41
Guideform Specifications
(cont.)
time to sum intermittent ground fault current spikes.
i. A cover with provisions for sealing the rating plug, the trip unit,
and the “ENTER” key on the protective trip unit to make the
installation tamper-resistant. All trip unit settings, ratings, and
target information shall be capable of being viewed with the
cover in place.
j. The unit shall be dual-rated for both 50Hz and 60Hz operation.
Noise immunity shall meet the requirements of ANSI Standard
C37.90.2
k. The trip unit shall have an integral, resettable trip counter to
record the number of long time, short time, instantaneous and
ground fault trips. Trip target information shall include fault
current magnitude and phase for long time and short time
trips and fault current magnitude (as a function of the sensor
rating) for ground fault trips. When the trip unit is supplied
with additional protective relay functions, the display shall also
provide target indication for each type of protective relay trip.
l. The trip unit shall display trip targets for longtime, short time,
instantaneous and ground fault trips.
m. All trip unit settings and trip target information shall be stored
in nonvolatile memory.
3. The trip units for the main and tie breakers shall include the fol-
lowing protective functions:
a. Adjustable long time current settings.
b. Adjustable long time delay with four time delay bands.
c. Long time pickup warning indicator.
d. Trip targets for overload, short circuit <and ground fault>.
e. Adjustable short time pickup and delay, with three delay bands,
and switchable I
2
t ramp.
f. SELECT ONE OF THE FOLLOWING IF GROUND FAULT
PROTECTION IS REQUIRED:
1) <Adjustable ground fault pickup and time delay, with three
delay bands, and switchable I
2
t ramp.>
2) <Defeatable ground fault function with adjustable pickup
and time delay, with three delay bands, and switchable I
2
t
ramp.>
g. OPTIONAL: <Switchable short time / instantaneous and
ground fault protection.>
h. OPTIONAL (Select one if req’d): Zone selective interlocking
<for ground fault only> <for both ground fault and short time>.
4. The trip units for feeder breakers shall include the following pro-
tective functions:
a. Adjustable long time current settings.
b. Adjustable long time delay with four time delay bands.
c. Long time pickup warning indicator.
d. Trip targets for overload, short circuit <and ground fault>.
e. <Adjustable short time pickup and delay, with three delay
bands, and switchable I
2
t ramp> and/or <adjustable instanta-
neous pickup>.
f. SELECT ONE OF THE FOLLOWING IF GROUND FAULT
PROTECTION IS REQUIRED:
1) <Adjustable ground fault pickup and time delay, with three
delay bands, and switchable I
2
t ramp.>
2) <Defeatable ground fault function with adjustable pickup
and time delay, with three delay bands, and switchable I
2
t
ramp.>
g. OPTIONAL: <Switchable short time / instantaneous and
ground fault protection.>
h. OPTIONAL (Select one if req’d): Zone selective interlocking
<for ground fault only> <for both ground fault and short time>.
5. The trip units shall include the following metering functions,
which shall be displayed on the LCD:
a. Current, rms (A or kA), each phase 2.0% accuracy.
b. OPTIONAL (Note - if any of the following are included, all will
be included)
1) Voltage, rms (V), line-to-line or line-to-neutral, +/-1.5%
accuracy.
2) Energy (kWh, MWh, GWh), total, +/-3.5% accuracy, user
resettable.
3) Demand (kWh, MWh, GWh) over an adjustable time period of
5 to 60 minutes, +/- 3.5% accuracy.
4) Peak Demand (kW, MW), +/- 3.5% accuracy, user resettable.
5) Real power (kW, MW), line-to-line, line-to-neutral, +/- 3.5%
accuracy.
6) Total (apparent) power (kVA, MVA), line-to-line, line-to-neutral,
+/-3.5% accuracy.
7) Frequency (Hz), +/-1Hz accuracy.
6. OPTIONAL: The trip unit shall include all of the following protec-
tive functions. However, it shall be possible to disable, by user pro-
gramming, any combination of unwanted protective functions.
a. Undervoltage, adjustable pickup - 50 to 90%, adjustable delay -
1 to 15 seconds.
b. Overvoltage, adjustable pickup - 110 to 150%, adjustable delay -
1 to 15 seconds.
c. Voltage unbalance, adjustable pickup - 10 to 50%, adjustable
delay - 1 to 15 seconds.
d. Current unbalance, adjustable pickup - 10 to 50%, adjustable
delay - 1 to 15 seconds.
e. Reverse power, selectable direction, adjustable pickup - 10kW to
990kW, adjustable delay - 1 to 15 seconds.
7. OPTIONAL: The trip unit shall include communication capability
as follows:
a. The trip unit, through dedicated secondary terminals on the
breaker, shall provide a communication port for communica-
tion with and access to a remote computer via the breaker sup-
plier’s standard communication network and protocol.
b. All metering, setpoints, protective trip counts, and other event
signaling shall be retrievable by the remote computer.
8. Current sensors shall be mounted on the breaker frame and shall
use encapsulated construction to protect against damage and mois-
ture. <For ground fault protection of a four-wire power system, a
fourth - neutral current - sensor shall be mounted in the cable
compartment, and shall be compatible with the phase current sen-
sors.>
