Thermal-electric simulink¯ model of diesel electric generators with economic dispatch in remote standalone systems

Abstract

Electric power systems in many remote rural villages generally consist of diesel electric generators (DEGs) serving relatively low and highly cyclical loads the majority of the time. Methods of improving the efficiency and operational lifetime of these systems are to load the DEGs closer to their rated capacity, employ heat recovery and utilize turbochargers. The efficiency of the DEG engine is directly proportional to the electric load and indirectly proportional to the ambient air temperature. Load and temperature profiles could be used in conjunction with generation scheduling (economic dispatch) for improving the efficiency and operational lifetime of DEGs. This paper investigates the relationship between village electrical loads, ambient air temperatures and efficiency of DEGs by developing a thermal-electric Simulink <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">reg</sup> model of the DEGs and employing economic load dispatch without the need to have all DEGs operational. Load and ambient air temperature profiles for two systems: 1) a DEG at the University of Alaska Fairbanks UAF Energy Center representative of those found in remote villages and 2) the Alaska remote rural village of Kongiganak, are analyzed to determine correlations between electrical loads, ambient air temperature, and DEG engine efficiency. The results demonstrate that while increased electrical loads cause an increase in operating efficiency due to the engine operating closer to its rated output, higher ambient air temperatures cause an overall decrease in engine efficiency mainly due to rejecting heat to a temperature closer to the engine's exhaust temperature.