| Abstract |
In much of the published analysis of the operation of active front end voltage sourced converters connected to power systems, the network is represented as a simple resistive inductive circuit. However real, multiple turbine, wind park collector systems have significant MV collector cabling and/or overhead lines, and depending on the wind farm, HV cabling which add distributed capacitance and so create resonances which interact with the active front end (network bridge) closed loop current control. The characteristics of these resonances, and hence the stability margins of the closed loop systems, are dependent on the number of collector cables in service, the system fault level, the number of turbines connected, power factor correction equipment, as well as the frequency dependency of such components. This can represent a significant range of operating conditions.
This paper presents the multiple methods by which the stability of such systems can be assessed using actual wind farm data, and then examines the stability implications when standard current controllers are used, such as those presented in much of the published literature. It will be shown that such systems can be robustly controlled to meet the demanding transient and steady state stability requirements required from modern power converters within such applications and how, through the use of the these techniques, large numbers of wind turbines operating on relatively low fault level supplies can be integrated into the power supply network. |
