Effect of wind turbine output current during faults on grid voltage and the transient stability of wind parks

Abstract

This paper deals with the effectiveness of faultinduced current injection into the system by wind turbines. First, a brief review of the grid code requirement on wind turbines to support voltage profile during fault is reviewed. Based on first principles, analytical expressions quantifying the effectiveness and the limits of the voltage support effort are formulated. This has then been extended to include the limits imposed on output current by the transient stability requirements of the wind park, in which stability constrained current limits through the link wind park -the point of the interconnection and the boundary conditions for stable operation have been derived. Using sample computations, the effect of the violation of this stability limit during fault on the wind park has been analyzed. Finally, a control scheme has been proposed, which on the basis of the voltage dip experienced by the network, reduces the real part of the wind park output current with the objective of enhancing the transient stability margin. Again the effectiveness of the proposed scheme has been demonstrated using sample computations. Index Terms-Grid fault, voltage support, doubly-fed induction machine, wind power, wind generation control, transient stability.I. Erlich is with the University Duisburg-Essen,

Phase angle calculation dynamics of type‐4 wind turbines in rms simulations during severe voltage dips

“…To cite the paper please use the doi provided on the Digital Library page. 5 reference increases to 1 pu and the active current (Id) reference, which is 1pu before the fault, decreases down to 0.45pu during the fault as observed in Figure 2-b and 2-c.…”

“…These methods are briefly reviewed here only for the sake of coherency, though solving the LOS is not the main scope of this paper. In [5], [6] and [7], a voltage dependent active current reduction method during low voltage faults is suggested to avoid LOS. Assuming that the impedance between the WT terminal and the faulted grid point around PoC, is highly inductive (high X/R ratio), it helps to avoid the LOS to reduce the active current reference as voltage goes down.…”

“…a solid three-phase fault), which are required by the grid codes today [3], are compromised which might need further discussions on necessity of these fault tests for WPPs. In [4] and [5], it is shown that if the remaining PoC voltage larger than the magnitude of the impedance between the WT terminal and the WPP PoC in per unit, the LOS occurrence can be avoided. Hence, the fault studies with a fault impedance or using a remote fault location from the PoC can be considered as a suggestion to the system operators for the future grid codes.…”

Comparison of Transmission Technologies with Regard to their Contribution to Power System Stability

“…VSC can give the priority to reactive current that is only limited to the nominal current of the HVDC system. The capability of the reactive power boosting depends on the ratio of rated power to short circuit power at the node the transmission system is connected to [10]. …”

Optimal Allocation of Wind Turbines by Considering Transmission Security Constraints and Power System Stability

“…Even in the case of modern WTs with power electronic converters, their capability to support voltage stability cannot be compared with the traditional support provided by conventional power plants. The main reason for this is the need to limit the in-feed current of the WTs during disturbances as a consequence of: (1) technical margins of the electronic power devices and (2) need to preserve transient stability of the wind park [16]. By contrast, conventional power plants are characterized by a huge overloading capacity for a relatively wide time window [17].…”