Study on Broadband Modeling Method of 10kV Capacitive Voltage Transformer Considering Reflection Characteristics

As a key voltage measurement device in distribution networks, 10kV capacitive voltage transformers (CVTs) are widely applied. An accurate broadband CVT model is critical for power system electromagnetic transient analysis. However, existing CVT modeling mainly targets 35kV and higher voltage levels, and is limited to characterizing only transmission or reflection characteristics, failing to represent both accurately at the same time. To overcome this issue, this paper presents a broadband modeling method for 10kV CVTs considering reflection characteristics. The CVT scattering parameters from 5 Hz to 100 MHz are measured via frequency sweep, then fitted by the vector fitting method and corrected for passivity, forming a broadband passive model that captures both reflection and transmission characteristics. Modeling on a typical 10kV CVT yields a full-band root-mean-square error below 0.0016. Lightning-impulse field-circuit co-simulation shows that the model effectively reflects the modulation of CVT reflection on the characteristic frequency of transient waveforms. Experimental validation under lightning impulse confirms good agreement between simulation and measurement in time and frequency domains: the characteristic frequency error of primary lightning overvoltage is about 20%, while the secondary disturbance voltage has characteristic frequency error below 2% and amplitude error below 15%. The proposed method offers reliable CVT model support for high-precision electromagnetic transient simulation of 10kV distribution networks.