A B C D E F G H I J K L M N O P Q R S T U V W X Y Z All
Chandel, Ashwani Kumar
- FFT Analysis on Partial Discharge Modeling of Transformer Solid Insulation
Authors
Source
Digital Signal Processing, Vol 8, No 8 (2016), Pagination: 211-216Abstract
The present paper focuses on formation and alteration of Partial Discharge (PD) with different applied high voltages. It is conducted by simulations based on an extended PD equivalent circuit in order to understand the characteristics of partial discharge in solid insulating materials. Mechanism of PD in solid dielectric material has been modeled using MATLAB Simulink. Partial discharge in solid insulation with a single cavity as defect is the main focus of the work. 50 Hz AC voltage sources of 1kV, 5 kV, 10 kV, 15 kV, 20 kV and 30 kV are applied to the modeled circuit to capture discharging current and discharging voltage which normally occurs in nanoseconds. For the accurate analysis of partial discharge, various digital signal processing techniques including Fourier Transform (FT), Short Time Fourier Transform (STFT), Fast Fourier Transforms (FFT) are employed on the captured signals. The proposed technique analyzes the simulation results in frequency domain and estimates the severity of insulation damage. The results thus obtained an act in defense of transformer against partial discharges and are helpful in extending its life.
Keywords
Partial Discharge, Cavity, Fast Fourier Transform, Digital Signal Processing, Transformer.
- Determination of Accelerated Thermal Aging Effect on Dielectric Strength of Dry-Type Transformers Insulation
Authors
1 Department of Electrical Engineering, NIT Hamirpur, H.P., 177005, IN
Source
Networking and Communication Engineering, Vol 8, No 9 (2016), Pagination: 311-314Abstract
The service life of high voltage transformers is mainly decided by the life of their solid insulation. These devices need to be monitored continuously throughout their life time. The health assessment of large power rating devices avoids the fire hazards which are originated from thermally stressed solid insulation, and improves the service life time. In the present paper, the effect of thermal stress on the dielectric strength of several insulating papers which are used in dry type transformers has been investigated. Thermally upgraded Kraft, Nomex-410 and Nomex-910 were thermally stressed at higher temperatures in a temperature ranging between 900C and 2400C. Subsequently, the data are analyzed and the effect of thermal stress on the life of dielectric materials is assessed by using simple regression technique. It has been determined that Nomex-910 has the better withstanding capability at high temperatures as compared to that of other insulating materials. The present aging analysis extracts the withstanding capability of several insulating materials at high temperatures. It also helps the industry people in predetermining the health status of insulation.