Study On Ultraviolet On-line Monitoring And Condition Assessment System For Insulator

With the development of national economy, promotion of power capacity and transmission voltage level, insulator flashover takes place frequently, which causes enormous economic losses. It is necessary to evaluate the contamination state of insulator accurately and take necessary measures quickly before flashover takes place. With on-line monitoring technique, we can achieve the real-time assessment of contamination level and early warning of insulator flashover. Therefore, on-line monitoring technique changes insulator maintaining mode, namely converting scheduled maintenance by condition-based maintenance.In order to achieve real-time assessment of insulator contamination state, Electrical Engineering Institute of Chongqing University have developed a kind of on-line monitoring set, which is based on ultraviolet(UV) pulse detection technology. In this paper, the previous system has been improved by assembling shadow shield and the camera module. In laboratory tests, we obtain various UV pulse data under extreme environment condition and establish an evaluation model of insulator contamination state based on the fuzzy comprehensive evaluation. This model focus on the influence of insulator shape, environmental condition and contamination property on the contamination accumulation of the insulator surface. Meanwhile, we utilize LabVIEW software to build up the evaluation algorithm. The evaluation software has multiple functions such as password landing, user management, parameter setting, data storing, data inquiring.The main works of this thesis include the following areas:â‘ The flashover mechanism of contaminated insulator is analyzed according to relevant references. The UV on-line monitoring set is improved by assembling shadow shield and the camera module. Meanwhile, debugging hardware system has been completed.â‘¡The influence factors of insulator contamination state are analyzed. Combining with data collected from the terminals in field, the evaluation factors and the hierarchy between factors are determined. The constant weight of each factor is determined by fuzzy analytic hierarchy process (FAHP) and the membership function of each factor is determined by the method of undetermined coefficient.â‘¢LabVIEW software is used to actualize the evaluate model and the early warning system of insulator contamination level. This system can automatically receive data from monitoring set and analyze monitoring data. The real-time state of insulator is displayed on the system screen. If the state of insulator is higher than the warning value, the system will alarm automatically.â‘£The laboratory tests are executed on the composite insulator FXBW-110/70 and the porcelain insulator XP-160. The data of ultraviolet pulses are collected under different operating voltages, contamination levels, and with the presence of faulty insulators. The tests verify the reliability of system and provide reference foundation to the establishment of evaluation criteria.