-
A General n-Port Network’s Equivalent Current Sources Theorem
Issue:
Volume 6, Issue 6, December 2018
Pages:
142-145
Received:
16 October 2018
Accepted:
16 November 2018
Published:
24 December 2018
DOI:
10.11648/j.jeee.20180606.11
Downloads:
Views:
Abstract: In this paper a general n-port network’s equivalent current theorem has been derived out, for n = 1, 2…. the traditional Norton’s Theorem is only a special case of it for n=1. When an n-port passive linear time-invariant network is connected to another n-port linear time-invariant network which contained sinusoidal sources with same frequency, this theorem provides a new way to calculate the port-current of the n-port passive network. But the short-port currents of the n-port network contained sinusoidal sources must be known at first. In sinusoidal networks, currents are vector quantity or complex quantity, including magnitude and phase angle. Ammeter can only be used to measure the magnitude of the current, not including its phase angle. So it is impossible to get the short-port currents by the short-port experiment. Moreover the short-port experiment may cause some dangerous events. So a special method to get the short-port currents is introduced in this paper, First to find out the open-port voltage vector ( including magnitude and phase angle), by measuring the voltages magnitude between some two points of the open-port with a voltmeter and by drawing a series of voltage vector triangles that one side vector is the sum of other two side vectors , if the phase angle of one side vector in a triangle is known, the phase angles of the other side vectors in the same triangle can be decided. In the first triangle, the first open-port voltage vector is contained, its phase angle can be assigned to be zero, then the phase angles of the other two voltage vectors in the first triangle can be decided. In the second triangle, one of the two above voltage vectors is contained, then the phase angles of the other two voltage vectors in the second triangle can be decided. Thus go on step by step, all the open-port voltage vectors can be obtained. And the open-port voltage complex matrix has been obtained. The equation related the short-port current complex matrix and the open-port voltage complex matrix has been derived out in this paper. So the short-port current complex matrix can be obtained.
Abstract: In this paper a general n-port network’s equivalent current theorem has been derived out, for n = 1, 2…. the traditional Norton’s Theorem is only a special case of it for n=1. When an n-port passive linear time-invariant network is connected to another n-port linear time-invariant network which contained sinusoidal sources with same frequency, this...
Show More
-
Study of the Gap Discharge Phenomenon Based on Three-Dimensional Fractal
Wang Shuai,
Yin Zelong,
Gu Liang,
Shuai Xiaoxiao
Issue:
Volume 6, Issue 6, December 2018
Pages:
146-152
Received:
10 November 2018
Accepted:
4 December 2018
Published:
28 December 2018
DOI:
10.11648/j.jeee.20180606.12
Downloads:
Views:
Abstract: The damage of arc to gas insulation protection will affect the safe and stable operation of power system seriously in the field of high voltage insulation. Therefore, it is a great theoretical value and practical significance to study the mechanism of gas discharge and find out the law of gas discharge under different conditions for ensuring the safe and stable operation of power system. In order to study the variation law of arc channel complexity under different voltage levels, this paper adopts the discharging experiment of needle-plate electrode, adds different high voltage to the needle-plate electrode under other conditions unchanged, carries out many experiments, and collects five groups of discharging channel plans of needle-plate gap under different voltage. The are discharge channel image in the experiment is restored to the three-dimensional image from the space angle, and the fractal dimension of arc discharge channel under different voltage pressure is calculated by box dimension method of fractal dimension. The results show that the complexity of discharge channel decreases with the increase of voltage level, that is, the lower the voltage level and the larger the fractal dimension.
Abstract: The damage of arc to gas insulation protection will affect the safe and stable operation of power system seriously in the field of high voltage insulation. Therefore, it is a great theoretical value and practical significance to study the mechanism of gas discharge and find out the law of gas discharge under different conditions for ensuring the sa...
Show More
-
Implications of the Large-Scale Deployment of Non-linear Loads
Jomo Nkumah Gill,
Gururaj Sudhindra Punekar
Issue:
Volume 6, Issue 6, December 2018
Pages:
153-159
Received:
9 September 2018
Accepted:
26 September 2018
Published:
4 January 2019
DOI:
10.11648/j.jeee.20180606.13
Downloads:
Views:
Abstract: Compared to yesteryear, non-linear loads now proliferate in homes, offices and the industrial environment. Non-linear loads now form a major component of the total loading in the typical electrical network. The Compact Fluorescent Lamp is but one example of a non-linear load that inherently produces and injects distorted currents into the electrical power network, which could create adverse consequences if appropriate and adequate harmonic mitigation techniques are not employed. CFLs are now a major component of the luminaires market around the world because consideration is being given worldwide to the phasing out of incandescent lamps. However, there are legitimate concerns over the quality of some CFLs. This paper investigates and compares the quality of some major brands of CFLs, in terms of parameters such as harmonic content, power factor, fundamental power factor, nonactive power, and apparent power. The wider implication of these results is ascertained by investigating the effects large scale installation of CFLs would have on a generalized electrical network. This work shows that CFLs with high harmonic currents increase the requirements of the source and other network components, as well as place a significant strain on them, since they draw a higher current and also consume a higher apparent power and nonactive power than is necessary for power delivery. Also, it is found that voltage harmonic limits can approach or exceed the IEEE limit of 5% as the number of CFLs deployed is increased. This situation is more pronounced if CFLs with higher current harmonic content are installed.
Abstract: Compared to yesteryear, non-linear loads now proliferate in homes, offices and the industrial environment. Non-linear loads now form a major component of the total loading in the typical electrical network. The Compact Fluorescent Lamp is but one example of a non-linear load that inherently produces and injects distorted currents into the electrica...
Show More
-
Practicing Digital Transformation by Developing New Smart City Business
Issue:
Volume 6, Issue 6, December 2018
Pages:
160-163
Received:
12 November 2018
Accepted:
4 December 2018
Published:
4 January 2019
DOI:
10.11648/j.jeee.20180606.14
Downloads:
Views:
Abstract: Sparkled by the development of clouding computing, big data, Internet of Things, and mobile computing technologies, digital transformation becomes an important theme across all industries. First, this conceptual paper analyzes the trend of digital transformations within the telecommunications industry both in China and around the world. It points out that broadcast television providers should focus on transitioning to the next-generation network and smart city businesses as main practices of digital transformation. As a case study, the challenges and opportunities ahead of China Radio and Television Network Co., Ltd. (CRTN) under the digitization trend are identified. Secondly, the paper proposes a SMART strategy for digital transformation and argues that the strategy applies well to corporations like CRTN. Thirdly, the paper studies the concepts, standards, and technologies of Smart Sustainable City proposed by ITU and the New Smart Cities being developed in China. Finally, the paper presents the Fiberhome’s Smart ICT 2.0+ solutions and states why they are suitable for CRTN’s digital transformation.
Abstract: Sparkled by the development of clouding computing, big data, Internet of Things, and mobile computing technologies, digital transformation becomes an important theme across all industries. First, this conceptual paper analyzes the trend of digital transformations within the telecommunications industry both in China and around the world. It points o...
Show More
