Asfar Ali Khan

Effect of contaminant pH and natural fog on naturally polluted porcelain disc insulator in northern region of India

Overhead power transmission lines cross regions which are different in environmental conditions. The reliable and uninterrupted operation of modern power system depends on reliable insulation. Outdoor insulation cannot be selected without having knowledge of prevailing pollution severity. This paper reports results of natural pollution tests that have been done at different locations. Flashover voltage (FOV) of porcelain disc insulator for different pH values and conductivity has been recorded to relate FOV with pH and conductivity of the contaminants. It is found that a decrease in pH and increase in conductivity of the contaminant lowers FOV of the insulators. Regular condition monitoring of porcelain insulators can be done using pH of the contaminants as an effective pollution severity indicator, it may further be used for devising proper maintenance schedule.

A study of flashover voltage of artificially polluted porcelain disc insulator under natural fog conditions

The availability of cheap and reliable supply of electrical energy plays very important role in the economic development and social welfare of any society. Overhead power transmission lines cross regions which are different in environmental conditions. The reliable and uninterrupted operation of modern power system depends on reliable insulation. Therefore outdoor insulation cannot be selected without having knowledge of prevailing pollution severity. This paper reports results of artificial pollution tests that have been done with different contaminants. The choice of contaminants for use in the present artificial pollution test was done with respect to the occurrence of soluble and non-soluble salts in natural pollution conditions. Flashover voltage (FOV) of porcelain disc insulator for different pH values and conductivity has been recorded to relate FOV with pH and conductivity of the contaminants. It is found that an increase in pH and conductivity of the contaminants lower FOV of the insulators. Regular condition monitoring of porcelain insulators can be done using pH of the contaminants as an effective pollution severity indicator, it may further be used for devising proper maintenance schedule.

Condition monitoring tool for electrical equipment — Thermography

Condition monitoring has become significant and inevitable for look after of electrical system, and has engrossed more and more attention globally. The no physical contact property of non-destructive condition monitoring techniques is now very significant and essential at diverse industrial process. Though, accessibility of CM methods are multiple for distinct problems such as partial discharge, thermal variation and frequency response. Operational analysis of all the characteristics for process in industries is still under progress. In this paper assessment of various problem in operation of power transformer and motors & insight on application of infrared thermograph as condition monitoring technique have been methodically conducted. IRISYS (IRI4010) thermal imaging camera is used for condition assessment of Power transformer and motors and necessary recommendations have been given based on the priority table.

Study the effect of contaminants on flashover performance of porcelain disc insulator by artificial pollution testing

Faults in high voltage insulator generally occur due to pollution flashover, which is one of the most crucial problem resulted by cumulative effect of both pollution and moisture. In this paper, the effect of contaminants on the performance of flashover voltage of porcelain insulator under various environmental conditions has studied by performing artificial pollution tests that nearly reflects the condition of natural deposition. Under natural conditions, a pollution layer has formed gradually which may contain a variety of chemical compounds of different properties. We have used many chemicals as contaminants to analyze their effect on flashover voltage of the discs by measuring the polluted surface conductivity and pH value for individual salts and their mixtures. ESDD is also determined in the work, to check the severity of pollution on insulator surface. Results of the present study also serve the information like the fluctuations of flashover voltage gradient with ESDD.

Assessment of solid insulating material using Partial Discharge characteristics

In this Paper, Partial Discharge analysis is performed in cavities artificially created in Insulation. The setup is according with Cigre-II Method. Circular Samples created from Perspex Sheet with different configuration with changing number of cavities. Assessment of insulation health can be performed by Partial Discharge measurement as this has been found to be important means of condition monitoring. The experiments are done using MPD 540, which is a modern partial discharge measurement system. By analyzing the PD activity obtained for various voids/cavities, it is observed that the PD voltages show variation for cavitys diameter, depth even for its ratios. This can be employed for scrutiny of insulation system.