The Design of a Capacitor Voltage Transformer

It is well known that voltage transformers of the usual electromagnetic type constitute a very costly item in high-voltage systems. Considerable savings could be effected by the use of voltage transformers of the capacitor type if their design could be perfected to give sufficient accuracy, i.e. if their ratio errors and phase angles under varying operating conditions could be reduced to values within such limits as are laid down in various standard specifications. The performance of a capacitor transformer with compensating reactor and intermediate voltage transformer is analysed in this paper and design formulae are developed which should serve to provide sufficient data for a comparison to be made with the usual electromagnetic type. It is suggested that savings are likely to be effected by the use of the capacitor voltage transformer in systems of 66 kV and above.