about | science | job profiles| faq | economics

< previous | next >

Our society has become much more dependent on electrical power than ever before. This has been no better illustrated than through the ensuing chaos and negative financial ramifications of the large scale power outages in the northeast of North America, Denmark, London and Italy since mid-2003. Although the causes of the blackouts were various, they did demonstrate how devastating power outages can be and how little spare electricity is available to spread around the power grid during peak hours.

Si-COAT 570 can help alleviate many of the operating issues that are plaguing modern power utilities. From an economic point of view, the cumulative effect of the electrical power saved through the reduction in power leakage is massive. However, even the reduction in maintenance costs at substations provides a positive payback typically within the first six months after coating. In either case, whether used in transmission/distribution systems or within substations, the savings flow directly to the utilities bottom line.

Transmission Line Economics

Leakage from transmission insulators is a well known problem and according to the Institute of Electrical and Electronics Engineers (IEEE) has been with us since the inception of outdoor transmission itself.

Historically, the low cost of energy production and its relative abundance made the leakage loss across individual insulators an insignificant expense of operation. However, our transmission and distribution systems have grown since those days and pollution levels are now a worldwide phenomenon. On a cumulative basis, electrical leakage from transmission and distribution insulators is a major, yet hidden, expense.

A detailed investigation into leakage currents was conducted by a large, prominent, and well respected North American power utility. The result was that at any point in North America, the average electrical current flowing across a transmission insulator is about 2 mA. The figure is based on weighted average annual weather patterns of 400 hours of fog creating a leakage current of 10 mA; 400 hours of rain at a leakage current of 20 mA; and 7960 hours of dry weather conditions with a leakage loss of 1 mA.

The performance of Si-COAT has been studied for many years in the field. What was found was that even in the most severe environments (IEC Class IV contamination zones, where average leakage current values average in the tens of milliamps) Si-COAT nearly entirely eliminates leakage current. Given the great power dissipation across a transmission line, this amounts to tremendous savings for the utility.

Si-COAT was also compared to composite insulators, particularly those made of silicone polymers. The confirmation by innumerable authorities of the unreliability of composite insulator performance is indisputable. Despite this fact, composite insulators were also assumed to eliminate leakage current for the purpose of the following economic comparison. As well, composite insulators and Si-COAT were assigned a service life of 15 years. Again, in the case of composite insulators on average, this figure is generous, while for Si-COAT it is conservative.

Based on 1000 exposed miles of a 500 kV transmission line, with four (4) transmission towers per mile and six (6) insulator strings per tower, the North American average of 2 mA leakage current was used to calculate the project economics of Si-COAT versus composite insulators. Power revenue to the utility was taken as USD 0.05 per kWh.

< previous | next >