Application and modelling of shape-memory alloys for structural vibration control : state-of-the-art review

One of the most essential components of structural design for civil engineers is to build a system that is resistant to environmental conditions such as harsh chemical environments, and catastrophic disasters like earthquakes and hurricanes. Under these circumstances and disturbances, conventional building materials such as steel and concrete may demonstrate inadequate performance in the form of corrosion, deterioration, oxidizing, etc. Shape Memory Alloys (SMAs) are novel metals with distinct features and desirable potential to overcome the inadequacies of existing construction materials and enable the structure to tolerate disturbances more efficiently. Shape Memory Effect (SME) and Pseudoelasticity (PE) have been the most attractive characteristics that scientists have focused on among the various features that SMAs exhibit. The SME enables the material to retain its original shape after severe deformation, whereas the PE behaviour of SMAs provides a wide range of deformation while mitigating a substantial amount of susceptible stresses. These behaviours are the consequence of the phase transformation between austenite and martensite. Many investigations on the modelling and application of SMAs in structural systems to endure applied dynamic loadings in the form of active, passive, and hybrid vibration control systems have been undertaken. The focus of this paper is to present an overview of the SMA-based applications and most frequently employed constitutive modelling, as well as their limits in structural vibration control and seismic isolation devices

Selected Papers from the 8th Annual Conference of Energy Economics and Management

This collection represents successful invited submissions from the papers presented at the 8th Annual Conference of Energy Economics and Management held in Beijing, China, 22–24 September 2017. With over 500 participants, the conference was co-hosted by the Management Science Department of National Natural Science Foundation of China, the Chinese Society of Energy Economics and Management, and Renmin University of China on the subject area of “Energy Transition of China: Opportunities and Challenges”. The major strategies to transform the energy system of China to a sustainable model include energy/economic structure adjustment, resource conservation, and technology innovation. Accordingly, the conference and its associated publications encourage research to address the major issues faced in supporting the energy transition of China. Papers published in this collection cover the broad spectrum of energy economics issues, including building energy efficiency, industrial energy demand, public policies to promote new energy technologies, power system control technology, emission reduction policies in energy-intensive industries, emission measurements of cities, energy price movement, and the impact of new energy vehicle

Novel Controls of Photovoltaic (PV) Solar Farms

Solar Farms are absolutely idle in the night and even during daytime operate below capacity in early mornings and late afternoons. Thus, the entire expensive asset of solar farms remains highly unutilized. This thesis presents novel technologies for utilization of PV solar farm inverter in nighttime for providing multiple benefits to power systems, as well as accomplishing the same objectives during the daytime from the inverter capacity left after production of real power. The new technology transforms a solar farm inverter functionally into a dynamic reactive power compensator known as STATCOM, and termed PV-STATCOM. A novel coordinated control of PV-STATCOMs is proposed for loss reduction in a distribution network. The saved energy is substantial and can be used for powering several homes annually. The second novel PV-STATCOM control involves a temporary curtailment of real power production and utilization of the available reactive power capacity to prevent the instability of a critical induction motor load. The third novel PVSTATCOM control is employed to significantly enhance the power transfer limit of a long transmission line both in the nighttime and also during daytime even when the solar farm is producing a large amount of real power. A new technique for short circuit current management is developed for a conventional PV solar farm that can potentially solve the problem due to which several solar farms have been denied connectivity in Ontario. This thesis has contributed to two patent applications and presented first time implementations of another two filed patents. A generalized PV solar system model in EMTDC/PSCAD software has been developed and validated with manufacturer\u27s datasheet. Another contribution of this thesis is the first time harmonics impact study of the largest solar farm in Canada, in the distribution utility network of Bluewater Power, in Sarnia, Ontario. This thesis makes a strong case for relaxing the present grid codes to allow solar farms to exercise these novel controls. This technology can open up new avenues for solar farms to earn revenues apart from the sale of real power. This will require appropriate agreements between the regulators, network utilities, solar farm developers and inverter manufacturers

Dynamic Stability Enhancement of Power System Using Fuzzy Logic Based Power System Stabilizer

