Application of external compensation to current transformers

The method of external compensation for CTs described briefly in the paper has been put into practice for more than two years in China. Since 1993 the authors have applied the method to some metering and protection CTs in general use in the UK. The compensation performances given in the paper show that the application of the technique is successful. It improves the accuracy by ten times, increases the capacity and extends the measuring range. All of these performances mean that the method is very effective. It is a feasible way to use CTs already installed in power systems. They can be improved to meet the needs of high accuracy, large capacity and a wide current range