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Strategy optimisation of large‐scale battery energy storage system (BESS) operation in active distribution networks (ADNs) is an actively pursued research topic concerned by electric power researchers. This study proposes a dynamic programming method (DPM)‐based operational strategy optimisation of vanadium redox flow battery (VRB) ESSs for the comprehensive performance of ADNs considering the dynamic characteristics of VRB. The dynamic characteristics of VRB based on self‐discharge rate, dynamic efficiencies, maximum absorption power, cycle life and apparent power are reasonably proposed to construct the operational restrictions of ESSs. VRB is safely and reasonably operated with high cycle life and ideal states by these dynamic operational restrictions. And then, DPM is used to decompose the multivariate optimisation problem into several univariate optimisation problems. Finally, different case studies showed that the developed operation strategy of VRB ESSs can greatly improve both the economy and the voltage quality of ADNs. Also, the curtailment rate of renewable energy in ADNs is greatly reduced by about 50% and VRB ESSs can get a perfect optimisation associated with a higher utilisation rate of about 0.8 and an ameliorative average efficiency of about 0.753.
Jiazhi Lei; David Wenzhong Gao; Jinhong Liu. Operational strategy optimisation of VRB energy storage systems considering the dynamic characteristics of VRB in active distribution networks. IET Renewable Power Generation 2021, 15, 1058 -1068.
AMA StyleJiazhi Lei, David Wenzhong Gao, Jinhong Liu. Operational strategy optimisation of VRB energy storage systems considering the dynamic characteristics of VRB in active distribution networks. IET Renewable Power Generation. 2021; 15 (5):1058-1068.
Chicago/Turabian StyleJiazhi Lei; David Wenzhong Gao; Jinhong Liu. 2021. "Operational strategy optimisation of VRB energy storage systems considering the dynamic characteristics of VRB in active distribution networks." IET Renewable Power Generation 15, no. 5: 1058-1068.
This study aims at specifying the operational risk assessment of active distribution networks (ADNs). Correspondingly, an operational risk assessment model based on point estimate method (PEM) considering probabilistic uncertainties of distributed generators-loads and power management of vanadium redox flow battery (VRB) energy storage systems (ESSs) was proposed. The probabilistic uncertainties of distributed generators and loads growth are mathematically modelled and discretised by PEM. Also, the distributed VRB ESSs are maximally used for the consumption of renewable energy and power supply of loads by the power management of VRB ESSs. The risk assessment indexes of expected energy not supplied and severity index for ADNs are constructed and the 2m + 1 PEM was used for the calculation. Finally, the case studies verified the effectiveness of PEM as the relative error is less than 1.75% and the excellent advantage on fast calculation. In addition, both the power management of distributed VRB ESSs and the dispersion of DGs or VRB ESSs have a significant influence on the operational risk assessment of ADNs.
Jiazhi Lei; Qingwu Gong; David Wenzhong Gao; Baohua Wang; Xiangyu Guan. Operation risk assessment of active distribution networks considering probabilistic uncertainties of distributed generators‐loads and power management of VRB ESSs. IET Renewable Power Generation 2020, 14, 1764 -1771.
AMA StyleJiazhi Lei, Qingwu Gong, David Wenzhong Gao, Baohua Wang, Xiangyu Guan. Operation risk assessment of active distribution networks considering probabilistic uncertainties of distributed generators‐loads and power management of VRB ESSs. IET Renewable Power Generation. 2020; 14 (10):1764-1771.
Chicago/Turabian StyleJiazhi Lei; Qingwu Gong; David Wenzhong Gao; Baohua Wang; Xiangyu Guan. 2020. "Operation risk assessment of active distribution networks considering probabilistic uncertainties of distributed generators‐loads and power management of VRB ESSs." IET Renewable Power Generation 14, no. 10: 1764-1771.
In allusion to the prediction for the failure rate of transmission lines under multiple external environmental factors, a comprehensive prediction method for the failure rate of transmission lines based on an multi-dimensional cloud model and Cholesky decomposition was proposed in this study. According to the historical data in meteorological early warning system and icing forecasting system, the mutual correlation degrees of these multiple external environmental factors are got by the grey relational algorithm and the comprehensive prediction model for the failure rate of transmission lines was established based on an multi-dimensional cloud model and Cholesky decomposition. In light with the external environmental factors in the next year, the failure rate of transmission lines was predicted by this proposed method. The test results based on actual data in Guizhou Power Grid show that this proposed comprehensive prediction method for the failure rate of transmission lines has high accuracy as the prediction error is about 2.05% and a much low computational burden as it only takes 30.25 s which is highly suitable for practical applications.
Jiazhi Lei; Qingwu Gong. Comprehensive prediction method for failure rate of transmission line based on multi‐dimensional cloud model. IET Generation, Transmission & Distribution 2019, 13, 1672 -1678.
