Research On Mechanism Analysis And Suppression Technology With Respect To EFT And Surge

Supported by Outstanding Teacher Foundation of State Education Ministry of China, the author makes an analysis of the characteristic of the Surge and EFT disturbance in this paper.A number of Protection Device, such as ferrite core ,filter, gas tube arresters, metal oxide variators, transient voltage suppressors, are tested.And their main technical parameters, which are impedance, response time, the level of the residual voltage, maximum peak pulse current and life times, are compared.Consequently a series of tests are performed on a microprocessor based protective relay taking account of the standard of IEC 61000-4-4 and IEC 61000-4-5.Then the responses of disturbance on each port of the relay are measured.According to the analyses of the data gained some advice is put forward to restrain the surge disturbance.Diverse protective measures should be taken since the disturbance applied on each port differs and the circuit characteristic of each port varies.