On-Line Stability Assessment of Practical Power Grids: Methods, Nonlinear Computations and Field Installations.
Hsiao-Dong Chiang (ECE, Cornell)

For many utilities around the world, there has been considerable pressure to increase power flows over existing transmission corridors. This consistent pressure has prompted the requirement for extending current energy management systems (EMS) to perform on-line transient stability assessment (TSA) and control. Such extension, however, is a rather difficult task and requires several break¬throughs in analysis tools, computation methods and control schemes.

Indeed, on-line TSA, concerned with power system stability/instability after contingencies, requires the handling of a large set of nonlinear differential equations in addition to the nonlinear algebraic equations involved in the static security assessment. TSA is designed to provide power system operators with critical information including, (i) transient stability subject to a list of contingencies and (ii) available (power) transfer limits at key interfaces subject to transient stability constraints. The PJM Interconnection, one of the largest utility in the world, has successfully designed and implemented a TSA system. TEPCO-BCU was selected as the leading fast screening tool for improving the performance of the PJM TSA system.

This talk will cover mathematical problem formulation, theoretical foundation, and the BCU method and demonstrate one practical application of the theory-based BCU method on the PJM interconnection system, a 14,000-bus power system dynamic model with a list of 3000 contingencies, with practical data in an on-line environment. This confirms the author’s belief that theory-based solution methods can lead to practical applications in large-scale nonlinear systems such as power systems.