A control algorithm for Parallel Connected Offshore Wind Turbines with permanent magnet synchronous Generators (PCOWTG) is presented in this paper. The algorithm estimates the optimal collective speed of turbines based on the estimated mechanical power of wind turbines without direct measurement of wind speed. In the proposed topology of the wind farm, direct-drive Wind Turbine Generators (WTG) is connected to variable low-frequency AC Collection Grids (ACCG) without the use of individual power converters. The ACCG is connected to a variable low-frequency offshore AC transmission grid using a step-up transformer. In order to achieve optimum wind power extraction, the collective speed of the WTGs is controlled by a single onshore Back to Back converter (B2B). The voltage control system of the B2B converter adjusts voltage by keeping a constant Volt/Hz ratio, ensuring constant magnetic flux of electromagnetic devices regardless of changing system frequency. With the use of PI pitch compensators, wind power extraction for each wind turbine is limited within rated WTG power limits. Lack of load damping in offshore wind parks can result in oscillatory instability of PCOWTG. In this paper, damping torque is increased using P pitch controllers at each WTG that work in parallel with PI pitch compensators.

This paper presents a novel control algorithm for variable speed wind generators (VSWG), designed to provide support to grid frequency regulation. The proposed control algorithm ensures that VSWG ‘’truly’’ emulates response of a conventional generating unit with non-reheat steam turbine (GUNRST) in the first several seconds after active power unbalance. A systematic method of analysis and synthesis of the new control algorithm is described in detail.

In this paper, the frequency response metrics of interconnected electric power systems (EPS) of Slovenia, Croatia and Bosnia and Herzegovina (ENTSO-E SCB control block) is presented. In the upcoming period in this region significant integration of wind energy is expected. Increased wind integration has great impacts on EPS frequency response due to decreasing total system inertia. A frequency response metrics calculation in a short period after a disturbance occurred is essential for design of any further frequency control action. Comparison of local bus frequency and frequency of centers of inertia is in the focus of this work. The regional EPS of South East Europe (SEE) is modeled using PSS/E. Frequency response metrics calculations and plots are performed using Python simulation language.

A new control algorithm for Directly Interconnected offshore Wind Turbines with permanent magnet synchronous Generators (DIWTG) is presented. In the DΓWTG offshore wind park configuration, Wind Turbines with Permanent Magnet Synchronous Generators (WTPMSG) are directly connected to the offshore AC collection grid without using a power converter. The offshore AC collection grid is then connected, via a transformer, to the offshore AC transmission grid. In order to achieve maximum power point tracking, the (collective) speed of DΓWTGs is controlled by an onshore back to back converter. By measuring the active power and speed of the permanent magnet generators, wind speed at each turbine is estimated and used for calculation of the reference speed of WTPMSGs. Voltage control at the power converter side is performed in a way which allow the DΓWTGs to be operated at a constant V/f where the maximum resultant frequency at nominal wind speed is 16.67 Hz.

A modied control algorithm of a variable speed wind generator (VSWG) for supporting power system frequency stabilization is presented in this paper. A comparison of the performance of this algorithm with active power control algorithms of VSWGs for supporting power system frequency stabilization, as published in the scientic literature, is also presented. A systematic method of analysis of the modied control algorithm is described in detail. It has been shown that by using the modied control algorithm, the VSWG \truly" emulates the inertial response of a conventional steam-generating unit with synchronous generators during the initial/inertial phase of primary frequency control, following loss of active power generation when wind speed is between cut-in (i.e. 4 m/s) and rated speed (i.e. 12 m/s). By the inclusion of a signal proportional to the frequency deviation as a power reference to the torque controller feedback loop of the modied control algorithm, it is ensured that the contribution of the VSWG to frequency stabilization is independent of the initial wind speed. This independence is kept as long as the wind speed is above the cut-in wind speed and slightly below the rated wind speed (i.e. 12 m/s). One of the important features of the modied control algorithm, namely a near-proportiona relationship between the initial wind turbine speed and the maximum wind turbine speed variation during the inertial response, has been identied. The results of the analysis provide a solid basis for further research in the area of VSWG contribution to frequency stabilization.

In this paper the analysis of a General Electric Wind Turbine Control Model (GEWTCM) and comparison with a Generic Wind Turbine Control Model (GWTCM) is presented. The analysis is performed for the GEWTCM stationary state. Based on the analysis, a systematic method for the GEWTCM initializations as well as a methodology for calculation of the GEWTCM operating point in steady state are presented. It has been shown that, due to lack of limiting of the pitch controller and pitch compensation, uniqueness of solution for initial and steady state values of all GEWTCM state variables are ensured except for the state variables of the pitch controller and pitch compensation. Conclusions from the analysis can help in the implementation of the wind turbine control model in power system dynamic simulation software packages in applications with variable wind speed.