see the IDMT curves for overvoltage protection section in this
manual.
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 input signal activation is
preselected with the global Blocking mode setting.
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.
The “Freeze timers” mode of blocking has no effect during the inverse
reset mode.
4.4.1.5 Timer characteristics
The operating curve types supported by PHPTOV are:
Table 411: Timer characteristics supported by IDMT operate curve types
Operating curve type
(5) ANSI Def. Time
(15) IEC Def. Time
(17) Inv. Curve A
(18) Inv. Curve B
(19) Inv. Curve C
(20) Programmable
4.4.1.6 Application
Overvoltage in a network occurs either due to the transient surges on the network or
due to prolonged power frequency overvoltages. Surge arresters are used to protect the
network against the transient overvoltages, but the relay's protection function is used
to protect against power frequency overvoltages.
Section 4 1MRS758755 A
Protection functions
410 REC615 and RER615
Technical Manual
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