E-field plays a major role in the aging processes of insulators mainly because it is the factor that triggers partial discharges and corona phenomenon. Insulators are directly affected by E-field both in their long and short term performances due to corona and arcing. The aim of this article is to explain the distribution of the electrical field its factors and effects in order to maintain the integrity of the electrical asset and especially the insulators. read more..
Corona discharge is a major threat to the integrity of non-ceramic polymer insulators (NCI). It produces Ozone, nitric oxides and emits Ultra Violet leading to erosion and decomposition of the insulators' and affecting their mechanical and electrical properties. Ongoing research is performed by utilities and high voltage laboratories to investigate the endurance of insulators to various environmental conditions and to their aging patterns. One of the studies conducted in Mexico aimed at correlating between findings by a corona camera which is nondestructive optical device and an E-filed measurement equipment. The use of corona camera can alleviate the task of preventive maintenance and streamline the maintenance processes provided its output is indeed reliable. read more.
Corona activity causes polymer insulators failures due to aging of the rubber material. The use of corona rings distribute the electrical field so that it will be more uniform with less probability for corona to appear thus, improving performances and reliability of the insulators. read more.
Maintaining the reliability of transmission lines is a costly task and usually very difficult to perform. Aerial inspection is one of the efficient ways to maintain the grid when considering labor cost, time consumption, distances, topographic barriers and safety. DayCor® ROM, especially designed for inspecting transmission lines with helicopters and UAV's offers a proficient and precise inspection of transmission lines in the safely way. read more.
Among the new insulating materials widely used in high voltage outdoor insulation systems, silicon rubber materials also called polymeric materials are very important; during last 20 years they have been applied for manufacturing outdoor insulators. These materials are organic in nature; therefore they are prone to decomposition under different environmental conditions; the most important among these conditions for consideration of w.r.t. of high voltage electrical insulation is the hydrophobicity...
Hydrophobicity theory, its importance for polymeric silicon rubber insulators, methods of hydrophobicity measurements - especially by leakage current, low molecular weight component chains responsible for hydrophobicity recovery, chemistry of hydrophobicity loss and recovery, hydrophobicity recovery related with temperature, humidity, UV radiation, corona, electric field and dry band arcing are overviewed in this paper. read more.
Over recent years, EPRI in the U.S. has been working to help affected utilities develop a strategy to address premature ageing of polymeric insulators on 115 and 138 kV lines due to high E-fields. This includes providing reference information, technical support and recommendations to assess the existing population and to specify polymeric insulators for new or replacement units. This edited INMR article from late 2013, contributed by Andrew J. Phillips and Chris Englebrecht of EPRI, offered an overview of such insulator failures and of the best strategy to manage the problem". read more.