Effect of equivalent salt deposit density on flashover voltage of contaminated insulator energized by HVDC

In Malaysia, the demand for electric power is increasing day by day due to more consumption of power in the industrial sector. Recently, the high voltage DC transmission lines are under construction near the coastal environments for transmitting the power to the all states of Malaysia. Therefore, there is a concern about the reliability of these systems especially under adverse environmental conditions due to sea salt spray contamination. This reliability of this contaminated insulator can be improved through its performance studies. For this performance study, an analytical expression between flashover voltage and ESDD of the contaminated insulator has been proposed using Dimensional Analysis technique. The results obtained from the analytical expression are compared with the experimental results and in close agreement are foun

Shape Preserving GOl Rational Interpolation.

A GCl rational quartic function has been constructed with three parameters to preserve the shape of positive and monotone curve data. Simple data dependent constraints are derived on one of the parameters to preserve the shape of data while other two are free to refine the shape of curve at user choice

G Scattered Data Interpolation with Minimized Sum of Squares of Principal Curvatures

One of the main focus of scattered data interpolation is fitting a smooth surface to a set of non-uniformly distributed data points which extends to all positions in a prescribed domain

Second Order Partial Derivatives Estimation Using a Modification of the Lagrange Quadratic Interpolant

Partial derivative values are required to construct a smooth interpolated surface which passes through given three dimensional scattered data points. These partial derivative values are not avaliable in practice for raw three dimensional scattered data and the estimation of these values is thus desirable. This research concentrates on estimating the partial derivative values up to the second order. Many current methods concentrate on first order partial derivatives estimation as most applications require only up to the first order derivatives

Modification of structure and properties of well-dispersed dendrimer coated multi-walled carbon nanotube reinforced polyester nanocomposites

This work reveals the structure and properties of dendrimer coated multiwall carbon nanotube (DMWCNT) reinforced unsaturated polyester resin (UPR) nanocomposite. Rheology, as well as the shear thinning behavior of nanosuspension exhibits the dispersion of DMWCNT in UPR matrix. The Raman spectra of DMWCNT-UPR nanocomposites along with the Fourier-transform infrared (FTIR) spectra of DMWCNT and DMWCNT-UPR nanocomposites indicate the interaction between DMWCNT and UPR in the nanocomposite system. Additionally, the surface morphology of DMWCNT and DMWCNT-UPR nanocomposites reveals well dispersion of DMWCNT in DMWCNT-UPR nanocomposites. X-ray diffraction (XRD) profile demonstrates structural properties of pristine UPR and nanocomposites. The Transmission Electron micrograph and Field Emission Scanning Electron micrograph show the fractured surface morphologies of DMWCNT-UPR nanocomposites. Comparative stress-strain behavior shows the deformation mechanism of DMWCNT-UPR nanocomposites

Classification of degraded polymer insulator using support vector machine

The ability to monitor closely the surface degradation condition of polymer insulator will be really beneficial to the power utility company in order to ensure smooth and safe power transmitted to the consumer. If the level of degradation condition could be classified, then it could ease the maintenance team to take proper action as to avoid any undesirable event from happening. In this study, it has implemented the leakage current signal parameters data in the classification process of degraded field-aged insulator. These signal parameters are extracted from the Spectrogram. Prior to this analysis, the leakage current signal is captured during the testing method of inclined plane tracking. The physical evaluations such as arithmetical mean of surface roughness and static contact angle are also measured for the purpose of comparison of surface conditions. The Support Vector Machine is implemented in the machine learning test, in which the percentage of classification accuracy between degraded sample and the controlled sample is recorded. To validate the classification results obtained, the insulator sheds under test was going through the Spray Method to determine the criteria of hydrophobicity class in Table 1 of the IEC TS 62073:2016. By using the percentage of total harmonic distortion data, the consistency results of the classification accuracy percentage have been successfully determined the two significant classes and the transition class between them. However, there is an existence of insignificant classes if the root means squared leakage current data is implemented. Therefore, by implementing the appropriate leakage current signal parameter data, the degradation classification could be determined accurately

Development of user panel for polarization and depolarization current (PDC) measurement analysis of high voltage (HV) machine insulation system

Insulation system is the backbone in any HV machine and as well as power system. However, degradation that always happens in the insulation system will reduce the lifespan of the machine. Thus, condition monitoring of the insulation system is highly recommended in order to maintain the reliability and efficiency of the machine during operation. Polarization and Depolarization Current (PDC) measurement is one of the time domain condition monitoring that been acknowledge by the researchers around the globe. This predictive maintenance with the aid of online monitoring provides an indication of the machine's condition. The development of measurement technologies and data analysis techniques using computational methods give an advantage in saving time and improve safety. This paper presents the user panel that had been developed for the application of PDC diagnostic methods. Through this panel the conductivity level based on PDC measurement on the machine insulation system can be analyze and monitored. The developed user-friendly panel enable user to run the recorded PDC data to evaluate the performance of the insulator in term of its conductivity. It was found that the conductivity level of the insulation material is related to its PDC curves. The system developed was found successfully helping user to do analysis on PDC data by giving the PDC pattern and conductivity of the tested insulator

A choice of weights for convex combination methods in estimating partial derivatives

Weights in convex combination methods are important parameters in the estimation of partial derivative values in three dimensional scattered data points. We introduce the three angles of the base triangle as weights in order to have more options for weight variety