بررسی شدت میدان‎های الکترومغناطیسی انتشار یافته از لامپ‎های فلورسنت فشرده متداول

مقدمه: در سال‏های اخیر استفاده از لامپ‏های فلورسنت فشرده در سطح کشور با هدف بهینه‌سازی مصرف انرژی افزایش یافته است. با توجه به اهمیت اثرات بهداشتی منابع روشنایی، هدف پژوهش حاضر بررسی شدت میدان‎های الکترومغناطیسی انتشار یافته از لامپ‎های فلورسنت فشرده متداول هست. مواد و روش­ ها: در این مطالعه 54 حباب لامپ فلورسنت فشرده از لامپ‌های تولید شرکت‌های داخلی و خارجی مورد بررسی قرار گرفت. شدت میدان‏های الکترومغناطیسی در دو محدوده‏ فرکانسی خیلی پایین و فوق‌العاده پایین به ترتیب با استفاده از دستگاه‏های مدل HI 3603 و HI 3604 شرکت Holaday اندازه‏گیری شد. داده‏ها با استفاده از نرم‌افزار SPSS تحلیل گردید. یافته‌ها: شدت میدان الکتریکی و مغناطیسی انتشار یافته از لامپ‌ها با افزایش فاصله از منبع کاهش یافت. در نقطه مرجع (25 سانتیمتری)، شدت مؤثر میدان الکتریکی در محدوده فرکانسی خیلی پایین و فوق‌العاده پایین به ترتیب 25/2 و 39/15 ولت بر متر و شدت میدان مغناطیسی به ترتیب 47/0 و 41/9 میلی‌آمپر بر متر تعیین گردید که کلیه مقادیر پایین‏تر از حدود مجاز کشوری بود. همچنین شدت مؤثر میدان الکتریکی و مغناطیسی برحسب شرکت سازنده اختلاف معناداری داشت (05/0P <) شدت میدان الکتریکی و مغناطیسی انتشار یافته از لامپ‏ها با افزایش فاصله از منبع کاهش یافت. نتیجه‌گیری: علیرغم پایین بودن شدت میدان‏های الکترومغناطیسی لامپ‎ها از حدود مجاز، با توجه به عدم دستیابی به شواهد قطعی در خصوص اثرات بیولوژیکی میدان‏ها، کاهش هر چه بیشتر مواجهه عمومی تا حد ممکن و منطقی ضروری است. در این راستا استفاده از لامپ‏های روشنایی با کیفیت مطلوب و استاندارد توصیه می‏گردد

Performance Evaluation of Lighting Fixtures and Installations for Renewable Energy Applications

Energy efficiency has been viewed as the most accessible and cost effective form of alternative energy. While lighting occupies only a percentage in the total electric loads in homes, technological advances in Light Emitting Diodes (LED) are becoming more convincing in their power consumption and lumens output. This paper evaluates the percentage lighting occupied in the total load spectrum on the two main buildings in Osun State University, verifies the light level in the library reading rooms (a place where adequate lighting is imperative) with recommended standards and comparison between the output of Compact Fluorescent Lamps (CFL) and the LEDs. Walk-through Energy audit approach was used to evaluate the percentage lightning occupies which involves identification and grouping of all electrical loads with their respective power rating in Watts. Similarly, illumination level verification campaign was conducted with the use of a digital light meter (sensor based device) connected to a Personal Computer for logging illumination level real time along the aisles and reading cubicles. The same light meter was used for comparing the output of installed CFL and proposed LED. Results indicate that lighting fixtures occupy 12.2% of the load spectrum. The lighting installations also do not conform to global illumination standards for the facility accessed while the output of the LED tested is still low. It is therefore recommended that better LED light sources be considered for efficient energy, reduction in environmental pollution associated with power generation, reduction in power needed to maintain a cooling effect and cost economy. Keywords: CFL, LEDs, lumens, illumination level verification, power sector, environmental pollution

