... voltage closedown over-current protection (with direction)* Low frequency decrease load (slip closedown, low current closedown)* Transformer ratio-differential protection(secondary ... has high sampling accuracy and can measure the parameters of loop U, I, P, Q, COS, F, kWh, kvarh ... slight gas, overtemperature, earthed, PT break, over-load, control loop break and so on * State of remote signal: Signal ...