Power systems are subjected to low frequency disturbances that might cause loss of synchronism and an eventual breakdown of entire system. The oscillations, which are typically in the frequency range of 0.2 to 3.0 Hz, might be excited by the disturbances in the system or, in some cases, might even build up spontaneously. These scillations limit the power transmission capability of a network and, sometimes, even cause a loss of synchronism and an eventual breakdown of the entire system. For this purpose, Power system stabilizers (PSS) are used to generate supplementary control signals for the excitation system in order to damp these low frequency power system oscillations.The use of power system stabilizers has become very common in operation of large electric power systems. The conventional PSS which uses lead-lag compensation, where gain settings designed for speci¯c operating conditions,is giving poor performance under di®erent loading conditions. The constantly changing nature of power system makes the design of CPSS a di±cult task. Therefore, it is very di±cult to design a stabilizer that could present good performance in all operating points of electric power systems. To overcome the drawback of conventional power system stabilizer(CPSS), many techniques such as fuzzy logic, genetic algorithm, neural network etc. have been proposed in the literature.In an attempt to cover a wide range of operating conditions, Fuzzy logic based technique has been suggested as a possible solution to overcome the above problem, thereby using this technique complex system mathematical model can be avoided, while giving good performance under di®erent operating conditions. Fuzzy Logic has the features of simple concept, easy implementation, and computationally e±cient. The fuzzy logic based power system stabilizer model is evaluated on a single machine in¯nite bus power system, and then the performance of Conventional power system stabilizer (CPSS) and Fuzzy logic based Power system stabilizer (FLPSS) are compared. Results presented in the thesis demonstrate that the fuzzy logic based power system stabilizer design gives better performance than the Conven- tional Power system stabilizer

Aeronautical Engineering: A continuing bibliography, supplement 96

This bibliography lists 448 reports, articles, and other documents introduced into the NASA scientific and technical information system in April 1978

Enhancing the Practical Applicability of Smart Tuned Mass Dampers in High-Rise Civil Engineering Structures

The ability of bones to concentrate material where the body needs most of its strength and the ability of trees to spread roots in search of moisture rich locations are only a few amongst the many examples of nature’s way of building adaptive “structures”. Even though civil engineering structures often appear inefficient, static and cumbersome, a new era of structural design aims to alter the status quo by mimicking nature’s way. This suggested adaptation process in civil structures often takes the form of passive, active and semi- active control. Through direct comparison of these methods, semi-active control is shown to combine the benefits of both active and passive systems and can be arguably considered the next step in improving dynamic structural performance; however the applicability of this exciting and novel for the structural engineering field technology, is not all-embracing. In order to enhance the development of this promising technology and contribute on the creation of a new era of “smart & thinking” structures that encompass an unconventional form of performance based design, this study aimed to develop enabling technologies and tools that enhance the selling strengths of semi-active and smart control using tuned-mass dampers. The original contributions to knowledge in this work are divided in three aspects. Firstly, the investigation of the influence of control algorithms on smart tuned-mass damper equipped high-rise structures, for which practical limitations have been taken into account. Leading to conclusion on the conditions for which each algorithm exhibits superior performance over the other. Secondly, the development of a fail-safe novel semi-active hybrid device configuration that enables performance gains similar to the active mass damper at considerably lower actuation and power demands. Finally, the development of a simple and robust at all gains control algorithm based on the modification of one of the most widely used controller in the engineering industry, namely the proportional-integral-derivative controller

Assessment of the value of flexibility by using stochastic scheduling tool

This thesis proposes novel analytical models for assessing the role and the value of various flexibility resources in the future low-carbon systems with high penetration of renewable energy resources. A novel stochastic scheduling model is developed, which optimises system operation by simultaneously scheduling energy production, standing/spinning reserves and inertia-dependent frequency regulation in light of uncertainties associated with wind energy production and thermal generation outages. The proposed model is shown to be particularly suitable for analysing the value of flexibility. Following this, the thesis presents an assessment of the value that energy storage may deliver to the owner in the application to energy and ancillary service markets. The results suggest that the value of energy storage is mainly driven by the temporal arbitrage opportunities created by volatility in energy prices. The value of energy storage is shown to be site-specific when there are active network constraints. A novel methodology is then proposed and applied to assess the role and the value of frequency regulation support (synthetic inertia (SI) and primary frequency response (PRF)) from wind plants (WPs). The results suggest the SI could effectively reduce the system operation cost in the system, especially with high penetration of wind generation. The analysis also demonstrates the value for WPs in providing PFR is system-specified. Combined provision of SI and PFR is required, in the case that there exists severe recovery effect associated with SI provision. This thesis also proposes a novel demand side response model (DSRM), which models and controls the recovery period during and after frequency regulation provision and thus optimally allocates multiple frequency services. The results attest the value of the DSRM compared with alternative approaches for demand response schemes. Moreover, this thesis quantifies the implications of electric vehicle deployment, heat pumps, industrial and commercial and dynamic time-of-use tariffs for the carbon emissions and renewable integration cost of the broader GB electricity system. Finally, this thesis investigates the value of enhanced flexibility from conventional plants. It has been shown that the value increases with penetration of RES; however, different systems may require different types of enhanced flexibility features. Moreover, different system scheduling methods, risk attitudes, frequency response requirements and carbon prices could significantly change the value of flexibility.Open Acces