PH-CEP Polymeric Cutout Insulators

EMC Pacific Pty Ltd’s PH-CEP hydrophobic polymeric resin technology has been successfully applied to enhance the performance of cutout insulators, providing electrical utilities with a solution to cutout insualtor integrity challenges.

Fractures are dangerous
Brittle fractures of cutout insulators in cold environments have been a significant issue for North American electrical utilities and are especially dangerous when engaging or disengaging a fuse tube.  Australian insulator manufacturer EMC Pacific identified that a solution for many cutout reliability issues could be achieved through combining the thermal crack resistance and hydrophobic properties of their proprietary PH-CEP polymeric resin with the well proven cut out insulator design.  A considerable investment was then made to independently test the technology through Powertech Labs in British Columbia, Canada.  

Preventing problematic failures
The EMC Pacific cutout insulator features a tough one piece PH-CEP moulding with sturdy metal line hardware.   There is no cemented or crimped fittings to the insulator body which eliminates the potential for moisture ingress to the insulator core, preventing problematic failures sometimes associated with ceramic and composite cutouts.

The shedding of the ‘D’ type cutout insulator is unique in comparison to any other and its design has proven to be instrumental in exceptional performance in very high pollution including coastal environments throughout South Africa for over 10 years.  Reasons include;

• Moulded skirts around the mounting hardware extend the BIL affording greater insulation from the live contacts to the mounting brackets.  They additionally create a flashover shield for earthed mounting brackets, a feature which has established this product in conditions where competitive products have failed.

• The ‘D’ type geometry of the EMCP cutout insulator assists in extending live contacts away from the mounting hardware.

• The significant shed angle provides for excellent natural wash off of pollutants and prevention of dry banding, extending insulator performance and life.

PH-CEP
EMCP’s specially formulated polymer resin material PH-CEP provides for permanency of hydrophobic properties.  This is achieved with the aid of technology at a nano-level found within EMCP’s proprietary (patent applied) hydrophobic silica (HSIL), a highly advanced water repelling filler for resin systems. 

The HSIL matrix is keyed into the parent material and does not leach away over time as with silicone oil based hydrophobic materials.  It provides an inner hydrophobic barrier which is slowly exposed through microscopic surface degradation during natural long-term ageing, providing a barrier to inclement weather and in turn contributing to superior performance throughout the insulator design life.  

Thermal Cycle Performance Testing

Additional to passing the normal dielectric, interrupting, temperature rise, radio interference and mechanical design tests, EMC Pacific’s PH-CEP cutout insulators succeeded through special thermal cycle testing of -50ºC to +50ºC, during which 100 fuse tube engagements were undertaken.  These included 25 from the left side at a 45 degree angle and 25 from the right side at a 45 degree angle at the -50 C and +50 C marks respectively. The distance from the top to the bottom fuse mounting points was measured at the beginning and the end of the thermal cycling along with visual inspections to insure that no external damage (permanent twisting, deflection, etc.) had occurred from the fuse tube engagements. The samples were then subjected to 30 minutes AC withstand test at 75% of the cut out flashover rating to determine if there were any internal voids or cracks, etc that could be exploited by high voltage. 

Ageing Tests
A dip wheel method tracking and Erosion Test of 30,000 cycles was completed with no erosion of the PH-CEP material and retention of hydrophobic properties was noted.  

To further prove the PH-CEP performance the cutout insulators were subjected for 1000 hours to an ageing procedure as per the test procedure of Annex C of IEC 61109(1992). The cutout insulators were energized at 15.8kVrms (based on 110% of a line to ground voltage of 14.4kV) for the duration of the test.   The test was done with a fuse and fuse tube installed.
The test applies various stresses in a cyclic manner: solar radiation simulation, artificial rain, dry heat, damp heat, high dampness at room temperature and salt fog at low concentration.  After 1,000 hours of aging the tested cutout insulators were rinsed with de-ionized water and were subjected to Visual examination, Steep-front Impulse Voltage Test and Power Frequency Voltage Test.  The fuse cutouts showed no evidence of tracking, no erosion and no puncture. The EMC Pacific PH-CEP cutout insulators withstood the required steep-front impulse voltage test and passed the required post ageing test requirements. 

 

The performance testing at Powertech Labs has demonstrated compliance to relevant IEC, ANSI, CSA & IEEE standards for voltage rating of 25kV and current rating of 200A.  The results have lead to significant interest in the EMC Pacific PH-CEP cutout insulator.

 

Please contact EMC Pacific for further details and technical data sheets.