Simultaneous STATCOM and Pitch Angle Control for Improved LVRT Capability of Fixed-Speed Wind Turbines

Abstract

A robust multivariable controller with the objective of enhancing the low-voltage ride-through (LVRT) capability of wind farms with fixed-speed induction generators is presented in this paper. The nonlinear dynamics of the wind generator is represented as a linear system and a norm-bounded nonlinear uncertain term, derived from the Cauchy remainder of the Taylor series. The designed robust controller provides acceptable post-fault performance for both small and large perturbations. Large disturbance simulations demonstrate that the designed controller enhances voltage stability as well as transient stability of the system during lowvoltage ride-through transients and thus enhances the LVRT capability of fixed-speed wind generators.

Improved low-voltage-ride-through capability of fixed-speed wind turbines using decentralised control of STATCOM with energy storage system

“…In most situations, the post-fault uncontrolled system has unstable post-fault trajectory. The difficulty in providing the LVRT capability is because of the non-linearities in the power system model [13]. Linear controllers have a limited range of operation which normally does not include post-fault voltage conditions [13].…”

“…The difficulty in providing the LVRT capability is because of the non-linearities in the power system model [13]. Linear controllers have a limited range of operation which normally does not include post-fault voltage conditions [13]. A solution to the LVRT problem is to design globally stabilising controllers [14].…”

Robust control strategy for PV system integration in distribution systems

“…However, the fact that such a controller cannot stabilize a system for severe large disturbances motivates the use of advanced control techniques, which consider nonlinear interactions and ensure stability under large disturbances [19,20].…”

Power system transient stability enhancement using direct drive wind generators

“…Recent grid codes prevent the disconnection of the wind farms as it can lead to the cascading failures in the system. Capability of the fixed speed wind turbine to ride through the faults can be improved by applying FACTS devices, fast pitching of the turbine blades during the fault period, using dynamic breaking resistors, or implementing superconducting magnetic energy storage (SMES) [10][11][12][13][14][15][16]. Among aforementioned solutions, SMES has been proved to be the most effective technology to improve the FRT capability of fixed speed wind generators but installation of SMES is not cost effective.…”