Hardware and software implementation of a travelling wave based protection relay

Fault generated transient signals can undoubtedly be employed to achieve ultra-high-speeds in transmission line protection. Even though such transient based schemes can quickly detect a faulty state on the power system, they face several challenges. Firstly, they have inherent reliability problems and secondly, it is difficult to implement them as a real-time product due to their excessive demand for high speed signal acquisition and processing. This paper examines the theoretical aspects and design procedure of a reliable, high speed protection scheme based on fault generated travelling wave information.

I. Introduction

The growing demand for quality power, high transmission efficiency and low stability margins emphasize the need for high speed fault detection. The capital investment involved in generation, transmission and distribution of electrical power is so high that proper precautions have to be taken to ensure that the equipments not only operate at their highest efficiencies, but they are also protected from possible faults. Uncleared faults could cause severe instability problems in the power network and damage expensive equipment. High speed fault isolation is essential in securing the power system from running into transient stability problems and to reduce the damage caused by electrodynamic and thermal stresses on the equipment.