Ten Delta results to test insulation value

normally, it is industrial prectice to get tested important equopment for ten delta value. But as per standard practice, with only one result it is not concluded healthyness of equipment. It is adviced to take ten delta values of critical equipment at the time of commissioing & that can be taken as reference. Thereafter, this values can be taken yearly or as per the suitablity. These resultas are to be compared with the reference results & we can monitor the detariation of the insulation of equipments by analising the different values taken at different time.

If this is your first reading, it will be taken as reference value & next reading will be used for analisis of the equipment.

Normally, the agancy who does the testing for you that will give you the analysis reports after studing all the results. Hence, it is prefered to get tested equipments with only one agancy preferably with same equipment for better analysis.

Its true that for analyses of insulation its history record is must . We are measuring ten delta of Current transformers above 15 years of age in service while taking the result in three or more steps it has been observed that the value of capacitance measured is not changing at 2Kv,4KV & 6KV & 10KV buit the measured ten delta value at 10KV rises abruptly to a value between 2 & 3 for lower test voltage its below the allowable limit that is below 1%.

Anurag

Agreed, but for analysis you must have historic values of the the results. ERDA is the best agency to do this tests & analysis also.

Or you can ask CT suppliers for analysis based on the test results. They can compare the test results with thrir other installations too.

thanks Ajay keep in touch.