AMA StyleJiazhi Lei, Qingwu Gong. Comprehensive prediction method for failure rate of transmission line based on multi‐dimensional cloud model. IET Generation, Transmission & Distribution. 2019; 13 (9):1672-1678.
Chicago/Turabian StyleJiazhi Lei; Qingwu Gong. 2019. "Comprehensive prediction method for failure rate of transmission line based on multi‐dimensional cloud model." IET Generation, Transmission & Distribution 13, no. 9: 1672-1678.
This paper aims at specifying the optimal allocation of a vanadium redox flow battery (VRB) energy storage system (ESS) for maintaining power balance of active distribution networks for wind power applications. Correspondingly, an optimal allocation approach for the VRB ESS was proposed. Different with the previous researches, the dynamic efficiency and life of VRB are considered in the proposed mathematical framework. Also, this proposed mathematical framework made a comprehensive assessment of the total benefits including the consumption of wind power, the reduced load interruption, greenhouse gas emission, network loss, and the capital cost of VRB ESS. These economic indicators are used to evaluate the penetration of VRB ESS and the economy of ADNs can achieve to the optimal with the designed VRB ESS. Finally, the proposed optimal allocation approach was validated and tested by a modified IEEE 33-bus system and IEEE 123 node system. Test results have demonstrated the effectiveness of the proposed optimal allocation approach associated with the power flow operation characteristics of active distribution networks.
Jiazhi Lei; Qingwu Gong; Jinhong Liu; Hui Qiao; Bo Wang. Optimal allocation of a VRB energy storage system for wind power applications considering the dynamic efficiency and life of VRB in active distribution networks. IET Renewable Power Generation 2019, 13, 563 -571.
AMA StyleJiazhi Lei, Qingwu Gong, Jinhong Liu, Hui Qiao, Bo Wang. Optimal allocation of a VRB energy storage system for wind power applications considering the dynamic efficiency and life of VRB in active distribution networks. IET Renewable Power Generation. 2019; 13 (4):563-571.
Chicago/Turabian StyleJiazhi Lei; Qingwu Gong; Jinhong Liu; Hui Qiao; Bo Wang. 2019. "Optimal allocation of a VRB energy storage system for wind power applications considering the dynamic efficiency and life of VRB in active distribution networks." IET Renewable Power Generation 13, no. 4: 563-571.
This paper aims at specifying the optimal allocation of a hybrid supercapacitor‐vanadium redox flow battery (VRB) energy storage system (ESS) for maintaining power balance of active distribution networks (ADNs) for wind power applications. Correspondingly, an optimal allocation approach for the hybrid ESS considering the application scenarios of supercapacitor ESS and VRB ESS was proposed. The supercapacitor ESS was used for restraining the high‐frequency components of net load power and a net load power spectrum analysis method based on dividing the variations of net load power was used to obtain the optimal capacity of supercapacitor ESS. For the allocation of hybrid ESS, a mathematical framework was proposed considering both the economy and reliability of ADNs associated with VRB′ dynamic operation characteristics. Finally, the proposed optimal allocation approach was validated and tested by a modified IEEE 33‐bus system. Test results have demonstrated the effectiveness of the proposed optimal allocation approach associated with the power flow operation characteristics of ADNs.
Jiazhi Lei; Qingwu Gong. Optimal allocation of a hybrid energy storage system considering its dynamic operation characteristics for wind power applications in active distribution networks. International Journal of Energy Research 2018, 42, 4184 -4196.
AMA StyleJiazhi Lei, Qingwu Gong. Optimal allocation of a hybrid energy storage system considering its dynamic operation characteristics for wind power applications in active distribution networks. International Journal of Energy Research. 2018; 42 (13):4184-4196.
Chicago/Turabian StyleJiazhi Lei; Qingwu Gong. 2018. "Optimal allocation of a hybrid energy storage system considering its dynamic operation characteristics for wind power applications in active distribution networks." International Journal of Energy Research 42, no. 13: 4184-4196.
The intermittency and variability of permeated distributed generators (DGs) could cause many critical security and economy risks to distribution systems. This paper applied a certain mathematical distribution to imitate the output variability and uncertainty of DGs. Then, four risk indices—EENS (expected energy not supplied), PLC (probability of load curtailment), EFLC (expected frequency of load curtailment), and SI (severity index)—were established to reflect the system risk level of the distribution system. For the certain mathematical distribution of the DGs’ output power, an improved PEM (point estimate method)-based method was proposed to calculate these four system risk indices. In this improved PEM-based method, an enumeration method was used to list the states of distribution systems, and an improved PEM was developed to deal with the uncertainties of DGs, and the value of load curtailment in distribution systems was calculated by an optimal power flow algorithm. Finally, the effectiveness and advantages of this proposed PEM-based method for distribution system assessment were verified by testing a modified IEEE 30-bus system. Simulation results have shown that this proposed PEM-based method has a high computational accuracy and highly reduced computational costs compared with other risk assessment methods and is very effective for risk assessments.
