System protection schemes in power networks: existing installations and ideas for future development

A common type of SPS (system protection scheme) that operates using local criteria is an under-frequency load shedding scheme. This is normally considered final intervention and is often only used when the power network has been divided into islands. Examples of other local SPS are out-of-step detection and undervoltage detection. The paper initially describes how SPS in Canada, France and Romania are used to defend system integrity during unforeseen or extreme contingencies. The examples should be considered as a source of information and also as a challenge to report on experiences with SPS. The paper then discusses possible ideas for future SPS based on available technology and known power system requirements