The setting parameter
Minimum operate time
defines the minimum desired
operation time for IDMT. The setting is applicable only when the IDMT curves are
used
The
Minimum operate time
setting should be used with great care
because the operation time is according to the IDMT curve but always
at least the value of the
Minimum operate time
setting. More information
can be found in
Chapter 11.2.1 IDMT curves for overcurrent protection
.
Timer calculates the start duration value START_DUR, which indicates the
percentage ratio of the start situation, and the set operating time, which can be
either according to DT or IDMT. The value is available in the monitored data view.
More information can be found in
Chapter 11 General function block features
.
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.
4.2.5.5 Application
During an earth fault, HAEFPTOC calculates the maximum current for the current
feeder. The value is sent over an analog GOOSE to other protection relays of the
busbar in the substation. At the configuration level, all the values received over
the analog GOOSE are compared through the MAX function to find the maximum
value. The maximum value is sent back to HAEFPTOC as the I_REF_RES input.
The operation of HAEFPTOC is allowed in case I_REF_RES is lower than the locally
measured harmonics current. If I_REF_RES exceeds the locally measured harmonics
current, the operation of HAEFPTOC is blocked.
Protection functions
1MRS758755 C
372 REC615 & RER615
Technical Manual
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