VT Guard Pro Ferroresonance Elimination Device Manual

This document describes the VT Guard Pro and VT Guard Pro–D, advanced protection devices designed to eliminate ferroresonant oscillations in medium-voltage inductive voltage transformers (VTs) connected in an open-delta configuration. It covers the devices’ damping functionality, application, advantages, and technical parameters, with the VT Guard Pro–D offering additional self-diagnostic features and auxiliary contacts for integration with superior systems.