Probabilistic N−1 security assessment incorporating dynamic line ratings

As power systems are operated closer to their technical limits, dynamic thermal line rating (DLR) can be used to enable additional dispatching flexibility. DLR is used to dynamically adapt the ampacity of the conductors, i.e. the maximum allowed amount of current a conductor can carry without overheating, according to the meteorological conditions. This paper proposes a probabilistic N-1 security assessment method that incorporates DLR in a probabilistic constraint. To model the probability distributions of certain meteorological values we use a copula approach. We calculate the distribution of the ampacity based on the distributions of the meteorological quantities using a model of the thermal behaviour of the line and given weather forecasts. From the resulting distribution, uncertainty realizations are sampled which are needed for a scenario based methodology which is used to deal with the developed chance constraint program.