Qingwu Gong; Jiazhi Lei; Hui Qiao; Jingjing Qiu. Risk Assessment for Distribution Systems Using an Improved PEM-Based Method Considering Wind and Photovoltaic Power Distribution. Sustainability 2017, 9, 491 .
AMA StyleQingwu Gong, Jiazhi Lei, Hui Qiao, Jingjing Qiu. Risk Assessment for Distribution Systems Using an Improved PEM-Based Method Considering Wind and Photovoltaic Power Distribution. Sustainability. 2017; 9 (4):491.
Chicago/Turabian StyleQingwu Gong; Jiazhi Lei; Hui Qiao; Jingjing Qiu. 2017. "Risk Assessment for Distribution Systems Using an Improved PEM-Based Method Considering Wind and Photovoltaic Power Distribution." Sustainability 9, no. 4: 491.
This paper used a Vanadium Redox flow Battery (VRB) as the storage battery and designed a two-stage topology of a VRB energy storage system in which a phase-shifted full bridge dc-dc converter and three-phase inverter were used, considering the low terminal voltage of the VRB. Following this, a model of the VRB was simplified, according to the operational characteristics of the VRB in this designed topology of a VRB energy storage system (ESS). By using the simplified equivalent model of the VRB, the control parameters of the ESS were designed. For effectively estimating the state of charge (SOC) of the VRB, a traditional method for providing the SOC estimation was simplified, and a simple and effective SOC estimation method was proposed in this paper. Finally, to illustrate the proper design of the VRB ESS and the proposed SOC estimation method, a corresponding simulation was designed by Simulink. The test results have demonstrated that this proposed SOC estimation method is feasible and effective for indicating the SOC of a VRB and the proper design of this VRB ESS is very reasonable for VRB applications.
Qingwu Gong; Jiazhi Lei. Design of a Bidirectional Energy Storage System for a Vanadium Redox Flow Battery in a Microgrid with SOC Estimation. Sustainability 2017, 9, 441 .
AMA StyleQingwu Gong, Jiazhi Lei. Design of a Bidirectional Energy Storage System for a Vanadium Redox Flow Battery in a Microgrid with SOC Estimation. Sustainability. 2017; 9 (3):441.
Chicago/Turabian StyleQingwu Gong; Jiazhi Lei. 2017. "Design of a Bidirectional Energy Storage System for a Vanadium Redox Flow Battery in a Microgrid with SOC Estimation." Sustainability 9, no. 3: 441.
The intermittency and variability of these permeated Distributed Generators (DGs) could critically cause many security and economy risks to distribution systems. This paper applied a certain mathematical distribution to imitate the output variability and uncertainty of DGs. And then, four risk indices EENS, PLC, EFLC and SI were established to reflect the system risk level of distribution system. For the certain mathematical distribution of the DGs' output power, a developed PEM (point estimate method)-based method was proposed to calculate these four system risk indices. In this developed PEM-based method, enumeration method was used to list the states of distribution systems, an improved PEM was presented to deal with the uncertainties of DGs and the value of load curtailment in distribution systems was calculated by an optimal power flow algorithm. Finally, the effectiveness and advantages of this proposed PEM-based method for distribution system assessment were verified by the tests of a modified IEEE 30-bus system. Simulation results have shown that this proposed PEM-based method has a high computational accuracy and highly reduced computational costs compared with other risk assessment methods and is very effective for risk assessments.
Qingwu Gong; Jiazhi Lei. Risk Assessment for Distribution Systems Using a Developed PEM-Based Method Considering Wind and Photovoltaic Power Distribution. 2017, 1 .
AMA StyleQingwu Gong, Jiazhi Lei. Risk Assessment for Distribution Systems Using a Developed PEM-Based Method Considering Wind and Photovoltaic Power Distribution. . 2017; ():1.
Chicago/Turabian StyleQingwu Gong; Jiazhi Lei. 2017. "Risk Assessment for Distribution Systems Using a Developed PEM-Based Method Considering Wind and Photovoltaic Power Distribution." , no. : 1.
