the invention has the advantages of high simulation precision, accurate analysis of arc dynamic characteristics, strong versatility and the like.

Description

Simulation Method of AC Fault Arc Based on Matlab/Simulink

technical field

The invention relates to an AC fault arc simulation method, in particular to an AC fault arc simulation method based on Matlab/Simulink.

Background technique

With the continuous development of social economy, the number of fire accidents has also increased year-on-year with urban construction and social development. Due to long-term operation and external force, the insulation of the line inside the house or inside the household appliance will cause aging, shedding or even breakage of the line insulation. This will lead to the generation of series and parallel arcs. When the arc burns, it will generate local high temperature and easily ignite the surrounding combustibles and cause a fire. Therefore, perfecting the dynamic model of the low-voltage arc helps us better understand the combustion process of the arc, and also provides more ways for the detection of the low-voltage arc.

The arc dynamic model has been the object of intensive research by many scientists for a long time, including two research methods. One method is to study its physical-mathematical model, that is, to study the physical process of arc combustion, write differential equations according to the law of energy conservation and the characteristics of arc column plasma, and solve the mathematical expression of arc. ) model and Mayer model. Another method is to study the purely mathematical model of the arc, which is the black box model. It regards the arc as a component with both ends, and only describes the external characteristics of the arc when it burns, represented by the Beland model and Matthews model. However, the existing Mayr model cannot accurately describe the physical process of the arc burning, so it is different from the actual arc experimental data; the Matthews model regards the voltage at both ends of the arc as a constant when the arc is burning, and when the arc is actually burning, the two arcs are different. The voltage at the terminal is not constant, it is a function of the current value passing through the line, so the Matthews model cannot accurately simulate the changes in the voltage and current at both ends of the arc when the AC arc is ignited.

Contents of the invention

The purpose of the present invention is to provide a Matlab/Simulink-based AC fault arc simulation method with high simulation accuracy, accurate analysis of arc dynamic characteristics, and strong versatility in order to overcome the above-mentioned defects in the prior art.

The purpose of the present invention can be achieved through the following technical solutions:

A kind of AC fault arc simulation method based on Matlab/Simulink, is characterized in that, comprises the following steps:

1) Based on the mathematical model of the DC arc, according to the relationship between the static characteristics and the dynamic characteristics of the arc, a hypothesis is put forward for the mathematical model of the dynamic volt-ampere characteristics of the arc, so as to establish the dynamics of the low-voltage series AC fault arc in the resistive system and the resistive-inductive system mathematical model;

2) Determine the combustion process of the AC fault arc by analyzing the dynamic mathematical model of the AC fault arc;

3) According to the combustion process and dynamic mathematical model of AC fault arc, the simulation model of AC fault arc is established through Matlab/Simulink software;

4) Run the simulation model of the AC fault arc in the resistive system and the resistive-inductive system, and output the simulation results of the simulation model.

Described step 1) is specifically:

11) The mathematical model of DC arc can be expressed by Ayrton's empirical formula as follows:

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; B</span>}}{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}}$

In the formula, U _a is the voltage at both ends of the DC arc, I _a is the DC arc current, and A and B are constants;

12) According to the relationship between the static and dynamic characteristics of the arc and the Ayrton empirical formula of the static characteristics, the mathematical model of the dynamic volt-ampere characteristics of the arc is proposed as follows:

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; a</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; b</span>}}{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; c</span>}}$

In the formula, u _a is the voltage at both ends of the AC arc, i _a is the AC arc current, and a, b, and c are constants;

13) When the system is a resistive system, set the load resistance as R;

Let the input AC voltage source be u _s (t), and

u _s (t)=U _m sinωt, where U _m is the maximum value of AC, ω is the frequency of AC

The dynamic mathematical model of the low-voltage series AC fault arc in the resistive system is as follows:

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&omega;t</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; a</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; b</span>}}{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; c</span>}}$

The obtained arc current i _a and arc voltage u _a are as follows:

${\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&omega;t</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; a</span>}<span\; class="notranslate">\; +</span>\sqrt{{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; a</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&omega;t</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ac</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&omega;t</span>}<span\; class="notranslate">\; )</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; R</span>}}$

