I. Introduction
Energy consumption globally has increased at an accelerated rate over the last three decades[1], with increase in energy demand attributed to the population growth and technological advancement [2]. The current challenges modern power systems face are growing energy demand, aging of present electricity transmission and distribution networks, and the impact of global warming. These challenges and the corresponding countermeasures adopted have had a detrimental effect on the reliability of Distribution Systems (DS) [1], [2]. Power systems reliability is defined as the extent to which the operation of various components in the grid yields electrical energy being provided to the end customers while maintaining standards limits and fulfilment of demand [3]. In the past, the reliability of power systems was mainly investigated upon the transmission and generation, while DS reliability was less investigated. However, literature shows that around 80% of electrical supply interruptions to end consumers has root causes at the distribution level [4]. The power system reliability assessment is essential in the planning, design, and operation of the DS as the ultimate goal of the electrical power utilities is to provide uninterrupted electrical services to their customers at minimum cost while providing a satisfactory quality service [5], [6]. System security and adequacy are the requirements under which the distribution network is considered. System adequacy refers to a static assessment, qualifying the capacity of the system to adequately deliver the energy demanded by the customers by carrying out an evaluation based on the components or equipment being used [7]. Thus system adequacy focuses on the system's design, structure, and installed component capacity [8]. System security of supply refers to the ability of the system to respond to any given contingency or disturbances such as loss of a line, generating unit, and/or transformer substation [9]. Thence, metrics of reliability that concentrate on the system security is called dynamic reliability, while static reliability focuses on the system adequacy attributes [10]. Reliability indices are evaluated for a particular area under various scenarios to find the optimum sizing and siting of newer equipment (e.g., tie-line), which asses the planning and operation methodology [10]. Common methods rely on the analytical predictive reliability assessment described in [11] for standard reliability metrics such as expected energy not supplied (EENS). EENS is defined as the amount of energy in MWh not supplied based on a probability of equipment failure and the interruption duration.