Reliability study of a micro-grid power system

Deregulation and restructuring of old centralized power system has brought a renaissance in the history of electric power system. It has unleashed an open competition among the utility service providers in the respective sector of electric power system, i.e. generation, transmission, and distribution. Also, it gives birth to the new concept of micro-grids, which is an epitome of larger grid, called macro-grid, in general. Small utility service providers having generating capacity less than 10 MW are the main players in the micro-grid market. Micro-grids works, generally, at low voltage (415 V). Added advantages of micro-grids are its CHP (combined heat and power) operation, less emission of dasiaSOx and NOxpsila, reduction of dasiaTransmission line congestionpsila, easy installation and control of its small distributed energy resources etc. to name a few. Like macro-grid, main motto of the micro-grid system is to cater reliable and quality power to its customers. This paper presents a 6-bus system to study the reliability of the system in four different case studies. To judge the best reliable condition in each of the cases, four parameters, such as bus voltages, maximum line flow, slack bus injection, and system line loss, are considered and in each case study, these parameters are compared in different changing situations for getting the best result out of those situations. Fast de-coupled load flow (FDLF) method in Compaq visual FORTRAN is used to analysis the various cases. In all the analysis, macro-grid is considered as a large virtual generator and is used as a slack bus.