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; a</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; b</span>}}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&omega;t</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; a</span>}<span\; class="notranslate">\; +</span>\sqrt{{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; a</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&omega;t</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ac</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; c</span>}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&omega;t</span>}<span\; class="notranslate">\; )</span>}}$

When the system is a resistive-inductive system, set the load impedance as z=R+jωL;

The dynamic mathematical model of the low-voltage series AC fault arc in the resistive-inductive system is as follows:

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&omega;t</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; L</span>}\frac{{\mathrm{<span\; class="notranslate">\; di</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}}{\mathrm{<span\; class="notranslate">\; dt</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; a</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; b</span>}}{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; c</span>}}$

Using the Euler method to solve the numerical solution of the above differential equation, the recursive formula of the arc current is obtained:

${\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; h</span>}}{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; max</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&omega;t</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}}\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; a</span>}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; b</span>}}{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; )</span>$

where h is the time step.

Described step 2) is specifically:

21) The combustion process of the AC series arc in the resistive system: In the positive half cycle of the power supply voltage, when the voltage at both ends of the contact increases with the increase of the power supply voltage, when the breakdown voltage is reached, the two ends of the arc are Combustion begins after the arc is broken down. At this time, the arc voltage changes with the arc current. When the arc current decreases to zero, the voltage at both ends of the arc rises to the arc-extinguishing voltage. At this time, the arc current enters the "zero rest" state. The arc current is zero, and the voltage across the contacts is equal to the power supply voltage in the circuit; in the negative half cycle of the power supply voltage, the generation and extinguishment of the arc repeats the previous process, and the directions of the arc current and voltage are opposite to those before;

22) Combustion process of AC series arc in resistive-inductive system: Due to the existence of inductance, the arc-extinguishing voltage of the arc is smaller than the power supply voltage, so when the arc current crosses zero, the voltage at both ends of the arc will suddenly change to the power supply voltage. The ignition will change with the power supply voltage, and the current will not change suddenly after re-ignition.

The simulation model of setting up the AC fault arc by Matlab/Simulink software is specifically:

The voltmeter and ammeter in the model are used to collect the arc voltage and current signals, the switch is used to determine the generation and extinguishment of the arc, the controllable voltage source is used to output the voltage drop of the arc, and the controller is based on the collected arc voltage and current signals. Control the closing and opening of the switch, calculate and control the output voltage of the controllable voltage source through the dynamic volt-ampere characteristics of the arc, and adjust the breakdown voltage and arc-extinguishing voltage of the arc by setting the distance between the arc electrodes.

The simulation process in step 4) needs input voltage, load and arc length parameters.

The simulation results of the simulation model in step 4) include the voltage at both ends of the AC fault arc of the resistive system and the resistive-inductive system and the current passing through the line.

Compared with the prior art, the present invention has the following advantages:

1) The simulation accuracy is high. Compared with the existing Mayr model and Matthews model, the present invention is closer to the actual arc data in both arc voltage and arc current.

2) Accurately analyze the dynamic characteristics of the arc. The Simulink arc mathematical simulation model established by the present invention is a mathematical model established according to the combustion process of the actual arc, which can accurately calculate and analyze the dynamic characteristics of the arc.

3) Strong versatility. The resistive system and resistive-inductive system targeted by the present invention basically cover common civil and industrial loads, and have certain versatility.

4) the present invention provides an experimental simulation platform for the research of AC fault arc, and this experimental simulation platform adopts general-purpose Matlab/Simulink software, utilizes simulation result to further study the concrete characteristic of the voltage of AC fault arc and current, is AC fault arc The detection has established a theoretical and experimental basis.

Description of drawings

Figure 1 is a circuit diagram of a series AC fault arc system;

Fig. 2 is the arc voltage and current waveform in the resistive system of the arc model established by the present invention;

Fig. 3 is the arc voltage and current waveform in the resistance-inductive system of the arc model established by the present invention;

Fig. 4 is a simulation model diagram of series AC fault arc;

Fig. 5 is a comparison diagram of the simulated current waveform and the actual data of the arc module in the resistive system;

Figure 6 is a comparison diagram between the simulated voltage waveform of the arc module and the actual data in the resistive system;

Fig. 7 is a comparison diagram between the simulated current waveform and the actual data of the arc module in the resistive-inductive system;

Fig. 8 is a comparison diagram between the simulated voltage waveform of the arc module and the actual data in the resistive-inductive system.

