Due to the increased demand for electrical energy, many countries were
prompted nowadays to search for new sources. One important source is the
photovoltaic energy. However, despite the great benefits of this source, some
defects where observed when linking to distribution networks (negative
impact on the protection system). Hence, an approach of improving the
protection system in distribution networks integrated with photovoltaic cells
is presented in this paper. The protection system improvement is proposed
by changing the impedance to resistance ratio (X/R) values of the networks
cables, which leads to increasing the overcurrent relays' response speed
when a fault occurs. A comparative analysis with different cable reactance
values was conducted. The electrical transient analyzer program (ETAP)
software was used to investigate and validate the effects on the relay’s
response times. Amriya Fallujah power station, located in Iraq, was
investigated as a case study. Simulation results show that it is possible to
increase the response speed of the overcurrent relay by reducing X/R of the
network cables. For more validation, the distance relay was used to compare
the best improvement results of changing the X/R ratio with the results of
changing the type of relay, which also shows the strength of the proposed
method.
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