PBI’s CRC Bushings with A Silicone Rubber Housing

Piedmont Bushings & Insulators, LLC (PBI) is a company tracing its roots in bushing design and manufacturing back forty years, particularly in bushings with RIP technology.

The traditional OIP bushing technology uses oil as its basic insulating medium. Use of oil has many severe drawbacks in bushing life, such as being susceptible to moisture ingress and oil leakage due to worn out seals. In turn greater vulnerability in an OIP bushing exists to lightning strikes or other factors that can trigger explosive failure. Additionally, excessive filling of oil reservoirs in horizontal mount applications can lead to severe operational problems. Unusually high operating temperatures on an OIP bushing can comprise its bushing life and again lead to severe operational problems.

Today, there is a bushing on the leading edge of bushing technology with proven operating experience. This is the Piedmont CRC bushing with capacitance grading. The Piedmont CRC bushing meets the requirements of variours bushing standards: ANSI/IEEE and CSA. This bushing uses RIP technology with silicone-rubber directly molded to the bushing core. A totally dry solution is offered. NO OIL. OIL-FREE. All serious drawbacks inherent in the use of insulating oil are eliminated; as well as many application specific advantages become available.

• RIP technology has superior thermal performance over OIP technology. This is quite important in de-regulated utility markets, where Utilities are running power transformers at higher loads, usually up to 140% of transformer nameplate rating. This increased bushing reliability maximizes on-line time and revenues for the deregulated utility.
• The simplicity in design of the direct-molded RIP bushing with out the need for so many seal interfaces of the OIP bushing provides the direct-molded RIP bushing with a much stronger barrier against moisture.
• The totally dry solution in bushings allows the standard bushing to be mounted in any orientation; as well as stored in any position.
• Flexible, durable silicone-rubber weather sheds are superior to porcelain in tolerating vandal, seismic, shipping, handling and collateral damage.
• In addition, the silicone rubber has proven to be far superior to porcelain in contaminated environments due to the excellent characteristics of silicone rubber: long term hydrophobicity, excellent tracking, erosion and flashover resistance. As well as excellent resistance to ultra violet rays in sun light.

Again, the increased reliability and the application specific advantages of a totally dry bushing solution are all available in the Piedmont CRC bushing with direct molded silicone-rubber.

Currently, Piedmont CRC bushings are available in voltage classes from 15 through 69Kv and current ratings through 3000 amperes.