244 / 2018-09-24 19:19:42

Research on Contamination Deposition of Roof Insulator in Electric Fields

roof insulator,contamination deposition,high-speed airflow,charged particles,finite element analysis

With the rapid development of economy, high-speed railway has been spread across many provinces and regions in china. As an important high-voltage device to guarantee the safety of trains, the roof insulator faces a variety of challenges brought by complex climate and environment. When the train is running at high speed, high-speed wind is generated near the train, and the relative speed of roof insulator and air is much higher than the natural wind speed. Contamination particles around the roof insulator will be affected by high-speed airflow. At the same time, accompanying with the discharge of electric arc near the contact network, a large number of electric ions will be generated, which absorbed by contamination particles around the roof insulator to form charged particles. In electric fields, the movement of these charged particles will change, thus affecting the contamination deposition of the roof insulator, but existing numerical methods for analyzing the contamination deposition of roof insulator have not considered the effects of electric field. The methods usually used to study the contamination deposition of roof insulator in electric fields are test measurement at present. However, it is difficult to simulate the high-speed airflow environment, and high requirements are adopted for the test equipment, operation methods and sample quantities, so that manual test wastes lots of manpower and time. This paper adopted finite element (FE) analysis to build the model of contamination deposition of roof insulator combining the action of electric fields and airflow, considering the influence of electric fields on charged contamination particles. Based on the model, the influence of airflow speed which is considered to be higher than natural wind speed and the influence of particle size on contamination deposition of roof insulator were analyzed. The results are as follows. Firstly, the amount of contamination on the windward and leeward surfaces is more than that on the side of roof insulator under the action of electric fields, and the total amount of insulator contamination is more than that without considering the effect of electric fields. Secondly, the amount of roof insulator contamination and the influence of electric fields on contamination deposition decreases with the increase of airflow speed. When the airflow speed is high, the total amount of roof insulator contamination changes smaller than that without considering the effect of electric fields. Thirdly, the amount of roof insulator contamination increases and then decreases with the increase of particle size, and the influence of electric fields on contamination deposition of roof insulator decreases with the increase of particle size. When the particle size is large, the total amount of roof insulator contamination is not different from that without considering the action of electric fields. At last, this paper carried out the pollution test of roof insulator relying on the artificial wind tunnel and air-fog chamber, which verified the correctness of the simulation model. The above research can provide theoretical basis for the optimal design and prevention for pollution of high-speed train roof insulator, which has a great significance in engineering practice.