scholarly journals On the reduction of the third-order harmonic losses in low–voltage power cables used for feeding large LED and CFL lighting loads

2017 ◽  
Vol 6 (3) ◽  
pp. 46 ◽  
Author(s):  
N. J. Milardovich ◽  
L. Prevosto ◽  
M. Á. Lara ◽  
D. Milardovich

An experimental investigation of diversity factors of CFL (compact fluorescent lamps) in combination with LED (light emitting diode) lamps is presented in this paper. Attention was paid to the reduction of low–order harmonic currents, especially the third one; which is mainly responsible for the strong increase in power losses in the neutral conductor of low–voltage installations. The harmonic currents drawn by several LED and CFL lamps with nominal powers < 25 W were first measured to investigate the electrical characteristics of individual lamps. In addition, a series of experiments was conducted in which LED lamps were powered between lines through small autotransformers thus avoiding the use of the neutral conductor. The results showed in both cases a sensible reduction of the harmonic current of third order and therefore a marked reduction of the power losses associated with them.

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4851
Author(s):  
Jairo Hernández ◽  
Andrés A. Romero ◽  
Jan Meyer ◽  
Ana María Blanco

In the last decade, mainly due to political incentives towards energy efficiency, the share of lamps with power electronic interfaces, like Compact Fluorescent Lamps (CFL) and Light Emitting Diode (LED) lamps, has significantly increased in the residential sector. Their massive use might have a substantial impact on harmonic currents and, consequently, on the current flowing in the neutral conductor. This paper analyzes the impact of modern energy-efficient lighting technologies on the neutral conductor current by using a synthetic Low Voltage residential grid. Different load scenarios reflecting the transition from incandescent lamps, via CFL, to LED lamps are compared concerning the neutral conductor current at different points in the network. The inherent randomness related to the use of lighting devices by each residential customer is considered employing a Monte Carlo simulation. Obtained results show that the use of CFL has a greater impact on the neutral conductor current of Low Voltage (LV) residential grids and that, with increasing use of LED lamps, a decreasing impact can be expected in the future.


Author(s):  
Josifs Survilo ◽  
Antons Kutjuns

Operation Modes of HV/MV SubstationsA distribution network consists of high voltage grid, medium voltage grid, and low voltage grid. Medium voltage grid is connected to high voltage grid via substations with HV/MV transformers. The substation may contain one, mostly two but sometimes even more transformers. Out of reliability and expenditure considerations the two transformer option prevail over others mentioned. For two transformer substation, there may be made choice out of several operation modes: 1) two (small) transformers, with rated power each over 0.7 of maximum substation load, permanently in operation; 2) one (big) transformer, with rated power over maximum substation load, permanently in operation and small transformer in constant cold reserve; 3) big transformer in operation in cold season, small transformer-in warm one. Considering transformer load losses and no load losses and observing transformer loading factor β it can be said that the mode 1) is less advantageous. The least power losses has the mode 3). There may be singled out yet three extra modes of two transformer substations: 4) two big transformers in permanent operation; 5) one big transformer permanently in operation and one such transformer in cold reserve; 6) two small transformers in operation in cold season of the year, in warm season-one small transformer on duty. At present mostly two transformers of equal power each are installed on substations and in operation is one of them, hence extra mode 5). When one transformer becomes faulty, it can be changed for smaller one and the third operation mode can be practiced. Extra mode 4) is unpractical in all aspects. The mode 6) has greater losses than the mode 3) and is not considered in detail. To prove the advantage of the third mode in sense of power losses, the notion of effective utilization time of power losses was introduced and it was proven that relative value of this quantity diminishes with loading factor β. The use of advantageous substation option would make it possible to save notable amount of electrical energy but smaller transformer lifetime of this option must be taken into account as well.


