On-line Study Contingency Analysis (CA) is an integrated package developed by BSI for voltage security assessment to provide voltage assessment for large-scale power networks under base case and contingency case scenarios in real-time and on-line study environments.
The strategy of using effective schemes to rank a comprehensive list of all credible contingencies and of applying detailed analysis programs only to critical contingencies is widely accepted. In order to identify critical contingencies, which will severely violate static security constraints, BSI-CA employs two look-ahead ranking schemes, which are to be incorporated into the tool. The first look-ahead scheme ranks the set of all credible contingencies in terms of branch MVA violation and selects the top few critical contingencies. The second look-ahead scheme all credible contingencies in terms of bus voltage violation and selects the top few critical contingencies.
BSI-CA implements the most robust commercially available Continuous Power Flow (CPFLOW). CPFLOW can generate P-V Curves, Q-V Curves, or P-Q-V Curves in a reliable and fast manner. These curves are generated under the condition that the constant P-Q load component of a bus (or a collection of buses) varies, with the constant current load and constant impedance load being kept indeed constant. The nonlinear load model, ZIP-model, is popular in modeling nonlinear behaviors of load. ZIP-V curves can better trace power system steady-state stationary behavior due to load and generation variations.
A contingency is composed of a single or multiple items. Line, transformer, shunt, load and generator outages are considered in the contingency. Multiple outages of up to 60 pieces of equipment are allowed in a contingency. Contingency definitions for Remedial Action Schemes and Special Protection Schemes are supported as a package option.