Characterization Of Metal Particle Characteristics In GIS Based On Combined Acoustic And Electrical Detection

Gas-insulated metal-enclosed switchgear is widely used in modern power systems because of its safe and reliable operation,small footprint,and environmental friendliness.However,metal particle pollution in GIS Inevitable.Partial discharge occurs when free-moving metal particles move in the GIS,causing insulation breakdown and causing irreversible damage to the equipment.At present,domestic and foreign scholars' research on free-moving metal particles focuses on the theoretical derivation,motion characteristics and monitoring methods of particle motion.It is inadequate in terms of model building during particle motion and the extraction of characteristic quantities of monitoring signals.The analysis of monitoring results provides a theoretical basis and is difficult to meet the needs of actual projects.In order to improve the recognition level of the monitoring signal and accurately analyze the GIS particle failure,the particle collision coefficient is measured in this paper,and the particle simulation model is built.Based on this,the acoustic and electrical signals of the particle movement are analyzed,and the type of particles that can be characterized is extracted Characteristic parameters.In this paper,based on the metal particles appearing in the GIS equipment in operation and failure,the physical and chemical composition and physical form of the particles are analyzed,and the characteristics of the particles are summarized.The aluminum balls,stainless steel balls and copper balls with millimeter level are selected for analysis.According to the characteristics of particle failure,sensors and signal amplifiers were selected,a test platform was built,and the collision coefficients of aluminum balls,stainless steel balls,and copper balls were measured by ultrasound to establish a particle motion model.In this paper,the force of the particles between the electric field is derived,including the electric field gradient force and the magnetic field force.From the force of the particles,the motion formula of the particles between the electrodes is obtained.It is found that the motion pattern of the particles between the electrodes and the amplitude and frequency of the applied voltage The relationship with the initial phase angle.Based on the particle motion model and force analysis deduction,build a simulation model in the software,change the voltage amplitude,frequency and other variables,observe particle motion patterns,study particle motion characteristics,and lay the foundation for the extraction of particle characteristic parameters.In this paper,the motion test of free-moving particles between coaxial electrodes was carried out,the movement process and discharge phenomenon were observed,and the ultrasonic signals and UHF signals of the particles moving between the coaxial electrodes were extracted.A method for characterizing the motion characteristics of particles in an AC electric field is proposed.The particle size and material are preliminarily determined by three characteristic parameters of discharge probability,comparison of charge and discharge,and collision frequency,and particle type identification is achieved.