Undiagnosed Phenylketonuria Can Exist Everywhere: Results From an International Survey

peer reviewedMany countries do not have a newborn screening (NBS) program, and immigrants from such countries are at risk for late diagnosis of phenylketonuria (PKU). In this international survey, 52 of 259 patients (20%) with late diagnosed PKU were immigrants, and 145 of the 259 (55%) were born before NBS or in a location without NBS. © 2021 The Author

An energy cost minimization algorithm for wind turbine system design

Optimal Wind Turbine System (WTS) design for one location is not necessarily the optimal design for another location because the wind speed distribution may wary between locations. For wind turbine design, the most important design variables may be listed as generator capacity, rotor diameter and hub height. This is due to the fact that a larger rotor captures more energy and a larger generator can capture more energy as well but also costs more. Moreover, the wind speed increase with hub height but so does the tower cost. They must match one another and the optimal match is dependent on the site's wind conditions. Accordingly, this paper introduces a design optimization algorithm based on minimizing the cost of energy of a Horizontal Axis Wind Turbine (HAWT) to be operated at a specific wind site. The algorithm uses probability distributions of wind speed and computes optimal values of HAWTs' design parameters such as generator capacity, rotor diameter and hub height by taking into account site's wind condition to generate electrical energy in minimum cost. © 2011 Praise Worthy Prize S.r.l. - All rights reserved

Letter to the Editor: Regarding the Discussion on "A New Model for Wind Turbine Systems"

WOS: 000287030100008

Short term and medium term power distribution load forecasting by neural networks

WOS: 000227027800005Load forecasting is an important subject for power distribution systems and has been studied from different points of view. In general, load forecasts should be performed over a broad spectrum of time intervals, which could be classified into short term, medium term and long term forecasts. Several research groups have proposed various techniques for either short term load forecasting or medium term load forecasting or long term load forecasting. This paper presents a neural network (NN) model for short term peak load forecasting, short term total load forecasting and medium term monthly load forecasting in power distribution systems. The NN is used to learn the relationships among past, current and future temperatures and loads. The neural network was trained to recognize the peak load of the day, total load of the day and monthly electricity consumption. The suitability of the proposed approach is illustrated through an application to real load shapes from the Turkish Electricity Distribution Corporation (TEDAS) in Nigde. The data represents the daily and monthly electricity consumption in Nigde, Turkey. (C) 2004 Elsevier Ltd. All rights reserved

Modeling of wind turbine systems and analyses of their output characteristics on distribution systems with voltage/frequency dependent static loads (Part II: Modeling and simulation of wind turbine systems) [Rüzgâr türbini sistemlerinin modellenmesi ve farkli gerilim/frekans bagimli statik yüklü dagitim sistemlerinde çikiş karakteristiginin i·ncelenmesi (Bölüm II: Rüzgâr türbini sistemlerinin modellenmesi ve simülasyonu)]

2010 7th National Conference on Electrical, Electronics and Computer Engineering, ELECO 2010 -- 2 December 2010 through 5 December 2010 -- Bursa -- 83834In this paper, the effects of static loads on the output characteristics of Wind Turbine Systems are analyzed. For this purpose, Simulink realization of Wind Turbine Systems is provided by using Matlab/Simulink SimPowerSystems Blockset and simulated in a test system with voltage/frequency dependent static loads, which are also modelled in Matlab/Simulink. It is observed from simulations that a Wind Turbine Systems connected to a system experiences frequency deviation will exhibit different voltage and output power characteristics for different static load types

A network topology-based voltage stability index for radial distribution networks

This paper presents a network topology-based voltage stability index for identifying the most sensitive bus to the voltage collapse in the radial distribution networks. The developed index is based on the transferred active and reactive power equation of the distribution line. Network topology algorithm based on the bus-injection to branch-current (BIBC) matrix has been used for implementation of developed stability index to the radial distribution networks. The performance of the index is tested on different loading conditions for different load models and different substation voltage levels. Results suggest that the proposed index is reliable and can easily be applied to the modern radial distribution networks which have distributed generation (DG) sources and/or voltage controllers

