Description

BE1-67 Phase Directional Overcurrent Relays are designed for the protection of transmission and

distribution lines where the direction as well as the magnitude of the fault current (or power flow) is to be

considered in the tripping decision.

BE1-67 relays are directionally controlled, microprocessor based, time overcurrent relays. The directional

element is polarized by the phase-to-phase quadrature voltage of the power system. That is, the

directional element monitoring the phase A current uses the voltage between phases B and C to

determine the direction of current (or power) flow into the fault. Then, if enough current flows in the

tripping direction of the relay, the relay will pickup, time out, and trip. The angle of maximum sensitivity for

the relay is also adjustable to allow the directional characteristic to be matched to the line and system

conditions. 

The directional characteristic of the relay is adjustable to allow the relay to be sensitive for phase faults

and to maximize sensitivity at the characteristic angle representing typical power factor.

Twelve standard time-current characteristic curves are available to aid in the coordination of this relay

with other protective devices in the system. These include seven characteristic curves that are standard in

North America and five that are compatible with British or IEC standards requirements. Any of the curves

may be switch selected to suit requirements at the time of installation.