Classes

Performance of transformer differential relay at different neutral grounding resistance based on wavelet transform

Abstract Power transformer protective relay should block
the tripping during magnetizing inrush and rapidly should
operate the tripping during internal faults. There are a variety
of protective relays using different measuring techniques
to provide reliable and secure transformer protection. These
types of the protective relays include electro-mechanical,
solid state, digital and numerical relays. Within each group
of them, various algorithms are existed. A stand-alone digital
relay has been designed and implemented, where its

Prediction of Aged Transformer Oil and Paper Insulation

Abstract—Power and distribution transformers reliability is limited by the electrical insulation system quality, which also operates additionally as a heat transfer medium. On the other

Evaluations of the apparent soil resistivity and the reflection factor effects on the grounding grid performance in three-layer soils

Abstract: In this study, the apparent soil resistivity evaluation is estimated for three-layer soils by four strategies and the
obtained values are compared with experimental measurements done by using the four-electrode method. Different methods

Parameters affecting the arcing time of HVDC circuit breakers using black box arc model

Abstract: Arc interruption of high voltage direct current (HVDC) circuit breakers (CBs) is one of the main challenging factors for using HVDC grids. To evaluate the arc interrupting capability in HVDC CBs, black box arc models are used to represent the nonlinear arc conductance depending on Cassie and Mayr dynamic arc equations. Extensive simulation studies are carried out to investigate the effect of controlled and uncontrolled parameters on the CB arcing time.

Condition assessment of power transformers based on dissolved gas analysis

DGA is more sensitive and reliable technique for detecting and evaluating the incipient fault conditions in oilimmersed transformers. The most frequently interpretation technique that used in dissolved gas analysis is Duval triangle due to its simplicity and accuracy. Unfortunately the impacts of Ethane (C2H6) and Hydrogen (H2) were not included in Duval triangle in spite of their importance in diagnosing certain faults types. In addition, the problem of no decision associated with some cases that lie out of the specified codes appeared in Doernenburg, Roger's and IEC techniques.

Measurements of dielectric properties of High Density Polyethylene-Nano-Composites

Recently, polymers Nano-Composites for various important electrical apparatus are widely used. This paper studies the dielectric properties of high density polyethylene composed with different concentrations of clay-Nano-filler over a high frequency range of 200 to 2 MHz. This paper studies also the frequency and temperature dependence of relative permittivity (er) and loss tangent (tan delta) of pure high density polyethylene and polymer composites with clay-Nano-filler of different concentrations over high frequency range of 200 Hz to 2 MHz and a temperature range of 0–50 C.

Online monitoring of medium voltage overhead distribution lines polluted insulators severity

Abstract: This study describes online monitor of the pollution severity of heavy medium voltage overhead distribution

Investigating the effect of cavity size within medium-voltage power cable on partial discharge behaviour

Abstract: One of the common causes of cross-linked polyethylene (XLPE) insulation ageing and finally cable failure is the
presence of a cavity within cable insulation. Gas filled cavities can be initiated in XLPE cables during its manufacturing,
installing and operating conditions. Once the size of the cavity reaches the critical limit, noticeable partial discharge (PD) activity
develops. Therefore, the size of the cavity is one of the important factors that considered when investigating the PD activity in

Proposed heptagon graph for DGA interpretation of oil transformers

Abstract: Dissolved gas analysis (DGA) is one of the most acceptable methods used for detecting and evaluating gases
dissolved in mineral oil and also in the solid insulation of internal incipient faults in the power and distribution transformers based
on the oil samples. DGA has been proved the most accurate method for condition assessment of power and distribution
transformers. The fault types depend upon type and concentrations of each gas dissolved in oil. IEC, Rogers, Doernenburg and

Proposed heptagon graph for DGA interpretation of oil transformers

Abstract: Dissolved gas analysis (DGA) is one of the most acceptable methods used for detecting and evaluating gases
dissolved in mineral oil and also in the solid insulation of internal incipient faults in the power and distribution transformers based
on the oil samples. DGA has been proved the most accurate method for condition assessment of power and distribution
transformers. The fault types depend upon type and concentrations of each gas dissolved in oil. IEC, Rogers, Doernenburg and

Proposed heptagon graph for DGA interpretation of oil transformers

Abstract: Dissolved gas analysis (DGA) is one of the most acceptable methods used for detecting and evaluating gases
dissolved in mineral oil and also in the solid insulation of internal incipient faults in the power and distribution transformers based
on the oil samples. DGA has been proved the most accurate method for condition assessment of power and distribution
transformers. The fault types depend upon type and concentrations of each gas dissolved in oil. IEC, Rogers, Doernenburg and

Proposed diagnostic methodology using the cross-correlation coefficient factor technique for power transformer fault identification

Abstract: This study investigates the impact of electrical parameter variation of a high-frequency transformer model on its
sweep frequency response analysis (SFRA) signature to help in classification and interpretation. The simulations have
been done using MATLAB and compared with the reference data. The results of SFRA measurements are repeatable
up to and beyond 1MHz. The proposed diagnostic methodology using the Cross-Correlation Coefficient Factor (CCF) is
used to identify the transformer faults. CCF used to measure the degree of relationship between two variables that

Ground potential rise of faulty substations having equal and unequal spacing grounding grids conductors

Abstract: Grounding of power substations is to provide safety for personnel during normal and fault-to-ground conditions