Transient modeling of electromechanical relays

Electromechanical, plunger 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 Type 50 devices and incorporating them into a power system transient analysis. This paper is the second part of a summary report by Rensselaer Polytechnic Institute (RF’I) of work on relay modeling sponsored by the Bonneville Power Administration (BPA). Part I1 presents the Electro-Magnetic Transient Program/Alternative Transient Program (EMTP/ATP) model for plunger type 50 instantaneous overcurrent relays that compare with actual tests performed on the devices on a Power System Simulator (PSS) [l].