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Features Complete Digitrip 3000 Overcurrent Protection and Metering Reliable AC Powered - No battery or UPS required Current Powered on loss of voltage Low Burden Quick Power Up Response Works with Capacitive trip devices Operates with CT Saturation

The Digitrip-3000 overcurrent relay with optional Dual Source Power Supply provides complete three phase and ground protection for ac control power applications. It is a completely self-contained unit that provides both ac voltage and current power for operation. The unit fits into the IQ cutout and the current connections are the same as the standard DT-3000 relay. The voltage connection has been relocated from the side of the unit to the back of the unit.

The transition from voltage power to current power is smooth with no time delay.

The optional Dual Source Power Supply is recommended for use on all AC powered Digitrip 3000's where under voltage tripping or UPS (un-interruptible power supply) is not used. The Dual Source Power Supply has the advantage of operating on current only when the voltage has dropped below an acceptable level. The unit will operate even if no voltage has been present for an extended period of time. It is particularly valuable on capacitive trip breaker units. In addition, the unit does not contain batteries and is maintenance free.

Application of the Dual Source Power Supply provides a new level of redundancy for microprocessor based protective relays even in substations with dc power supply. Each Digitrip 3000 is powered by its own Dual Source Power Supply and is independent of common hardware failure such as a battery or UPS.

The Dual Source Power Supply contains 1 ac voltage transformer and 3 ac current transformer used to power the Digitrip 3000 overcurrent protective relay. The Dual Source Power Supply normally operates on its ac voltage. During extreme fault conditions, the ac voltage may drop below acceptable operating levels. If the voltage drops below 70%, then the power supply will switch to its ac current source. The current level must be at least 2 per unit (or 10 amps) in a single phase for proper current source operation. All three phase currents are summed together to provide relay operating power.

Any additional load or fault current in any of the other 2 phases improves the operating performance by reducing the minimum current requirement. There will be no affect to the DT3000 relay tripping time accuracy when the Dual Source Power Supply unit converts over from voltage power to current power.

• The Dual Source Power Supply can power up the DT-3000 from an initial state of no voltage and no current to no voltage and 2 per unit secondary current to operate and trip the DT3000 overcurrent relay with approximately 50 msec. additional time delay.

• The Dual Source Power Supply can operate when the primary CT's saturate.

• The Dual Source Power Supply will introduce additional burden on the primary CT's.