Isolation and Suppression of Forced Oscillations Through Wind Farms Under Grid Following and Grid Forming Control

Xianxian Zhao,Ying Xue,Xiao-Ping Zhang

doi:10.1109/access.2021.3082166

Xianxian Zhao, Ying Xue + Show 1 more

Open Access

https://doi.org/10.1109/access.2021.3082166

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Abstract

Forced Oscillations can occur even for a power system with good damping performance. With increasing high penetration of renewable energy generation towards 100% renewable generation in the power grid, exploitation of future control potential from wind turbines becomes inevitable. This paper develops an isolation and suppression method of Forced Oscillations by using wind farms (WFs) under both grid-following and grid-forming control principles. The proposed method controls a WF to absorb or release active and reactive power in a timely manner and as a result Forced Oscillations are prevented from spreading to the rest of the power grid and hence they are isolated. The Forced Oscillations of the disturbed area, which is bounded by the location of WF installation, are also reduced and suppressed. The proposed method is easy to implement and economically effective as there is no requirement of extra energy storage and power electronic devices, and a prior knowledge of the frequency of Forced Oscillations is not required. With the proposed control method, the loss of wind power capture is negligible. Furthermore, the control method is also able to damp natural oscillations. Simulations of both doubly fed induction generator (DFIG)-, and permanent magnetic synchronous generator (PMSG)-based WFs under either grid-following or grid-forming control principle, with constant or varying wind speeds and different WF locations with respect to the source of Forced Oscillations, on the modified two-area and IEEE 39-bus power systems, using Real-time Digital Simulator (RTDS) and Dymola, are used to verify the effectiveness of the proposed method.

Highlights

Compared to intrinsic natural interactions among dynamic components due to low or negative damping of a system [1], Forced Oscillations are incurred by periodic external disturbances at frequencies close or equal to the natural frequencies of the system modes and have been observed in power systems [2]–[9]
This paper has proposed an isolation and suppression method for Forced Oscillations using wind farms (WFs);
By controlling WFs to release or absorb active and reactive power opposite to the oscillating power from the selected isolation wall, the Forced Oscillations are isolated within the disturbed area and are prevented from propagating to the rest of the system

Summary

INTRODUCTION

Compared to intrinsic natural interactions among dynamic components due to low or negative damping of a system [1], Forced Oscillations are incurred by periodic external disturbances at frequencies close or equal to the natural frequencies of the system modes and have been observed in power systems [2]–[9]. In the second category of methods, instead of a complete elimination of Forced Oscillations, increasing system damping in [15]–[17], shifting the resonant frequency using a unified power flow controller [18], and injecting oscillating active power of utility energy storage systems in [19] are proposed to suppress Forced Oscillations. In [3] an E-STATCOM approach was proposed to isolate and suppress Forced Oscillations by incorporating an energy storage unit into static synchronous compensator (STATCOM) The disadvantages of this method are twofold: (1) Extra power electronic hardware and energy storage devices are required, and the cost and maintenance requirements of the associated devices must be considered; (2) Resonant controllers are adopted that require a priori knowledge of the frequency of the external disturbance.

PRINCIPLES OF THE PROPOSED ISOLATION AND SUPPRESSION OF FORCED OSCILLATIONS

PRINCIPLES OF THE PROPOSED METHOD

METHOD

THE PROPOSE METHOD REALIZED IN A GRID-FORMING WTS

Findings

CONCLUSION