Transient modeling of electromechanical relays. Part I: armature type overcurrent relay

Electromechanical, armature type 50 relay is modelled in EMTP/ATP using TACS. Mechanical, magnetic, and electrical characteristics are represented in the form of simple mathematical models that can provide a useful tool for studying the dynamic responses of the armature type 50 devices and incorporating them into a power system transient analysis. This paper is the first part of a summary report by the Rensselaer Polytechnic Institute @€’I) of work on relay modeling sponsored by the Bonneville Power Administration (BPA). Part I presents the Electro-Magnetic Transient ProgrdAltemative Transient Program (EMTP/ATP) model for armature type 50 instantaneous overcurrent relays that compares with actual tests performed on the devices on a Power System Simulator (PSS). The companion paper (Part 11) describes similar modelling efforts of plunger type 50 instantaneous overcurrent relays.