UR Family Firmware 5.84 - Release Notes
27
Self-Test Diagnostic Alarms
C
Added alarms and improved functionality
Products: All except C30
Impacted firmware: All to 6.05, 7.00 to 7.26, 7.30 to 7.42
Corrected firmware: 5.84, 6.06, 7.27, 7.60 and up
Workaround: None
Description: Prior to the corrected releases, the UR produced visible alarms for most internal diagnostic
events, even when relay protection availability was not compromised. In the corrected firmware, the UR
alarm design has been changed to generate user alarms only when protection is compromised. In
addition, internal diagnostics are revised for lower sensitivity to internal alarms, such as redundancy
checks, to allow for more secure, robust protection with fewer nuisance alarms. The UR design continues
to maintain extensive monitoring on availability of all protection elements. The design also provides
robustness through a recovery mechanism that is initiated to minimize downtime for protection
availability. As a result of this change, new self-tests are added to the design. See the manual for more
information. The new releases fix the issue.
GE tracking number: 760-20
Transformer Protection Systems – G30, T35, T60
P
Corrected firmware to prevent latching of “XFMR PCNT DIFF PKP” and “XFMR PCNT DIFF 5TH"
operands for Transformer Percent Differential element
Products: G30, T35, T60
Impacted firmware: All to 6.05, 7.00 to 7.26, 7.30 to 7.61
Corrected firmware: 5.84, 6.06, 7.27, 7.70 and up
Workaround: None
Description: The “XFMR PCNT DIFF PKP” and “XFMR PCNT DIFF 5TH" operands of the Transformer Percent
Differential element can remain latched after activation and are reset only by rebooting the relay.
The new releases correct the issue.
GE tracking number: 770-16
P
Improved percent differential 2nd harmonic inhibit mode at low differential currents
Products: G30, T35, T60
Impacted firmware: All to 7.25, 7.30, 7.31
Corrected firmware: 5.84, 7.26, 7.32, 7.12K, 7.40
Workaround: None
Description: A cutoff of 0.04 pu prevents inaccurate measurement, for example when the differential
current is less than 0.04 pu, the differential current and its 2nd harmonics component are forced to zero.
This can lead to a false trip during transformer energization when both components in any phase
(specifically Ibd and Icd) drop below 0.04 pu in two out-of-three inhibit mode.
In the new releases, the two-out-of-three 2nd harmonic inhibit logic is applied only if all three phase
differential currents exceed the cutoff level of 0.04 pu. In cases where differential current in any phase
drops below 0.04 pu, the logic is reverted to one-out-of-two logic, ensuring reliable inhibit during
energization.
GE tracking number: 726-2