Indices System and Methods for Urban Power Grid Security Assessment

An integrated indices system for urban power grid security assessment is proposed, which includes five kinds of indices such as capability of supplying power safely, static voltage security, topological vulnerability, transient security and risk indices. The indices system can scientifically and fully reflect the security level of power grid and provide a quantitative base for the establishment of emergency management technology and measures. The traditional indices and methods for power system security assessment are improved and some indices are first proposed such as "number of lost components after N-K contingencies" and "the largest power supply region index". Based on utility theory and considering effects of external environment on failure probability of lines, risk indices are constructed including "overload risk index", "low voltage risk index", "voltage collapse risk index" and "angle instability risk index". Power System Security Assessment Indices Calculation and Analysis Software is developed, which provides an accessorial and practical tool for power system plan and operation. At last, one urban power grid is used as a research example and the results show effectiveness of the indices system and practicability of the software.