By Isabelle Heriakian / Published on Thu, 2010-03-11 16:08
A prospective wind farm consisting of 21 turbines with 2 MW double-fed induction generators is planned to be connected to a 110 kV substation in distribution system.
In this case study, different network configurations are modelled.
The influence of the accuracy of grid modelling on grid harmonic impedance characteristic at a particular point is analysed, and a comparison of the results is done for the different network configurations.
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By Sergio Ferreira / Published on Wed, 2010-03-10 17:19
In Case Study 6, the investment costs and environmental payoffs of newly built houses were compared. In this case study, the renovation options of a standard house (see Glossary and parameter settings in Appendix) will be compared both in terms of the environmental benefits obtainable with the investment of 1 million Euros in each case.
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By Sergio Ferreira / Published on Wed, 2010-03-10 17:13
In case studies 3-4 the environmental benefits of a Low-Energy House (LEH) were compared to a Passive House (PH) both equipped with the best available technology to suit the house type.
In this case study, the environmental comparison was complemented with an economic assessment of the decision alternatives. This case study can be thought of as a cost-benefit analysis of building a new house with different environmental and economic costs and benefits.
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By Sergio Ferreira / Published on Wed, 2010-03-10 17:10
In case studies 1-4, considerations of energy use were purely environmental. Decision-making processes, however, need to factor in economics as this may change rankings entirely: if a limited amount of money has to be spent, cheaper solutions may be implemented numerous times and thus the multiple uses of smaller changes may even outperform a single grandiose scheme. To assess the economic aspects of electricity use, a simple yet powerful exercise will be conducted in this chapter.
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By Sergio Ferreira / Published on Wed, 2010-03-10 17:06
In previous case studies, the best available fossil fuel-based heating system was compared with the best available electric heating system. A relatively outdated technology of heaters, however, may in the future prove to imply the environmentally cleaner solution. Night storage (or accumulation) heaters are electric appliances that produce and store heat overnight when electricity from the grid is cheaper due to a situation of more available provision than demand, and release it throughout the day.
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By Sergio Ferreira / Published on Wed, 2010-03-10 16:58
Low Energy and so-called Passive Houses (LEH and PH, respectively) represent innovative design and technologies implemented in favour of energy efficiency. Compared to a standard house, both of these housing types have increased window surface area facing south, increased insulation on both walls and windows, sand-lime brick replacing the traditional bricks. The general description of the housing types is provided in the Glossary, while the list of parameters defining the houses in the model is provided in Supplement A.
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By Sergio Ferreira / Published on Wed, 2010-03-10 16:51
In this case study, the analysis targets a comparison between heating systems in a low-energy house. The definition of a low-energy house can be found in the Glossary.
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By Sergio Ferreira / Published on Wed, 2010-03-10 16:47
Case study 1 was constructed with the intention of assessing how the choice of power grid mix influences the environmental impact of producing electricity. Electric power can be produced from various renewable and non-renewable resources, and the technologies to harvest renewable resources are gaining momentum, together with the global pressure to increase their contribution to energy provision.
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By Sergio Ferreira / Published on Wed, 2010-03-10 15:48
Developing economic well-being and preserving a healthy environment are not opposed forces but do, on the contrary, have a primary relationship and require a similar way of thinking: maximising the efficiency of a product over its life cycle will minimise its total financial cost as well as the total environmental impact over its life cycle.
The case studies below were developed to substantiate this Life-Cycle-Thinking by delivering high-level messages supporting decision making on the sustainable energy arena.
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By Isabelle Heriakian / Published on Tue, 2010-03-09 16:20
This case study is an assessment of electric power quality in a low voltage supply network in rural environment, based on measurements.
The subject of measurements was a low voltage line in which large disturbances occurred in the supply voltage, being the cause of customers' complaints. A modernisation of the installation was done; additional insulated cable was added and then the MV/LV transformer was replaced with a new one of larger rated power.
The conclusion from the final measurements is to consider other mitigation solutions.
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By Isabelle Heriakian / Published on Thu, 2010-03-04 17:44
This case study presents the control of quality parameters of electric power supplied from a low-voltage network to household consumers and public utility buildings.
The measures aimed at the power quality improvement, taken by the electric power supplier, are presented.
A comparison is done before and after replacement of a transformer to assess whether or not the choice was right.
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By Isabelle Heriakian / Published on Thu, 2009-11-05 01:00
This case study presents a methodology for improving power quality in an important industrial estate. A project was initiated to reduce the number of interruptions and enhance power quality in the estate and focused on reducing weak points in the power distribution system by inspecting distribution lines in both customer and utility areas. Once weaknesses were identified, corrective action would be taken and preventative measures taken to prevent re-occurance in order to provide high power availability to customers.
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By Isabelle Heriakian / Published on Mon, 2009-11-02 13:36
A semiconductor plant experienced a problem where the LV side main circuit breaker was tripped by voltage dips. As a result, power to all connected loads was interrupted and manufacturing processes were halted. The main cause of this problem was the unsuitable design of the under-voltage protection system. When a voltage dip occurred it was misinterpreted as an under-voltage event by the protection system, which erroneously tripped the circuit breaker.
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Case studies
By HDK / Published on Mon, 2009-06-15 06:31
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By Glycon Garcia / Published on Fri, 2009-06-12 08:35
In late 2006, the U.S. Agency for International Development, the International Copper Association, and AES Eletropaulo, an electricity distribution company, embarked as partners on an ambitious project in São Paulo, Brazil to test their integrated approach to slum electrification and loss reduction.
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By Isabelle Heriakian / Published on Mon, 2009-05-11 09:17
A theatre encountered a situation where incorrect operation of the earth fault protection system of a back-up generator tripped the circuit breaker unexpectedly when dimmer loads were fully used.
The generator was used to supply critical loads via an automatic transfer switch (ATS) and the problem was caused by high levels of third harmonic current produced by dimmers and an inappropriate installation of neutral and ground system.
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By Sergio Ferreira / Published on Mon, 2008-11-10 16:30
This Application Note aims at describing the use of energy and the potential energy savings in the hotel sector, on the basis of theory and practical case studies. Hotels and restaurants represent some 9% of total energy consumption in the utility buildings sector. Utility buildings are offices, shops, hotels, restaurants, educational establishments and care institutions.
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By Hans De Keulenaer / Published on Wed, 2008-06-11 18:18
The implementation of capacitor reactive power compensation in the Lubin Mine has produced the expected technical and economic effects. One should, however, be aware that compensation could be applied only to the level determined by reactive power demand. Currently this level in the Lubin Mine is 11‑12 MVAr. In case of a significant increase of the concentration of output in the distant areas of the mine, other technical measures will be necessary. The objective of a currently undertaken study is to develop a technically and economically feasible method for power supply of distant production sections, which consists in their electrical separation. All concept studies of the power supply system development should also take into consideration rational management of reactive power in both the supply networks and the loads. The rational management of reactive power should be based upon a continuous monitoring of load and reactive power flow.
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By David Chapman / Published on Tue, 2008-05-13 15:53
Wind Farm Development and Operation - A Case Study dicusses the development of a small wind farm. It includes a financial analysis highlighting the importance of an accurate energy yield assessment and adequate feed-in tariff.
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