A Numerical Calculation Method of the Stray Capacitance of Potential Transformers

The potential transformer (PT) is important in the power system simulations. The stray capacitance of the PT will make the power system prone to produce ferromagnetic resonance, and prone to cause abnormal port current rise during the induction withstand voltage test. Therefore, it is important to evaluate the stray capacitance of PT. This paper analyzed the winding structure of the PT in detail and evaluated the equivalent capacitance by calculating the electric field energy between the winding layers. The calculated results are in good agreement with the finite element simulations, which proves the effectiveness of this method.