| Polymer insulating materials play an important role in power and electronics systems. The insulation failure will cause short-circuit, fires even explosion in the in electrical appliances and devices. In space and nuclear power stations, polymer insulating materials are inevitably exposed to various kinds of rays. The rays can change the structures and electrical performance of the polymers. High-energy radiation will seriously affect the application of polymer insulation materials. Accordingly, it becomes necessary to investigate the effects of the radiation on insulation materials, which is very important for the application in project.With the development of aerospace and the nuclear technology, more and more electrical and electronic equipment are used in various irradiation environments. In practice, many environments factors are co-existing. Besides the High-energy radiation, the polymer insulating materials are affected by the factors of vacuum, magnetic field and so on. However, the knowledge about the effects of Multifactor irradiation on the electrical performance of the polymer insulating materials is limited. Therefore, it is very important to investigate the insulation failure of the polymer insulating materials under the combined irradiation environments.In this paper, polybutylene naphthalate (PBN), and polybutylene terephthalate (PBT), polyethylene terephthalate (PET), Epoxy resin (EX) and Polycarbonate (PC), which use in practical transformers, motors, relays, cables and capacitors and other equipment, were toke as the experimental samples. The samples were irradiated in air up to 100 kGy and then up to 1000 kGy with a dosage rate of 10 kGy/h by using a 60Co gamma-source. Based on point-plate tracking failure and IEC60112 method, the effects of high-energy radiation, low pressure and strong magnetic field on the tracking failure were investigated. The study and results are as follows:1. For the change of polymer dielectric insulating properties in radiation environment, this paper studied the effects of high-energy radiation on the tracking failure of PBN, PBT, PET, EX, PPO under high-voltage pulse. By investigating the two important parameters of time to tracking failure and discharge quantity, the regular pattern of the tracking failure was obtained. The experimental results suggest that the chemical structure of the polymers play a main role in the result of radiation reaction, which is related to cross-linking and degradation reaction. 2. Based on the above study, the effect of radiation modification on tracking failure of the polymer insulating materials was studied. With IEC60112 international standard experiment, the variation of erosion depth and weight loss of Irradiated polycarbonate mixed with 3% polyethylene (modified PC) was investigated. A recurrence plot analysis of discharge current has been made to evaluate the tracking resistance more consistently. Obtained results showed that after Gamma-ray irradiation, the tracking resistance was improved. The irradiation effects on the tracking resistance can be visually identified by the recurrence plot.3. With the rapid development of power and electronics technology, more and more transmission lines and power equipment work in the highlands. High-altitude environment has the characteristics of low air pressure and strong ultraviolet radiation, which worsens the dielectric performance of the insulation in electrical equipment. The experience, mechanism and formula of low altitude are no longer applicable, but the research of insulation failure of the polymer is still few. Based on this background, the effects of low pressure and high-energy radiation on the tracking failure of polymers were investigated, and the mechanism of the two factors was analyzed .the results can lay a foundation for the insulation failure analysis for power equipment in high-altitude environment.4. Electricity and magnetism are inextricably linked. Because of high current there are high-intensity magnetic fields in the electrical equipment such as transformers, motors, etc. Meanwhile, the magnetic field strength in the GIS circuit breaker is also very large when the electromagnetic transient. The magnetic fields have great impact on insulating properties of power electronic devices and the equipment. Therefore, the effects of magnetic field and high-energy on the tracking failure of polymers were investigated, and the mechanism of differences was analyzed. The results have significance in the design and manufacture of electrical equipment applied in magnetic field and radiation conditions.
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