The influence of network characteristics and environmental conditions on voltage dip performance in MV networks

The paper is focused on the possible influence that some network characteristics (i.e. network configuration, type of neutral operation, geographical area, lines and cable length...) and environmental phenomena (lighting) may have on voltage dip performance in Medium Voltage (MV) networks. The investigation has been performed by applying both correlation techniques and Multiple Linear Regression analysis (MLR) on the voltage dips collected along several years of monitoring by the Italian MV network monitoring system QuEEN. As to the network characteristics and environmental factors used in the performed analysis they are referred to the data supplied in the past for the monitoring system and to the lighting data provided by the Italian lightning location system SIRF. The percentage contribution of each network and environmental factor to the voltage dips statistic, irrespective of the other parameters, have been evaluated by multiple linear regression methods. The results of these analysis confirm that the overhead line length has got a significant influence on the phenomena while cable lines length has, as expected, only a negligible effect. The influence of lightning seems to be not so critical as expected and this happen also with the neutral type of operation while voltage dips performances depend, in a non-negligible way, on the belonging to a geographical area.