The role of risk modelling in the Great Britain transmission planning and operational standards

This paper presents three case studies of risk-based standards from Great Britain: the pre-liberalisation generation planning standard, the present method for setting operational reserve requirements, and the transmission network planning standard. These illustrate a number of key issues in developing planning and operational standards for wind, including: the benefits of risk-based standards in adapting to new circumstances; the importance of considering model assumptions carefully when interpreting risk calculations; the difficulty in calculating the cost of risk; and the need to account for uncertainty in system background. The transmission network planning standard is studied in particular detail, especially how the present combination of deterministic and probabilistic sections might evolve for use in a future power system with a very high renewable penetration.