Appropriate methods to analyse power conversion harmonics

Nowadays, non-linear loads represent the majority of the residential electrical consumers. The limits on emission and immunity are imposed by IEC- standards, however there is a lack in the domain 2 – 150 kHz. Where power quality standards focus on the current, EMC standards use voltage limits. An appropriate method for measuring high frequency grid disturbances is explored. Measurement techniques described by the existing standards for power quality and EMC are investigated. The aim of this work is to find a robust measurement method for the considered frequency range 2 - 150 kHz. Experimental results are presented in order to validate the analyzed methods

Power quality and electromagnetic compatibility: special report, session 2

The scope of Session 2 (S2) has been defined as follows by the Session Advisory Group and the Technical Committee: Power Quality (PQ), with the more general concept of electromagnetic compatibility (EMC) and with some related safety problems in electricity distribution systems. Special focus is put on voltage continuity (supply reliability, problem of outages) and voltage quality (voltage level, flicker, unbalance, harmonics). This session will also look at electromagnetic compatibility (mains frequency to 150 kHz), electromagnetic interferences and electric and magnetic fields issues. Also addressed in this session are electrical safety and immunity concerns (lightning issues, step, touch and transferred voltages). The aim of this special report is to present a synthesis of the present concerns in PQ&EMC, based on all selected papers of session 2 and related papers from other sessions, (152 papers in total). The report is divided in the following 4 blocks: Block 1: Electric and Magnetic Fields, EMC, Earthing systems Block 2: Harmonics Block 3: Voltage Variation Block 4: Power Quality Monitoring Two Round Tables will be organised: - Power quality and EMC in the Future Grid (CIGRE/CIRED WG C4.24, RT 13) - Reliability Benchmarking - why we should do it? What should be done in future? (RT 15

The Impact of the Use of Large Non-Linear Lighting Loads in Low-Voltage Networks

The principal numerical and experimental results obtained by the authors on the harmonic power losses in low-voltage networks in the lighting area have been summarized in this review. Light-emitting diodes (LEDs) and compact fluorescent lamp (CFL) loads were considered. Four-core cables and four single-core cable arrangements were examined. The cables were modeled by using electromagnetic finite element analysis software. It was found that the cross section of the neutral conductor plays an important role in the derating of the cable ampacity due to the presence of a high level of triplen harmonics in the distorted current. In order to reduce the third-order harmonic currents in the neutral conductor, an experimental investigation of diversity factors for LED in combination with CFL and LED lamps was also performed. Attention was paid to the reduction of the third-order harmonic current, which is mainly responsible for the strong increase in power losses in the neutral conductor of low-voltage installations. The convenience of having LED lamps designed to operate as two-phase loads is suggested for certain applications

Investigations of power quality problems in modern buildings

This thesis was submitted for the degree of Master of Philosophy and awarded by Brunel University.This thesis presents the results of measurements made in a typical office building (Tower A) and a Residential building (Kilmorey Hall), all located in the campus of Brunel University, West London for period of one week. The collected data were statistically treated to establish the best period that characterizes the harmonic distortions and other disturbances in these buildings. The chosen period was considered as best to get the correct harmonic distortions in the day, and at a specific interval. One phase was also chosen to represent the others after some considerations. The frequency of measurement was also noted. All the data collected were evaluated based on the limits proposed by International Standards: European, IEEE, and G4/5 Recommendations. Comparisons of the collected data were made between these two buildings. For the purpose of this project, the statistical treatment of the collected data characterizing the voltage harmonics was considered. The period of 9am to 5pm on a week day (Tuesday 26th October) was best for Tower A as it had the highest loading pattern for the week. This is a day-load establishment, because it is an office building. The period for Kilmorey Hall was Monday 1st November between the hours of 6pm up to 11pm, being considered as wholly residential building. All readings were spaced at 8minutes interval for frequency of measurement. The methodology presented in this project is useful for quantification and qualification of the harmonic distortion of voltage and current. It is estimated that more than 30% of the power currently being drawn from the utility companies is now consumed by sensitive non- linear load, and still increasing, both industrially and commercially [20]. Non- linear load is steadily increasing in residential areas also. The effect of continuous overvoltage was also considered even though the overvoltage was within the International Standards. The result was proved to cause unnecessary and unwanted overconsumption. This could not be helping to reduce carbon emission. Effects of Compact Fluorescent Lamps with electronic gears (CFLs) were also investigated as a rising source of harmonic production in Modern buildings