Introduction to the History of Selective Protection

Author: Walter Schossig, Germany

Introduction

The intention of this series of articles is to begin to piece together the true account and timeline associated with PAC developments and to recognize the achievements of the pioneers of early and modern PAC technology.

The technological developments and accomplishments of protection equipment are rarely a cause célèbre within the power industry. It is easy to understand why this is so when one considers that the little black box often pales into insignificance when compared with the physical scale, size and cost of generators, transformers and switchgear. Indeed protection topics are often only discussed after a disturbance or blackout.

Nowadays we achieve a high security of supply thanks in part to the secure and reliable performance of protection, automation and control (PAC) equipment.  Indeed people take the availability of electricity for granted and pay little attention to the effort required to reach this state.

That is why it is useful to consider the first steps of electrical power supply protection and to note the technological development from the early fuse protection up the current state of the art initiatives. Such consideration may provide an insight into the silent, often obscure work on protection and substation automation systems. This will be the first in a series of articles where we will outline the steps in the development of PAC equipment. We admit that there may be information in the articles which may be subject to debate particularly with regard to the historical accuracy of certain events and the fact that we do not have access to all records. Indeed the articles may appear to be biased towards European developers but this Eurocentric perspective is due to access and availability to data. We warmly welcome contributions from our readers, particularly those who may be familiar with historical developments that may have been going on in parallel in other regions, e.g. United States, Japan, former USSR etc.

Technological developments typically follow certain rules and in general you can observe three stages of development. Initially, there can be quite a gentle or silent start-up however this ripple is often followed by a stormy wave of developments which eventually moves towards a more steady state with ongoing incremental activity. This reflects the fact that new ideas are often treated with skepticism and, in the absence of any real need, are not put into practice unless genuine technical or practical reasons exist for doing so. Necessity breeds invention and those ideas that satisfy needs in the industry are more likely to be successfully pursued.  Another driver for inventions is of course the goal to overtake the competition in the market place. In such cases existing ideas are often recycled and improved. One invention supersedes the other. As the German protection pioneer Hans Titze mentioned in his award winning ("Conrad-Matschoß-Medal") publication in 1962, "New ideas sometimes appear like an avalanche: new, up to now unknown and new approaches appear." This observation is valid even today as people rush to exploit the possibilities offered by new technological developments.  

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Let?s start with organization in protection testing