Author(s):  
J. S. Adeleke ◽  
A. B. Wahab ◽  
E. A. Olanipekun

Over the years, visual comfort has been described as a major requirement needed to enhance optimal performance of occupants in any learning environment in tertiary institutions. This is reflected in the poor performance of the commonly used Fluorescent Lamps (FL) occasioned by its constant burn-off, high failure rate and reduced durability. Hence, there is a shift to the adoption of Compact Fluorescent Lamp (CFL) and Light Emitting Diode (LED). This study therefore examined the pattern of electricity consumption involving the adoption of FL, CFL and LED in the purposively selected lecture theatres of Obafemi Awolowo University, Ile-Ife, Nigeria. The study was carried out using energy monitor to obtain the consumption data of the lamps for periodic logging at intervals of 1 hr, 3 hrs, 6 hrs, 12 hrs, 1 day, 7 days, 1 month and 3 months respectively; and also to determine the payback period of each of the lamps. From the data collected, patterns of electricity used, electricity savings were calculated and compared to establish performance potentials of each of the lamps. The study found that there was a significant difference in the pattern of electricity consumption of FLs compared with that of CFLs and LEDs, but a reduced margin existed between CFLs and LED lamps. It showed that the FLs consumed 681.576 kWh, 1619.466 kWh and 5652.432 kWh, CFLs consumed 387.302 kWh, 692.479 kWh and 1936.600 kWh, while LED consumed 294.188 kWh, 426.608 kWh and 1499.015 kWh. There were significant differences in consumption with 43, 47 and 65% reduction in electricity consumption using CFLs while 57, 73 and 73% using LED fittings were obtained. The CFLs performed better in terms of return on investments by having a lower payback period when compared to LED. The study concluded that replacing FL with CFL and LED would be desirable option in order to enhance optimal performance of lecture theatres, but in terms of payback period, it would be beneficial to retrofit FLs with CFLs.


Author(s):  
Anati Syahirah Hedzir ◽  
Norasmahan Muridan ◽  
Nurul Fadzlin Hasbullah

We review the dominant mechanism and characteristics of it which gave rise to the existence of forward and reverse leakage current in nitride based light emitting diode (LED). LED is one of the promising device to be used as a lighting source because it does not contain mercury unlike fluorescent lamps. However, the existence of leakage current can affect the reliability and efficiency of LED. Hence, its importance to understand the mechanism that responsible for its existence. The occurrence of leakage current is divided into three main parameters: 1) low bias; 2) medium or high bias; 3) temperature dependence. In low reverse bias, Poole-Frenkel is the dominant mechanism while tunneling is the dominant mechanism in high bias region. Furthermore, in forward bias, defect assisted tunneling is most likely the dominant mechanism. In low forward bias, electrons are the dominant carriers in defect assisted tunneling while in medium forward bias, holes are the dominant carriers.  Moreover, Variable Range Hopping (VRH) is reported to be dominant when the temperature of conduction is below 200K. 


2013 ◽  
Author(s):  
Roger Buelow ◽  
Keith Kazenki ◽  
Greg Flies

Due to the recent push for energy efficient technology, LEDs have developed to be able to meet and surpass fluorescent lamps in terms of efficiency and lifetime. Additional focus on LEDs has allowed the initial investment price to decrease allowing LEDs to become a feasible option. Installing LEDs during the construction of ships allows for a greater TOC savings from increased energy efficacy, lower maintenance costs and a simpler electrical design schematic. There are three options available to incorporate LEDs on a ship: LED lamps, LED fixtures or a combination of the two.


Due to electrical energy reduction need, in the recent years, alternative light sources like Compact Fluorescent Lamps (CFL) and Light Emitting Diode lamps (LED) are replacing the classical incandescent light bulbs. Although they consume less power, these lamps have the disadvantages of being a significant source of harmonics. This means that the lightning network should be redesigned taking into account the magnitude of the current harmonic components and of the null current. To this aim, an accurate model easy to build and a fast analysis are very useful. This paper presents three models for different types of energy saving light bulbs, two existing ones and a new implementation, a procedure for model parameters identification and a comparison of the models. Some errors criteria are considered, both qualitative and quantitative. The periodic steady state response is computed using a frequency domain analysis.


