Person: Da Silva, Izael
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- PublicationOn Site Calibration of Inductive Voltage Transformers(WSEAS, 2009) Da Silva, I. P.; Demetri, I.; De Silos, A. C.; Brandao, F. A (Jr); Da Silva, IzaelThe accuracy class of an IVT – Inductive Voltage Transformer – is typically assessed in laboratory installations either by comparing with another IVT presenting greater accuracy and traceable to a national laboratory or by using a capacitive divider. Calibration in the field is considered herein, using results obtained from typical open and short circuit tests and winding resistances, performed with common meters. A Möllinger & Gewecke graphic diagram is employed together with the results of an accuracy test previously carried out to determine the exact value of the winding turn relation and of the primary winding dispersion reactance. These values are used to calculate the phase and ratio errors, which must lie between definite limits, defined by the accuracy class of the instrument. Four commercial IVTs were tested to determine the validity of the procedure. The errors are compared with those obtained with the Schering-Alberti method (AC Bridge and comparison with standard IVT)
- PublicationInductive Voltage Transformers Calibration by the Parameters(WSEAS, 2010) Brandao, F.A; Da Silva, I. P.; Demetri, I.; De Silos, A. C.; Diaz, E. M; Da Silva, IzaelThe accuracy class of an IVT - Inductive Voltage Transformer - is typically assessed in laboratory installations either by comparing with another IVT presenting greater accuracy and traceable to a national laboratory or by using a capacitive divider. Calibration in the field using internal parameters is considered herein, using results obtained from typical open and short circuit tests and winding resistances, performed with common meters. A Möllinger & Gewecke graphic diagram is employed together with the results of an accuracy test previously carried out to determine the exact value of the winding turn relation and of the primary winding dispersion reactance. These values are used to calculate the phase and ratio errors, which must lie between definite limits, defined by the accuracy class of the instrument. Four commercial IVTs were tested to determine the validity of the procedure. The errors are compared with those obtained with the Schering-Alberti method (AC Bridge and comparison with standard IVT).
- PublicationInnovative Energy Access for Remote Areas “The LUAV-Light up a Village” Project(Springer Link, 2015-03-04) Da Silva, I. P.; Da Silva, IzaelThe Light-up a village (LUAV) program is a rural development initiative designed to improve access to modern energy solutions in remote areas of developing countries. The initiative addresses the challenge of Pico PV market penetration by empowering rural communities to actively participate in lighting up their own villages using micro-solar systems. The LUAV business model was designed by an energy company, Barefoot Power (BFP), which began the LUAV field in 2012 in Uganda. The program incorporates local SACCOs and Community Based Organizations (CBO) as well as local governmental bodies in the identification and recruitment of participants. A LUAV program is designed to involve at least 100 households per community by providing each home with its own power generation solar system to run lighting and mobile device charging services. The participating households are given the option to either pay for the micro solar power system upfront or to pay for it in 3–12 monthly installments. For this pilot program, BFP sourced for funding from private investors to operate a revolving fund which is managed the SACCOs and CBOs who have the mandate to manage debt recovery and keep the revolving fund active. Through this business model, 18 LUAV projects were implemented in Uganda during the 18 month trial period providing lighting and mobile charging services to 3,000 plus households. The program’s success has a growing interest and plans are underway to replicate it in South Sudan, Rwanda and Kenya in 2014. According to the latest count more than 7,000 households have adopted the micro-system through LUAV.
- PublicationEconomics of a Gasification Based Mini Grid - a case study of a 10 kW Unit in Uganda(2007-01) Da Silva, I. P.; Buchholz, T.; Volk, T; Tennigkeit, T; Da Silva, IzaelSmall-scale wood gasification systems have the potential to contribute to the rural electrification in Uganda. This paper presents an economic analysis of a 10 kW gasifier unit and its minigrid installed on a Ugandan farm. The bioenergy system has been running stable on a six hour daily base for seven months. When the gasifier is operated close to the rated capacity, the gasifier system is economically attractive compared to diesel generated electricity Results indicate that replicating successful wood gasification systems stipulates integration of sustainable fuelwood supply and viable business models.
- PublicationReducing Carbon Emissions in a Third Level Educational Institution in Sub-Sahara Africa(Springer International Publishing Switzerland, 2015) Da Silva, I. P.; Ronoh, G.; Ouma, C.; Jerono, C.; Da Silva, IzaelThe effort to reduce carbon emissions as the arguably most prevalent cause of global warming has been a positive trend in most African countries. One of the most successful strategies towards reaching that goal is the shift from fossil fuel power generation to renewable sources of energy such as wind, hydro, geothermal and solar. As Kenya sits on the equator it enjoys an all year round insolation between 5 and 6 kW/m2/day which is more than double of the average insulation in Germany, a country where solar energy is widely used. Taking advantage of a green line of financial support created by the French Government, Strathmore University embarked in a project to install a 600 kW roof-top, grid connected solar PV system to cater for its electricity needs. Having as a background of the newly instituted Feed-in-Tariff regulation, the system is designed to produce more than the required self-consumption such that the extra power can be sold to the utility via a PPA (power purchase agreement) and the revenue used to pay for the electricity used by the university at night. This paper describes the whole process from the technical, regulatory, educational and financial aspect highlighting the positive and negative events along the path such that it can be useful for other private sector institutions interested in greening their sources of energy, invest in renewable energy and thus reduce their operation costs. The authors have written this work having in mind not only countries in Africa but all other countries which sit in the so called “solar belt”.
