scholarly journals Nonsinusoidal load current effect on the electrical and thermal operating parameters of oil filled power distribution transformers

Author(s):  
Emil Cazacu ◽  
Maria-Catalina Petrescu ◽  
Valentin Ionita ◽  
Lucian Petrescu
2021 ◽  
Vol 30 (1) ◽  
pp. 677-688
Author(s):  
Zhenzhuo Wang ◽  
Amit Sharma

Abstract A recent advent has been seen in the usage of Internet of things (IoT) for autonomous devices for exchange of data. A large number of transformers are required to distribute the power over a wide area. To ensure the normal operation of transformer, live detection and fault diagnosis methods of power transformers are studied. This article presents an IoT-based approach for condition monitoring and controlling a large number of distribution transformers utilized in a power distribution network. In this article, the vibration analysis method is used to carry out the research. The results show that the accuracy of the improved diagnosis algorithm is 99.01, 100, and 100% for normal, aging, and fault transformers. The system designed in this article can effectively monitor the healthy operation of power transformers in remote and real-time. The safety, stability, and reliability of transformer operation are improved.


Author(s):  
N. B. Ngang ◽  
N. E. Aneke

There have been incessant power failures in our power network, which has arisen as a result of over current, over voltage, harmonic distortion caused by ripples to mention a few, This could be overcome by determining the harmonic mean from a given harmonic distortion data ,optimizing the mean from a given distortion data, training the optimized result to minimize harmonic in power distribution transformer, designing a Simulink model for mitigating the resultant effect of harmonics which are the sinusoidal components of a complex wave, using simplex optimizationtechnique. The optimization technique used is 69% better than the conventional method like proportional integral derivative (PID) in terms of minimizing harmonic in power transformer.


Author(s):  
Jadiel Caparrós Da Silva

Distribution transformers are present in large quantities in the electrical system, in addition to being essential equipment for delivering quality and reliable energy to consumers. This distribution transformers have a dielectric insulation and refrigeration system, with Insulating Mineral Oil (IMO) being the most used. However, the large-scale use of IMO entails a very high environmental risk, because in addition to its fossil origin (petroleum), it also has low biodegradability and is highly toxic and polluting to the environment. In view of this, substitution alternatives for the IMO began to be sought, where, over the years and with technological advances, Insulating Vegetable Oil (IVO) with characteristics similar to the IMO emerged, in addition to being highly biodegradable and providing an alternative sustainable development for the construction of transformers. Thus, the objective of this work is to carry out an analytical study about the characteristics and benefits of using the vegetable fluid for the equipment and for the environment, in addition to comparing the efficiency and cost parameters of IVO and IMO according to current standards. As a contribution, this paper seeks to provide a broad theoretical foundation on IVO and IMO in order to provide conceptualization to agroenergy researchers.


2020 ◽  
Vol 4 (2) ◽  
pp. 321-326
Author(s):  
Akinlolu Olosunde ◽  
Rowland Benjamin Ekpo

Transformer failure is a major problem confronting the Nigerian power sector, hindering the transmission and distribution of electric power to various households, institutions, and industries. Many of these transformer developed problem due to the old age of the transformers, overloading, in-availability of technical expertise, poor maintenance culture, manufacturer's faults, just to mention few. The present research focuses on providing half exponential power model for the failure of already installed transformers, with respect to years of installation up to the time of the first failure, using secondary data from the south western part of Nigeria as a case study. The results obtained showed that half exponential power performed better in modeling the first time failure of power transformers. This was possible because of the present of shape parameter which gives flexibility to half exponential power when compared with a half normal distribution.


Author(s):  
Emil CAZACU ◽  
Laurentiu-Marius DUMITRAN ◽  
Lucian PETRESCU

Electrical transformers are some of the most important equipment in the entire electricity distribution chain. Their operation with optimal values of the parameters (electrical, thermal and mechanical) ensures the continuous supply of consumers. The modern electrical loads of power distribution transformers are often nonlinear and generate several power quality problems, especially the distortion of the waveform of the current that flows through the windings of the transformer. This generates additional stresses (electrical and thermal) of the various components of the transformer (originally designed to operate in pure sinusoidal mode) which can cause abnormal (faulty) operation of the transformer and ultimately reducing its life (estimated by the manufacturer for permanent sinusoidal regime). In order to prevent or diminish the negative effects of the nonsinusoidal regime on the transformer, a deliberate limitation (reduction) of its maximum load is performed. The procedure is known as transformer derating. Its main aim is to establish the most appropriate declassification factors (denomination), resulting from the correlation of the nominal and constructive data of the transformer with the power quality parameters, measured in its secondary part (usually, these are the current distortion level and the corresponding spectrum harmonic). This paper analyzes qualitatively and quantitatively these aspects and proposes a downgrading procedure for in-service transformers which it illustrates in a case study.


2018 ◽  
Vol 64 ◽  
pp. 07006
Author(s):  
Cheng Huang Che ◽  
Jing Yeh Jia

The Power Control Unit (PCU) in Micro-satellites program proposed to develop by NSPO, acts as the satellite power control and distribution center. One of the modules in the PCU, named the Power Distribution (PD), the main function provides the rated voltage and current of each power outlet for the satellite subsystem. When overload or short-circuit happens and persists for a time period, PD will limit the load current in a pre-designed value, and shut off the load to avoid damage on essential devices. In this paper, we will introduce the PCU EBB function and circuit design of PD.


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