9 results
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2. Assessing the Performance of ROCOF Relay for Anti-Islanding Protection of Distributed Generation Under Subcritical Region of Power Imbalance.
- Author
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Alam, Mollah Rezaul, Begum, Most. Tasneem Ara, and Muttaqi, Kashem M.
- Subjects
RECEIVER operating characteristic curves ,REACTIVE power ,DIGITAL computer simulation - Abstract
In practice, the load-curve and distributed generation (DG) penetration level determines the power imbalance level that a network can experience if islanding occurs. Therefore, with the prior knowledge of load-curve and DG penetration level, the setpoint of rate-of-change-of-frequency (ROCOF) relays can be adjusted so as to make them suitable for a real network. This paper first investigates the subcritical power imbalance region of ROCOF relays through analytical formulation followed by extensive simulation study in order to establish the maximum boundary limit of ROCOF's nondetection zone (NDZ) under all possible deficit/excess of active and/or reactive power imbalance scenarios. Second, ROCOF's reliability (assessed by detection rate and false alarm rate) is expressed analytically and then, validated numerically by simulating a test network of Australia in MATLAB and OPAL-RT real-time digital simulation platform. Finally, ROCOF's performance is assessed through receiver operating characteristics curves and a detailed reliability study under variable setpoints and detection time of the relays; the assessment considers the number of islanding events associated with the time-wise percentage of power imbalance level computed from the net load demand and variable DG penetration in a real network. All these test results demonstrate a clear operational guideline for ROCOF relay. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
3. Multiobjective Long-Period Optimal Planning Model for a Grid-Connected Renewable-Battery System.
- Author
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Khezri, Rahmat, Mahmoudi, Amin, and Aki, Hirohisa
- Subjects
CONSUMPTION (Economics) ,WIND speed ,ENERGY management ,ELECTRICITY pricing ,WIND turbines - Abstract
This article develops a practical framework for the multiobjective optimal planning of a grid-connected renewable-battery system considering a long-period operation. The capacities of wind turbine, solar photovoltaic (PV), and battery storage are optimized by minimizing three objective functions: cost of electricity (COE), grid dependence (GD), and total curtailed energy (TCE). A new rule-based energy management is developed for the long-period operation, where: 1) the capacity degradations of PV and battery are applied; 2) purchase and sell electricity prices are updated for each year using interest and escalation rates; and 3) the salvation value of the components is considered to achieve a realistic economic analysis of the planning problem. The developed multiobjective optimal planning model is examined using the long-period (ten years) real data of wind speed, solar insolation, ambient temperature, and load consumption for a grid-connected household in Australia. It is found that a household with the minimum GD (0.008%) results in a COE of 116 ¢/kWh with a TCE of 100 MWh in ten years. The proposed optimal planning framework based on the long-period operation is compared with the short-period operation. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
4. Joint Energy Disaggregation of Behind-the-Meter PV and Battery Storage: A Contextually Supervised Source Separation Approach.
- Author
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Wang, Fei, Ge, Xinxin, Dong, Zengbo, Yan, Jichuan, Li, Kangping, Xu, Fei, Lu, Xiaoxing, Shen, Hongtao, and Tao, Peng
- Subjects
BATTERY storage plants ,SOLAR batteries ,SMART meters ,ELECTRIC vehicle batteries ,SMART homes ,ELECTRIC batteries ,SOLAR system - Abstract
An increasing number of residential customers have installed hybrid rooftop solar battery systems (HRSBSs). Currently, most HRSBSs are installed behind-the-meter (BTM), where only customers’ net load is measured by smart meters. This invisibility poses significant challenges to the system operation. Disaggregating BTM PV generation and battery charging/discharging profile of customers can enhance the grid-edge observability. This article proposes an energy disaggregation method to jointly separate the PV generation and battery charging/discharging power from the net load. First, a Home Smart Battery Management model is built to simulate the battery charging/discharging profile. Second, an optimal disaggregation model is established based on a contextually supervised source separation method. Furthermore, the feature vectors of PV, load, and battery are extracted as the input of the disaggregation model. Case studies on two datasets from Australia and China show that the proposed method has a promising disaggregation performance. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
5. Adaptive and Predictive Energy Management Strategy for Real-Time Optimal Power Dispatch From VPPs Integrated With Renewable Energy and Energy Storage.
