Protection of Microgrids

The concept of microgrids goes back to the early years of the electricity industry although the systems then were not formally called microgrids. Today, two types of microgrids can be seen: independent and grid connected. The protection requirement of these two types differs as the protection needs of an independent microgrid are intended for protecting components and systems within the microgrid, whereas a grid connected microgrid demands both internal and external protection. The first part of this chapter is dedicated to independent microgrids. How protection devices such as residual current circuit breakers, miniature and moulded case circuit breakers, and surge protective devices should be selected for an example microgrid is discussed while referring to the relevant standards. In the next section, the protection of a grid connected microgrid is discussed. Particularly, micro-source protection, microgrid protection, loss of mains protection and fault ride-through requirements are discussed while referring to two commonly used distributed generator connection codes. An example with simulations carried out in the IPSA simulation platform was used to explain different protection requirements and calculation procedures. Finally, grounding requirements are discussed while referring to different interfacing transformer connections and voltage source inverter connections.

Comparison of Income Tax Base in Visegrad Countries

The objective of the research was to compare the procedures for the calculation of income tax in the Visegrad Four (V4) countries. The statutory income tax calculation procedures are very similar in the V4 countries. Particular systems differ parametrically. Based on a literature review, synthesis of knowledge, comparison and simulation calculations, it can be stated that Hungary has the lowest corporate tax rate, and in the simulative calculations it also produced the lowest tax and highest profit after taxation for a fictitious entity in Hungary. Income tax in the V4 countries differs mainly in the possibility of applying the loss of previous years, in the impact of depreciation on the amount of the tax and in the income tax rebate linked to the employment of the disabled.

Numerical analysis of the transmission loss of dissipative mufflers with polygonal cross-section

Dissipative mufflers are often used for the reduction of broadband noise transmitted in ducts. Many common calculation procedures for the transmission loss of such mufflers require conventional shapes like rectangular or circular cross-sectional areas. In an effort to analyze the effect of the cross-sectional area of dissipative mufflers on the resulting noise reduction, the transmission loss of axially uniform mufflers with polygonal cross-sectional areas was investigated using the finite element method. The mufflers are designed to have the same open area, and hence in a practical application would lead to a similar pressure drop. The results were compared to those obtained with the well known approximative method of Piening. Good agreement between simulation and estimation was found regarding basic trends at low frequencies, while notable differences were revealed regarding the maximum transmission loss.

A New K-Means Clustering Algorithm for Customer Classification in Precision Marketing

K-means is wildly used in data mining and clustering for its powerful data clustering ability, but its inherent limitations affect its application fields and accuracy. Theoriginal K-means algorithm is improved and applied in customer clustering in precision marketing. Firstly, integrates K-means algorithm with particle swarm optimization according to analyzing the source of the K-means calculation limitations; Secondly, improves the improved algorithm in its operation time, convergence speed, global solution exploration ability successively and redesigns the calculation procedures; Finally applies it in customer classification in precision marketing and the experiment results shows that the new algorithm can increasecustomer clustering effectiveness, validity, accuracy and has satisfactory results in practice.

Develop of New Tools for 4D Monitoring: Case Study of Cliff in Apulia Region (Italy)

The monitoring of areas at risk is one of the topics of great interest in the scientific world in order to preserve natural areas of particular environmental value. The present work aims to develop a suitable survey and analysis methodology, in order to optimise multi-temporal processing. In particular, the phenomenon investigated the monitoring of cliffs in southern Apulia (Italy). To achieve this objective, different algorithms were tested and implemented in an in-house software called ICV. The implementation involved the use of different calculation procedures, combined and aimed at the analysis of the phenomenon in question. The validation of the experimentation was shown through the elaboration of a series of datasets of a particular area within the investigated coastline.

Low carbon of lime plaster repair: life cycle assessment approach in achieving sustainable maintenance management for heritage buildings

PurposeLow carbon repair epitomises sustainable maintenance management for heritage buildings. However, there is little recognition of this aspect, coupled with impractical assessment of repair impact strategies. This paper aims to present a decision-making process based on life cycle assessment (LCA) approach of lime plaster repair options for heritage buildings.Design/methodology/approachCalculation procedures of LCA were carried out to enable sustainable maintenance management appraisal for heritage buildings upon embodied carbon expenditure expended from lime plaster repair during the maintenance phase.FindingsCalculation procedures could be understood as a carbon LCA of lime plaster repair and recognised in reducing CO2 emissions. This underpins low carbon of lime plaster repair in achieving sustainable maintenance management of heritage buildings.Practical implicationsIt must be emphasised that the LCA approach is not limited to heritage buildings and can be applied to any repair types, materials used and building forms. This supports environmentally focused economies and promotes sustainable maintenance management solutions.Social implicationsThe LCA approach highlights the efficiency of repair impact strategies through evaluation of low carbon repairs options.Originality/valueThe LCA approach results show that low carbon repair, contextualised within maintenance management, relays the “true” embodied carbon expenditure and stimulates sustainable development of heritage buildings.

Numerical parametric study on steel-concrete composite floor beams vibrations due to pedestrian traffic

Human perception of floor vibrations and uncompromised serviceability of equipment are two most important acceptability criteria considering floor vibrations. While verification of deflection is a simple and well-known procedure in structures' design for serviceability limit state, the fulfilment of floor vibrations acceptability criteria are presented in different standards in the form of various calculation procedures. Results achieved through those calculation procedures are presented in the form of various classification of floor structures. Classification of composite floor structures due to vibrations is inconsistent considering different calculation procedures. Comparison of various calculation procedures for the definition of composite floor vibrations is presented in this paper. In addition, a parametric analysis is performed on the wide range of steel-concrete composite floor structures, through analysis of various composite floor layouts and a wide range of imposed loads values. The analysis of the relation between deflection, vertical vibrations and accelerations of steel-concrete composite floor beams is presented in this paper. The results of the parametric analysis are given through direct relation between deflections of composite beams and achieved floor class for the fulfilment of vibrations acceptability criteria due to the pedestrian walking.

Micrometeorological Methods for Greenhouse Gas Measurement

Micrometeorological techniques are useful if greenhouse gas (GHG) emissions from larger areas (i.e. entire fields) should be integrated. The theory and the various techniques such as flux-gradient, aerodynamic, and Bowen ratio as well as Eddy correlation methods are described and discussed. Alternative methods also used are Eddy correlation, mass balance techniques, and tracer-based methods. The analytical techniques with current state-of-the-art approaches as well as the calculation procedures are presented.