/images/TDUpdate2.gif/images/southwire_100x70.jpgYear-Long Tests Assure 230 kV Reliability - 2009year-long-tests-assure-230-kv-reliability.htmPre-qualification testing by independent laboratory puts Southwire first among providers of cable systems up to 230 kV
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Year-Long Tests Assure 230 kV Reliability - 2009

Pre-qualification testing by independent laboratory puts Southwire first among providers of cable systems up to 230 kV

Investments in HV underground are significant, and reliability is a must-have. Southwire HV Solutions has taken an additional step in proofing underground HV reliability by initiating year-long accelerated-aging tests of 230 kV cable and accessories for underground installation.

"By late 2009, this year-long testing cycle will provide pre-qualification test results that meet current American AEIC CS9-06standards and exceeds current international IEC 62067standards for 230 kV cable," says Thomas Wilki, director of underground transmission for Southwire HV Solutions. "Only a handful of firms world-wide have initiated tests of this scale," says Wilki. "This program confirms Southwire’s position as the underground HV leader in North America."

NEETRAC test setup simulates real-life installation
Testing is being performed at the independent National Electric Energy Testing Research and Applications Center (NEETRAC) High Voltage laboratory just south of Atlanta, Georgia. The test setup simulates a complete underground HV installation. The cable loop is approximately 500 feet long, and it includes duct-bank sections, splices in manholes, and terminations on steel structures and bonding equipment.

Test loop includes splices, manholes and terminations.

Test includes two cable types
Two different 230 kV solid-dielectric cable constructions are under test. Both use a 2000 mm2 (~4000 kcmil) copper segmental conductor with 750 mil of XLPE insulation. One construction uses a corrugated copper sheath and polyethylene jacket. The other uses concentric copper neutrals and a laminated copper sheath bonded to the polyethylene jacket.

"These conductor sizes and the available segmental conductor architecture put Southwire at the forefront in the underground HV market," says Wilki. "Customers will be able to plan and implement systems with more power capacity."

4,000 kcmil segmental conductor allows very high system capacity.

Test protocol stimulates accelerated aging
During the year-long test, the cables are held at 1.7 times their rated voltage while undergoing repeated heating and cooling cycles. Each cycle consists of six hours of heating, two hours held at temperature, and 16 hours of cooling.

The IEC 62067 standard requires 180 heating cycles with a maximum temperature of 90° C. (194° F). The AEIC CS-9 standard requires that 90 of the 180 heating cycles are performed at the cable’s rated emergency temperature, which is 105° C (221° F).

To qualify to both standards, the cables will undergo 90 cycles to 90 °C followed by 90 cycles to 105 °C. At the end of the year, NEETRAC will apply lightning impulse voltages of 1050 kV to cable samples. Testing is scheduled to be complete by late 2009.