- Author
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Mohy-ud-din, Ghulam, Muttaqi, Kashem M., and Sutanto, Danny
- Subjects
ENERGY management ,ENERGY storage ,RENEWABLE energy sources ,LOAD forecasting (Electric power systems) ,ELECTRIC power distribution ,ADAPTIVE natural resource management ,POWER resources - Abstract
Virtual power plants (VPPs) have become a driving force for the decentralized energy industry, due to their efficient management and control of distributed energy resources. Most of the operation strategies for VPPs are designed based on the day-ahead forecasts. However, the prediction errors of the renewable energy sources (RES) and loads in the power dispatch schedule can lead to a suboptimal operation. In this article, an adaptive and predictive energy management strategy for a real-time optimal operation of VPPs is proposed based on the model predictive control technique with a feedback correction (FC) to compensate for the prediction error. This strategy has two parts: 1) receding-horizon optimization (RHO), and 2) FC. In the first part, a hybrid prediction algorithm based on the integration of the time-series model and the Kalman filter is used to forecast the output powers of RES and the loads. Based on the prediction, the RHO model schedules the operation following the latest forecast information. In the second part, the receding schedule is adjusted based on the fast-rolling gray model's ultrashort-term error prediction. The FC is applied to minimize the adjustments for compensating the prediction error. The proposed strategy is implemented on a VPP in a real electricity distribution system in New South Wales, Australia. The simulation results demonstrate the effectiveness of the proposed strategy with a better tracking of the actual available resources and a minimal mismatch between demand and supply. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
6. Coordinated Optimal Energy Management and Voyage Scheduling for All-Electric Ships Based on Predicted Shore-Side Electricity Price.
- Author
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Wen, Shuli, Zhao, Tianyang, Tang, Yi, Xu, Yan, Zhu, Miao, Fang, Sidun, and Ding, Zhaohao
- Subjects
ELECTRICITY pricing ,ENERGY management ,PRODUCTION scheduling ,NAVIGATION ,SHIPS ,NAVIGATION in shipping ,MICROGRIDS - Abstract
Unlike a land-based standalone microgrid, a shipboard microgrid of an all-electric ship (AES) needs to shut down generators during berthing at the port for exanimation and maintenance. Therefore, the cost of onshore power plays an important role in an economic operation for AESs. In order to fully exploit its potential, a two-stage joint scheduling model is proposed to optimally coordinate the power generation and voyage scheduling of an AES. Different from previous studies that only consider the operation cost of the ship itself, a novel coordinated framework is developed in this article to address the shore-side electricity price variations on the ship navigation route. A deep learning-based forecasting method is utilized to predict the electricity price in various harbors for ship operators. Then, a hybrid optimization algorithm is designed to solve the proposed multiobjective joint scheduling problem. A navigation route in Australia is adopted for case studies and simulation results demonstrate the high energy utilization efficiency of the proposed algorithm and the necessity of on-shore power influence on the AES voyage. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
7. Real-Time Estimation of Model Parameters and State-of-Charge of Li-Ion Batteries in Electric Vehicles Using a New Mixed Estimation Model.
