Study Of The Electromagnetic Disturbance Caused By The Switching Operation Of The Distribution Switchgear On The Secondary Equipment(s)

In modern power distribution systems,the application of intelligent power distribution equipment(s)greatly improves the technical level of management and operation for power distribution system.At the same time,the electromagnetic transient phenomenon during the switching operation of distribution equipment(s)makes itself become a powerful source of disturbance.The secondary equipment(s)such as transformers distributed around or inside the distribution equipment(s)are sensitive to electromagnetic disturbance.In addition,the overall size of intelligent distribution equipment(s)is small,and the secondary equipment(s)is close to the primary equipment(s).Hence,the transient fast overvoltage(VFTO)and the transient ground potential rise(TGPR)generated during the switching operation are easy to affect the secondary equipment(s).However,at present,the researches on the electromagnetic interference of secondary equipment(s)during the switching operation mainly focus on the high voltage.As for intelligent distribution,relevant research has not been carried out.In this thesis,the electromagnetic transient caused by switching operation is measured by means of the detection platform of the action characteristic for distribution switchgear.The experimental results include the Transient ground potential rise(TGPR),the transient enclosure voltage(TEV)and the port disturbance voltage on electronic voltage/current transformer(VT/CT).The waveform characteristics of the measured results such as peak,rising edge and main frequency are analyzed.The voltage transmission characteristics of VT are obtained based on experimental data.In addition,the simulation model of switching electromagnetic disturbance is built,the influence of different switching parameters and working conditions on the disturbance is analyzed.Based on the measured electromagnetic disturbance waveform,the evaluation criteria of damped oscillation wave are supplemented and the requirements for the evaluation of anti-disturbance degree of power distribution switch cabinet are put forward.Finally,a filter design method is proposed to prevent high-frequency disturbance above a certain frequency from affecting secondary equipment(s)through the transformer without affecting signals below this frequency.