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example

The simulation calculation and experimental verification comparison of the present invention all adopt the Chinese industrial AC power, that is, the AC frequency ω=50Hz. In the AC single-phase resistive system shown in Figure 1, let the power supply voltage R=56.5Ω, the current and the voltage waveform at both ends of the series AC fault arc in the resistive system can be calculated numerically as shown in Figure 2.

In the AC single-phase resistive-inductive system shown in Figure 1, let the power supply voltage z=56.5+j22Ω, the current and the voltage waveform at both ends of the series AC fault arc in the resistance-inductive system can be obtained through numerical calculation, as shown in Figure 3.

Fig. 4 is the mathematical model of AC fault arc established according to the present invention, and the simulation model of AC fault arc built in Matlab/Simulink software. The voltmeter 5 and ammeter 6 in the model are used to collect the arc voltage and current signals, the switch 4 is used to determine the generation and extinguishment of the arc, the controllable voltage source 7 is used to output the voltage drop of the arc, and the controller 3 collects the incoming arc voltage and current signal to control the closing and opening of the switch 4, and calculate and control the output voltage of the controllable voltage source through the dynamic volt-ampere characteristics of the arc, and adjust the breakdown voltage and extinguishment of the arc by setting the distance between the arc electrodes. The magnitude of the arc voltage, where 1 is the input terminal and 2 is the output terminal.

Implementation mode of AC single-phase resistive system:

Establish a series AC fault arc test resistive system as shown in Figure 1, so that the power supply voltage Load R=56.5Ω, the arc generator includes a fixed electrode and a moving electrode according to the standard of UL1699, wherein the fixed electrode is a copper rod, the moving electrode is a graphite rod with a diameter of 6.4mm, and the arcing end of the carbon rod Sharpen, the distance between the two ends of the arc is 0.2mm during the experiment, and the voltage and current data of the arc are measured. At the same time, Matlab/Simulink software is used to simulate the arc module shown in Figure 4 under the same conditions, and the voltage and current waveforms of the series AC fault arc in the resistive system are compared with the actual waveforms as shown in Figure 5 and Figure 6, respectively.

Implementation mode of AC single-phase resistive-inductive system:

Suppose the power supply voltage in the resistive-inductive system of the series AC fault arc test shown in Figure 1 The load z=56.5+j22Ω, the voltage and current data of the arc are measured in the experimental platform. At the same time, Matlab/Simulink software is used to simulate the arc module shown in Figure 4 under the same conditions, and the voltage and current waveforms of the series AC fault arc in the resistive-inductive system can be compared with the actual waveforms as shown in Figure 7 and Figure 8, respectively.

The measured current and voltage data of the 0.15mm series arc in the pure resistive system and the simulation data of the Matthews arc model, the Mayr arc model and the model established by Matlab/Simulink software are imported into Matlab for FFT harmonic analysis , its harmonics are mainly odd harmonics, compare the analysis data list as Table 1. It can be seen that the model established in this paper is the closest to the actual arc data in terms of harmonic composition.

Table 1

Claims (4)

1. the AC fault electric arc emulation mode based on Matlab/Simulink, is characterized in that, comprise withLower step:

1) Mathematical Modeling based on direct-current arc, according to the relation of static characteristic of arc and dynamic characteristic, to moving of electric arcThe Mathematical Modeling of state C-V characteristic proposes hypothesis, thereby sets up the low-voltage series connection in resistive system and resistance sense systemAC fault Arc dynamic mathematical model;

2), by the analysis to AC fault Arc dynamic mathematical model, determine the combustion process of AC fault electric arc;

3) according to the combustion process of AC fault electric arc and dynamic mathematical models, by Matlab/Simulink softwareSet up the simulation model of AC fault electric arc;

4) in resistive system and resistance sense system, move the simulation model of AC fault electric arc, and Output simulation mouldThe simulation result of type;

Described step 1) be specially:

11) Mathematical Modeling of direct-current arc can be expressed as follows by the empirical equation of Ayrton:

$U_a=A+\frac{B}{I_a}$

U in formula_aFor direct-current arc both end voltage, I_aFor direct-current arc electric current, A, B are constant;