Author(s):  
Imanuel M. Thenu ◽  
Gondo Puspito ◽  
Sulaeman Martasuganda

<p>ABSTRACT<br />Lift net fishermen usually use fluorescent lamp as attractor to lure fish. As price of fuel rise, fishermen are forced to find another option to change their attractor into some much lower cost and more energy-save lamp, or in other words, to change into LED lamp. This research are providing evidence that sunked LED lamps can be utilized as a helper tools, and also determined the best time for catching fish in the lift net. Two lift net used in this research, one of them used sunked LED lamps and the other used ordinary fluorescent lamps. Lift net are operated as long as 20 nights, with four catching times per night, between 18.00-21.00, 21.00-00.00, 00.00-03.00, and 03.00-06.00. Results showed that LED lamps give a better result with 11 organisms successfully catch (287,6 kg), compared to ordinary fluorescent lamps with only six organisms (238,3 kg). The best time for catching with LED lamps are between 18.00-21.00 (121 kg), while between 21.00-00.00 (67,4 kg), 00.00-03.00 (46,9 kg) and 03.00-06.00 (52,3 kg).<br />Key words: fluorescent lamp, lift net, light emitting diode, Palabuhanratu,sunked lights</p><p>-------</p><p><br />ABSTRAK<br />Nelayan bagan biasa menggunakan lampu fluorescent sebagai atraktor untuk memanggil ikan. Harga bahan bakar yang mahal menyebabkan nelayan harus beralih memakai jenis lampu lain yang hemat energi, seperti lampu LED (light emitting diode) Penelitian bertujuan untuk membuktikan bahwa lampu celup LED dapat digunakan sebagai alat bantu penangkapan ikan pada bagan dan menentukan waktu operasi penangkapan terbaik. Dua bagan digunakan dalam penelitian ini. Masing-masing menggunakan lampu celup LED dan lampu fluorescent. Bagan dioperasikan selama 20 malam. Dalam 1 malam dilakukan 4 kali penangkapan, yaitu antara jam 18.00-21.00, 21.00-00.00, 00.00-03.00 dan 03.00-06.00. Hasil penelitian menunjukkan bahwa penggunaan lampu celup LED pada bagan menghasilkan 11 jenis organisma tangkapan seberat 287,6 kg, atau lebih banyak dari lampu fluorescent sejumlah 6 organisma (238,3 kg). Adapun waktu penangkapan terbaik pada bagan yang menggunakan lampu LED adalah antara pukul 18.00-21.00 yang menghasilkan tangkapan seberat 121 kg, sedangkan 21.00-00.00 (67,4 kg), 00.00-03.00 (46,9 kg) dan 03.00-06.00 (52,3 kg).<br />Kata kunci: lampu fluorescent, bagan, light emitting diode, Palabuhanratu, lampu celup</p>


Author(s):  
Brian Thomas

A multidisciplinary team of engineering students traveled to Nairobi, Kenya in May 2006 to implement a service learning project between academic sessions. Low power, white light emitting diode (WLED) based lighting devices were designed and built by student participants and members of the student organization Engineers with a Mission during the months preceding the trip. Photometric performance and power consumption data are given for these devices, which were subsequently installed in seventeen homes in the large and infamous Kibera slum. A locally manufactured, technologically appropriate wind generator was purchased and installed to charge a single, centrally located deep cycle battery. Power from this battery was distributed to the LED-based lights through a student designed and built circuit breaker panel and a radial network of indoor/outdoor extension cords that served as low voltage transmission lines. The project provided a learning environment for alternative energy techniques, appropriate technologies, global and multicultural awareness, poverty apprehension, the realities of project implementation, and the social responsibility of those in the engineering profession. A network of Kenyan organizations consisting of a university, a non-governmental organization, a small business, and a community organization, was formed to facilitate sustainability and provide ongoing analysis and maintenance.


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