Effects of Connecting Photovoltaic Power Plants on a Long Electrical Line

In this paper, we studied the effects of connecting photovoltaic power plants along a long electrical line, in order to analyze the maximum power that can be connected, without causing negative effects on the line normal operation. The medium voltage (MV) network chosen for the study is the one related to the Bonţida distributor, supplied at both ends from two power stations, respectively from Gherla 110 / 20kV and Jucu 110 / 20kV. According to the normal operating scheme, the consumer parts related to the two substations are sectioned somewhere in the middle of the main axis Gherla - Jucu. The main objective of this case study is to identify the connection effects of photovoltaic power plants (PVP), in the modeled 20 kV network, on the components of the modeled area: electrical lines, transformers, consumers. For this purpose, along the main axis of the Bonţida distributor, six possible coupling points of 3 MW PVP were foreseen. The distance between two consecutive PVPs was about 3 km each. In order to highlight the effects pursued, after the realization of the network model, by using the software Paladin DesignBase, the calculation program of the steady state run for the of the steady state run, depending on the connection of the six PVP: total power losses, electrical lines and transformers loading, as well as the values of voltage drops to end-users.