Acquisition And Diagnosis Of Aging Characteristic Quantity Of Natural Ester Insulation Oil

With the continuous development of science and technology and the continuous improvement of people's awareness of environmental protection,the traditional primary chemical energy such as oil and coal is gradually exhausted.In order to solve the increasingly prominent problem of environmental deterioration,all walks of life are moving towards green and efficient development.The research and application of natural ester insulating oil provides a new idea for the green development of large power transformers.The traditional mineral insulating oil will cause great pollution to the environment in the process of preparation and degradation,and its oxidation stability is low.Once explosion occurs,it will seriously endanger the safety of people and equipment.Compared with mineral oil,natural ester insulating oil has higher oxidation stability,and the degradation rate is as high as 98%.It has a wide range of sources and low cost.In order to study the aging law of natural ester insulation system,this paper chooses appropriate methods and aging characteristics,and carries out experimental analysis.Based on the research and analysis of aging characteristics and aging criteria of traditional mineral insulating oil-paper system,the aging characteristics of natural ester insulation system are analyzed in this paper.The chemical testing methods used in traditional mineral oil-paper system are difficult to carry out in the field,and are restricted by various factors.Dielectric response methods are all electrical measurements,without complex and expensive chemical instruments and reagents,without collecting insulation samples,simple testing methods,testing process will not cause damage to transformer insulation.Compared with the traditional electrical measurement methods such as insulation resistance and power frequency dielectric loss/capacitance,the dielectric response method has more abundant information,which can more accurately reflect the insulation defects and insulation deterioration which are difficult to reflect by the traditional methods,and then more reliable evaluation of transformer life.After comparing three commonly used dielectric response test methods,the frequency domain dielectric spectroscopy method,which is easy to operate and less affected by environmental noise,is selected as the test method used in this paper.Then,some physical,chemical and electrical aging parameters are selected for research and analysis,and the applicability of these parameters in natural ester insulation system is evaluated.Finally,the DIRANA dielectric response analyzer is used to build the test platform.Through the experiments under different water content,temperature and aging degree,the following conclusions are drawn: 1)the increase of water content can increase the relative complex dielectric constant,and has certain regularity;2)the increase of temperature can make the characteristic frequency of interfacial polarization shift to the right,representing the polarization sound.At the same temperature,with the aging degree deepening,the dielectric loss curve appears new peak value in the low frequency band,which strengthens the polarization degree of oil-paper insulation.It is proved that the aging characteristics selected in this paper can reflect certain aging laws.