The Design and Behaviour of AC Current Transformers in HVDC Applications

AC current transformers used in HVDC applications are analyzed. Their behaviour is studied and the requirements necessary for accurate operation noted. Equations describing both the steady state sinusoidal responses and the transient responses of ac current transformers are shown with particular emphasis on HVDC operation. Curves of expected transformer responses for both normal and fault current conditions in an HVDC valve group are featured. Finally design aspects for ac current transformers utilized in HVDC operation are discussed.