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Top1 Introduction
In distribution networks the R/X ratio is much higher than in transmission systems. Therefore, throughout the distribution feeders there is a greater loss of power and hence a gradual electrical energy loss (Bansal et al, 2010; Baran & Wu, 1998; Chis et al, 1997; Haque, 199; Haque, 1996). Therefore, minimization of loss has become one of the greater problems for many utilities all over the world that needs to be adhered to. Capacitors placement and network reconfiguration are two extensive well known frequently used techniques minimization of loss in distribution networks (Baran & Wu, 1998; Chis et al, 1997; Haque, 199; Haque, 1996; Narasimham et al, 2013). Lately, because of aspects such as power electronics, restructuring of electricity market and environmental concerns etc. distribution generators (DG) have gained cogent importance (Narasimham et al, 2013; Ackermann et al, 2001). Ranging from some kWs to some MWs, DGs may be considered to be electrical power generating sources linked precisely to distribution networks (Khatod & Viral, 2012). In recent times, numerous technologies related to DGs have come up covering conventional to non-conventional sources (Ackermann et al, 2001; Khatod & Viral, 2012). Even though energy injection is the primary objective of DG units, however, if arranged and regulated strategically DGs are capable of serving numerous economic and technical utilities to consumers (Khatod et al, 2013). Voltage and loadability improvement, real power loss reduction, increased energy efficiency, upgraded system reliability and security are some results of such benefits (Ackermann et al, 2001; Khatod & Viral, 2012). Some financial benefits include saving of transmission and distribution cost along with reduction in whole sale electricity price, enhanced productivity, reduced fuel costs and saving of world fuel (Hung & Mithulananthan, 2013; Bansal et al, 2013). As far as current power industry deregulation along with the electricity market security is concerned, DGs observe a crucial function in spinning reserve, frequency control, etc. (Al Abri et al, 2013). However, improper operation and poor planning of DG exhibits a few contrary properties in distribution system functioning. Based on size and location, DGs can cause voltage rise, harmonic distortion, reverse power flows, etc. (Al Abri et al, 2013; Esmaili, 2013). Thus reduction in power loss is a crucial factor which is to be adhered to by proper DG operation.
Optimum DG sizing as well as siting for derogation of loss in distribution systems has lately gained substantial diligence of broad class of scientists and researchers. (Khatod & Viral, 2012; Khatod et al 2013; Hung & Mithulananthan, 2013). In many of the prevailing works on appropriation as well as sizing of DGs, researchers have acknowledged various concerns such as stability of system and voltage profile enhancement (Esmaili, 2013), harmonic pollution reduction (Harrison & Ochoa, 2011), profit maximization (Bhattacharya et al, 2004; Celli et al, 2005) and loading margin (Lee & Park, 2009) in either separate or collective-objective issue formation.