Impact of Ferroresonance on protective relays in Manitoba Hydro 230 kV electrical network

Catastrophic circumstances and equipment failures in electrical networks are mostly caused by emerging unidentified phenomena. Resonance and Ferroresonance are those phenomena, which have been investigated since, many years ago. Manitoba Hydro 230 kV electrical network has experienced Ferroresonant states several times. Such conditions may occur in effect of short circuit, breaker phase failure, transformer energizing, load rejection, accidental or scheduled line disconnection, and plant outage. One of the significant consequences of resonant and Ferroresonant states can be an apparent mis-operation or tripping some protective devices and inaccurate operation of instrument transformers. In this paper by means of PSCAD/EMTDC simulation software, Ferroresonant states are analyzed in Manitoba Hydro 230 kV network. Ferroresonant states are classified in to adequate modes by Ferroresonance detection tools, furthermore; kinds of protective relays subjected to Ferroresonance are simulated in the power network, and operation of relays is assessed.