Risk evaluation of transmission system operation modes: concept, method and application

This paper presents a Monte Carlo based method for probabilistic risk evaluation of transmission system operation modes. The method focuses on simulations of operation measures which include load transfers, generation pattern changes, network reconfigurations and switching actions. An important characteristic in risk evaluation of transmission system operation modes is noncoherence. This characteristic is also analyzed and explained. Inclusion of dynamic ratings of circuits and a simulation capability over any time length are the other two features of the presented method. The probabilistic operation risk evaluation method is an enhancement to and should be combined with traditional system analysis techniques. The proposed method has been applied to BC Hydro´s metro system. The case study given in the paper indicates that the lowest risk operation mode can be identified under different operation conditions. This helps perform transmission system operation risk control and partial risk transfer from one area to another or from one kV level to another with a reduced total risk level.