UR Family Firmware 5.83 - Release Notes
11
Description: In a three-line terminal system, the Line Differential Element operates in master-master mode
provided there is not any channel failure. If one communication channel fails, the 87L element changes to
master-slave mode. When in that mode, the channel failure blocks the disturbance detector element
50DD SV in the slave relays, and the master relay (relay with no channel failure) trips the slave relays by
sending DTT commands if a fault within the differential zone is detected. Therefore, if the disturbance
detector element “50DD SV” is set to supervise the line differential element “87L” and there is a line fault
while the 87L element is in Master-Slave mode, the slave relays do not trip after receiving the DTT signal
issued by the Master relay. This FW version introduces a change to the 87L element so a local source
disturbance detector “SCRx 50DD” is used in parallel to supervise the 87L element when the “50DD SV”
element is not available. This allows the slave relays trip after receiving the DTT command from the Master
relay upon the condition described above. This fix only affects users who have L30 or L90 devices applied
to a three-line terminal system and have enabled both the master-slave mode and the 50DD SV
supervision. Affected users can either upgrade their UR device with the corrected firmware version or use
the UR FlexLogic to implement the parallel supervision explained.
GE tracking number: 601-2
F
The voltage memory for distance polarization in L90 relays has been changed to ensure only actual
voltage values are used when there is an important difference between system and sampling
frequencies
Products: L90
Corrected firmware: 5.83, 6.02, 7.10
Workaround: Not applicable
Description: Inter-relay communication (IRC) between L90 devices located at each line terminal is primarily
required for line differential and pilot scheme applications. Single or redundant communication channels
can be applied. After recovering from a channel failure, L90 devices must synchronize for the Line
Differential Element to go back to normal operation. The synchronization process can cause the tracking
(sampling) frequency to deviate from the system frequency. A significant difference between the “system
frequency” and “sampling frequency” can cause the distance element to operate if voltage memory is
used for distance polarization. This FW release prevents the use of voltage memory for distance
polarization when under the described condition. This issue only affects users who have both (line
differential and distance) protection elements enable. Users who set both distance and line differential
elements to enable simultaneously are advised to upgrade their relay firmware version with this version.
For further information on the voltage memory for distance polarization, see the L90 instruction manual.
GE tracking number: 710.11
F
The Distance protection element has been changed to ensure that setting changes to Line protection
elements, made when the relays is in service, do not cause the phase distance element to operate
Products: L90
Corrected firmware: 5.83, 7.10
Workaround: Not applicable
Description: Setting changes to UR devices can be carried out by uploading a complete setting file or
editing individual setting fields via front panel or UR setup software. When editing individual settings to a
relay that is in service and reading close-to-nominal current and voltage signals, changing any of the line
differential or distance protection setting fields can cause the phase distance element to operate. This FW
release ensures the phase distance element does not operate under the described conditions. Standard
operating procedures require users to remove the relay from service when protection related settings are
changed or updated. Users who follow this type of procedure are not at risk of experiencing a miss
operation.
GE tracking number: 710-12
E
Increased security for line differential protection when experiencing Phase and Frequency Locked
Loop (PFLL) transition errors
Products: L30, L90
