Experimental Comparison of Conventional and Optical VTs, and Circuit Model for Optical VT

This paper compares the performances of an optical voltage transformer (OVT) and a conventional voltage transformer (VT) in a laboratory for steady state and transients. It also presents a developed equivalent circuit model for OVT. In addition, OVT impulse response has been investigated, and field records have been evaluated to confirm that optical systems can satisfactorily replace magnetic transformers. Both experimental results and field records show that the transient performance of an OVT is better than that of a conventional one, and the performance of OVT is comparable to that of the magnetic VT. Differences are found within experimental errors. A transfer function for OVT is derived by using the obtained frequency response characteristics. A circuit model is developed from the derived transfer function by using a network synthesis method. The model is verified through the frequency response results and tested with PSPICE simulation program. The results show that the developed model can be used as a legitimate OVT model.