Relation of traveling waves to fault locators

THE RESPONSE of a fault locator utilizing traveling waves to measure distance to a fault depends not only on the design of the fault locator but also on the characteristics of the waves themselves. A mathematical analysis of a 3-phase system shows that because of losses and coupling between lines, two surge components are produced which travel at different speeds. The slow wave is equivalent to a current flow in the three wires in parallel, with a ground return; the fast wave is equivalent to current flow confined to the line conductors.