Purpose This paper aims to propose a simplified model of vanadium redox flow batteries (VRBs) for VRB energy storage system (ESS) design considering the operational characteristics of VRB, and a VRB ESS, considering the low terminal voltage of VRB, was presented. Design/methodology/approach According to the designed topology of VRB ESS and the simplified model of VRB, a small perturbation analysis method was used to establish the transfer function of VRB ESS, and the controller parameters of VRB ESS under constant charging and discharging current were designed. Findings Test results have demonstrated that this designed VRB ESS has fast response, small overshoot, strong adaptation and high steady precision, which strongly verified the reasonable design. Practical implications This simplified model of VRB can be suitably used for VRB ESS design. This designed VRB ESS realized the bidirectional power flow of VRB and AC grid. In this designed VRB ESS, phase-shifted full-bridge converter and a single-phase inverter were used and VRB was charged and discharged under constant current. Originality/value The paper presents a topology of VRB ESS which can realize the bidirectional power flow of VRB and AC grid. Considering the complexity of VRB model, a simplified model of VRB was proposed for the controller parameters design of VRB ESS, and this method can be used in application.
Jiazhi Lei; Qingwu Gong; Jun Ye. Design of an energy storage system based on vanadium redox flow battery considering a simplified model of VRB. COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 2017, 36, 153 -167.
AMA StyleJiazhi Lei, Qingwu Gong, Jun Ye. Design of an energy storage system based on vanadium redox flow battery considering a simplified model of VRB. COMPEL - The international journal for computation and mathematics in electrical and electronic engineering. 2017; 36 (1):153-167.
Chicago/Turabian StyleJiazhi Lei; Qingwu Gong; Jun Ye. 2017. "Design of an energy storage system based on vanadium redox flow battery considering a simplified model of VRB." COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 36, no. 1: 153-167.
Wind power has achieved great development in Northern China, but abundant wind power is dissipated, rather than utilized, due to inflexible electricity production of combined heat and power (CHP) units. In this paper, an integrated CHP system consisting of CHP units, wind power plants, and condensing power plants is investigated to decouple the power and heat production on both the power supply side and heat supply side, by incorporating electrical energy storage (EES) and thermal energy storage (TES). Then the integrated CHP system dispatch (ICHPSD) model is formulated to reach the target of reducing wind power curtailment and primary energy consumption. Finally, the feasibility and effectiveness of the proposed ICHPSD model are verified by the six-bus system, and the simulation results show that EES has a better effect on wind power integration than TES. The annual net benefits by incorporating EES and TES increase with increasing wind penetration, but they gradually approach saturation. Introducing both EES and TES can largely increase the amount of wind power integration and improve the operation efficiency of the system.
Rongxiang Yuan; Jun Ye; Jiazhi Lei; Timing Li. Integrated Combined Heat and Power System Dispatch Considering Electrical and Thermal Energy Storage. Energies 2016, 9, 474 .
AMA StyleRongxiang Yuan, Jun Ye, Jiazhi Lei, Timing Li. Integrated Combined Heat and Power System Dispatch Considering Electrical and Thermal Energy Storage. Energies. 2016; 9 (6):474.
Chicago/Turabian StyleRongxiang Yuan; Jun Ye; Jiazhi Lei; Timing Li. 2016. "Integrated Combined Heat and Power System Dispatch Considering Electrical and Thermal Energy Storage." Energies 9, no. 6: 474.
With the penetration of distributed generators (DGs), operation planning studies are essential in maintaining and operating a reliable and secure power system. Appropriate siting and sizing of DGs could lead to many positive effects forthe distribution system concerned, such as the reduced total costs associated with DGs, reduced network losses, and improved voltage profiles and enhanced power-supply reliability. In this paper, expected load interruption cost is used as the assessment of operation risk in distribution systems, which is assessed by the point estimate method (PEM). In light with the costs of system operation planning, a novel mathematical model of chance constrained programming (CCP) framework for optimal siting and sizing of DGs in distribution systems is proposed considering the uncertainties of DGs. And then, a hybrid genetic algorithm (HGA), which combines the GA with traditional optimization methods, is employed to solve the proposed CCP model. Finally,the feasibility and effectiveness of the proposed CCP model are verified by the modified IEEE 30-bus system, and the test results have demonstrated that this proposed CCP model is more reasonable to determine the siting and sizing of DGs compared with traditional CCP model.
Qingwu Gong; Jiazhi Lei; Jun Ye. Optimal Siting and Sizing of Distributed Generators in Distribution Systems Considering Cost of Operation Risk. Energies 2016, 9, 61 .
AMA StyleQingwu Gong, Jiazhi Lei, Jun Ye. Optimal Siting and Sizing of Distributed Generators in Distribution Systems Considering Cost of Operation Risk. Energies. 2016; 9 (1):61.
Chicago/Turabian StyleQingwu Gong; Jiazhi Lei; Jun Ye. 2016. "Optimal Siting and Sizing of Distributed Generators in Distribution Systems Considering Cost of Operation Risk." Energies 9, no. 1: 61.