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UR Family Firmware 5.83 - Release Notes
Corrected firmware: 5.83, 6.02, 7.20
Workaround: Not applicable
Description: When line differential protection (87L) schemes are exposed to extremely noisy or unreliable
channel conditions, the PFLL element can lose synchronism and then re-synchronize. GE strongly
recommends that, for maximum security, the disturbance detector element (50DD) be assigned to
supervise operation of the 87L element. Failing to follow this recommendation can potentially cause the
87L element to misoperate during re-synchronizing attempt. This improves the 87L element security to
prevent misoperation when, under the described conditions, the 50DD element is not supervising the 87L
element. Customers who have followed GE recommendations for heavily noisy channels or having reliable
inter-relay communication are not required to take action.
GE tracking number: 720-7
Motor protection system - M60
F
Changes to Voltage Dependent Thermal overload element add security when starting very high
inertia motors
Products: M60
Corrected firmware: 5.72, 5.83
Workaround: None
Description: Two key variables of the Thermal overload protection element have been changed to
increase the element’s security:
- The “Voltage Dependent Thermal Overload curve” has been modified (10% more Stall current at 100%
volts) to give motors a longer acceleration time. This is especially useful when protecting very high inertia
motors
- Negative sequence currents are now filtered to properly bias the equivalent motor heating current
“Ieq” when the relay senses significant motor load changes.
If your thermal overload element is not set for voltage dependent, no action is required.
GE tracking number: 572-1
Common protection and control elements
P
The Restricted Ground fault algorithm has been changed to correctly apply timers that determine the
value of negative sequence restraining current used during transformers energization and operation
Products: G30, G60, L90, T60
Corrected firmware: 5.83, 7.10
Workaround: Not applicable
Description: The Restricted Ground Fault element uses the maximum among the three current
components as restraining signal:
Irest = max (IRO, IR1, IR2)
Where, the negative-sequence component of the restraining signal (IR2) is calculated as follows:
IR2 = 1 x |I_2| or IR2 = 3 x |I_2|
Multiplier “1” is used right after five cycles of complete transformer de-energization, while multiplier “3” is
used right after two cycles of complete transformer energization (during transformer’s normal operation).
UR devices with previous FW versions showed timers were set to 10 and four cycles instead. This FW
version fixes this out-of-spec issue. For details on the “Restricted Ground Fault” element, see the
Instruction manual of any applicable UR device.
GE tracking number: 710-13