Abstract In this paper, we investigate the possibility of integrating 12 GW of onshore and offshore wind energy in the power system of the Netherlands. Interconnection capacities to the rest of the synchronous UCTE system and HVDC connections to Great Britain and Norway are modelled as flow gates, while sufficient transmission capacity for integrating wind is assumed to be present within the Dutch system itself. For this case study, we use realistic time series of aggregated 15-minute wind power production and forecast, based on one year of wind speed measurements and forecasts at various locations in the Netherlands and its coastal waters, and multi-turbine wind farm models. The technical capabilities of the foreseen conventional generation portfolios of the Netherlands and its neighbouring countries are modelled in detail, in terms of ramping abilities, fuel efficiency, and minimum up and down times. Particular attention is also paid to wind energy developments in Germany, since high correlations exist between the wind power outputs of the two countries. A preliminary evaluation in terms of margin at peak load, minimum load problems, and ability of conventional units to follow the load less wind variations is made, based on the net load duration curves of Netherlands and Germany in 2020. It is shown that smaller amounts of wasted wind (i.e. wind energy that cannot be taken by the system) due to minimum load problems occur when exchanges of excess wind energy can be scheduled between the two countries close to the operation time. This shows the importance of having larger geographic areas and well-organized cross-border trading to facilitate larger amounts of integrated wind energy. However, wasted wind cannot be completely avoided due to correlations in low load - high wind situations between the two countries. These results are confirmed through detailed chronological simulations of one year of operation, using a unit commitment and economic dispatch tool specifically ada- pted to perform wind integration studies. The potential for demand-side management to allow for a better integration of wind power is briefly explored.

DC power flow is a commonly used tool for contingency analysis. Recently, due to its simplicity and robustness, it also becomes increasingly used for the real-time dispatch and techno-economic analysis of power systems. It is a simplification of a full power flow looking only at active power. Aspects such as voltage support and reactive power management are possible to analyse. However, such simplifications cannot always be justified and sometimes lead to unrealistic results. Especially the implementation of power flow controlling devices is not trivial since standard DC power flow fundamentally neglects their effects. Until recently, this was not an issue as the application of power flow controlling devices in the European grid was limited. However, with the liberalisation of European electricity market and the introduction of large wind energy systems, the need for real power flow control has emerged and therefore, the use of these devices has been reconsidered. Several phase shifting transformers (PST) are being installed or planned in order to control flows. Therefore, it is important to fundamentally re-validate the fast, but less accurate, DC power flow method. In this paper the assumptions of DC power flow are analysed, and its validity is assessed by comparing the results of power flow simulations using both the DC and AC approaches on a modified IEEE 300 bus system with PSTs.

In a liberalized electricity market, the use of phase shift ing transformers or other power ¿ow controlling devices allows the transmission system operator to utilize the avail able grid infrastructure in a more optimal way. However, each phase shifter adds a degrees of freedom to the control problem, making optimization more dif¿cult. In this paper, the coordination problem is solved by using Particle Swarm Optimization (PSO). The goal is to give an overview of how PSO is used to solve this particular problem, and to demon strate a new area of application for the method.

A tendency to erect ever more wind turbines can be observed in order to reduce the environmental consequences of electric power generation. As a result of this, in the near future wind turbines may start to influence the behavior of electric power systems by interacting with conventional generation and loads. Therefore, wind turbine models that can be integrated into power system simulation software are needed. A model that can be used to represent all types of variable-speed wind turbines in power system dynamics simulations is presented. The modeling approach is commented upon, and models of the subsystems of which a variable speed wind turbine consists are discussed. Some results obtained after incorporation of the model in PSS/E, a widely used power system dynamics simulation software package, are presented and compared with measurements.