System Parameters

All sensing is performed using an IT-D isolation module. Each IT-D isolation

module includes two channels that are capable of sensing either dc current

or dc voltage. The dc system current is sensed using an appropriately scaled

25. 50. 75. or 100-millivolt nominal metering shunt. DC voltages are sensed

by direct connection for nominal levels up to 1.500 Vdc. The BE1-11d can

utilize two IT-D modules to sense a single dc current and up to three dc

voltages.

The IT-D digitally samples the sensed inputs at a rate proportional to the

rectification system nominal power input frequency. The sampling rate is

established to maintain a high accuracy of the measurement for a dc signal

with ripple content.

High-speed fiber optic communications between the IT-Ds and the BE1-11d

transmit the magnitudes of the system measurement to the protection system.