ABB Relion 620 Series Applications Manual page 74

Section 3
RER620 application
68
follows the status of the function, irrespective of, from where it is enabled or disabled i.e.
Local/Remote.
The status of the HLT function is stored in non-volatile memory i.e. the status is
maintained even when the relay power is cycled.
Figure 50: LHMI - captioned HLT and R/L push-buttons and LEDs
The HLT function does not automatically initiate changes to settings. If
any such changes are desired, for e.g., sensitive protection settings, it is up
to the user to do such changes.
The HLT function is configured in RER620 as a part of its default configuration and is
implemented using function blocks and logic gates. The application configuration/logic
scheme is shown in figure below.
L_Flag or R_Flag represents the HLT function status, which can be activated and
deactivated locally through pushbutton 8 (Key 8, Figure 50) or remotely through
SPCGGIO1_8 (Figure 50) respectively. The logic as designed accounts for the end user to
accurately activate or deactivate the Logic based on the customer's implementation
procedure. For example, If SCADA or HMI system activates the logic then, the RER620
will not allow for the local deactivation of the logic.
1MAC308145-MB E
RER620
Application Manual