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I am a PhD Student at Hongkong Polytechnic University. My research work includes Power System Analysis for Low Voltage DC (LVDC) grids, Power Flow Solution Algorithms for LVDC and Hybrid AC/DC distribution system, Future grid structures for LVDC and for Hybrid LVAC/LVDC distribution.
This paper presents static synchronous compensator (STATCOM) integration into a doubly-fed induction generator (DFIG) based wind park (WP), analyses the impact of STATCOM on the WP high voltage ride-through (HVRT) capability, and proposes a transient function for the STATCOM to improve the WP HVRT capability. An actual WP is adopted as a test system. The STATCOM size is selected considering the grid code requirement for power factor control, and various wind turbine (WT) and medium voltage (MV) feeder outage scenarios. The WP HVRT capability is assessed with electromagnetic transient (EMT) simulations by analyzing the responses to a parametric voltage waveform. The external system is represented by a Thevenin equivalent. The pre-described voltage waveforms are applied to the Thevenin source in order to assess the conformity of the HVRT capability to Hydro-Quebec specifications. The WP simulation model includes all details regarding collector grid and overvoltage protection. The simulation results demonstrate that, STATCOM usage provides a noticeable improvement in HVRT capability of the WP, especially with the proposed transient function.
Ulas Karaagac; Ilhan Kocar; Jean Mahseredjian; Lijun Cai; Zahid Javid. STATCOM integration into a DFIG-based wind park for reactive power compensation and its impact on wind park high voltage ride-through capability. Electric Power Systems Research 2021, 199, 107368 .
AMA StyleUlas Karaagac, Ilhan Kocar, Jean Mahseredjian, Lijun Cai, Zahid Javid. STATCOM integration into a DFIG-based wind park for reactive power compensation and its impact on wind park high voltage ride-through capability. Electric Power Systems Research. 2021; 199 ():107368.
Chicago/Turabian StyleUlas Karaagac; Ilhan Kocar; Jean Mahseredjian; Lijun Cai; Zahid Javid. 2021. "STATCOM integration into a DFIG-based wind park for reactive power compensation and its impact on wind park high voltage ride-through capability." Electric Power Systems Research 199, no. : 107368.
There is an increasing interest in low voltage direct current (LVDC) distribution grids due to advancements in power electronics enabling efficient and economical electrical networks in the DC paradigm. Power flow equations in LVDC grids are non-linear and non-convex due to the presence of constant power nodes. Depending on the implementation, power flow equations may lead to more than one solution and unrealistic solutions; therefore, the uniqueness of the solution should not be taken for granted. This paper proposes a new power flow solver based on a graph theory for LVDC grids having radial or meshed configurations. The solver provides a unique solution. Two test feeders composed of 33 nodes and 69 nodes are considered to validate the effectiveness of the proposed method. The proposed method is compared with a fixed-point methodology called direct load flow (DLF) having a mathematical formulation equivalent to a backward forward sweep (BFS) class of solvers in the case of radial distribution networks but that can handle meshed networks more easily thanks to the use of connectivity matrices. In addition, the convergence and uniqueness of the solution is demonstrated using a Banach fixed-point theorem. The performance of the proposed method is tested for different loading conditions. The results show that the proposed method is robust and has fast convergence characteristics even with high loading conditions. All simulations are carried out in MATLAB 2020b software.
Zahid Javid; Ulas Karaagac; Ilhan Kocar; Ka Chan. Laplacian Matrix-Based Power Flow Formulation for LVDC Grids with Radial and Meshed Configurations. Energies 2021, 14, 1866 .
AMA StyleZahid Javid, Ulas Karaagac, Ilhan Kocar, Ka Chan. Laplacian Matrix-Based Power Flow Formulation for LVDC Grids with Radial and Meshed Configurations. Energies. 2021; 14 (7):1866.
Chicago/Turabian StyleZahid Javid; Ulas Karaagac; Ilhan Kocar; Ka Chan. 2021. "Laplacian Matrix-Based Power Flow Formulation for LVDC Grids with Radial and Meshed Configurations." Energies 14, no. 7: 1866.
