•Two-area interconnected power system is considered for the study.•Control Performance Standard based Proportional-Integral controllers are designed.•PI and PI+ controllers are designed using Beta ...Wavelet Neural Network approach.•Redox Flow Battery Hydrogen generative Aqua Electrolizer are added for investigation.•PI+ controller improves the dynamic quality of power system with Aqua Electrolizer.
This paper investigates a renewable energy resource’s application to the Load–Frequency Control of interconnected power system. The Proportional-Integral (PI) controllers are replaced with Proportional-Integral Plus (PI+) controllers in a two area interconnected thermal power system without/with the fast acting energy storage devices and are designed based on Control Performance Standards (CPS) using conventional/Beta Wavelet Neural Network (BWNN) approaches. The energy storing devices Hydrogen generative Aqua Electroliser (HAE) with Fuel cell and Redox Flow Battery (RFB) are incorporated to the two area interconnected thermal power system to efficiently damp out the electromechanical oscillations in the power system because of their inherent efficient storage capacity in addition to the kinetic energy of the generator rotor, which can share the sudden changes in power requirements. The system was simulated and the frequency deviations in area 1 and area 2 and tie-line power deviations for 5% step- load disturbance in area 1 are obtained. The comparison of frequency deviations and tie-line power deviations of the two area interconnected thermal power system with HAE and RFB designed with BWNN controller reveals that the PI+ controller designed using BWNN approach is found to be superior than that of output response obtained using PI+ controller. Moreover the BWNN based PI+ controller exhibits a better transient and steady state response for the interconnected power system with Hydrogen generative Aqua Electroliser (AE) unit than that of the system with Redox Flow Battery (RFB) unit.
Purpose:
Although fluorescence molecular imaging is rapidly evolving as a new combinational drug/device technology platform for molecularly guided surgery and noninvasive imaging, there remains no ...performance standards for efficient translation of “first-in-humans” fluorescent imaging agents using these devices.
Methods:
The authors employed a stable, solid phantom designed to exaggerate the confounding effects of tissue light scattering and to mimic low concentrations (nM–pM) of near-infrared fluorescent dyes expected clinically for molecular imaging in order to evaluate and compare the commonly used charge coupled device (CCD) camera systems employed in preclinical studies and in human investigational studies.
Results:
The results show that intensified CCD systems offer greater contrast with larger signal-to-noise ratios in comparison to their unintensified CCD systems operated at clinically reasonable, subsecond acquisition times.
Conclusions:
Camera imaging performance could impact the success of future “first-in-humans” near-infrared fluorescence imaging agent studies.
If one jurisdiction regulates power plant emissions with a cap-and-trade (mass) program and another with an intensity (rate) standard, is it a good idea for them to link? Specifically, what effects ...does introducing electricity and rate-mass allowance trade between differently-regulated regions have on emissions and ultimately welfare? We explore these questions first with a simple theoretical model and then with a sophisticated numerical model of the electricity sector. The theoretical model isolates the policy effects by assuming that two otherwise identical regions are regulated differently. With fixed demand, their autarky marginal abatement costs are identical, but electricity prices are lower in the rate-limited region. Adding electricity trade shifts generation to the rate-limited region, expanding its allowance allocation, while emissions remain capped in the mass-capped region. Adding rate-mass allowance trade exacerbates this shift in generation and expansion of emissions. The increase of emission damage could make the net welfare effects negative. However, if the mass cap is sufficiently more stringent than the rate limit, allowing rate-mass allowance trade in the presence of electricity trade can lower emissions. The numerical model of the eastern US illustrates the effects predicted in the theoretical model, and projects their magnitudes. In our simulation that is loosely based on the US Clean Power Plan, the estimated CO2 damage makes the estimated net benefits of allowing rate-mass trading negative. Our results also illustrate that linking can shift the geographic distribution of SO2 and NOX emissions, which can counteract the effect of the CO2 damage on estimated total welfare.
•Rate-mass trade is allowance trade between power plants in mass- & rate-limited areas.•2 kinds of “linking:” rate-mass trade, and adding transmission lines between the areas•We use theoretical and numerical models to examine each kind's effects on emissions.•With simulated Clean Power Plan, both kinds worsen CO2 emissions and total welfare.•Each kind can instead lower emissions if stringency differs enough between the 2 areas.
The area-level coordination of regulation capacity by automatic generation control (AGC) is an effective approach to mitigate wind power fluctuations in interconnected power system with high wind ...penetration. However, the applicability of this method is restricted by the existing AGC strategy. For this reason, power systems in China are experiencing serious wind curtailments to meet the power balance. In this study, a distributed coordination AGC strategy based on regulation marginal cost (RMC) is proposed for coordinating regulation capacity in different areas to remove frequency deviations. Detailed regulating characteristics of the AGC strategy in the existing power systems are discussed. Based on the above analysis, a distributed coordination RMC controller is designed to meet the proposed multi-area coordination rule using a partial primal-dual sub-gradient algorithm. In this proposed controller, the coordination signal containing RMC is exchanged with adjacent controllers through communication networks. The simulation results prove that the distributed coordination RMC strategy can economically coordinate the regulation capacity of an interconnected power system and satisfy the frequency control performance standard.
