When the user-programmable IDMT curve is selected, the operation time characteristics
are defined by the parameters
Curve parameter A
,
Curve parameter B
,
Curve parameter
C
,
Curve parameter D
and
Curve parameter E
.
If a drop-off situation happens, that is, a fault suddenly disappears before the trip delay is
exceeded, the timer reset state is activated. The functionality of the timer in the reset state
depends on the combination of the
Operating curve type
,
Type of reset curve
and
Reset
delay time
settings. When the DT characteristic is selected, the reset timer runs until the set
Reset delay time
value is exceeded. When the IDMT curves are selected, the
Type of reset
curve
setting can be set to "Immediate", "Def time reset" or "Inverse reset". The reset
curve type "Immediate" causes an immediate reset. With the reset curve type "Def time
reset", the reset time depends on the
Reset delay time
setting. With the reset curve type
"Inverse reset", the reset time depends on the current during the drop-off situation. If the
drop-off situation continues, the reset timer is reset and the
PICKUP
output is deactivated.
The "Inverse reset" selection is only supported with ANSI or user
programmable types of the IDMT operating curves. If another operating
curve type is selected, an immediate reset occurs during the drop-off
situation.
The setting
Time multiplier
is used for scaling the IDMT trip and reset times.
The setting parameter
Minimum trip time
defines the minimum desired trip time for
IDMT. The setting is applicable only when the IDMT curves are used.
The
Minimum trip 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 trip time
setting. For more information, see the
IDMT curves for overcurrent protection
The timer calculates the pickup duration value PICKUP_DUR, which indicates the
percentage ratio of the pickup situation and the set trip 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
.
Section 4
1MRS240050-IB C
Protection functions
176
REF615R
Technical Manual
Summary of Contents for RELION REF615R
Page 1: ... RELION PROTECTION AND CONTROL REF615R Technical Manual ...
Page 2: ......
Page 27: ...Section 18 Glossary 653 Table of contents REF615R 21 Technical Manual ...
Page 28: ...22 ...
Page 36: ...30 ...
Page 46: ...40 ...
Page 115: ...3 15 4 Settings 1MRS240050 IB C Section 3 Basic functions REF615R 109 Technical Manual ...
Page 118: ...112 ...
Page 318: ...312 ...
Page 388: ...382 ...
Page 456: ...450 ...
Page 520: ...514 ...
Page 652: ...646 ...
Page 656: ...650 ...
Page 658: ...652 ...
Page 663: ...657 ...