Application of intelligent fault diagnosis technology in HVDC system

It has very important theoretical and practical values to research fault diagnosis of nonlinear system because of its universality and complexity. Up to now, there have been few fault diagnosis methods for nonlinear time-delay system. This paper proposes a fault diagnosis and estimation method(FDEM) for a class of nonlinear time-delay system based on P-type iterative learning. Different from the other methods, FDEM introduces a parameter called dummy fault to approach actual fault using P-type iterative learning policy. Besides, FDEM not only can track system fault quickly, but it also can estimate fault signals precisely. Two typical nonlinear time-delay system simulation results are given. Furthermore, HVDC(High Voltage Direct Circuit)system is analyzed detailedly and FDEM is used for fault diagnosis of HVDC system.