Siemens 6MD85, Manual

Page: 953 / 1256

Logic
[lospasym-100611-01.tif, 4, en_US]
Figure 8-13 Logic Diagram of the Voltage-Balance Supervision
The
Threshold min/max
parameter is the criterion by which a phase-to-phase voltage unbalance is meas-
ured. The device calculates the ratio between the minimum (V
min
) and the maximum (V
max
) phase-to-phase
voltage.
Enter the lower limit of the maximum phase-to-phase voltage (V
max
) with the parameter
Release
threshold
. This specifies the lower limit of the operating range of this function.
Delay failure indication
If it falls below the balance factor
Threshold min/max
and at the same time the maximum phase-to-phase
voltage exceeds the
Release threshold
, the delay of the failure indication begins, (parameter:
Delay
failure indication
). If both conditions persist during this time, the indication
Failure
is generated.
Blocking the Function
The following blockings reset the picked up function completely:
•
Externally or internally via the binary input signal
>Block function
•
A protection pickup
The pickup signal of a protection function blocks the
Failure
indication.
Application and Setting Notes
Parameter: Threshold min/max
•
Recommended setting value
(_:102) Threshold min/max
=
0.75
The
Threshold min/max
parameter is used to set the ratio between the minimum (V
min
) and the maximum
(V
max
) phase-to-phase voltage. Siemens recommends using the default setting.
8.3.5.4
Supervision Functions
8.3 Supervision of the Secondary System
SIPROTEC 5, High-Voltage Bay Controller, Manual 953
C53000-G5040-C015-9, Edition 11.2017