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Publications

Publications by CPES

2019

Impact of future energy policy on water resources in Kazakhstan

Authors
Rivotti, P; Karatayev, M; Mourao, ZS; Shah, N; Clarke, ML; Konadu, DD;

Publication
ENERGY STRATEGY REVIEWS

Abstract
As part of its strategic economic and social plan, Kazakhstan has a target of increasing the share of renewables and alternative energy sources in power generation to 50% by 2050. This greatly contrasts with the current situation, where around 90% of electricity is produced from fossil fuels. To achieve the target, the introduction of between 600 and 2000 MW of nuclear power is expected by 2030. This would impact water resources, already under stress due to significant losses, heavy reliance on irrigation for agriculture, unevenly distributed surface water, variations in transboundary inflows, amongst others. This study presents an integrated analysis of the water-energy systems in Kazakhstan, to investigate the water resource availability to support such energy system transition.

2019

Predicting health risk from exposure to trihalomethanes in an Olympic-size indoor swimming pool among elite swimmers and coaches

Authors
Gouveia, P; Felgueiras, F; Mourao, Z; Fernandes, ED; Moreira, A; Gabriel, MF;

Publication
JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH-PART A-CURRENT ISSUES

Abstract
Disinfection by-products (DBP) such as trihalomethanes (THM) are formed when chlorine and bromine interact with natural organic materials in chlorine-treated swimming pools. Epidemiological evidence demonstrated an association between exposure to swimming pool environment and adverse health effects. Therefore, this study aimed to assess carcinogenic and non-carcinogenic risk of long-term exposure of elite swimmers and their coaches. In an Olympic-size indoor chlorinated swimming pool, THM levels were determined in water (21-69 mu g/L), in the boundary layer above the water surface (59-397 mu g/m(3)), and in the air surrounding the pool (28-390 mu g/m(3)). These values were used to predict multi-pathway chronic daily intake (CDI), cancer risk (CR) and hazard index (HI). Oral and dermal CDI for swimmers were 2.4 x 10(-6) and 2.0 x 10(-8), respectively. The swimmers' inhalation CDI (1.9 x 10(-3) mg/kg/day) was estimated to be sixfold higher than levels obtained for coaches (3.3 x 10(-4) mg/kg/day). According to guidelines, the HI was acceptable, but CR exceeded the recommended limit for both, coaches (CR: 5.5 x 10(-7)-8.5 x 10(-5); HI: 6.5 x 10(-4)-1 x 10(-1)) and swimmers (CR: 1.4 x 10(-5)-3.6 x 10(-4) HI: 1.6 x 10(-2)-4.3 x 10(-1)). Our findings provide further support to the need to develop comprehensive guidelines to safeguard the health of individuals involved in elite swimming.

2019

A maximum power point tracking for photovoltaic systems based on Monod equation

Authors
Camilo, JC; Guedes, T; Fernandes, DA; Melo, J; Costa, F; Sguarezi Filho, AJ;

Publication
Renewable Energy

Abstract

2019

Harmonics and flicker in an iron and steel industry with AC arc furnaces

Authors
Pérez Donsión, M; Jar Pereira, S; Oliveira, FT;

Publication
Renewable Energy and Power Quality Journal

Abstract
An AC arc furnace is an unbalanced, non-linear and time-varying load, which can cause many power quality problems to the electric network inside the plant and in its electrical vicinity. Although different studies addressing harmonics and flicker analyses on arc furnaces can be found in the bibliography, it is very difficult obtain an exact model that considers all the parameters that influence the process, and therefore it is necessary to obtain actual measurements under different conditions. This paper presents measurement results for harmonic distortion, flicker and unbalance obtained over three different measurement campaigns on an iron and steel industry (SNL), as well as the pertinent conclusions. Measurement campaigns were performed on an AC arc furnace of 83 MW (170 TM) with a 120 MVA transformer connected by a ‘dirty’ 220 kV line (55 km) to the Substation of Carregado, where other feeders supply industrial and domestic consumers. Finally, the dynamic behaviour of an SVC will be analysed and compared to that of a STATCOM by means of simulation studies.

2019

Voltages in the network and inside industrial plants. Case of PSA-vigo

Authors
Pérez Donsión, M; Oliveira, FT;

Publication
Renewable Energy and Power Quality Journal

Abstract
The main objective of this paper consists in presenting a survey of voltage sags and short interruptions in different places along the geography of Galicia measured throughout two years. Effects and the possible solutions of the voltage sags and short interruptions in one industrial installation, PSA-Vigo, that produce cars, are also addressed. Finally, we will establish the corresponding conclusions.

2019

Short-Circuit Calculation in Unbalanced Three-Phase Power Distribution Systems with Distributed Generation

Authors
Reiz C.; Leite J.B.;

Publication
2019 IEEE PES Conference on Innovative Smart Grid Technologies, ISGT Latin America 2019

Abstract
This work proposes a method to calculate the short- circuit currents in unbalanced three-phase power distribution systems with distributed generation (DG) from non- and renewable energy resources. It takes into account the physical and operational features of four different types of DGs: synchronous, induction, photovoltaic and double-fed induction generator (DFIG). The DG formulations depend upon the connection type that can be directly coupling to the power grid or by using electronic converters or coupling transformers. The proposed method uses the bus impedance matrix with Kron reduction for each generator and superposition conception in the short-circuit current calculation. The results are achieved under a real-work unbalanced distribution network with 135 buses providing typical values of the short-circuit current that are compared with values from commercial software in the evaluation of the proposed methodology.

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