Abstract
Electric power should deliver a predicable per condition for the technological, economic, and political development of any countries and it is vital for each individual. Power outage is series problem in Ethiopia at the hole of distribution network. This is due to frequent interruptions and much time service restoration. That is why most customers of Ethiopia have their day-to-day activities highly affected and they are strongly complaining to Ethiopia electric utility daily. But this power outage affected customer cost and the Ethiopian utility. In most developing countries including Ethiopia, distribution systems have received considerably less of the attention to reliability modeling and evaluation than have generating and transmitting systems. Life is directly or indirectly dependent on electric power so a utility should deliver reliable power every day for 24 hours and each year for 8,760 hours to satisfy human needs and to perform their works as much as possible with less economy.
TopIntroduction
Deliver electrical energy to their customers is the primary function of the electric power system. This electricity is supplied as economically as possible with an acceptable degree of quality. Reliability of power system is one of the features of power quality. Economy and reliability are the two competitive features because increased reliability of supply generally requires increased capital investment. These two constraints are balanced in many ways from different countries and by different electric power utilities, although generally they are all based on various sets of criteria. A wide range of related measures or indicators can be determined using probability theory (Alkuhayli et al., 2012). A single all-purpose formula or technique does not exist. The approaches and their respective mathematical expressions depend on the defined problem and determined assumptions. There are different assumptions must be made in the practical applications of probability and statistical theory. Reconfiguration of the radial distribution network is utilized for the purpose of loss minimization, reliability enhancement, voltage profile improvement and load balancing. The validity of the analysis is directly related to the validity of the model used to represent the system (Alhelou et al., 2019; Makdisie et al., 2018; Alhelou et al., 2018; Alhelou et al., 2016; Haes Alhelou et al., 2019; Njenda et al., 2018). The actual failure of the distribution system rarely complete fit the analytical descriptions used in the analysis and must be taken to ensure that significant errors are not included through oversimplification of the problem. The most important aspect of good modelling and analysis is to have a complete understanding of the engineering implications of the system. No amount of probability theory can circumvent this important engineering aspect (Singh 2014; Khan et al., 2019; Khan et al., 2018; Khan et al., 2017; Banteywalu et al., 2019; Anteneh et al., 2019; Molla et al., 2019, Molla et al., 2018, Jariso et al. 2018). There are two main categories of evaluation techniques:
Analytical techniques represent the system by a mathematical model and evaluate the measures or indicators from this model using mathematical solutions.
Key Terms in this Chapter
Protective Relay: It is an intelligent electronic devices (IEDs) which receive measured signals from the secondary side of CTs and VTs and detect whether the protected unit is in a stressed condition (based on their type and configuration) or not. A trip signal is sent by protective relays to the circuit breakers to disconnect the faulty components from power system if necessary.
Power Quality Issue: A power quality problem might be defined as any electric power delivering condition that causes appliances to prevent their use.
Reliability: A measure of the degree of certainty that the relay, or relay system, will perform correctly.