Electric Field Analysis of a 400 kV Overhead Insulator–Tower System
Application ID: 143551
The design of overhead insulator involves the evaluation of maximum electric field intensity in particular regions like metal ends, weather shed and corona rings. The metal surfaces will have corona inception once the electric field intensity reaches the threshold level. So, the design process includes electric field analysis of insulator under standard terminal voltage excitation. In this case, a 400kV insulator is considered which is the line voltage.
The existing insulator model is simulated without tower in 2D axis symmetric dimensions. When it is simulated this way, the potential difference between HV and ground end leads to symmetrical charge distribution on both ends since geometry is symmetrical on both ends. This electric field values on both ends also will show similar values. In the field scenario, the HV end will be connected to the transmission lines and the ground metal end will be connected to the large tower area which will provide more surface for the charge to distribute reducing the electric field intensity in the ground end. The existing CIGRE standard explicitly mentions the importance of simulating the entire tower to evaluate the field values of electric field. Hence this model simulates the insulator along with tower to evaluate the electric field intensity on insulator.
A single circuit three phase 400kV system is considered and the phase difference between the three phases is applied in the excitation.
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