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1,096 results on '"Jia, Hongjie"'

209. Bilateral Inertia and Damping Emulation Control Scheme of VSC-HVDC Transmission Systems for Asynchronous Grid Interconnections

Author

Zhu, Jiebei, Shen, Zhipeng, Yu, Lujie, Bu, Siqi, Li, Xialin, Chung, Chi Yung, Booth, Campbell D., Jia, Hongjie, and Wang, Chengshan

Abstract

This paper proposes a novel bilateral inertia and damping emulation (BIDE) control scheme for VSC-HVDC transmission systems that can autonomously provide inertial and damping responses to two VSC-HVDC interconnected asynchronous AC grids in a similar fashion of synchronous generators. For each VSC station, the energy for inertia emulation comes from augmented DC link capacitance whereas the energy for damping emulation comes from the interconnected grid on the other side. This proposed approach is communication-free as the essential information of two grid frequencies for inertia and damping emulation can be obtained from the locally measured variables dictated by the BIDE control algorithms. Modal analysis is carried out to investigate the impacts of BIDE-emulated inertia time constants and damping factors on system small-signal stability, and to obtain the optimal control parameters. The effectiveness of the proposed BIDE scheme is verified through controller hardware-in-the-loop experiments, in the presence of load changes and grid faults. The results show that the BIDE scheme can effectively enhance the stability and damp the frequency oscillations for both AC grids.

Published
2023
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222. User-friendly rolling control strategy for a heat pump heating system considering building thermal inertia

Author

Qian Xiao, Xianjun Meng, Qi Yan, Yunfei Mu, Lijia Du, and Jia Hongjie

Subjects
Energy conservation, Building management system, Heating system, law, Computer science, Heat transfer, Thermal, Operating cost, Building envelope, Automotive engineering, Heat pump, law.invention
Abstract

A user-friendly rolling control strategy for a heat pump heating system (HPS) considering building thermal inertia is proposed. A model of a typical HPS is established to reflect the thermal dynamic processes in different HPS parts. A model of the building heat load is also developed considering the actual heat transfer processes related to the building. Based on this, a control strategy framework for the HPS is proposed considering building thermal inertia and temperature comfort level. The optimal temperature set-point of the HPS in each control horizon is determined by the strategy through rolling control. A case study of a single-family residential building on a typical winter day in northern China demonstrates the benefit of the proposed strategy in terms of reducing the operating cost without disturbing the temperature comfort level. The impacts of the penalty factor regarding deviation from the user-expected indoor temperature and of the building envelope are further analysed and compared.

Published
2020

223. A Novel Detection and Localization Approach of Open-Circuit Switch Fault for the Grid-Connected Modular Multilevel Converter

Author

Jin, Yu, Xiao, Qian, Jia, Hongjie, Ji, Yanchao, Dragicevic, Tomislav, Teodorescu, Remus, Blaabjerg, Frede, Jin, Yu, Xiao, Qian, Jia, Hongjie, Ji, Yanchao, Dragicevic, Tomislav, Teodorescu, Remus, and Blaabjerg, Frede

Abstract

The open-circuit fault detection and localization (FDL) technique can improve the reliability of the modular multilevel converter (MMC). However, the conventional software-based FDL methods usually have a heavy computation burden or a limited localization speed. This paper proposes a simplified and fast software-based FDL approach for the grid-connected MMC. Firstly, the errors between the measured state variables (the output current and the circulating current) and their estimated values are calculated. By comparing these errors with their threshold values, the switch fault can not only be detected, but also be localized to the specific arm. Then, the capacitor voltages in this faulty arm are collected, and the submodule (SM) with the highest capacitor voltage is selected. To confirm the switch fault in this SM, a modified Pauta criterion is presented to check the abnormal voltage data. As a result, the computation burden of the proposed software-based FDL approach is significantly reduced, and the faulty SM can be localized in a short period. Simulation and experimental results verify that the proposed approach can effectively detect and locate different open-circuit faults, and it is immune to the step of power references.

Published
2022

226. Synthetic Resilience Exploration and Economic Defense Strategy for Microgrid-Level AC/DC Hybrid Energy System.

Author

Dong, Chaoyu, Wang, Junjun, Li, Xiangke, Jin, Chi, Jiang, Wentao, Zhang, Zhe, and Jia, Hongjie

Abstract

For the ac/dc hybrid energy system, a resilience-oriented defense strategy is developed for survivability enhancement when subject to severe energy disruptions. On account of heterogeneous components, an integration index of synthetic resilience (SR) is formulated to assess the resilience capability of hybrid energy systems in the event of sudden energy changes. The derived SR is systematically illustrated in this work, which not only reveals its convexity feature but also visualizes the inherent self-healing resources during the ac/dc energy interaction. Based on the proposed resilience index and interlinking bridge of bidirectional converter, an economic defense strategy concerning uncertainties from renewable energies and loads is developed and system resilience is consequently reinforced by dispatching distributed energies according to individual marginal cost. Without the global coordination and mode transition, the system resilience is significantly strengthened and assessed by the proposed index and defense strategy, which formulates an operational paradigm for the microgrid-level energy hybridization considering load variation and renewable energy penetration. To completely demonstrate the effectiveness of the proposed index and defense strategy for the hybrid energy system, the controller-hardware-in-the-loop experiment results have been provided from six aspects of steady-state operation, dc demand variation, ac demand variation, renewable energy fluctuations, dc energy source failure, and ac energy source failure. [ABSTRACT FROM AUTHOR]

Published
2023
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227. Day‐ahead optimal scheduling of building energy microgrids based on time‐varying virtual energy storage.

Author

Mu, Yunfei, Zhang, Yaqing, Jia, Hongjie, Yu, Xiaodan, Zhang, Jiarui, Jin, Xiaolong, and Deng, Youjun

Subjects
MICROGRIDS, ENERGY storage, HEAT storage, ELECTRIC capacity, BUILDING envelopes, THERMAL comfort, COMMERCIAL buildings, POWER plants
Abstract

The thermal inertia of a building envelope endows a building with a heat storage capability, introducing scheduling flexibility to a building energy microgrid (BEM). The flexibility is usually modelled as virtual energy storage (VES) and used to optimize the operation of BEMs to reduce electricity costs. However, the VES capacity is impacted by and varies with variations in indoor/outdoor temperature. If only the building envelope's effect on heat transfer is considered, without proper quantification of scheduling flexibility provided by the building envelope, the scheduling scheme (especially VES charging/discharging schemes) will deviate from the actual VES operating conditions, which may affect the thermal comfort of individuals in buildings or bring high electricity costs. In this paper, a time‐varying building VES model (TVES) with three time‐varying parameters (virtual electric capacity (VEC), state of charge (SOC), and charge and discharge power) is proposed to quantify the electricity storage capability of the VES at different time periods for participating in operation of the BEM. Based on the TVES, a day‐ahead optimal scheduling strategy is developed for the BEM to simultaneously reduce the electricity cost and guarantee the user's thermal comfort, where the proposed time‐varying parameters of TVES are taken as constraints in the optimization. Numerical studies verify the effectiveness of the proposed TVES and optimal scheduling strategy. [ABSTRACT FROM AUTHOR]

Published
2023
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