UR Family Firmware 5.83 - Release Notes
13
P
Changes to the “IEEE Very Inverse overcurrent curve” ensure accurate tripping times when
configured with very low pickup value
Products: B30, C60, C70, D30, D60, F35, F60, G30, G60, L30, L60, L90, T35, T60
Corrected firmware: 5.83, 5.90
Workaround: None
Description: This firmware version introduces changes to the “IEEE Very Inverse Overcurrent Curve” that
make its operating time to better match the specification when the configured pickup value is lower than
0.1 per unit. Devices with previous firmware versions can operate faster than the specified time under
such conditions. Users for whom Time Overcurrent applications require pickup values higher than 0.1 per
unit are not affected by this issue and a firmware update is not required.
GE tracking number: 590-15
F
Potential Overfrequency misoperation at low RMS metered values
Products: D60, F60, G30, G60, L90, M60, N60, T60; however mostly Generator Protection applications
Corrected firmware: 5.83, 7.20
Workaround: None
Description: At very low signal sources (less than 5%), the measured frequency value can be incorrectly
perceived as much higher than actual, at low frequency levels. This effect is experienced typically during
static generator startup. The measured frequency is based on zero-crossings, which can be invalid.
The following changes were made to correct the frequency metering at low signal and frequency levels:
• Hysteresis is increased to 5% of the signal RMS cutoff threshold
• Five consecutive cycles of good RMS waveform metered signal are checked to validate a good signal.
GE tracking number: 720-57
U
The “Negative Sequence and Neutral Directional Overcurrent” elements have been modified to deliver
enhanced security and dependability when sensing very low levels of V2 (V0) and significant levels of
I2 (I0)
Products: C70, D30, D60, F60, G30, G60, L30, L60, L90, M60, T60
Corrected firmware: 5.83, 5.72
Workaround: None
Description: This firmware version introduces important changes to the “Negative sequence directional”
and the “Neutral directional” overcurrent elements, which improve the element’s security and
dependability.
(1) Polarizing voltage compensation with offset impedance is only applied when the current magnitude I2
or I0 exceeds 0.2pu. This avoids overcompensation that might lead to possible directionality errors when
in presence of conditions with low levels of I2 or I0 currents.
(2) Both polarizing and operating quantities are now checked against cutoff level settings that are
selectable by the user at “Product Setup\Display Properties” for application flexibilities.
GE tracking number: 572-2
P
The “Fault Type” comparator logic, that is part of distance protection elements, has been changed to
correctly block the ground distance elements when sensing a double-line-to-ground fault
Products: D30, D60, G60, L60, L90, T60
Corrected firmware: 5.83, 7.10
Workaround: None
Description: In order to maintain selectivity during a double-line-to-ground fault, the ground distance
element is supervised by the “Fault Type” comparator that uses phase angle between the negative and
zero-sequence currents. However, the “Fault Type” comparator can also be removed when under the
following conditions:
a. During an open pole condition or