Emc Measuring Instruments Of High-frequency Transfer Function Modeling Method

Steep transients will be caused by FACTS equipments operational within substations due to frequent switching of power electronic devices, which thereby results in serious high-frequency conducted and radiated interference through near-field coupling and far-field radiation. This affects the surrounding electromagnetic environment and poses potential threats to normal operation of the sensitive secondary electronic equipments positioned nearby.Theoretic analysis and digital simulation is important, however, measurements and experiments, normally as the last ditch for validation, render even more significance in EMC investigation, especially when the time- and frequency-domain characteristics of the electromagnetic interference being studied are complicated. So methodology with instrumentation and measurement in EMC are extremely emphasized.In fact, the frequency characteristics of a sensor or an antenna does not present a flat line, which poses difficulty in recovering the input signal from a sensor's output, especially when the original signal possesses multi-frequency components. Therefore the frequency characteristics of a sensor or an antenna must be rectified, otherwise big error will be caused. Based on the available frequency response characteristics of a measurement transducer, an equivalent frequency-domain transfer function can be established and digital compensation can be realized to the measured data series in the time domain, which can effectively improve the measurement accuracy.PT and CT are normally designed specifically for applications at SOHz, thus physical modelling is quite difficult due to lack of the model parameters at high frequency. The practical way is to establish their equivalent models with mathematical methodology based on frequency response. A equivalent model of high frequency transfer function was proposed, in order to realized the digital compensation of measurement equipment's error. The information of amplitude and phase is considered in the frequency domain, at the same time, optimization algorithm is used to get the parameter of the model, in order to improve the accuracy of model in the...