Nowadays the economic analysis of an induction motor’s life cycle is the clearest way to measure the viability of actions to promote energy-efficient technologies to the end user. The cost ...effectiveness in motors replacement by energy-efficient motors is a well-known practice that leads to energy savings, however this paper presents the cost-effectiveness of low-power induction motors which have their efficiency improved after rewinding. This process improves the investment viability and brings the greatest financial and energetic savings. In this paper, low-power induction motors are rewound and their efficiencies are measured by tests A and B from IEEE standard 112/2017. The rewound motors have better cost-effectiveness than replacement by IE3/Premium and even IE4/Super-Premium units. The rewound motors increase between 3 and 4 percentage points in relation to former efficiency and the payback is less than 2 years, regardless of the efficiency measurement method.
A new policy instrument, known as a low carbon fuel standard (LCFS), is a promising approach to decarbonize transportation fuels. An LCFS has several important features: it applies a lifecycle carbon ...intensity standard, incorporates market mechanisms by allowing credit trading and targets all transport fuels. A harmonized international framework is needed that builds on newly enacted LCFS policies adopted in California and the European Union.
•Mixed-integer nonlinear programming applied to CO2 capture retrofit heat integration.•Coal plant retrofit with CCS powered by specialized gas-fired system.•Facility constrained to meet CO2 emission ...performance standard of 499kgCO2/MWh.•Optimal design and operations differ for min capital cost and max NPV objectives.•Detailed optimization of heat recovery steam generator using categorical variables.
Computational optimization is used to simultaneously determine the design and planned operating profile of a flexible coal–natural gas power station with CO2 capture, under a CO2 emission performance standard. The facility consists of a coal-fired power station undergoing retrofit with CO2 capture. The CO2 capture energy demand is provided by a specially designed combined cycle gas turbine (CCGT). The heat recovery steam generator (HRSG) component of the CCGT is modeled and optimized in detail, with explicit treatment of the discrete aspects of the HRSG configuration, including the number and sequential arrangement of HRSG internal components. Variable facility operations are represented by discrete operating modes selected based on the electricity price–duration curve. Two objectives, the minimization of capital requirement and the maximization of net present value, are considered in a bi-objective mixed-integer nonlinear programming formulation. Pareto frontiers, which define the optimal tradeoffs between these two objectives, are generated for six scenarios constructed from recent historical data from West Texas, the United Kingdom, and India.
For a 440MW coal plant in a scenario based on 2011 West Texas data, the minimum effective net present cost required for the retrofit (which meets the CO2 emission performance standard) varies from $278 to 383million, and the minimum total capital investment requirement ranges from $346 to 517million. The variations in these optimized values correspond to the range of the Pareto frontier within the bounds of the problem. The net present cost of the retrofit is less than the present value of the existing coal plant, $476million, indicating that a retrofit is preferred over decommissioning. In the case of very low energy prices, however, decommissioning is shown to be the preferred option. The UK and India scenarios demonstrate that optimal designs can vary greatly depending upon location-specific economic conditions.
The Canadian Forces Firefighter Physical Fitness Maintenance Evaluation (FF PFME) requires firefighters in full fire-protective ensemble, including self-contained breathing apparatus, to correctly ...complete 10 work-related tasks on a measured and calibrated course. Fitness for duty is inferred from completion time of the course. We hypothesized that completion time may be dependent on pacing strategy and day-to-day fluctuations in biological function. To examine variability in performance, 20 females and 31 males (mean ± SD; age, 27.6 ± 10.5 years; height, 176.7 ± 8.3 cm; mass, 77.3 ± 13.4 kg) were familiarized with the FF PFME and then completed the test on 6 separate days. Pre-test behaviours (e.g., sleep, diet) and test conditions (e.g., calibration, time of day) were consistent. Repeated-measures ANOVA revealed a significant decrease in completion time between tests 1 and 6 (18.7%) and between all sequential pairs (e.g., tests 1 and 2). There was also a small but significant increase in the fraction of total test time for task completion and a corresponding decrease in the time to transition between tasks. The performance improvements cannot be explained by differences in effort (heart rate and perceived exertion). Coefficient of variation for tests 1, 2, and 3 was 7% and for tests 4, 5, and 6 was 2.6%. The results indicate the importance of practice on performance and the potential for false-positive or false-negative decision errors if biological variability is not taken into account.
Celotno besedilo
Dostopno za:
DOBA, FSPLJ, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Along with the International Maritime Organization (IMO), the United States Maritime Administration has developed its own ballast water management legislation under the dual authority of the US Coast ...Guard and the Environmental Protection Agency. The IMO and US ballast water management regulations are globally recognized as the most significant and influential regimes. Complexity and certain regulatory differences pose considerable concern amongst all stakeholders in the shipping industry, predominantly ship owners and ship operators. This paper presents a conceptual study which overviews, emphasises, and compares key provisions of these two sets of regulations by targeting and unveiling significant points from their perspective since they represent the largest group of stakeholders. Therefore, the paper aims to support shipowners and operators in better understanding the Ballast Water Management regulations and their differences. In addition, the study may benefit in choosing an adequate ballast water treatment system to be installed onboard ships, considering the sea areas where ships intend to operate. Finally, the paper can also help policy makers understand those differences that could present a major barrier in the efficient and smooth ballast water management implementation.
Initial allocation modes and schemes are studied in this paper to provide guidelines for allocation of carbon emission permits in power system. We first introduce different allocation modes and the ...need to apply free allocation to assignability of emission permits. Then, we compare two different allocation schemes, which are based on historical emissions and generation performance standard. Further, a new allocation scheme based on Boltzmann distribution is proposed. Finally, a case study on Shanghai power grid in China is conducted to compare the allocation effects of these schemes respectively. The analytical results show that Boltzmann distribution based scheme has the best performance and should be adopted when developing initial allocation of carbon emission permits in Chinese power systems.
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