Sources of uncertainty and error in available transfer capability computation

Summary form only given. This paper focuses on the various types of uncertainty and error that can impact available transfer characteristics (ATC) calculations and their use in power system operations. It begins with a discussion of the sources of uncertainty in the modeling and real-time measurements. The errors discussed and illustrated include: (i) equivalents or parameter error; (ii) line rating errors; and (iii) setpoint or measurement errors. This is followed by the uncertainty and error associated with contingency selection and evaluation. The errors to be discussed and illustrated will include: (i) error in contingency description; (ii) the “missed” contingency. Finally, the presentation addresses and illustrates the following computational sources of uncertainty and error: (i) linear vs. nonlinear flow calculations; (ii) MW vs MVA limits; (iii) neglecting voltage constraints; (iv) neglecting voltage collapse margins; and (v) neglecting stability margins. The presentation includes computer simulations to illustrate the sources of error and the impact on ATC calculations. It also demonstrates the misuse of ATC numbers for multi-path capabilities