## 1 Introduction  
A fundamental objective in developing distribution networks is ensuring a stable, cost-effective, and secure electricity supply. Achieving this goal requires a structured and strategic planning approach, which serves as a core operational process for distribution system operators. In the long run, enhancing the distribution system should facilitate a reliable and economically viable power supply while improving overall power quality [1]. A critical aspect of distribution network development is ensuring high reliability, as power supply interruptions can lead to significant economic and operational challenges. Proper assessment of reliability indicators plays a key role in network planning, allowing for the identification of system vulnerabilities and guiding investment decisions aimed at reducing outages. In power distribution, reliability refers to a system's ability to consistently deliver electricity under predefined conditions over a given period without interruptions to consumers [2]. However, maintaining a high level of reliability is particularly challenging in semi-urban and rural areas. Limited financial resources, aging infrastructure, and network design constraints often slow down improvements in system performance. While smart grid technologies are widely deployed in developed networks, in many regions where power systems are still developing and in the early stages of modernization, improving basic infrastructure in semi-urban and rural networks remains a prerequisite before large-scale automation and smart grid functionalities can be introduced. The liberalization of the electricity market has heightened the urgency of reducing economic losses caused by power outages. These evolving demands, alongside regulatory changes in electricity supply, have shaped the framework for tariff structures that incorporate reliability-based pricing or impose financial penalties on distribution network operators failing to meet reliability standards. Prevailing regulatory models in various countries, including Spain and Finland, incentivize investments to improve system reliability, as reliability performance directly influences operators' revenues [3]. Compensation for unsupplied electrical energy varies across countries, depending on their respective regulatory frameworks, laws, and distribution system regulations and practices [4; 5]. In regions where such mechanisms exist, distribution system operators (DSOs) are responsible for compensating consumers when unsupplied energy results from faults in the distribution network, power outages, or insufficient equipment maintenance. It is also important to note that many countries do not explicitly regulate the price of unsupplied electrical energy. Instead, it is negotiated individually between consumers and suppliers upon request. From the perspective of DSOs, improving reliability is crucial, as it enhances consumer trust and reputation, reduces compensation costs, and strengthens competitiveness in the market. The electric system reliability metrics defined in [2] identify four key indicators for evaluating electric system reliability: _System Average Interruption Duration Index_ (_SAIDI_), _System Average Interruption Frequency Index_ (_SAIFI_), _Customer Average Interruption Duration Index_ (_CAIDI_), and _Momentary Average Interruption Frequency Index_ (_MAIFI_). These metrics are widely recognized and used by electric utilities in the United States to measure and report system reliability. In European countries, _SAIDI_ and _SAIFI_ are the primary reliability indicators for performance assessment [4; 5]. Their values vary significantly across different DSOs, and improving these indicators is one of their primary objectives. According to the DSO Annual Business Report in Serbia, _SAIDI_ and _SAIFI_ are included among the non-financial performance indicators, where their annual values are compared to those from the previous year.