BC Hydro´s Transmission Reliability Margin Assessment in Total Transfer Capability Calculations

NERC requires considering the uncertainties in assessing the total transmission capability (TTC) by calculating a term called transmission reliability margin (TRM). As part of a new BC Hydro TTC calculator, an improved 2m +1 point estimation based method (PEM) was developed to estimate the standard deviation of TTC due to the uncertainties of system parameters including forecasted system load, generation patterns, inter-tie schedules and change in projected load and dispatch conditions as a result of system stress. The standard deviation of TTC is used to determine TRM. The developed method has now been accepted as part of new BC Hydro´s TTC calculator for determining TRM in real-time and pre-scheduling timeframes. Typical results on BC Hydro´s large scale system, which were obtained using the developed TRM method, are presented in this paper. The presented TRM method has already been filed as an attachment to a BC Hydro´s report to NERC for meeting the mandatory reliability compliance.