Impact assessment of grid tied rooftop PV systems on LV distribution network

Abstract

Due to the high demand for electricity in the world today and the need to reduce carbon footprint, the power system is undergoing a profound change and this change is paving way for renewable electricity generation into the traditional grid, making the conventional network become smarter. The convention which has been in existence over several decades has changed; thus, consumers of electricity have now become prosumers; generating and feeding electricity into the low voltage network. Despite the benefits of prosuming, some researchers say their presence create stability, reliability and power quality (over and under-voltages, and high harmonic distortion levels) problems which in effect lead to overloading of transformers and feeders, extreme line losses, and failure in network protection exceeding the limits in the low voltage grid.The objective of this paper is to evaluate the effect of rooftop PV generations on distribution losses (power losses) and network voltage profile (voltage regulation on LV network) in a typical traditional grid setup. The study employs an empirical analysis of the power system, forward/backward sweep based on BIBC and BCBV matrices and python simulation to arrive at its conclusion under two different scenarios, nine different loading conditions and six PV (from 1kWp to 6kWp) injections.The results obtained show that a grid connected with rooftop PV systems have the potential of reducing distribution losses substantially and also do not violate standardized voltage limits. The net power loss recorded on the network with PV injections from 1kWp to 6kWp were in the range of 1.1kW–88.9kW at poor power factors and 0.7kW and 89.1kW at improved power factors, respectively. The variation in the voltage profile ranges between 0.97pu and 1.05pu for both the conventional and prosumer grids.