Research on Power Transformer Relay Protection and Operation Processing

Author(s):  
Xiaoyu Sun ◽  
Ling Wang ◽  
Xiuxia Wang
2020 ◽  
Vol 4 (1) ◽  
pp. 67-72
Author(s):  
Plamen Antonov Stanchev ◽  
Mediha Enver Mehmed-Hamza

In the medium voltage electrical power lines, the most common fault is the phase to ground fault. The determining factors for selection of the neutral grounding mode of the medium voltage electrical power lines are the selectivity of the relay protection, the transient voltages during phase to ground fault, the magnitude of the fault currents, etc. The paper studies the influence of the transient resistance of phase to ground fault on the selectivity and sensitivity of the earth fault protection when the neutral of the power transformer is grounded through active resistance in medium voltage power grids.


2011 ◽  
Vol 317-319 ◽  
pp. 1241-1244
Author(s):  
You Jie Ma ◽  
Ya Guang Yang ◽  
Xue Song Zhou

This document mainly analyses the sources of harmonic and harmonic hazards in power system. The article mainly from a few key links of power system which are electric power capacitor, power transformer, electric motors, relay protection to illustrate harmonic hazards and described harmonic treatment methods.


2019 ◽  
Vol 140 ◽  
pp. 04007
Author(s):  
Daniil Ivanchenko ◽  
Artem Smirnov

The paper deals with experimental identification of transformer internal faults, an important factor in reliability and sustainability of power supply systems. Task of identification of transformer internal faults requires increasing sensitivity of relay protection by calculation of components most sensitive to interwire faults from transformer current. In order to study internal faults in transformer, the model in Simulink MATLAB was developed on the basis of transformer constitutive equations. Transformer with short circuited wires was simulated as a multiwinding transformer. We provide the calculation of transformer parameters. Model was applied for analysis of transients in power transformers, such as interwire fault, transformer inrush, and fault in transformer connections. Analysis of power transformer internal faults by means of time-dependent symmetrical components of currents is provided. These symmetrical components were calculated for the first harmonic of current by means of discrimination of firs harmonic by low-pass filter and compensating elements implementing phase shift. Described method allows calculation of symmetrical components during transient and under non-sinusoidal conditions. Simulation results showed the advantage of instantaneous symmetrical components of other direct values. Those components were implemented in relay protection algorithms for identification of internal faults in transformers.


Author(s):  
Dr. Hitesh Paghadar

Increasing environment noise pollution is a matter of great concern and of late has been attracting public attention. Sound produces the minute oscillatory changes in air pressure and is audible to the human ear when in the frequency range of 20Hz to 20 kHz. The chief sources of audible sound are the magnetic circuit of transformer which produces sound due to magnetostriction phenomenon, vibration of windings, tank and other structural parts, and the noise produced by cooling equipments. This paper presents the validation for sound level measurement scale, why A-weighted scale is accepted for sound level measurement, experimental study carried out on 10MVA Power Transformer. Also presents the outcomes of comparison between No-Load sound & Load sound level measurement, experimental study carried out on different transformer like - 10MVA, 50MVA, 100MVA Power Transformer, to define the dominant factor of transformer sound generation.


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