نتایج جستجو برای: power transformer

تعداد نتایج: 494887  

Low- impedance transformer ground differential relay is a part of power transformer protection system that is employed for detecting the internal earth faults. This is a fast and sensitive relay, but during some external faults and inrush current conditions, may be exposed to maloperation due to current transformer (CT) saturation. In this paper, a new intelligent transformer ground differentia...

Journal: :amirkabir international journal of electrical & electronics engineering 2013
a. ghassemi e. zarezadeh s. saeed fazel

ac railway traction loads are usually huge single phase loads. as a result, a significant amount of negative sequence current (nsc) is injected into utility grid. moreover, harmonics and consumption ofreactive power are further power quality problems that the supply network is encountering. in this paper, acompensation strategy with the aid of railway power conditioner (rpc) is proposed to over...

2011
DRAGANA NAUMOVIC-VUKOVIC SLOBODAN SKUNDRIC LJUBISA NIKOLIC ALEKSANDAR ZIGIC DRAGAN KOVACEVIC SRDJAN MILOSAVLJEVIC

Present development and production of power transformers with lower losses in addition to replacement of outdated transformers assume regular measurement of losses in both load and no-load regime. These measurements are very demanding especially in the case of on-situ measurements. The complexity of the measurements grows with the size of transformer. This paper presents one typical test of los...

2017
Jingzhi Zhang Huihua Liu Yunqiu Wu Chenxi Zhao Kai Kang

An ultra-wide locking range transformer-based injection-locked frequency divider (ILFD) is presented. By making use of a 4-order transformer-based resonator and an inductive gain peaking technique, the proposed ILFD can achieve high performance in terms of wide locking range and low power consumption. Fabricated in a standard 65nm CMOS process with a core area of 0.18mm, the ILFD measures a loc...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تهران 1387

چکیده ندارد.

2011
Sanjay A. Deokar Laxman M. Waghmare

In recent years there has been very extensive use of power electronic devices, which result in harmonic proliferation in the power distribution system. In this paper, as per IEEE C 57.110 standards, procedure to calculate total loss in the distribution transformer under non-linear distortion environment is proposed. The power factor capacitor performance under non-linear load conditions is also...

2009
Anjali Chatterjee Nirmal Kumar Roy

Economically transformers constitute one of the largest investments in a Power system. For this reason, transformer condition assessment and management is a high priority task. If a transformer fails, it would have a significant negative impact on revenue and service reliability. Monitoring the state of health of power transformers has traditionally been carried out using laboratory Dissolved G...

2010
MOHAMMAD MASOUM

Ferroresonance is a highly destructive power quality phenomenon caused by complex oscillations generated by nonlinear magnetizing inductances in ferromagnetic materials and capacitive elements in power systems. In an effort to better understand ferroresonance and predict bifurcations and responses, an improved nonlinear transformer model for dynamic and steady-state operating conditions is deve...

2015
Amr A. Adly Salwa K. Abd-El-Hafiz

Transformers are regarded as crucial components in power systems. Due to market globalization, power transformer manufacturers are facing an increasingly competitive environment that mandates the adoption of design strategies yielding better performance at lower costs. In this paper, a power transformer design methodology using multi-objective evolutionary optimization is proposed. Using this m...

2003
M. H. Wang

The power transformer is a major apparatus in a power system; it is of great importance to detect incipient failures in power transformers as early as possible in order to minimize system outage. In this paper, the modified grey model was applied to predict the oil-dissolved gas trend of power transformers. Then, the future fault of power transformer can directly be identified by the trend anal...

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