An efficient discrete-time approach for the computation of the steady-state operating point of a wind park is presented in this paper. The Finite Differences method and a Newton approach are applied to determine the steady-state solution of the wind park. Besides, the incorporation of sparse techniques improves the efficiency of the discrete-time solution in terms of storage and computational effort. The wind park is modeled using a time domain frame of reference, suitable for stability studies. While the wind generators are described with a reduced order model for the asynchronous machine, the wind turbine model takes into account the dimension of the turbine and incorporates a pitch angle controller. Each wind generator incorporates a capacitor bank at its terminals for reactive compensation of the induction generator. The dynamic response of a 100 MW wind park is reported using measured wind speed sequence as input to each wind generator. Furthermore, comparisons in terms of convergence and computational effort required to determine the steady-state solution are reported with the Finite Differences method and a Brute Force method. Speed up factors up to 42 are obtained for a 100 MW wind park described with 300 ordinary differential equations.

Steady-state solution of a wind park using the finite differences and the Newton methods

The research work presented in this paper focuses on analyzing the steady-state and transient operation of a wind farm interconnected to the medium voltage network through a voltage source converter with neutral point clamped structure, VSC-NPC. As first part of the analysis, a number of wind speed variations are carried out to observe the steady-state performance of the system. For transient conditions, two particular study cases are performed in the test network: a) the occurrence of voltage sag, b) the occurrence of voltage swell. The simulation results illustrate the favorable impact of the multilevel controller on the distribution network performance.

Analysis of wind farm and multilevel converter interactions in medium voltage networks under steady-state and transient conditions

This paper shows the steady state and transient behavior of a Multilevel Voltage Source Converter with Neutral-Point Clamp, VSC-NPC, interconnecting wind generation to medium voltage grids. The benefits on loads close to wind generation are also analyzed. The purpose of VSC operating as inverter is to support the wind generation system performance and dynamic interaction with the network. For analyzing the transient behavior of the electrical network, several voltage sags and swells are applied to the grid. The simulation results show how the distribution network is protected against these disturbances. The various network operation scenarios have been carried out in Simulinkcopy.

J. Sosa-Ruiz

Papers

Analysis of wind farm and multilevel converter interactions in medium voltage networks under steady-state and transient conditions

Wind generation and multilevel VSC-NPC integration to distribution networks: Analysis under steady-state and transient conditions