Abstract-The voltage level of power system is continuously improved. Partial discharge (PD) test is an important means to detect the insulation performance of high voltage electrical equipment. The electromagnetic environment of the test site is complicated. The extracted PD signal is submerged by noise. In order to get a more real PD signal, noise removal is inevitable. Aiming at this aspect, this paper proposes using empirical mode decomposition (EMD) and high order partial differential equation (PDE) to suppress the interference signal. The simulation results show that using this method to deal with the effect of PD signal is very obvious.

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Abstract. The paper presents ways for determining parameters of the characteristic impedance ) (s Z a , the value of time constant τ , ε ′ and ε ′ ′ , through formula transformation and frequency spectroscopy method (FDS).Finding out the values of coefficient α with Cole-Cole model. Building double-relaxation model to fit complex dielectric permittivity ε in different temperature and moisture level, and finding the influence of them on the parameters of the ColeCole model.