How close should field test results compare to nameplates?
The initial C1 capacitance, and on bushings rated 550kV BIL and above, the C2 capacitance, should be within 1% of the nameplate values. In some installations, the capacitance may read slightly higher than the nameplate, but the effect should be small. The power factors should be within 10% of nameplate. The test results obtained after installation at the site should become the reference values. All subsequent test results should be compared to the reference values. Be sure to consider the accuracy of the test set you are using before determining the condition of the bushing.
