TRANSIENT PROPAGATION CHARACTERISTICS OF s320kV XLPE CABLE CONSIDERING FREQUENCY AND TEMPERATURE EFFECTS

Transient propagation characteristics in HVDC cables are of considerable importance for overvoltage calculation and fault location. This paper presents an improved calculation method for wave propagation of a ±320 kV XLPE cable considering frequency and temperature effects as well as a multi-layer distributed model. The material parameters of the cable under different temperatures and in a wide frequency range, 0.1 Hz~100 MHz, were measured. And the results were fitted into the calculation of the impedance and admittance, which was compared with the methods with the approximation of semiconducting layers. It is found that the method proposed in this paper has a better accuracy than others in a wider frequency range. The contribution of the semiconducting layer on total impedance and admittance are both significant, which is required to model separately. Above 1 MHz, the effect of the frequency on the semiconducting material leads to the change of admittance value, which results in differences in the propagation characteristics. Particularly, for the attenuation coefficient, the relative error can be up to 31.5%. In addition, it shows that the effect of the temperature is significant on the propagation characteristics in the low frequency.