Impacts of distributed generations on distribution system reliability

A stable and reliable electric power supply system is an inevitable pre-requisite for the technological and economic growth of any nation. Due to this, utilities must strive and ensure that the customer's reliability requirements are met and the regulators requirements satisfied at the lowest possible cost. It is known fact around the world that 90% of the of the customer service interruptions are caused due to failure in distribution system. The electric utility company will strive to achieve this objective via many different means, one of which is to defer the capital distribution facility requirements in favor of a renewable distributed generation solution by an independent power producer to meet the growing customer load demand. The evaluation of reliability of distribution networks including renewable and non-renewable distributed generations, is presented in this master thesis. The Monte Carlo simulation algorithm is applied to a test network. The network includes three types of distributed energy resources solar photovoltaic (PV), wind turbine (WT) and gas turbine (GT). In order to make the study more realistic, an stochastich model for the renewable sources has been developed. PV and WT stochastic models have been used to simulate the randomness of these resources. Wind velocity and sunlight intensity are those important paramteres that are variable of time and in this master thesis for wind velocity weibull distribution and for the sunlight insolation normal distribution have appiled to measure their uncertainity. This study shows that the implementation of distributed generations can improve the reliability of the distribution networks. Modeling of DGs in reliability assessment and computing of related indices such as SAIFI, SAIDI is introduced. Using model development and case studies it is discussed and shown that location and numbers of DGs effect in distribution reliability indices. Finally, analysis results demonstrates that DG has the ability of improving the reliability of system and customer.