The study on the problem of measuring dielectric loss for large capacitance electric apparatus with Schering bridge and shunt

It is noted that errors in dielectric loss measurements on large capacitance electric apparatus (LCEA) using Schering bridge and shunt under power frequency and high voltage often arise. Different results for the same test sample are often obtained when using different shunts or different bridges. The origin of this problem is investigated. A very small stray inductance is found to exist in the shunt and the bridge symmetric state fails by the interference of the shunt. It is also pointed out that the calculation formula for determining the dielectric loss with Schering bridge and shunt (CFDLS) is derived from the hypothesis that there is no inductance in the shunt and the bridge in a perfect symmetric state. But in most cases, the condition of practical measurement of LCEA cannot be in accordance with this hypothesis, and the CFDLS should therefore be completed and modified