Download 369faq_b1 - GE Grid Solutions

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GE
Multilin
369 FREQUENTLY ASKED QUESTIONS
1.
Can I send a 269 setpoint file to a 369 relay?
Yes. Using the 369 PC program, a 269 setpoint file can be sent to the
369. Note: any settings/features that are not in the 269 setpoint file will
not be changed on the 369 unit and will be set as default values. All
setpoints should be confirmed before operating the relay.
2.
Can I use an 86 lockout on the 369?
Yes, but If an external 86 lockout device is used and connected to the
369, ensure that the 369 is reset prior to attempting to reset the lockout
switch. If the 369 is still tripped, it will immediately retrip the lockout
switch. Also, if the lockout switch is held reset, the high current draw
of the lockout switch coil may cause damage to itself and/or the 369
output relay.
3.
Can I assign more than one output relay to be blocked when
using Start Inhibits?
Yes, but keep in mind that if two output relays are wired in series to
inhibit a start, it is possible that another element could be programmed
to control one or both of the relays. If this is happening and the other
element is programmed with a longer delay time, this will make it seem
as if the Start Inhibit is not working properly when in fact, it is.
4.
Can I connect three voltage transformers to achieve a delta
configuration in the 369?
Yes, but it is unnecessary since the 369 will calculate Vca based on
the measured Vab and Vcb.
5.
Can I name a digital input?
Yes. By configuring the digital input as "General", a menu will appear
that will allow naming.
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369FAQ_B1.doc
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GE
6.
Multilin
Can I apply an external voltage to the digital inputs on the 369?
No. The 369 uses an internal voltage to operate the digital inputs.
Applying an external voltage may cause damage to the internal
circuitry.
7.
No display, no characters on the display, but there is a backlight.
Press the HELP key, when all the LEDs are illuminated, press ENTER
to automatically set the contrast to 145. You may also communicate
with the relay using the 369 PC program to check the contrast setting.
8.
What are the merits of a residual ground fault connection versus
a core balance connection?
The use of a zero sequence (core balance) CT to detect ground
current is recommended over the G/F residual connection. This is
especially true at motor starting. During across-the-line starting of
large motors, care must be taken to prevent the high inrush current
from operating the ground element of the 369. This is especially true
when using the residual connection of 2 or 3 CTs. In a residual
connection, the unequal saturation of the current transformers, size
and location of motor, size of power system, resistance in the power
system from the source to the motor, type of iron used in the motor
core and saturation density, and residual flux levels may all contribute
to the production of a false residual current in the secondary or relay
circuit. The common practice in medium and high voltage systems is
to use low resistance grounding. By using the doughnut CT scheme,
such systems offer the advantages of speed and reliability without
much concern for starting current, fault contribution by the motor, or
false residual current. When a zero sequence CT is used, a voltage is
generated in the secondary winding only when zero sequence current
is flowing in the primary leads. Since virtually all motors have their
neutrals ungrounded, no zero sequence current can flow in the motor
leads unless there is a ground fault on the motor side.
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369FAQ_B1.doc
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GE
9.
Multilin
Can I upload setpoint files from previous versions to the latest
version of firmware?
Yes, with the exception of setpoint files from versions 1.10 to 1.12.
Unfortunately, these setpoint files must be rewritten, as they are not
compatible.
10.
Can I use the learned values with motors that have start times
faster than 500 milliseconds?
Yes, but keep in mind that for motors that have start times faster than
500 milliseconds, there will not be any data for the very first start. For
following starts, the 369 will be able to provide data based on previous
start information.
11.
I need to update the options for my 369/RRTD in the field, can I do
this?
Yes. All options of the 369/RRTD can be turned on or added in the
field except for the Profibus and Ethernet options for the 369. To do
this, contact the factory.
12.
Can the 369 be used as a remote display unit, similar to the 269
remote?
Yes. Every 369 can be used as remote. When ordering the 369, an
external 15 foot cable must be ordered.
13.
Is there a limit to the lead length of my RTD?
Yes. Correct operation will occur providing all three wires are of the
same length and the resistance of each lead is not greater than 25% of
the RTD 0°C resistance. This can be accomplished by using identical
lengths of the same type of wire. If 10 ohm copper RTD's are used,
special care should be taken to keep the lead resistance as low as
possible.
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GE
14.
Multilin
I cannot store setpoints into the relay.
Check and make sure the ACCESS switch is shorted (terminals 57 and
58). Also, check for any PASSCODE restrictions from page S1
Setpoints / 369 Setup / Setpoint Access.
15.
Can the RRTD module be used as a standalone unit?
Yes. The RRTD unit with the IO option has 4 output relays, 6 digital
inputs, and 4 analog outputs. With this option, the RRTD can provide
temperature protection.
16.
The 369 relay displays a high unbalance reading (or wrong power
reading), yet the power system is balanced, what could be the
possible reasons?
It is highly possible that the secondary wiring to the relay is not correct.
High unbalance (and wrong power) can be read when any of the A, B,
or C phases are swapped, or the relay is programmed as ABC
sequence when the power system is actually ACB and vice versa. The
easiest way to verify is to check the voltage and the current phasor
readings on the 369 relay and make sure that each of the respective
voltage and current angles match.
17.
Can 4-wire RS485 (full duplex) be used with 369?
No, the 369 communicates in 2-wire half-duplex mode only. However,
there are commercial RS485 converters that will convert a 4-wire to a
2-wire system.
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