In this paper, a model is proposed for the optimal operation of multi-energy microgrids (MEMGs) in the presence of solar photovoltaics (PV), heterogeneous energy storage (HES) and integrated demand response (IDR), considering technical and economic ties among the resources. Uncertainty of solar power as well as the flexibility of electrical, cooling and heat load demand are taken into account. A p-efficient point method is applied to compute PV power at different confidence levels based on historical data. This method converts the uncertain PV energy from stochastic to deterministic to be included in the optimization model. The concept of demand response is extended and mathematically modeled using a linear function based on the quantized flexibility interval of multi-energy load demand. As a result, the overall model is formulated as a mixed-integer linear program, which can be effectively solved by the commercial solvers. The proposed model is implemented on two typical summer and winter days for various cases. Results of case studies show the important benefits for maximum PV utilization, energy efficiency and economic system operation. Moreover, the influence of the different confidence levels of PV power and effectiveness of IDR in the stochastic circumstances are addressed in the optimization-based operation.
Jingshan Wang; Ke-Jun Li; Yongliang Liang; Zahid Javid. Optimization of Multi-Energy Microgrid Operation in the Presence of PV, Heterogeneous Energy Storage and Integrated Demand Response. Applied Sciences 2021, 11, 1005 .
AMA StyleJingshan Wang, Ke-Jun Li, Yongliang Liang, Zahid Javid. Optimization of Multi-Energy Microgrid Operation in the Presence of PV, Heterogeneous Energy Storage and Integrated Demand Response. Applied Sciences. 2021; 11 (3):1005.
Chicago/Turabian StyleJingshan Wang; Ke-Jun Li; Yongliang Liang; Zahid Javid. 2021. "Optimization of Multi-Energy Microgrid Operation in the Presence of PV, Heterogeneous Energy Storage and Integrated Demand Response." Applied Sciences 11, no. 3: 1005.
Industrial sector is of great significance for the economic growth of every country. The energy crisis in Pakistan has become the prime stumbling block in the economic development of the country. There are many industrial processes that...
Zahid Javid; Ke-Jun Li; Rizwan Ul Hassan; Jian Chen. Hybrid-Microgrid Planning, Sizing and Optimization for an Industrial Demand in Pakistan. Tehnicki vjesnik - Technical Gazette 2020, 27, 781 -792.
AMA StyleZahid Javid, Ke-Jun Li, Rizwan Ul Hassan, Jian Chen. Hybrid-Microgrid Planning, Sizing and Optimization for an Industrial Demand in Pakistan. Tehnicki vjesnik - Technical Gazette. 2020; 27 (3):781-792.
Chicago/Turabian StyleZahid Javid; Ke-Jun Li; Rizwan Ul Hassan; Jian Chen. 2020. "Hybrid-Microgrid Planning, Sizing and Optimization for an Industrial Demand in Pakistan." Tehnicki vjesnik - Technical Gazette 27, no. 3: 781-792.
The steady-state performance of modular multilevel converter (MMC) can be optimized by the following methods: circulating current injection, third-harmonic signal injection, and average capacitor voltage control. However, most of the papers, due to the deficiencies of their MMC models, are limited to the study of just adopting one method and only optimizing a single-aspect performance. Thus, this paper proposes a general MMC model for the comprehensive study of the steady-state performance optimization. The general model is built based on an equilibrium equation between the internal quantities and the external quantities of the MMC. This general model is capable of analyzing the optimization where the optimizing methods are used in combination to improve the multi-aspect performance of the MMC. In addition, more influence factors are taken into account; hence the calculation error can be smaller than 1% and even the minor effect of each optimizing method can be reflected. The proposed model is compared with traditional models; and it is found that both dc and fundamental components in modulation signals will be affected by the injected circulating current, rather than constant values in the traditional models. Finally, the proposed MMC model is verified by both simulation and experiment.
