In-Service Stresses on PMC HV Insulators and Conductors have some advantages than porcelain or glass insulators. The PMC have good pollution performance and hydrophobicity resistance.
In-service, PMC insulators and conductors are subjected to the combined action of severe mechanical, electrical and environmental (chemical) stresses. The mechanical stresses consist of multi-axial loads caused by the weight of the lines, manufacturing residual stresses, dynamic stresses caused by Aeolian vibrations (high cycle fatigue) and line galloping (low cycle fatigue), complex multi-axial stresses dominated by transverse compression near the mechanical connections (suspension clamps). In addition, the lines can be affected by the manufacturing/installation stresses created by excessive bending of the conductors around mandrels, travelers and tensioners, and mishandling of the insulators mostly during either manufacturing or installation. The electrical and environmental stresses imposed on the PMC insulators and conductors in-service are equally complex and consist of high voltage fields (up to 735kV), corona, partial discharges and extreme leakage currents. In addition, internal galvanic reactions between the aluminum strands and carbon fibers in the PMC conductor design can occur if the dielectric barrier (see Fig. 3) is compromised either by mechanical loads, mishandling, or aging.
The chemical stresses can also be damaging to PMC insulators and conductors. In the case of the conductors, prolonged exposure to elevated temperatures up to 180°C in air may lead to physical and chemical aging of the composite core in the presence of ozone and atomic oxygen. Other pollutants such as nitric acid, sulfur, alkalis, chlorine, etc. can also concentrate on the insulator and conductor surfaces in highly contaminated areas. Vandalism can be a major problem, as well. In certain areas gunshot damage to transmission lines is a common phenomenon.
Most HV insulators are manufactured of PMC materials used for power system having good electrical and mechanical properties.
Relative Articles:
Porcelain insulators,silicone rubber insulators
Silicone rubber insulators manufacturers in India
Composite silicone rubber insulators
Advantages silicone rubber insulators
Silicone rubber insulator property
©2014 Zhengzhou Orient Power Co., Ltd All rights reserved. Tel/Fax: +86 371 86097078
sales@composite-insulator.com Orient is a composite insulator manufacturer for products of composite insulator and polymer insulator