ABB RELION 620 Series Technical Manual page 776

Section 4
Protection functions
4.11.5
770
value settings. The resulting threshold value for the comparator can be increased or
decreased depending on the sign and value of the Start value Add setting.
Timer
Once activated, the timer activates the START output. The time characteristic is
according to DT. When the operation timer has reached the value set by Operate delay
time, the OPERATE output is activated. If the starting condition disappears before the
module operates, the reset timer is activated. If the reset timer reaches the value set by
Reset delay time, the operation timer resets and the START output is deactivated.
The timer calculates the start duration value START_DUR, which indicates the
percentage ratio of the start situation and the set operation time. The value is available
in the monitored data view.
Blocking logic
There are three operation modes in the blocking function. The operation modes are
controlled by the BLOCK input and the global setting in Configuration/System/
Blocking mode which selects the blocking mode. The BLOCK input can be controlled
by a binary input, a horizontal communication input or an internal signal of the
protection relay's program. The influence of the BLOCK signal activation is
preselected with the global setting Blocking mode.
The Blocking mode setting has three blocking methods. In the "Freeze timers" mode,
the operation timer is frozen to the prevailing value, but the OPERATE output is not
deactivated when blocking is activated. In the "Block all" mode, the whole function is
blocked and the timers are reset. In the "Block OPERATE output" mode, the function
operates normally but the OPERATE output is not activated.
Application
The function block can be used for any general analog signal protection, either
underprotection or overprotection. The setting range is wide, allowing various
protection schemes for the function. Thus, the absolute hysteresis can be set to a value
that suits the application.
The temperature protection using the RTD sensors can be done using the function
block. The measured temperature can be fed from the RTD sensor to the function input
that detects too high temperatures in the motor bearings or windings, for example.
When the ENA_ADD input is enabled, the threshold value of the internal comparator
is the sum of the Start value Add and Start value settings. This allows a temporal
increase or decrease of the level detector depending on the sign and value of the Start
value Add setting, for example, when the emergency start is activated. If, for example,
Start value is 100, Start value Add is 20 and the ENA_ADD input is active, the input
signal needs to rise above 120 before MAPGAPC operates.
1MRS757644 F
620 series
Technical Manual