Patent ID: 8838402

Claim:
A method for voltage measurement with a transformer configuration including three single pole voltage transformers each respectively having a primary winding, a secondary winding and a tertiary winding, wherein the primary windings are connected to primary voltages and the tertiary windings of the voltage transformers are open-delta connected with each other, the method comprising: measuring secondary voltages from the secondary windings; and determining values of the primary voltages on the basis of the secondary voltages measured from the secondary windings and a turns-ratio between the primary winding and the secondary winding, wherein the determining of the values of the primary voltages comprises: applying a correction to the measured secondary voltages on the basis of: at least one of (i) one or more parameters of the voltage transformers and (ii) one or more quantities in a known relation to one or more parameters of the voltage transformers, at least one of (iii) one or more parameters of a circuit connected to the secondary windings and (iv) one or more quantities in a known relation to one or more parameters of the circuit connected to the secondary windings, and at least one of (v) one or more parameters of a circuit connected to the tertiary windings and (vi) one or more quantities in a known relation to one or more parameters of the circuit connected to the tertiary windings.