1  Application of Distributed Generation to Enhance Loadability of Distribution System, A Case Study 1 Abraham Lomi 2 , Nguyen Cong Hien 3 , Mithulananthan N. 4 e-mail: abraham@itn.ac.id Abstract There has been a great interest in integration of distributed generation (DG) units at distribution level in the recent years. DGs can provide cost-effective, environmentally friendly, higher power quality and more reliable energy solutions than conventional generation. Understanding the wide variety of DG options available along with their technical benefits in today’s changing electric market environment can be daunting. Technical benefits of DGs can range from loss reduction to reduction in feeder loading. Loadability enhancement is another benefit that DG can add to distribution system, if properly placed and appropriately sized. This paper presents a simple methodology for placing a distributed generation with the view of increasing loadability and voltage stability of distribution system. Effectiveness of the proposed placement technique is demonstrated in a practical distribution system of Pujon in Malang, Indonesia. Keywords: Distributed generation, loading margin, loadability, weakest bus, voltage stability. 1. Introduction In the past, due to the “economy of scale” power generating stations were often large and their capacities in range of 150-1000 MW, even larger in some cases. Clearly, such type of big power stations required large facilities, including land and personnel needed to operate and high capital investment. Moreover, since these big power stations cannot be constructed close to load center for some obvious reasons, there is a need for long Extra High Voltage (EHV) or Ultra High Voltage (UHV) transmission lines, including transmission substations. Similar to power stations, these transmission lines and substations need ample amount of money and resources for design, constructions, operation and maintenance. Moreover, the lengthy structure of these transmission lines makes those lines are vulnerable to natural hazards, such as heavy wind, snowstorms and lightning strikes. ____________ 1) This project is sponsored by DGHE, Department of National Education. 2) Department of EE Institut Teknologi Nasional, Malang. 3) Energy Program, Asian Institute of Technology, Bangkok. 4) School of Information Technology, The university of Queensland, St Lucia Campus, Brisbane, Qld 4072. These natural hazards, in some cases, become the major reason for partial or full blackout of the power system triggered by some line outages. Given these conditions added with economical and environmental pressure due to green house gas (GHG) emission and consequent climate change in the recent past been changing way of generation approaches of electric power utility. By considering above issues one of the best alternatives for change in traditional way of generation and delivery arrangement is to introduce distributed generation based on renewable energy resources. Given the sizes of these plants they can be conveniently located closed to load centers. Distributed generation is currently being used by some customers to provide some or all of their electricity needs. There are many different potential applications for DG technologies. For example some customers use DG to reduce demand charges imposed by their electric utility, while others use it to provide premium power or reduce environmental emissions. DG can also be used by electric utilities or distribution companies enhance their brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by Institut Teknologi Nasional Malang Repository