Search

Abstract Subsynchronous control interaction (SSCI) associated with wind farms has become one of the major challenges for maintaining the stability and reliability of modern power systems. SSCI is mainly caused by the active participation of fast-acting wind turbine converter (WTC) controls in the phenomenon. It can damage the system equipment, reduce the amount of power generation, and degrade the power quality. Thus, it is urgent to develop practical mitigation techniques for the SSCI in order to achieve a smooth and reliable operation of grid interfaced wind farms. This study presents an overview of potential SSCI mitigation techniques at various stages of the power system, including system planning, operation, control, and protection phases at both network and generation sides. In particular, this paper reviews the active damping controls utilizing flexible ac transmission systems (FACTS) and WTC controls. Finally, it outlines the challenges and future work in studying SSCI mitigation techniques in practical wind power systems. Highlights • SSCI mitigation techniques: planning, operation, control and protection stages. • Review of active damping control techniques in network and generation sides. • Challenges and limitations of various SSCI mitigation techniques are discussed. • WTC control modifications and shunt-VSC using filters are recommended approaches. [ABSTRACT FROM AUTHOR]

The subsynchronous control interaction (SSCI) occurs when the wind turbine converter (WTC) controls interact with the series-compensated or weak AC network. The mechanism and attributes of the emerging interaction phenomenon invilving wind turbine generators (WTGs) are quite different from the traditional subsynchronous resonance or oscillation (SSR/SSO) phenomenon in steam turbine-generators (STGs). The SSCI is characterized by various system-wide parameters, including the wind speed and its uneven distribution in a wind power plant, varying number of WTGs connected to the grid, type of the WTGs, parameters of the WTC controls, level of series compensation, stiffness of the grid, etc. Such system-wide parameters change over time and thus make the modeling and analysis rather challenging to conduct SSCI studies. An ideal modeling approach for the SSCI is expected to preserve the system topology as well as valid for a wide range of operating conditions and parameters of the system. On the other hand, an ideal stability analysis method is supposed to give key quantitative information, such as the magnitude, frequency, and origin of the oscillation, as well as the component level participation indices. This paper provides a comparative insight into the application of existing and emerging modeling and stability analysis approaches for SSCI investigations in large-scale wind farms. It highlights the strengths and weaknesses of various modeling methods and analysis criteria. Finally, the paper underlines the recent advancements and points out towards the research directions in small/large-signal impedance modeling and stability approaches for accurate and quantitative investigation of the SSCI. • SSCI is a system-wide phenomenon thus the modeling and analysis is challenging. • Strengths and weaknesses of the existing modeling and stability analysis methods in the time and frequency-domain are discussed. • An modeling method should preserve system topology and remains valid under a wide range of operating conditions. • An ideal stability analysis method should give key quantitative information: magnitude, frequency and source. [ABSTRACT FROM AUTHOR]

This paper concerns with the emerging power system stability issues, classification, and research prospects under a high share of renewables and power electronics. The decades-old traditional power system is undergoing a fast transition with two most prominent features: 1) high-penetration of renewable power generators, utilizing intermittent renewable sources such as wind and solar, and 2) high-penetration of power electronic devices in the generation e.g., wind turbine converters and solar power inverters, transmission e.g., flexible ac or dc transmission system converters, and distribution/utilization systems e.g., electric vehicle and microgrid. The development of modern power systems with dual high-penetrations, i.e., high-penetrations of renewables and power electronic devices, influences the power system dynamics significantly and causes new stability issues. This paper first overviews equipment-level features and system-level stability challenges introduced under the dual high-penetration scenario of the modern power system. Next, the impacts of emerging stability challenges on various aspects of the classical stability issues and classifications are highlighted. Under this context, this paper discusses the validity and limitations of the existing classical and extended power system stability classifications proposed by different IEEE/Cigre Working Groups. Furthermore, a new power system stability classification framework is proposed, which not only maintains the inherent logic of the classical classification but also provides wide coverage and future adaptability of the emerging stability issues. Finally, various classification-oriented research prospects in the power system stability domain are highlighted. • Discussion on the device- and system-level features of power systems with dual high-penetrations. • Emerging stability issues due to dual high-penetrations and their impact on stability classifications. • A critical review of existing classical and extended power system stability classifications of 2004 and 2020. • Highlighting the classification-oriented future research directions. [ABSTRACT FROM AUTHOR]