Changhong Zhao, Assistant Professor
Department of Information Engineering
The Chinese University of Hong Kong (CUHK)
Graduate students
- Yujin Huang, 2023 -
- Bohang Fang, PhD 2025.
- Heng Liang, PhD 2025.
- Runjie Zhang, MPhil 2025.
- Tong Wu, PhD 2021 (with Angela Zhang). University of Central Florida (8/2024).
Postdocs
- Kaiping Qu, 2024 - 2025 (with Yue Chen). Fuzhou University.
- Wanjun Huang, 2021 - 2022. Beihang University.
- Wei Lin, 2021 - 2022. Chongqing University (1/2025).
- Sidun Fang, 2020 - 2021. Chongqing University.
Research
projects
Joint optimization of distribution network topology and nonlinear power flow.
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Consider an optimal
topology and power flow (OTPF) problem in power distribution networks, which
jointly optimizes the on/off status of power lines and the generations, loads,
and power flows, for more reliable and efficient operation.
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Develop OTPF
solution algorithms with improved scalability and optimality, considering unbalanced three-phase nonlinear AC power flow models, uncertainties of renewable generations and loads, and key reliability
indices, e.g., voltage stability, that do not have closed-form expressions.
Accelerating large-scale optimization of nonlinear power flow.
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Develop a hierarchical,
distributed, spatially recursive algorithm with improved gradient calculation
to solve large-scale nonlinear optimal power flow (OPF) problems fast and
accurately.
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Integrate
hierarchical distributed computing with decentralized neural networks learned
from data to predict iterative descent directions of decision variables, for
faster solution.
Machine learning for reliable and efficient power system operation.
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Develop a
neural-network-based machine-learning method to design decentralized nonlinear
frequency and voltage feedback controllers for power systems.
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Steer power system
dynamics to a new equilibrium after the operating condition changes, while
guaranteeing asymptotic stability and transient safety of frequency and
voltage.
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Reduce the maximum
frequency and voltage deviations, their variances under noisy power injections
and measurements, and control efforts integrated over time.
Optimizing fast frequency response of distributed energy resources (DERs).
-
Develop a systematic
framework for DERs to provide inertial and primary-frequency response to the
transmission network, under nonlinear AC power flow models and safety
limits of distribution networks.
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At the distribution
level, quantify the capabilities of DERs to provide fast frequency reserves.
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At the transmission
level, control the power exchanges at substations to optimize the rate
of change of frequency, frequency overshoot, settling time, and steady state.