12) according to the Ayrton empirical equation of the relation of static characteristic of arc and dynamic characteristic and static characteristic, to electric arcDynamically the Mathematical Modeling of C-V characteristic proposes to suppose that formula is:

$u_a=a+\frac{b}{i_a+c}$

U in formula_aFor alternating current arc both end voltage, i_aFor alternating current arc electric current, a, b, c are constant;

13), in the time that system is resistive system, establishing load resistance is R;

If the alternating-current voltage source of input is u_s(t), and

u_s(t)＝U_mSin ω t, wherein U_mFor alternating current maximum, ω are ac frequency

Low-voltage series connection AC fault Arc dynamic mathematical model in resistive system is as follows:

$U_m\sin \mathrm{\&omega;}t=i_{a}R+a+\frac{b}{i_a+c}$

The arc current i obtaining_aWith electric arc both end voltage u_aAs follows respectively:

$i_a\left(t\right)=\frac{U_m\sin \mathrm{\&omega;}t-cR-a+\sqrt{{(cR+a-U_m\sin \mathrm{\&omega;}t)}^2-4R(ac+b-{\mathrm{cU}}_m\sin \mathrm{\&omega;}t)}}{2R}$

$u_a\left(t\right)=a+\frac{2bR}{U_{m}sin\mathrm{\&omega;}t+cR-a+\sqrt{{(cR+a-U_{m}sin\mathrm{\&omega;}t)}^2-4R(ac+b-{\mathrm{cU}}_{m}sin\mathrm{\&omega;}t)}}$

In the time that system is resistance sense system, establishing load impedance is Z=R+j ω L;

In resistance sense system, low-voltage series connection AC fault Arc dynamic mathematical model is as follows:

$U_{m}sin\mathrm{\&omega;}t=i_{a}R+L\frac{{\mathrm{di}}_a}{dt}+a+\frac{b}{i_a+c}$

Obtain the recurrence formula of arc current by the numerical solution that Euler method solves the above-mentioned differential equation:

$i_a^{n+1}=i_a^n+\frac{h}{L}(U_m\sin \mathrm{\&omega;}t-i_a^{n}R-a-\frac{b}{i_a^n+c})$

Wherein h is time step;

Described step 2) be specially:

21) combustion process of AC series electric arc in resistive system: in the positive half period of supply voltage, work as contactThe voltage at two ends increases along with the rising of supply voltage, in the time reaching breakdown voltage, and the breakdown electric arc in electric arc two endsAfter take fire, now arc voltage changes along with the variation of arc current, in the time that arc current is reduced to zero,The voltage at electric arc two ends rises to blowout voltage, and now arc current enters " zero stops " state, and arc current is zero,The voltage at contact two ends equals the supply voltage in circuit; In supply voltage negative half-cycle, the generation of electric arc with put outThe repetition of going out process before, the direction of arc current and voltage is with contrary before;

22) combustion process of AC series electric arc in resistance sense system: due to the existence of inductance, the blow-out electricity of electric arcPressure is less than supply voltage, so in arc current zero passage moment, the voltage at electric arc two ends can suddenly change to supply voltage,If electric arc is not restriked, can change along with supply voltage, the after-current of restriking also can not be undergone mutation.

2. a kind of AC fault electric arc emulation mode based on Matlab/Simulink according to claim 1,It is characterized in that, described pass through Matlab/Simulink software to set up the simulation model of AC fault electric arc concreteFor:

Voltmeter in model and ammeter be used for gathering arc voltage and current signal, and switch is with deciding electric arcProduce and extinguish, controllable voltage source is exported the voltage drop of electric arc, controller according to gather come in electric arc voltage andCurrent signal, carrys out the closed and disconnected of gauge tap, and calculated and controlled by the dynamic C-V characteristic of electric arc canThe output voltage of control voltage source regulates breakdown voltage and the blow-out of electric arc simultaneously by the spacing of arc electrodes is setThe size of voltage.

3. a kind of AC fault electric arc emulation mode based on Matlab/Simulink according to claim 2,It is characterized in that described step 4) in simulation process need input voltage, load and arc length parameter.

4. a kind of AC fault electric arc emulation mode based on Matlab/Simulink according to claim 2,It is characterized in that described step 4) in the simulation result of simulation model comprise resistive system and resistance sense systemSystem AC fault electric arc two ends voltage and by the electric current of circuit.