The Impact Of Surface Contamination On Total Electric Field Under HVDC Conductors

HVDC power transmission is playing an increasingly important role in energy fesources distribution of China, nowadays. DC lines operating in polluted areas may absorb a large amount of contamination, which seriously affects the corona discharge and its associated audible noise, electric field, ion current density from the transmission lines. Consequently, the work of the thesis is of academic and engineering value, probiding a reference for the prediction study of coating contamination effect on the total electric field of HVDC power lines.To fully study the effects of conductor surface condition on photon count and corona streamer pulses, conductors coated with different kinds of contamination are investigated and compared with a clean one. An experimental system based on an indoor corona cage was established to exclude the interference from environmental factors. Kaolin, salt and carbon were used as the coating contamination during the experiment. Moreover, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis and SPIP were employed to characterize the surface morphology of the conductor samples.Simulation coating system was designed and tuilt to study the pollution characteristics by taking a pollution experiment. Coating conductors with different roughness are tested during the experiment to illustrate the corona characteristics. Meanwhile, the simulation of contamination is divided into uniform and nonuniform cases.Finally, artificial coating conductors and simulating coating conductors were compared to study the characteristics of total electric field. And thus the equivalent condition of the two methods were obtained. By simulating the the coating conductors, the surface electric field were studied.