Distribution Systems Forward/Backward Sweep-based Power Flow Algorithms: A Review and Comparison Study

WOS: 000261675000006Because of different characteristic features of distribution networks, such as radial structure and high R/X ratio, distribution system load flow analysis differs significantly from transmission systems. Accordingly, a number of methods that are specially designed for the solution of the power flow problem in radial distribution systems are found in the literature. Most of the developed methods are based on the forward/backward sweep processes for the solution of the ladder networks. In this article, various distribution system load flow algorithms, based on the forward/backward sweeps, are reviewed, and their convergence ability is quantitatively evaluated for different loading conditions, R/X ratios, and sub-station voltage levels. Moreover, the effects of static load modeling on the convergence characteristics of algorithms are also investigated

Application of SVC on dynamic load for different load types

39th International Universities Power Engineering Conference (UPEC 2004) -- SEP 06-08, 2004 -- Univ West England, Bristol, ENGLANDWOS: 000231594700051This paper investigates the effect of different characteristics of dynamic load on the system voltage profile and active/reactive power variations. For the dynamic load, exponential recovery load model is used and four different exponents of the load are considered to model different dynamic loads. For the voltage control, Static Var Compensator (SVC) is implemented and dynamic analysis of SVC on voltage control is simulated with a simple-three bus power system using Matlab SimPowerSystems Blocksets. The simulation results indicate that significant improvement on voltage profile could be achieved by using SCVs for different dynamic loads.Power Syst & Elect Res Grp, IEEE Comp Soc, IEE, Int Councik Large Elect Syst, IEEE Reg 8, Power Engn Soc, Natl Grid Transco, EDF, WUHAN HI-TECH Elect Engn Co Chin

Location of facts devices on power system for voltage control

39th International Universities Power Engineering Conference (UPEC 2004) -- SEP 06-08, 2004 -- Univ West England, Bristol, ENGLANDWOS: 000231594700069The modelling of the load has a significant effect in the electrical power systems. This paper presents the effect of different static load models on the location of Static VAr Compensator (SVC). The static load types, in which active and reactive powers vary with voltage as an exponential form, are used. The effect of appropriate location of the SVC on voltage control for variable load conditions is investigated. For this purpose each load is varied as a stair-case and voltages are controlled at the desired levels by using minimum number of Static Var Compensator (SVC). Modelling and simulation of the system are performed using Matlab SimPowerSystems Blocksets. PI controllers are used to control SVC firing angles. The studied power system is a simple five-bus system.Power Syst & Elect Res Grp, IEEE Comp Soc, IEE, Int Councik Large Elect Syst, IEEE Reg 8, Power Engn Soc, Natl Grid Transco, EDF, WUHAN HI-TECH Elect Engn Co Chin

Analysis of facts devices for dynamic loads using Matlab

Ministry of Macedonia;Aristotle University of Thessaloniki, Thessaloniki, Greece;Insitiute of Electrical Engineers, IEE;Institute of Electrical and Electronic Engineers, IEEE;Technical Chamber of Greece, TCGUPEC 2003, 38th International Universities' Power Engineering Conference -- 1 September 2003 through 3 September 2003 -- Thessaloniki -- 62394The modern power system is a complex dynamic system consisting of a large number of different dynamic devices, such as synchronous machines and loads. The system is continually subjected to sudden small disturbance in load. Load parameters are generally uncertain and loads often exhibit some dynamic response. This paper investigates the effect of dynamic loads on Thyristor Controlled Series Capacitors (TCSC) and Static Var Compensator (SVC) devices. In this paper, a PI controller is used to control of SVC and TCSC using Matlab Simulink and Power System Blockset. The graphic interface of Simulink provides a user-friendly environment where the power circuit and control system are represented in the same diagram. The design and testing of Flexible AC Transmission Systems (FACTS) devices are verified using Matlab. The studied power system is a simple two buses system with the 100 km distributed parameter line. For different load levels, we examine the effects of SVC and TCSC on the load voltages