Rockwell Automation 865 Differential Protection Relay - Manual (Page 9)

Chapter
1
865-UM001A-EN-P – July 2009
Overview
Introduction The Allen-Bradley 865 differential protection system includes all the
essential protection functions needed to protect transformers for
distribution networks of utilities, industry, power plants and offshore
applications as well as motor and generator differential protection.
Further, the device includes several programmable functions, such as
thermal and circuit breaker protection and communication protocols
for various protection and communication situations. An optional
arc flash protection feature is also available.
The Allen-Bradley 865 can be used for selective differential
overcurrent, short-circuit protection of generators, transformers
and motors in solidly or impedance earthed power systems. The
relay can also be used for single, two or three-phase overcurrent
and/or sensitive earth fault protection.
The modern technology in association with an extensive self-
supervision system and a reliable construction ensures extremely
high system availability for the Allen-Bradley 865 protection
relay.
Main Relay Features The main features of Allen-Bradley 865 are:
•
Fully digital signal handling with a powerful 16-bit
microprocessor, and high measuring accuracy on all the setting
ranges due to an accurate 16-bit A/D conversion technique
•
Wide setting ranges for the protection functions, e.g. the earth
fault protection can reach a sensitivity of 0.5%
•
The device can be matched to the requirements of the application
by disabling the functions that are not needed
•
Flexible control and blocking possibilities due to digital signal
control inputs (DI) and outputs (DO)
•
Easy adaptability of the relay to various substations and alarm
systems due to flexible signal-grouping matrix in the relay
•
Freely configurable display with six measurement values