Dynamic simulation of high-speed protection

Progessively reducing the measuring time of high-speed primary protection emphasises its dynamic response, both in the initial development and design of protection, and in its subsequent application. Of growing importance is the interaction between the distinguishable transient responses of the primary system protected, the transducers from which relaying signals are derived, and the measuring processes of the protection itself. To study and to evaluate this interaction requires considerable detail in modelling each primary-system and protectionsystem element that contributes to it. The paper reports an extensive computer simulation that has been developed to meet these requirements. Marshalled in a large overlay scheme, the simulation includes detailed models for the primary system protected, (including synchronous-generator units, transformers and transmission circuits), capacitor voltage transformers, current transformers, the transducer-protection interface, and the measuring andtiming sequences of the protection. The paper provides an account of the development of the simulation and of the analytical techniques on which it is based.