Zhijie Liu; Ke-Jun Li; Jinyu Wang; Wentao Liu; Zahid Javid; Zhuo-Di Wang. General Model of Modular Multilevel Converter for Analyzing the Steady-State Performance Optimization. IEEE Transactions on Industrial Electronics 2020, 68, 925 -937.
AMA StyleZhijie Liu, Ke-Jun Li, Jinyu Wang, Wentao Liu, Zahid Javid, Zhuo-Di Wang. General Model of Modular Multilevel Converter for Analyzing the Steady-State Performance Optimization. IEEE Transactions on Industrial Electronics. 2020; 68 (2):925-937.
Chicago/Turabian StyleZhijie Liu; Ke-Jun Li; Jinyu Wang; Wentao Liu; Zahid Javid; Zhuo-Di Wang. 2020. "General Model of Modular Multilevel Converter for Analyzing the Steady-State Performance Optimization." IEEE Transactions on Industrial Electronics 68, no. 2: 925-937.
Role of Renewable Energy Resources (RES) is increasing day by day due to continuously depleting fossil fuels. Moreover, to make environment-friendly power generation, RES is one of the best options. According to the International Renewable Energy Agency (IRENA), the number of countries which aim their grids synchronized with RES has reached 180. This increasing trend of RES integration is causing new vulnerabilities in power system. This paper studies the impact of an increase in load under the different percentage levels of wind generation. Six cases are discussed, each with 10% increase in wind penetration along with 5% increase in load at every step. Modified IEEE-14 bus system is analyzed under various scenarios to evaluate the minimum voltage level, minimum angle, active and reactive power loss in the power system. Mat-Power and MATLAB are used to evaluate the power system. Results show that 20-30% wind generation penetration has a good impact on power system's performance. However, further increase in wind generation results in more power losses.
Rizwan Ul Hassan; Zahid Javid; Aamer Abbas Shah; Rizwan Ahmed. Impact of Load Variations on Power System Performance under High Penetration of Wind Generation. 2019 IEEE 2nd International Conference on Automation, Electronics and Electrical Engineering (AUTEEE) 2019, 166 -171.
AMA StyleRizwan Ul Hassan, Zahid Javid, Aamer Abbas Shah, Rizwan Ahmed. Impact of Load Variations on Power System Performance under High Penetration of Wind Generation. 2019 IEEE 2nd International Conference on Automation, Electronics and Electrical Engineering (AUTEEE). 2019; ():166-171.
Chicago/Turabian StyleRizwan Ul Hassan; Zahid Javid; Aamer Abbas Shah; Rizwan Ahmed. 2019. "Impact of Load Variations on Power System Performance under High Penetration of Wind Generation." 2019 IEEE 2nd International Conference on Automation, Electronics and Electrical Engineering (AUTEEE) , no. : 166-171.
Industrial sector is of great significance for economic growth of every country, but industries are polluting our environment day by day. Most of the customers at industrial and commercial level use Diesel Generator (DiG) as a reliable alternative source of electrical power when grid supply is unavailable. The use of DiG during loading shedding hours would increase Cost of Energy (COE) per KWh and also enhance the environmental emissions. With the distinct emphasis on the implementation of an industrial microgrid in Faisalabad, Pakistan has been specified in this paper. The prospective benefits of the microgrid fall into three major kinds: cost reduction, fuel saving, and improved environmental emissions. The optimization objective of this work is to maximize these benefits. This study contributes to the on-going studies about hybrid microgrid system for industrial loads and draws the attention towards clean form of energy to reduce the environmental emissions and energy saving. Different cases are studied; microgrid sizing, techno-economic exploration and environmental effects are addressed using (Hybrid Optimization Model for Electric Renewables) HOMER. The results show that COE and environmental emissions have been significantly reduced for the proposed system.
Zahid Javid; Li Kejun; Rizwan Ul Hassan; Jian Chen. Energy Saving and Carbon Reduction by Utilizing the Renewable Resources and Recycling the Waste of Industries for Power Generation. 2019 IEEE 2nd International Conference on Automation, Electronics and Electrical Engineering (AUTEEE) 2019, 261 -264.
