Research On Infrared Detection Blind Area And Diagnosis Strategy Of High-Voltage Porcelain Insulators

Under the long-term effects of electrical and mechanical loads and poor natural conditions,insulators may produce low or zero value insulators(i.e.insulators deterioration),which poses a major risk to the safety and stability of the power grid operation.Hence,the deterioration detection of insulators has traditionally been a focus in the inspection of power system equipment.At present,however,the method for such detection is still restricted to manual test of poor safety and low accuracy with a must of power outage for maintenance,struggling to meet the requirements of the smart grid on equipment status diagnosis.Under this backdrop,infrared thermal image technology,featuring non-contact and high precision,becomes a development direction of insulator deterioration detection.Nonetheless,more efforts shall be strengthened on the new technology given its theoretical weakness and low accuracy.To this end,the paper conducts a research from the following aspects:1.In order to solve false negative problems of the insulator detection,based on the△-Y transformation and the electric network voltage distribution calculation method of insulator strings,the paper proposes a method to compute the blind areas of the infrared detection using equivalent circuit transformation method.Meanwhile,this paper takes the range of infrared detection blind areas into consideration leveraging quantitative analysis.The results show that voltage distribution and temperature range are two core influential factors of the infrared detection blind areas,at the same time,the variation curves between the two factors and the blind areas are found.Based on blind areas variation detection data,this paper also proposes multiple methods to narrow blind areas such as segmenting insulator strings while detecting and choosing different temperature ranges,etc.2.High voltage infrared experiment is conducted in the high pollution laboratory of Jiangxi Electric Power Research Institute.The experiment contents are as follows : according to the calculation results in Chapter three,the deteriorated insulators at different locations in the blind areas of the infrared detection are chosen.Besides,the rules of the voltage distribution and infrared thermal image of insulator strings in different locations and under different environmental conditions are studied.The reasonableness of the method for calculating the blind area of infrared detection is verified by experiment.Through experimental analysis,it is concluded that environmental humidity is one of the core factors that affect the heating of insulators disk,and the voltage distribution and the change rules of deteriorated insulators disk under different humidity conditions are obtained.And the best humidity range suitable for blind area insulators is obtained.3.A new method based on the two dimensional eigenvector of steel cap and disk is presented,which solves the lapse in zero value insulators detection and faulty positioning of insulators,significantly improves the accuracy of infrared thermal image detection,and enables a promising prospect of field application.4.An intelligent detection system for deteriorating insulators based on new detection method is developed.The system can intelligently process infrared atlas,and diagnose the state of insulators via intelligence recognition algorithm.In this paper,the quantitative calculation method of infrared detection blind area is first put forward.Through high voltage experiment,a new method to diagnose insulators in the blind area is obtained,which reduces the false neglect rate of zero value insulators,greatly improves the accuracy of infrared detection,and provides a guide to the reduction of power grid breakdown reduction.