Imcorp, provider of the Factory Grade test for power cable systems, recently released its 2012 Annual Cable System Quality Rating for utility-scale renewable-energy sites. This test locates existing cable system defects and predicts future reliability of new or old cable systems ranging from 5 kilovolts (kV) to 500 kV.
The average utility-scale renewable site contains approximately 100 medium-voltage cable systems. Without the Factory Grade test and pre-energization repairs being made, Imcorp states the average 2012 facility is at risk for 13 cable system failures before the end of the design life. This represents a 14 percent increase of at-risk cables at each facility over sites constructed in 2011.
However, Imcorp claims renewable-energy sites using the Factory Grade test were able to locate, mitigate and avoid outages associated with these embedded defects.
The Factory Grade test found that 87 percent of cable systems installed in 2012 at utility-scale U.S. renewable-energy sites met the manufacturers’ quality control standards on the initial test (the Cable System Quality Rating, or CSQR).
But 2012 was the first time in five years that the renewable energy CSQR declined. Last year was also a record-breaking year for capacity constructed. Imcorp believes that the fall in CSQR may be attributable to the scarcity of qualified installation personnel to meet the increased demand.
Imcorp is an engineering services company and a specialist in underground power cable diagnostics. Based on assessments of thousands of new cable systems, the company maintains a database of medium- and high-voltage cable installation performance. The company’s technology has tested more than 45,000 cables spanning more than 65 million feet of underground power cable.
Whether Imcorp’s predictions of failures are accurate remains to be seen; however, it may be worth keeping an eye open for unexpected failures that require the attention of a capable contractor.