Avoiding Frequency Second Dip in Power Unreserved Control During Wind Power Rotational Speed Recovery

Qu, Yanbin; Kim, Hak-Man; Song, Huihui

doi:10.1109/tpwrs.2017.2761897

Cited by 86 publications

(51 citation statements)

References 17 publications

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“…This was due to a small reduction in the generated power compared to the prefault active power (thus, not operating in the MPP) [47]. The fast power reserve approach defines the overproduction power ∆p as a constant value independent of the power system configuration and frequency deviation [48][49][50][51] or as a variable value depending on the frequency deviation or minimum rotor speed limits [52][53][54]. With these three techniques, as the additional power ∆p is provided, the rotor and generator rotational speeds decrease (subsequently, modifying their torques).…”

Section: Vswts Frequency Control Strategiesmentioning

confidence: 99%

An Adaptive Control Scheme for Variable Speed Wind Turbines Providing Frequency Regulation in Isolated Power Systems with Thermal Generation

et al. 2020

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The lack of synchronous inertia, associated with the relevant penetration of variable speed wind turbines (VSWTs) into isolated power systems, has increased their vulnerability to strong frequency deviations. In fact, the activation of load shedding schemes is a common practice when an incident occurs, i.e., the outage of a conventional unit. Under this framework, wind power plants should actively contribute to frequency stability and grid reliability. However, the contribution of VSWTs to frequency regulation involves several drawbacks related to their efficiency and equipment wear due to electrical power requirements, rotational speed changes, and subsequently, shaft torque oscillations. As a result, wind energy producers are not usually willing to offer such frequency regulation. In this paper, a new control technique is proposed to optimize the frequency response of wind power plants after a power imbalanced situation. The proposed frequency controller depends on different power system parameters through a linear regression to determine the contribution of wind power plants for each imbalance condition. As a consequence, VSWTs frequency contribution is estimated to minimize their mechanical and electrical efforts, thus reducing their equipment wear. A group of sixty supply-side and imbalance scenarios are simulated and analyzed. Results of the case study are compared to previous proposals. The proposed adaptive control reduces the maximum torque and rotational speed variations while at the same time maintaining similar values of the load shedding program. Extensive results and discussion are included in the paper.

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Section: Vswts Frequency Control Strategiesmentioning

confidence: 99%

An Adaptive Control Scheme for Variable Speed Wind Turbines Providing Frequency Regulation in Isolated Power Systems with Thermal Generation

et al. 2020

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“…This means that if a large amount of kinetic energy is released to support the frequency and the recovery time is short, a big frequency second dip (FSD) will happen. If the released kinetic energy is small for a faster rotor speed recovery, the level of frequency support is limited [10]. In order to avoid big FSD and smoothly restore WTSs to the MPPT operating point, methods [10]- [12] have been proposed to carefully design the over-production and restoration processes.…”

mentioning

confidence: 99%

Fast Frequency Support From Wind Turbine Systems by Arresting Frequency Nadir Close to Settling Frequency

Zhao

Xue

Zhang

2020

IEEE Open J. Power Energy

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The recent power cut incident in the UK indicated that frequency control to reduce frequency nadir and eliminate frequency second dip is highly desirable for power grids with high penetration of wind energy. This paper proposes a fast frequency support scheme for wind turbine systems (WTSs) that can enable frequency nadir to be significantly reduced and close to the settling frequency and eliminate frequency second dip. In the proposed frequency support scheme, in order to achieve similar frequency support performance and ensure stability of WTSs under varying wind speeds, different levels of wind power penetration and system conditions, an adaptive gain, which is a function of real-time rotor speed and wind power penetration level, is proposed. In the proposed scheme, rotor speeds of WTSs are proposed not to be recovered to the optimal operating points during the primary frequency control, but recovered during the secondary frequency control. Simulation results on the IEEE two-area power system with a doubly fed induction generator (DFIG)-based wind farm and the IEEE 39-bus power system with permanent magnetic synchronous generator (PMSG)-based wind farms using real-time digital simulator (RTDS) and Dymola are presented to verify the effectiveness of the proposed scheme. Index Terms-Wind turbine system, fast frequency support, frequency second dip, frequency nadir, rate of change of frequency (ROCOF), primary frequency control.

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“…In recent research, the predetermined power profile and deloading strategies have been proposed for RG units to participate in power balance regulation. Firstly, the predetermined strategy modifies the power profile of RG units [24,25]. When frequency fluctuations happen, the output of wind turbines is set according to a predesigned curve [26][27][28][29].…”

mentioning

confidence: 99%

Emulation Strategies and Economic Dispatch for Inverter-Based Renewable Generation under VSG Control Participating in Multiple Temporal Frequency Control

2020

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As the increasing penetration of inverter-based generation (IBG) and the consequent displacement of traditional synchronous generators (SGs), the system stability and reliability deteriorate for two reasons: first, the overall inertia decreases since the power electronic interfaces (PEIs) are almost inertia-less; second, renewable generation profiles are largely influenced by stochastic meteorological conditions. To strengthen power systems, the concept of the virtual synchronous generator (VSG) has been proposed, which controls the external characteristics of PEIs to emulate those of SGs. Currently, PEIs could perform short-term inertial and primary frequency responses through the VSG algorithm. For renewable energy sources (RES), deloading strategies enable the generation units to possess active power reserves for system frequency responses. Additionally, the deloading strategies could provide the potential for renewable generation to possess long-term frequency regulation abilities. This paper focuses on emulation strategies and economic dispatch for IBG units to perform multiple temporal frequency control. By referring to the well-established knowledge systems of generation and operation in conventional power systems, the current VSG algorithm is extended and complemented by the emulation of secondary and tertiary regulations. The reliability criteria are proposed, considering the loss of load probability (LOLP) and renewable spillage probability (RSP). The reliability criteria are presented in two scenarios, including the renewable units operated in maximum power point tracking (MPPT) and VSG modes. A LOLP-based economic dispatch (ED) approach is solved to acquire the generation and reserve schemes. The emulation strategies and the proposed approach are verified by simulation.

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Avoiding Frequency Second Dip in Power Unreserved Control During Wind Power Rotational Speed Recovery

Cited by 86 publications

References 17 publications

An Adaptive Control Scheme for Variable Speed Wind Turbines Providing Frequency Regulation in Isolated Power Systems with Thermal Generation

An Adaptive Control Scheme for Variable Speed Wind Turbines Providing Frequency Regulation in Isolated Power Systems with Thermal Generation

Fast Frequency Support From Wind Turbine Systems by Arresting Frequency Nadir Close to Settling Frequency

Emulation Strategies and Economic Dispatch for Inverter-Based Renewable Generation under VSG Control Participating in Multiple Temporal Frequency Control

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