# Effects of On-Site PV Generation and Residential Demand Response on Distribution System Reliability
## 1 Introduction
### Literature Review  
In recent years, integrating modular RESs into the power system as well as demand side management implementations have been widely investigated in the literature to cope with reliability issues and increase the quality of services. In this respect, [PERSON] et al. [6] proposed a reliability-based DR program in which traditional DR programs such as summer vacation period DR program, direct load control, and demand bidding were reconstructed considering the system requirements. The presented structure consisting of consumer data management and program operation parts aided network operation, especially in emergency conditions, by trading emergency DR resources instantly. [PERSON] et al. [8] examined the effect of aggregated electric water heaters (EWHs) DR capability and their load shifting performance analysis, especially in peak hours for the purpose of achieving reliability improvement. According to the results, it should be highlighted that the reliability indices were enhanced thanks to the provided certain amount of operating reserve by aggregated EWHs. The optimization-based strategy also aimed to reduce end-users' total cost while maintaining the comfort levels. In order to improve the reliability indices in modern power systems, controllable demand sources were taken into consideration in [9] as an alternative for extra generation (reserves). On the other hand, DR implementation affects the generating system reliability. In [10], the short-term reliability model of DR capacity was proposed using a multi-state continuous-time Markov chain model. A stochastic security constrained scheduling approach integrating DR model was presented in [11] with the objective of determining an optimal strategy for the independent system operator considering market conditions, system security, and reliability needs as well as air pollution. Moreover, total operational cost was also aimed to be minimized by implementing an efficient DR program through mixed-integer linear programming. [PERSON] et al. [12] conducted a study in which the effects of stochastic demand side load shifting approach on electricity price volatility and reliability issues were examined by using optimal power flow combined with some reliability evaluation techniques in restructured power systems. Additionally, in [13], the impacts of real-time price-based DR application on system reliability were investigated by taking into account nodal price volatility and potential DR resources. The optimal power system operation was guaranteed within the generation and the transmission constraints. However, no attempt was made to investigate RES-based generating unit's impact on the power grid reliability indices in studies [12; 13]. [PERSON] et al. [14] created a model for a micro-grid including loads, distribution generators, and energy storage systems (ESSs) combined with possible DR strategies for reliability evaluation in a distribution system unlike the obsolete conventional methods. RES penetrations as well as charging/discharging strategies of ESSs were taken into consideration evaluating their impacts on the operational perspective. In order to validate the effectiveness of the proposed scheme, sequential Monte Carlo simulation and minimal path method were used. The effects of the DR program on the reliability assessment of a microgrid was also studied in [15] considering its complicated architecture. The authors in [16] presented a new bus weighting methodology with the aim of optimizing system operation, especially in case of unfavorable weather conditions or peak demand periods. It is significant to indicate that expected interruption costs were decreased approximately by 20% thanks to the proposed framework, in which it is possible to distribute the total system's DR requirement in critical loading events. [PERSON] et al. [17] proposed a reliability assessment model considering aging period of conventional power equipment for determining reliability of the distribution network also including PV generation.