solistereo.blogg.se - Inmr from scan

can obtain statistics on performance and degradation of installed insulator assets.is safe to operate on energized lines using an isolating hot-stick or drone.does not rely on judgement of testing personnel to identify defects.has high sensitivity to detect even small defects (including floating defects) before they produce detectable IR or UV radiation.does not depend on climatic conditions or is affected by angle of view.includes automatic counting of the insulator’s sheds or bells and records measurements and their locations in a quantifiable database.

alerts line personnel instantly of any conductive defect that is dangerous by means of a visual alarm (i.e.

A reliable and safe insulator testing technique: Several testing methods have been used for this purpose, each with its own relative strengths and weaknesses. Since the useful service life of insulators is hard to predict, they must be verified periodically to ensure line reliability. 1: Testing composite insulator using electric field method. Similarly, energized composite insulators with small or floating defects might not generate much heat or UV until the defect becomes relatively large. Moreover, energized porcelain insulator strings with only a few defective bells do not generate heat or corona and no IR or UV is produced across a shorted bell in the absence of voltage. Any drop in E-field surrounding an insulator due to a defect is measurable from any angle. Since this methodology does not depend on measuring heat or corona discharge, readings are not impacted by factors such as wind, noise, sunlight or the sensor’s angle of view. This database can then be used to determine compromised insulators with defects and can also predict degradation over time based on quantifiable data collected. Measurements obtained from periodic checks on in-service energized insulators can be systematically downloaded and stored to provide a diagnostic database. Significant work has recently been done with the goal of allowing such data to be processed instantly and yield a graphic that displays the relative size and location of defects, enabling the user to ‘visualize’ them. This methodology has been refined over the years to detect even small and floating defects and display and record their size, type and location. Location of the defect and its length are measured as the sensor moves along the length of the insulator.

This enables detection of the size of the defect, provided the sensor module is sufficiently sensitive. Moreover, length of that distortion is directly proportional to size. Any conductive defect, internal or external, causes distortion in the strength of that E-field in the immediate vicinity of the defect.

Potential difference gradient along an energized insulator creates an electric field (E-field) that surrounds the insulator in concentric circles. An overview is also presented of some of the most common problems encountered on porcelain and composite line insulators, including moisture ingress, carbon tracking, surface contamination and manufacturing defects. Charles Jean of Positron Power in Canada reviews how this methodology evolved and claims it can prove effective in detecting even small defects that might not always be identified using other inspection methodologies. The methodology utilizes measurement of E-field distribution along insulators to detect presence of any conductive defects as well as record and display their severity and location. Early detection of defective insulators avoids risk of significant problems and enables scheduled maintenance as well as maximum safety prior to live-line work. The electric field method has been used for over 30 years to test and verify the condition of energized porcelain and composite insulators on overhead transmission lines.