Calculation and measurement of winding disk capacitances with wound-in-shields

The authors calculate the capacitance of a pair of power transformer winding disks containing wound-in-shields by means of a simple formula and by means of a detailed circuit model. In addition, experiments were performed to check the formula under various conditions such as changing the number of shield turns and attaching the shield to the high voltage terminal at different points or letting it float. Unlike a static capacitance calculation, these capacitances depend on inductive effects as is borne out in this study.