Short-Term Advanced Forecasting and Storage-Based Power Quality Regulation in Wind Farms.

Abstract

This Chapter contains the results of our research activities in the line to reduce both: the uncertainties in power forecasting and the lack in power quality for Wind Farms connected to public grids. Our approach is a suite of studies that are focused on power forecasting for Electricity Markets and also an innovative simulation technique to evaluate the quality by using a coupled storage systems as water reservoirs, inertial systems or chemical batteries. The use of renewable energy sources (RES) in electricity generation has many economical and environmental advantages, but has a downside in the instability and unpredictability introduced into the public electric systems. The more important renewable sources, wind and solar power, are mainly related to the weather in a local geographic area. However, the weather is a chaotic system with limited predictability. Many countries follow two trends in the development and planning of their public electric systems; the first is the increase in the generation power from RES and the second one is the transition to open electricity markets. These two trends have a common impact on the public grids, because they both increase the number of agents in the system and the level of uncertainty in the balance between generation and load. The access of more and bigger RES electricity producers can increase the risk of fail and decrease the service quality. That risk can be reduced by increasing the power reserve based on high response gradient systems. These, e.g. diesel or hydraulic, have a high speed of change in their generated power, that is suitable to balance the frequent sudden and unpredictable changes of RES-based electricity production. Therefore, the positive impact of the use of RES on the cost of fuel consumption would have a negative impact on the global cost of electricity systems. The control and planning of public electric systems covers a widespread set of levels, ranging from the hundred millisecond domain associated to the frequency and voltage controlErlich et al. (2006), to the yearly planning domain. Precise regulations for these levels are the concern of the national Electricity Authorities of each country as well as to supranational agencies. The EC Project STORIESPanteri (2008) provides an overview of existing regulations and the respective legislative framework related to RES implementation at a European level. In each national system, the Transmission System Operator(TSO) deals with the management of the electric system in the different control and planning levels. With the increasing penetration Short-Term Advanced Forecasting and Storage-Based Power Quality Regulation in Wind Farms 9