  Over the past years, the share of electricity production from wind power
plants has increased to significant levels in several power systems across
Europe and the United States. In order to cope with the fluctuating and
partially unpredictable nature of renewable energy sources, transmission system
operators (TSOs) have responded by increasing their reserve capacity
requirements and by requiring wind power plants to be capable of providing
reserves or following active power set-point signals. This paper addresses the
issue of efficiently incorporating these new types of wind power control in the
day-ahead operational planning. We review the technical requirements the wind
power plants must fulfill, and propose a mathematical framework for modeling
wind power control. The framework is based on an optimal power flow formulation
with weighted chance constraints, which accounts for the uncertainty of wind
power forecasts and allows us to limit the risk of constraint violations. In a
case study based on the IEEE 118 bus system, we use the developed method to
assess the effectiveness of different types of wind power control in terms of
operational cost, system security and wind power curtailment.
