Measuring dissipation factor of voltage divider of capacitor voltage transformers

A method for measuring a dissipation factor of a capacitor voltage divider (CVD) of a capacitor voltage transformer (CVT), the CVT comprising the CVD, an intermediate voltage transformer (IVT), and a compensating reactor (CR) connected between the CVD and the IVT, the method comprising:

• measuring, utilizing a current sensor, a grounded specimen test (GST) mode current passing through a first capacitor of the CVD by coupling the current sensor in series with the first capacitor;
• measuring, utilizing the current sensor, an ungrounded specimen test (UST) mode current passing through a second capacitor of the CVD by coupling the current sensor in series with the second capacitor;
• obtaining, utilizing one or more processors, a GST mode capacitance and a GST mode dissipation factor from the GST mode current;
• obtaining, utilizing the one or more processors, a UST mode capacitance and a UST mode dissipation factor from the UST mode current;
• and
• calculating, utilizing the one or more processors, the dissipation factor of the CVD according to an operation defined by the following:
• tan
• ⁢
• δ
• CVD
• =
• C
• GST
• ×
• tan
• ⁢
• δ
• GST
• +
• a
• ×
• C
• UST
• ×
• tan
• ⁢
• δ
• UST
• C
• GST
• +
• a
• ×
• C
• UST
• where:
• tan δCVD is the dissipation factor of the CVD,
• CGST is the GST mode capacitance,
• tan δGST is the GST mode dissipation factor,
• a is a capacitance ratio defined by a=C1/C2 where C1 is a capacitance of the first capacitor and C2 is a capacitance of the second capacitor,
• CUST is the UST mode capacitance, and
• tan δUST is the UST mode dissipation factor.