- PublicationBook review : Renewable Energy for Residential Heating and Cooling Policy Handbook(ICE Publishing, 2012-08) Da Silva, I. P.; Da Silva, IzaelThe scope of this book, as far as REHC projects are concerned, covers programme phases: portfolio planning, programme design, implementation and evaluation. It also covers market maturity stages from initial deployment to full market. It considers instruments such as: economic incentives, regulations, information and market activities. As the title mentions, the content is applicable to the residential sector only: new and existing buildings, including single and multi-family dwellings. As far as technology is concerned, it covers active solar thermal systems for air and water heating; biomass (pellets, wood and wood waste); geothermal (ground source and heat-pump) and finally heat-pump technologies based on ambient air heat (air-to-air and air-to-liquid)
- PublicationAltruistic versus profit maximising system operators of rural power systems(IEEE, 2007-07-20) Sendegeya, A.; Amelin, M.; Soder, L.; Lugujjo, E.; Da Silva, I. P.; Da Silva, IzaelThis paper presents a methodology using Monte Carlo Simulation for analysing and compare the impact of two types of monopolistic rural power system operators (altruistic and profit maximising operators) on the probability distribution of tariff levels and reliability of the system. The market has price sensitive consumers. The developed model has been demonstrated on two power systems: only diesel genset and a wind-diesel hybrid system showing the impact of the generation costs and capacity of generation from wind on the tariff levels, expected profit and reliability.
- PublicationElectricity from wood-fired gasification in Uganda - a 250 and 10kW case study(IEEE, 2016-06) Buchholz, T.; Da Silva, I. P.; Furtado, J.; Da Silva, IzaelWood gasification systems have the potential to contribute to the rural electrification in Sub-Saharan Africa. This paper presents an operational and economic analysis of two wood-based gasification systems (250 and 10 kW) installed in Uganda in 2007. Both systems proved their potential to compete economically with diesel generated electricity when operating close to the rated capacity. At an output of 150 kW running for ~12 h/day and 8 kW running for ~8h/day, the systems produced electricity at US$ 0.18 and 0.34/kWh, respectively. A stable electricity demand close to the rated capacity proved to be a challenge for both systems. Fuelwood costs accounted for ~US$0.03/kWh for both systems. Recovery of even a small fraction of the excess heat (22%) already resulted in substantial profitability gains for the 250 kW system. Results indicate that replicating successful wood gasification systems stipulates integration of sustainable fuelwood supply and viable business models.
- PublicationTriple Helix as a strategic tool to fast-track climate change adaptation in rural Kenya - case study of Marsabit County(Springer, 2021) Da Silva, I. P.; Bricca, D; Micangeli, A; Davide, F.; Cherubini, P.; Da Silva, IzaelThe lack of affordable, clean, and reliable energy in Africa’s rural areas forces people to resort to poor quality energy source, which is detrimental to the people’s health and prevents the economic development of communities. Moreover, access to safe water and food security are concerns closely linked to health issues and children malnourishment. Recent climate change due to global warming has worsened the already critical situation. Electricity is well known to be an enabler of development as it allows the use of modern devices thus enabling the development of not only income-generating activities but also water pumping and food processing and conservation that can promote socioeconomic growth. However, all of this is difficult to achieve due to the lack of investors, local skills, awareness by the community, and often also government regulations. All the above mentioned barriers to the uptake of electricity in rural Kenya could be solved by the coordinated effort of government, private sector, and academia, also referred to as Triple Helix, in which each entity may partially take the other’s role. This chapter discretizes the above and shows how a specific county (Marsabit) has benefited from this triple intervention. Existing government policies and actions and programs led by nongovernmental organizations (NGOs) and international agencies are reviewed, highlighting the current interconnection and gaps in promoting integrated actions toward climate change adaptation and energy access.
- PublicationRural electrification practicalities of using single wire earth return for low cost grid extension - the case of Ntenjeru Uganda(International Conference on Energy and Sustainability, 2009-08) Bakkabulindi, G.; Da Silva, I. P.; Lugujjo, E.; Da Silva, IzaelThe fact that the vast majority of Uganda’s rural areas remain un-electrified makes it imperative that low cost distribution technologies be implemented in order to provide affordable electricity to rural households. Such low cost technologies include the Shield Wire System (SWS), Single Wire Earth Return (SWER) and appropriate engineering techniques. The SWER technology is presented in this paper as well as the implications of its proposed implementation for electrification of the village of Ntenjeru in Uganda. While SWER can reduce the costs of electrification by more than a third compared to conventional high tension transmission lines, there are stringent grounding and safety issues as well as load capacity constraints involved. Furthermore, with the earth used as a current return path, soil resistivity analysis is important in these systems. Since soil resistivity can vary sharply over varying terrain and in different weather conditions, robust SWER systems have to be carefully designed. An analysis of the financial and electrical load implications of this technology in Uganda’s local conditions will be presented and its viability as a sustainable method for electric energy distribution in the chosen case study area.