塑壳断路器分断特性及其静态电弧仿真研究

发布时间：2018-11-17 11:33

【摘要】：塑壳断路器(MCCB)是一种负责接通、承载以及分断正常或非正常(短路电流)电流的一种低压电器保护设备。当塑壳断路器过载或者短路时,动、静触头快速分离,触头之间产生的电弧随着触头的分离而被拉长,在栅片的作用下电弧被分割成若干小短弧而趋向熄灭。然而,电弧具有极高的温度,长时间反复的燃烧会破坏断路器的开断性能,严重损害了断路器的电寿命,甚至会危及到整个电网的可靠运行。因此,研究塑壳断路器触头的分断特性以及电弧运动特性对于优化塑壳断路器灭弧系统具有重要的意义。本文围绕塑壳断路器触头分折特性及电弧的运动特性的研究主要包括以下内容：首先,基于激光位移传感器建立了一套可以对塑壳断路器分断时刻触头分断角速度、角位移进行非接触式测量的试验系统。利用所建立的试验系统分别对NM1-630S-3300系列额定10A、16A、25A塑壳断路器在12倍额定电流下触头分断的动态特性进行测量,得出不同型号的断路器其角位移是不同的。当额定电流增大时,触头平均角速度增大。第二,基于COMSOL Multiphysics有限元软件建立了栅片灭弧室中面向不规则导体的电-磁耦合瞬态建模方法,通过该模型分别求解了栅片灭弧室的稳态和瞬态响应过程。为对模型进行验证,建立了一套可以对栅片灭弧室灭弧效率直接进行测量和评估的测试系统,通过数控瞬时恒流源提供激励电流,利用不同空间位置分布的霍尔芯片,对断路器灭弧室内的磁感应强度进行直接测量,并对其灭弧效率进行计算。试验结果显示所建立的耦合模型可以较好预测栅片灭弧室中的磁通密度大小及其分布。在此基础上研究了不同磁导率和电导率对于灭弧室效率的影响。仿真结果表明,栅片灭弧效率随着栅片磁导率的增大而增加。进一步提高栅片的磁导率,其灭弧效率趋近饱和。当电导率处于较小值时,对栅片灭弧室的效率影响较小；进一步增大册片的电导率,其灭弧效率将会降低。提高灭弧栅片的电导率可以减小灭弧室内吹弧磁场和磁吹弧力的瞬态响应峰值,增大其瞬态响应时司。最后,基于Comsol Multiphysics有限元软件建立一套可以实现流场、电磁场、温度场耦合计算的静态电弧仿真模型。基于高速摄像机、短路实验系统、数据采集系统建立一套可以记录电弧从产生到熄灭的试验系统。从而可以从试验和仿真的方法研究电弧运动的动态特性,为灭弧室的优化设计提供试验、理论依据。本文利用所建立的试验系统和仿真系统研究塑壳断路器分断时刻触头分断的动态特性以及分断时刻静态电弧特性,并且得到相关的结果,对塑壳断路器灭弧系统的优化设计具有一定的指导价值。
[Abstract]:Plastic case Circuit Breaker (MCCB) is a low voltage electrical protection device which is responsible for switching on, carrying and breaking normal or abnormal (short circuit current) current. When the plastic case circuit breaker is overload or short circuit, the dynamic and static contacts are separated rapidly, the arc produced between the contacts is elongated with the separation of the contacts, and the arc is divided into several short arcs and tends to be extinguished under the action of the grid. However, the arc has a very high temperature, long time repeated combustion will destroy the breaker's breaking performance, seriously damage the circuit breaker's electrical life, and even endanger the whole power grid reliable operation. Therefore, it is of great significance to study the breaking characteristics and arc motion characteristics of the contact of the molded case circuit breaker for optimizing the arc extinguishing system of the plastic case circuit breaker. The main contents of this paper are as follows: firstly, based on the laser displacement sensor, a set of angular velocities can be established to break the contact at break time of the plastic case circuit breaker. An experimental system for non-contact measurement of angular displacement. By using the test system established, the dynamic characteristics of the contact breaking of the NM1-630S-3300 series of rated 10A / 16A / 25A plastic case circuit breakers under 12 times rated current are measured, and it is concluded that the angular displacement of different types of circuit breakers is different. When the rated current increases, the average angular velocity of the contact increases. Secondly, based on the COMSOL Multiphysics finite element software, an electric-magnetic coupling transient modeling method for irregular conductors in a grid interrupter is established. The steady-state and transient response processes of the gate interrupter are solved by the model. In order to verify the model, a testing system is established to measure and evaluate the arc-extinguishing efficiency of the grid interrupter directly. The excitation current is provided by the numerical control instantaneous constant current source, and the Hall chip with different spatial distribution is used. The magnetic induction intensity in the arc extinguishing chamber of circuit breaker is measured directly and the arc extinguishing efficiency is calculated. The experimental results show that the coupling model can be used to predict the flux density and its distribution in the grid interrupter. On this basis, the effects of different permeability and conductivity on the efficiency of the interrupter are studied. The simulation results show that the arc extinguishing efficiency increases with the increase of the permeability. Further increasing the permeability of the gate strip, the arc extinguishing efficiency is approaching saturation. When the conductivity is small, the efficiency of the gate interrupter will be less affected, and the arc extinguishing efficiency will be decreased when the conductivity of the sheet is increased. Increasing the electrical conductivity of the arc extinguishing gate can reduce the transient response peak of the arc blowing magnetic field and the magnetic arc blowing force in the interrupter and increase the transient response time of the arc extinguishing gate. Finally, based on Comsol Multiphysics finite element software, a set of static arc simulation model is established, which can realize the coupling calculation of flow field, electromagnetic field and temperature field. Based on high speed camera, short circuit experiment system and data acquisition system, a set of test system can record arc from generation to extinction. Therefore, the dynamic characteristics of arc motion can be studied from the methods of experiment and simulation, and the theoretical basis for the optimum design of the interrupter can be provided. In this paper, the dynamic characteristics and static arc characteristics of the contact at break time of the molded case circuit breaker are studied by using the established test system and simulation system, and the relevant results are obtained. It has certain guiding value for the optimum design of arc extinguishing system of molded case circuit breaker.
【学位授予单位】：温州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM561

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