AMA StyleZahid Javid, Li Kejun, Rizwan Ul Hassan, Jian Chen. Energy Saving and Carbon Reduction by Utilizing the Renewable Resources and Recycling the Waste of Industries for Power Generation. 2019 IEEE 2nd International Conference on Automation, Electronics and Electrical Engineering (AUTEEE). 2019; ():261-264.
Chicago/Turabian StyleZahid Javid; Li Kejun; Rizwan Ul Hassan; Jian Chen. 2019. "Energy Saving and Carbon Reduction by Utilizing the Renewable Resources and Recycling the Waste of Industries for Power Generation." 2019 IEEE 2nd International Conference on Automation, Electronics and Electrical Engineering (AUTEEE) , no. : 261-264.
With the increasing integration of rooftop photovoltaic (PV) generation and plug-in electric vehicles (EVs) into the households at user level, household consumers become prosumers. The coordination between the household prosumers and distribution network (DN) becomes essential to the energy management and optimal operation for both entities. In this paper, the residential prosumer cluster is considered as a residential microgrid (RMG) and a hierarchical DN integration method for the multi-RMGs is presented. A two-level hierarchical distributed optimization model is established based on the analytical target cascading to coordinate the RMGs and DNs. At the RMGs level, each RMG is required to individually optimize the energy consumption scheduling in every household by taking into account the effect of time-of-use electricity price on the demand response of EVs and flexible loads. At the DN level, the optimally coordinated operation problem is formulated as a relaxed optimal power flow model based on the second order cone programming by considering the power flow balance constraints. Case studies on the modified IEEE 33-bus system demonstrate the feasibility and effectiveness of the proposed method by achieving coordinated economic optimality as well as coordinated operating points for all entities.
Jingshan Wang; Ke-Jun Li; Zahid Javid; Yuanyuan Sun. Distributed Optimal Coordinated Operation for Distribution System with the Integration of Residential Microgrids. Applied Sciences 2019, 9, 2136 .
AMA StyleJingshan Wang, Ke-Jun Li, Zahid Javid, Yuanyuan Sun. Distributed Optimal Coordinated Operation for Distribution System with the Integration of Residential Microgrids. Applied Sciences. 2019; 9 (10):2136.
Chicago/Turabian StyleJingshan Wang; Ke-Jun Li; Zahid Javid; Yuanyuan Sun. 2019. "Distributed Optimal Coordinated Operation for Distribution System with the Integration of Residential Microgrids." Applied Sciences 9, no. 10: 2136.
Zhijie Liu; Ke-Jun Li; Jinyu Wang; Zahid Javid; Meiyan Wang; Kaiqi Sun. Research on Capacitance Selection for Modular Multi-Level Converter. IEEE Transactions on Power Electronics 2018, 34, 8417 -8434.
AMA StyleZhijie Liu, Ke-Jun Li, Jinyu Wang, Zahid Javid, Meiyan Wang, Kaiqi Sun. Research on Capacitance Selection for Modular Multi-Level Converter. IEEE Transactions on Power Electronics. 2018; 34 (9):8417-8434.
Chicago/Turabian StyleZhijie Liu; Ke-Jun Li; Jinyu Wang; Zahid Javid; Meiyan Wang; Kaiqi Sun. 2018. "Research on Capacitance Selection for Modular Multi-Level Converter." IEEE Transactions on Power Electronics 34, no. 9: 8417-8434.
Zahid JAVID. Cost Effective Design of High Voltage Impulse Generator and Modeling in Matlab. 2018, 1 .
AMA StyleZahid JAVID. Cost Effective Design of High Voltage Impulse Generator and Modeling in Matlab. . 2018; ():1.
Chicago/Turabian StyleZahid JAVID. 2018. "Cost Effective Design of High Voltage Impulse Generator and Modeling in Matlab." , no. : 1.
