Reliability Evaluation of a Radial Distribution System with the Placement of Shunt Capacitors and Fault Passage Indicators Considering Normal and Adverse Weather Effects

The radial distribution system (RDS) is the most common practice in the power system operation, to supply power to the customers through the radial feeder sections from the distribution substation (DSS). The failure in the feeder sections and distribution substation leads to customer interruptions. So, it is necessary to evaluate the distribution system reliability by including the failures of both feeder sections and DSS to obtain a realistic approach for customer interruptions. The customer failure statistics revealed that over 80% of interruptions are due to radial network topology and the feeder section’s high failure rates. The high reactive currents during the peak load conditions are one of the causes of feeder section failure rates. The placement of shunt capacitors on the radial feeder (SC) supplies a portion of the total reactive current required at load points. Hence, the current passing through the feeder sections and their failure rates will be reduced. Additionally, the placement of fault passage indicators (FPI) improves the process of power restoration from sustained faults. The FPI is a smart device used to install on overhead lines to speed up the fault identification process. In practice, the weather conditions around the RDS will have an impact on component failure rates of both DSS and feeder sections. If the weather conditions are constant and normal the weather is modelled as normal weather (NW). However, the RDS is always subjected to varying weather conditions such as normal and adverse weather (AIV) then the weather is modelled as two weather (TW) model. In AW, weather is more severe and can increase the component failure rate. This paper evaluates the reliability of an RDS considering the failures of both radial feeder and DSS in NW and TW by a) the optimal placement of SCs based on the cost function using the particle swarm optimization method (PSO), b) the optimal placement of FPIs based on the system performance reliability indices. Further, with the optimal placement of both SCs and FPIs the RDS reliability is evaluated in NW and TW.