Power System Reliability Assessment Considering Coal-Fired Unit Peaking Characteristics

The large-scale integration of renewable energy and the serious safety issues faced by coal-fired units during peak regulation pose significant challenges to the reliable operation of power systems. Traditional probabilistic production simulation (PPS) methods fail to account for the fluctuations in load demand and the time-series variability of renewable energy, and they do not sufficiently consider the lifespan degradation of coal-fired units during actual peak regulation operations, which results in an inaccurate reflection of system reliability. This paper proposes an improved PPS method. First, this method rigorously considers the time-series fluctuations of load demand and renewable energy. Secondly, a multi-state model is established for coal-fired units, incorporating lifespan degradation and failure rates under different output conditions, which are dynamically updated based on load demand and operational status. An equivalent multi-state model for wind power output is also developed for different time periods. Finally, the Universal Generating Function (UGF) algorithm is used for PPS, enabling the calculation of system reliability indices, as well as dynamic costs such as unit start-up and shutdown, to assess the system’s capability to accommodate wind power. The impact of different peak regulation capabilities of units on system reliability is also studied. This paper presents the theoretical foundation, algorithm implementation, and related case studies, verifying the rationality and effectiveness of the proposed method in addressing the above-mentioned issues.