Abstract:
Compared with conventional voltage transformers,electronic voltage transformers(EVTs) have potential transfer advantages in transmitting transient voltage.Firstly,the equivalent circuit of typical electronic voltage transformer was established,the transfer function was constructed to analyze its frequency response characteristics. Then,the PSCAD simulation model of typical electronic voltage transformer was established based on the transfer function to simulate and analyze its transient response characteristics. Lastly,the transmission performance of electronic voltage transformer and capacitive voltage transformer for different transient voltage signals was analyzed and compared from the aspects of fault transient,impulse response and step response. The analysis shows that the electronic voltage transformers have better frequency response and transient response characteristics than the conventional voltage transformers. The optical voltage transformer has the best performance and is the ideal voltage transformer for broadband voltage sensing.The capacitive divider type electronic voltage transformer can not transfer DC component,so it is generally only used for AC voltage measurement. Due to the great influence of stray capacitance,the measurement frequency band of the resistive divider type electronic voltage transformer is limited,and it is generally only used in the middle and low voltage power grid.The results of simulation analysis have a certain guiding significance for the selection of voltage transformer used for voltage measurement in power grid.