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Yifei Guo

Publications and source records attributed to Yifei Guo.

21 records · Page 2Linked to original sources

Learning-Based Real-Time Event Identification Using Rich Real PMU Data

A large-scale deployment of phasor measurement units (PMUs) that reveal the inherent physical laws of power systems from a data perspective enables an enhanced awareness of power system operation. However, the high-granularity and non-stationary nature of PMU time series and imperfect data quality could bring great technical challenges to real-time system event identification. To address these issues, this paper proposes a two-stage learning-based framework. At the first stage, a Markov transition field (MTF) algorithm is exploited to extract the latent data features by encoding temporal dependency and transition statistics of PMU data in graphs. Then, a spatial pyramid pooling (SPP)-aided convolutional neural network (CNN) is established to efficiently and accurately identify operation events. The proposed method fully builds on and is also tested on a large real dataset from several tens of PMU sources (and the corresponding event logs), located across the U.S., with a time span of two consecutive years. The numerical results validate that our method has high identification accuracy while showing good robustness against poor data quality.

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Secondary Voltage Control of Microgrids Using Nonlinear Multiple Models Adaptive Control

This paper proposes a novel model-free secondary voltage control (SVC) for microgrids using nonlinear multiple models adaptive control. The proposed method is comprised of two components. Firstly, a linear robust adaptive controller is designed to guarantee the voltage stability in the bounded-input-bounded-output (BIBO) manner, which is more consistent with the operation requirements of microgrids. Secondly, a nonlinear adaptive controller is developed to improve the voltage tracking performance with the help of artificial neural networks (ANNs). A switching mechanism is proposed to coordinate such two controllers for guaranteeing the closed-loop stability while achieving accurate voltage tracking. Given our method leverages a data-driven real-time identification, it only relies on the input and output data of microgrids without resorting to any prior information of primary control and grid models, thus exhibiting good robustness, ease of deployment and disturbance rejection.

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Two-Layer Volt/VAR Control in Unbalanced Active Distribution Systems: Efficient Optimization and Accurate Tracking

This paper proposes a novel two-layer Volt/VAR control (VVC) framework to regulate the voltage profiles across an unbalanced active distribution system, which achieves both the efficient open-loop optimization and accurate closed-loop tracking. In the upper layer, the conventional voltage regulation devices with discrete and slow-response characteristics are optimally scheduled to regulate voltage profiles in an hourly timescale while improving economic operations based on the receding horizon optimization (RHO) in a centralized manner. A generalized linearized branch flow model (G-LBFM) is developed to incorporate tap changers into branches, which significantly reduces the computational complexity compared to the original mixed-integer non-convex case. In the lower layer, we develop an integral-like control algorithm rather than resorting to the droop-based rules for real-time reactive power dispatch of distributed energy resources (DERs) to achieve accurate voltage tracking and mitigate fast voltage fluctuations in a decentralized (purely local) fashion. Further, a sufficient stability condition of the integral rule is presented to guarantee the closed-loop stability. Case studies are carried out on the unbalanced IEEE 123-Node Test Feeder to validate the effectiveness of the proposed method.

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