Microversatrip Plus™ And Pm™ Trip Units; Enhancements - GE Power Break II Manual

MicroVersaTrip Plus™ and PM™ Trip Units
The Enhanced MicroVersaTrip PlusTM And
MicroVersaTrip PMTM Trip Unit Systems
The Enhanced M icroVersaTrip Plus and M icroVersaTri p PM
trip unit systems for Power Break® I I insulated case breakers
consist of the trip unit, the trip actuator, current sensors and
rating plugs. The term "trip unit system" applies to the combi­
nation of these fou r components which form the solid-state
circuit brea ker tripping system.
M icroVersaTri p Plus trip u nits provide a com plete range of
sta ndard and optional overcurrent and g round-fault pro­
tective functions. M icroVersaTrip PM u n its add advanced
metering, commun ications and p rotective relaying functions.
M icroVersaTrip PM trip units a re designed to function as p a rt
of the G E POWER LEADER™ Power Ma nagement System.
Components of M ic roVersoTrip Plus t r i p u n it system
True R M S Sensing
Enha nced M icroVersaTrip Plus and MicroVersaTrip PM trip
un its continue to use GE's p roven tech nique of measuring
true rms currents (and voltages for M icroVersaTrip PM trip
units) of both sinusoidal and h a rmoni ca lly distorted wave­
forms. The frequent sampling (64 times per cycles per phase)
a l lows precise calculations of true rms current. The sampling
rate al lows waveform measurement up to the 3 1st harmonic
to ach ieve accuracies of 99%. G E's true rms sensing avoids
potential u nderprotection or overprotection problems associ­
ated with peak-sensing tripping systems.
Enhancements to MicroVersaTrip Plus
and MicroVersaTrip PM Trip Units
Enhancements include several new functions that simplify
p rogra m m ing and make fault displays easier to read and
i nterpret .
14
Batteries
Replaceable, long-l ife lithium batteries provide p rogra m m ing
and display power to the trip unit's LCD on command. Th e
trip unit can be removed from the breaker, and a l l setpomts
can be d efined at a techni cian's desk. The i ntegral conserva­
tion feature extends battery l ife. The batteries a re a utomati­
cally shut off when no p rogramming operation or d isplay
req uest is called for within 30 seconds after the last key 1s
p ressed. The batteries a lso enable the user to read fau lt
displ ays on a n open breaker.
The battery is i ntended to power the Tri p Unit when it i s
otherwise un powered. At low currents the Trip U nit Display
n ot active. Pressing the BATTERY key under these conditions
wil l n ot activate the d isplay. The MicroVersaTrip Plus trip unit
display is on as long as a small amount of current ( m ini­
mum 20% of current sensor rating) is flowing in the breaker
current sensors. The displays of installed MicroVersaTrip PM
u nits a re visible at all times due to an external +24Vdc power
supply accessory.
The batteries a re not required to maintain programmed
settings, or store trip information. They simp ly p rovide a
local power source to energize the progra m m e r when no
othe r source of power is availa ble. All setpoints, time delays
and other programming functions a re stored in n on-volatile
memory within the trip unit's m icroprocessor.
Batteries h ave a two-year l ife under normal use. They a re
user-replaceable.
LCD
The LCD - liquid crystal display- has increased contrast to
improve legibility in poor l ig hting conditions. N ew interna­
tional displays symbols are use for various
fu nctions (e.g., "I»" for short circuit and "I>" for overload).
Trip O perations Counter
The enha nced MicroVersaTrip Plus and MicroVersaTrip PM
Trip u n it a lso store and display the total n u m ber of trips due
to long time overloads, short time and instantaneous short
circuits, and g round faults. Each display stores u p to 2 5 6
operations p e r trip category before resetting t o zero. Each
counter can be ind ividually reset t h rough the keypad.
Accessory Integ ration
Four accessories a re integrated through the MicroVersaTrip
Plus a n d M icroVersaTrip PM trip un its. Drop-in shunt trip (with
or without lockout). bell alarms (with or without lockout) and
the undervoltage release modules fit into keyed pockets.
They o perate through the trip units, and not through a ny
external mechanism. All accessory wiring is pre-wired to
secondary termina ls, and no user wi ri ng is necessary. When
activated, the sh unt trip (with our without lockout) and un­
dervoltage release modu les send a signal to the trip u nit to
energ ize the trip actuator and open the breaker.
IS
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programming