Distributed Energy Resource (DER) technology (e.g. microturbine, fuel cell) has greatly been advanced in recent years. These DERs are often used as the main components of a CHP-microgrid system and may be called as CHP-based DER. CHP-based DERs can provide power and heat with reliability and quality tailored to the requirements of end-users. As deregulation regime is penetrating more and more into the electricity market, competition among the IPPs is becoming acute. To sustain in this market, cost of electricity generation is to be reduced, not only using modern CHP-based DER technology but also, at the same time, deploying them in the microgrid system as per their type, capacity-size and bus-location. A cost-benefit analysis based method is proposed, in this paper, to enhance the reliability of both 6- and 14-bus meshed as well as radial microgrid networks. In this regard, various costs and benefits relating to CHP-based DER deployment have been taken into account for economic feasibility study. Higher the value of benefit to cost ratio (BCR), than one, better will be the selection of type, capacity-size, and bus-location of CHP-based DERs in respect of utility's benefit. More the Utility's benefit, lesser will be the price of electricity and ultimately, gainer will be the consumers. In this paper, bus-locations have been selected by loss sensitivity analysis and Particle swarm optimization (PSO) technique has been used to maximize BCR.