The outputs of the function are the START, TRIP and BLOCKED signals. The non-directional
overcurrent function uses a total of eight (8) separate setting groups which can be selected from one
common source.
The function can operate on instant or time-delayed mode. In time-delayed mode the operation can be
selected between definite time (DT) or inverse definite minimum time (IDMT). The IDMT operation
supports both IEC and ANSI standard time delays as well as custom parameters. The function includes
CT saturation checking which allows the function to start and operate accurately during CT saturation.
The operational logic consists of the following:
• input magnitude selection
• input magnitude processing
• saturation check
• threshold comparator
• block signal check
• time delay characteristics
• output processing.
The basic design of the protection function is the three-pole operation.
The inputs for the function are the following:
• operating mode selections
• setting parameters
• digital inputs and logic signals
• measured and pre-processed current magnitudes.
The function outputs START, TRIP and BLOCKED signals which can be used for direct I/O controlling
and for user logic programming. The function generates general time-stamped ON/OFF events to the
common event buffer from each of the three (3) output signals. In instant operating mode the function
outputs START and TRIP events simultaneously with an equivalent time stamp. The time stamp
resolution is 1 ms. The function also provides a resettable cumulative counter for the START, TRIP and
BLOCKED events.
The following figure presents a simplified function block diagram of the non-directional overcurrent
function.
Figure. 5.3.2 - 71. Simplified function block diagram of the I> function.
A
AQ
Q-F201
-F201
Instruction manual
Version: 2.04
75
Содержание AQ-F201
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