Section 1: Introduction; Protection Requirements Of Feeders; Relay Features; Setpoint Programming - GE Multilin 565 Instruction Manual

Protection Requirements of Feeders

Protection of three phase feeders is necessary to avoid
equipment damage and personnel injury during fault condi-
tions. The fact that continuous reliable power must be pro-
vided to the distribution network means that the feeder pro-
tection relay must protect the network and personnel and yet
not cause unnecessary loss of power or nuisance tripping.
The ideal Feeder Management Relay should at least monitor
phase current, ground current and voltage in the network,
provide indications if any of these reach predetermined levels
and provide appropriate trip signals if fault conditions de-
velop.
The advent of current microprocessor technology has ena-
bled the development of feeder management relays which do
this task much better than conventional relays and provide
other desirable features. Measured values of phase current,
ground current and voltage can be displayed.
Entering setpoints to the microprocessor based Relay is
made easier by use of a keypad and a LCD display to guide
the user. A "help" menu is available at all times.

Relay Features

The Multilin Feeder Management Relay is designed to pro-
vide complete and accurate feeder protection under all oper-
ating conditions. The relay provides complete Time/Overcur-
rent phase and ground protection by monitoring feeder phase
currents and ground currents. These are sensed by current
transformers (CT's).
Overcurrent phase and ground current trip setpoints are
programmed by a comprehensive selection of industry stand-
ard curve shapes including moderately inverse, normal in-
verse, very inverse, and extremely inverse. In addition to the
pre-selected curves there is also a programmable custom
curve. If none of the pre-selected curves are suitable for the
application, the user can enter his own data to form the
custom curve.

Setpoint Programming

The relay can have its setpoints programmed locally, from the
front panel. In this case the alphanumeric display guides the
user through the setup, step by step, giving clear English
language instructions. There is also a HELP key which can be
pressed at any time to get information and assistance about
the current programming step.
The status of the system is clearly displayed at all times by
LED indicators and more detailed information can be shown
on the display screen if requested through the keypad.
When an output relay is activated to cause a trip/alarm the
Relay will display the cause of the trip/alarm.
All setpoints are tamper-proof. This is achieved through the
use of a combination of a Access wire jumper at the back of
the relay and personalized codes. These codes allow even
the wire jumper to be overridden, for added security.

Inputs

The Relay has inputs which can be used for indication of
breaker status or external differential trips such as the indus-
try standard '87T'.
One set of inputs is designated "Analog Select", and can be
connected to four dry contacts of a programmable logic
controller (PLC). Selected outputs can be requested one by
one, through these inputs by the PLC. Information can be
requested on values such as individual phase currents and
the Relay will send the requested value through the analog
output terminals in either 0-1mA or 4-20mA format as re-
quired.

Outputs

Six electromechanical output relays are included in the 565/
575 Relay. These are named Trip, Close, Aux. 1, 2, 3, and 4.
These relays can be allocated various functions, by using the
flexibility of the software programming.
Actual value and Setpoint information is sent out through the
RS485 port on the rear of the relay. ** An RS232 printer driver
port is also available for printing out events from the event
recorder if an Option Card is installed. ** In addition, a front
panel RS232 programming port is provided.

Memory Features

In order to simplify fault analysis and thus improve system
reliability, several memory features have been built into the
Relay. The event recording feature provides a record of the
events leading to a trip so that the faulty feeder system
component can be located easily.
The memory feature provides a record of the cause of all
trips. This is extremely useful in determining preventive main-
tenance requirements and identifying problem areas.

Typical Applications

The Relay is ideally suited for primary protection of medium
and high voltage distribution systems.
INTRODUCTION
1-1