- Author
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Sarrafan, Kaveh, Muttaqi, Kashem M., and Sutanto, Danny
- Subjects
ELECTRIC vehicle batteries ,LITHIUM-ion batteries ,PLASMA sheaths ,PARAMETER estimation ,BATTERY management systems ,TRAFFIC congestion - Abstract
A precise estimation of the state of charge (SoC) of the lithium-ion battery is crucial for reducing range-anxiety and improving the performance of the electric vehicle (EV) battery management system. An accurate estimation of the SoC, however, has remained elusive due to the complex and nonlinear behavior of the battery. In this article, a new mixed estimation model (MEM) for the battery parameters and the SoC estimation is proposed, where the route is specified before the travel. The new MEM uses a combination of a battery power-based method (BPBM), a combined model, and a partial adaptive forgetting factor recursive least-square (PAFF-RLS) SoC calibration algorithm to make use of the best characteristics of each model to determine a better and more accurate SoC estimation. The partial adaptive forgetting factors solves the issue of the different rate changes in the battery parameters and reduces the complexity of the algorithm compared to the fully adaptive recursive models. The BPBM allows various traveling factors to be included in the model, such as the environmental conditions, the effect of auxiliary loads, and the traffic congestion. To verify the validity of the PAFF-RLS algorithm, two laboratory tests using real-time driving cycles have been conducted on a 2012 Nissan Leaf 31.1 Ah Manganese-oxide Li-ion battery cell. The effectiveness of the MEM model has been demonstrated by driving the Nissan Leaf along two selected routes in Australia. The results demonstrate the great accuracy of the proposed method for the SoC estimation, when compared with those from the previous models. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
8. Optimal Capacity of Solar PV and Battery Storage for Australian Grid-Connected Households.
- Author
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Khezri, Rahmat, Mahmoudi, Amin, and Haque, Mohammed H.
- Subjects
SOLAR batteries ,BATTERY storage plants ,ENERGY storage ,PHOTOVOLTAIC power generation ,HOUSEHOLDS ,ELECTRIC power consumption ,ENERGY management - Abstract
This article determines the optimal capacity of solar photovoltaic (PV) and battery energy storage (BES) for grid-connected households to minimize the net present cost of electricity. The real-time rule-based home energy management systems using actual annual data of solar insolation, ambient temperature, household electricity consumption, and electricity rates are used in the optimization process. The above-mentioned technique is applied to two system configurations—household with a solar PV and a BES. The uncertainty analysis is implemented using ten years of real data to confirm the optimal results. An accurate cash flow analysis is also presented to illustrate the customer payment in each year during the project lifetime. The sensitivity analysis is conducted by varying the cost and capacity of system components, grid constraint, average daily electricity demand, and retail price of electricity. A typical grid-connected household in South Australia is considered as the case study. A practical guideline is presented for the residential consumers in South Australia to select the optimal PV/BES based on their daily average electricity demand and the available rooftop space for PV installation. Finally, the proposed optimization method is applied to households of other Australian States and a comparison of results is presented. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
9. A Cost–Benefit Analysis of Electric Loaders to Reduce Diesel Emissions in Underground Hard Rock Mines.
- Author
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Jacobs, William, Hodkiewicz, Melinda R., and Braunl, Thomas
- Subjects
ELECTRICAL load ,COST effectiveness ,HARD rock mining ,DIESEL motor exhaust gas ,MINERAL industries - Abstract
With recent developments in understanding the adverse health effects of diesel particulate matter (DPM) and growing emphasis on sustainability, zero-emission electric vehicles are becoming an increasingly common option in underground mining systems. As exposure regulations become stricter and with potential savings in the cost of ventilation, fuel, and consumables, there is also rising economic incentive to consider alternatives to diesel machinery. As a result, the diesel–electric debate is fundamental to any underground mining company's triple bottom line. A cost–benefit analysis for electric load haul dump units (eLHDs) was conducted in the context of Western Australian underground hard rock mines. This included a review of the issues affecting the diesel–electric debate and the development of a parametric life-cycle-cost model. The results indicate that eLHDs are not yet a universal solution to all underground mining systems. eLHDs can offer lower operating costs and do contribute many qualitative benefits, particularly with respect to reduced exposure to DPM. However, they also have several drawbacks, primarily associated with trailing cable management. Nevertheless, with a suitable mine design, eLHDs are a viable option and could provide a pathway for zero-emission electric machinery in the Australian mining industry.
Preamble —Western Australia is one of the world's leading mineral provinces. In the 2012–2013 financial year, Western Australia's mineral and petroleum sales totaled A$102 billion, representing some 42 $\%$ of Australia's total merchandise exports. As such, changes to the Western Australian mining industry has national and international economic implications. [ABSTRACT FROM PUBLISHER]- Published
- 2015
- Full Text
- View/download PDF
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