Study of EHV Power Grid Over-voltage Monitoring system based on Rogow ski coil

An EHV Power Grid Over-voltage Monitoring scheme was studied according to Rogow ski coil on earth line of transformer Bushing tap, simulation and test proved the feasibility of this scheme. With the analysis the transformer Bushing tap current in overvoltage event, a new current transformer which uses Mn and Zn as magnetic core was developed. The amplitude-frequency response of current transformer in 100Hz~1.5MHz was less than or equal to 5%. Based on the simulation and experiment of bushing tap, accurate simulation model from transformer bushing tap current to voltage was established, integration reduction and trigger circuit was designed in addition. Upon the above research, the EHV Power Grid Over-voltage Monitoring System based on Rogow ski coil was developed. The System was calibrated by the Fifth Metering and Measuring Centre Station for Mechanical Industry. The amplitude and wave form parameters measurement accuracy for standard lightning and operation overvoltage were 5.0. After the commissioning, the Over-voltage Monitoring System operates satisfactorily.