The Reliability Evaluation of Large-scale Power Supply System and Voltage Sag Based on the Analytical Method

Because of increasing scale and complexity of electrical system power supply network, new requirements for service ability of electrical system are put forward. Over the past few decades, on the topic of service ability of electrical system analysis the research on power generation and transmission system reliability is attached importance and service ability is neglect, because failures of power generation systems and transmission systems often cause serious consequences. However, power supply system directly connecting with the user is in the end of the entire power system, which is important link to connecting with customers, distribution of electricity to customers and supply power to customers, service ability has a direct relationship with users. The problem of service ability gets more and more attention because of increased demand of quality of supply. In this paper, aiming at power supply system service ability assessment of a large-scale power supply system and voltage sag is studied. Several commonly used typical circuit structure of power supply system are proposed, and reliability analysis and comparison of them are finished. A new assessment algorithm is proposed aiming at circuit-complex and large amounts of data of large-scale power supply system, which is EMEA method combining minimum cut set method. Comparing with previous FMEA method, EMEA method combining minimum cut set method can take into account the trend and voltage constraints after a fault, efficiently assess load points and the overall system reliability, and identify the weak links in the network. At the same time, a analytical method of voltage sag is proposed, which is also called line piecewise analysis. This method considers each possible fault lines in turn, analyzes the circuit section by section with a certain step length, and calls failure analysis program. Two methods above are applied in a large-scale power supply system undermine and a 14 node test power system of Kailuan Coal Mine Group, the experiment results proves the effectiveness and feasibility of two methods above.