This paper presents a decentralized technique based protection and control scheme for the active radial distribution network. A partitioning method for radial distribution network with multi-distributed energy resources is developed considering island operation possibility of DER, hence, the active distribution network is partitioned into zones with DER and zones without DER. Directional node configuring method is proposed to identify the positional relation of circuit breakers (CBs) on boundaries of zones. After configuring each intelligent feeder terminal units (IFTUs) with the directional node relationship information, the connection relationship between zones can be obtained automatically. So that only by communicating with its neighbors, the IFTU can decide which CBs should be opened when a fault occurs. Peer to peer communication technique is established for interacting fault measurement information among the adjacent IFTUs, fast and accurate faulted zone location and isolation can be achieved. Meanwhile, seamless islanding of the zone integrating DERs can be realized to keep supplying power to the islanded feeder continuously after distribution network splitting. Moreover, power balance control for intentional islanding is discussed to ensure the islanding stable. Finally, results of case studies demonstrate the feasibility and effectiveness of the proposed scheme.
Jingshan Wang; Ke-Jun Li; Mingqiang Wang; Ying Sun; Zahid Javid. A decentralized technique based protection and control scheme for distribution network with high DER penetration. 2017 IEEE Industry Applications Society Annual Meeting 2017, 1 -6.
AMA StyleJingshan Wang, Ke-Jun Li, Mingqiang Wang, Ying Sun, Zahid Javid. A decentralized technique based protection and control scheme for distribution network with high DER penetration. 2017 IEEE Industry Applications Society Annual Meeting. 2017; ():1-6.
Chicago/Turabian StyleJingshan Wang; Ke-Jun Li; Mingqiang Wang; Ying Sun; Zahid Javid. 2017. "A decentralized technique based protection and control scheme for distribution network with high DER penetration." 2017 IEEE Industry Applications Society Annual Meeting , no. : 1-6.
With the increasing penetration of renewable energies, the seamless integration and related energy management problems present challenges to the traditional power grid. Voltage source converter based multi-terminal HVDC (VSC-MTDC) has been regarded as a prospective emerging technology for the above mentioned issues. With its flexible control characteristics, it is expected that VSC-MTDC systems will play important role in the future power grid. Furthermore, a multi-voltage level VSC-MTDC systems will have the potential to enhance the flexibility and redundancy of the power system. This paper presents control algorithms for a multi-voltage-level DC network to improve the utilization rate of renewable energies and mitigate the coordinated and interconnected problems of distributed renewable energies and urban power load. The operating of auto-power-balancing mode and the power cooperation mode and their corresponding control strategies are analyzed in this paper. For the auto-power-balancing mode, the centralized DC power control is proposed to mitigate the disturbance caused by power fluctuation. For the power cooperation mode, the unbalanced power redistribution control is proposed to eliminate the unbalanced power when the master station encounters problems. The simulation in PSCAD/EMTDC for a twelve VSC-MTDC system demonstrates the effectiveness of the proposed operation modes and corresponding control strategies.
Kaiqi Sun; Ke-Jun Li; Wei-Jen Lee; Zhuo-Di Wang; Zhijie Liu; Meiyan Wang; Zahid Javid. Operation and control for multi-voltage-level dc network to improve the utilization rate of renewable energies. 2017 IEEE Industry Applications Society Annual Meeting 2017, 1 -8.
AMA StyleKaiqi Sun, Ke-Jun Li, Wei-Jen Lee, Zhuo-Di Wang, Zhijie Liu, Meiyan Wang, Zahid Javid. Operation and control for multi-voltage-level dc network to improve the utilization rate of renewable energies. 2017 IEEE Industry Applications Society Annual Meeting. 2017; ():1-8.
Chicago/Turabian StyleKaiqi Sun; Ke-Jun Li; Wei-Jen Lee; Zhuo-Di Wang; Zhijie Liu; Meiyan Wang; Zahid Javid. 2017. "Operation and control for multi-voltage-level dc network to improve the utilization rate of renewable energies." 2017 IEEE Industry Applications Society Annual Meeting , no. : 1-8.