Setting Guidelines; General; Setting Of Common Parameters - ABB RET650 Applications Manual

1MRK 504 169-UEN A
10.2.3
10.2.3.1
10.2.3.2
Transformer protection RET650 2.2 IEC
Application manual
first case influences the operation of all voltage-dependent functions while the
second one does not affect the impedance measuring functions.
The negative sequence detection algorithm, based on the negative-sequence
measuring quantities is recommended for use in isolated or high-impedance earthed
networks: a high value of voltage 3U
sequence current 3I is a condition that is related to a fuse failure event.
2
The zero sequence detection algorithm, based on the zero sequence measuring
quantities is recommended for use in directly or low impedance earthed networks:
a high value of voltage 3U
condition that is related to a fuse failure event. In cases where the line can have a
weak-infeed of zero sequence current this function shall be avoided.
A criterion based on delta current and delta voltage measurements can be added to
the fuse failure supervision function in order to detect a three phase fuse failure.
This is beneficial for example during three phase transformer switching.

Setting guidelines

General

The negative and zero sequence voltages and currents always exist due to different
non-symmetries in the primary system and differences in the current and voltage
instrument transformers. The minimum value for the operation of the current and
voltage measuring elements must always be set with a safety margin of 10 to 20%,
depending on the system operating conditions.
Pay special attention to the dissymmetry of the measuring quantities when the
function is used on long untransposed lines, on multicircuit lines and so on.
The settings of negative sequence, zero sequence and delta algorithm are in percent
of the base voltage and base current for the function. Common base IED values for
primary current (IBase), primary voltage (UBase) and primary power (SBase) are
set in Global Base Values GBASVAL. The setting GlobalBaseSel is used to select a
particular GBASVAL and used its base values.

Setting of common parameters

Set the operation mode selector Operation to On to release the fuse failure
function.
The voltage threshold USealIn< is used to identify low voltage condition in the
system. Set USealIn< below the minimum operating voltage that might occur
during emergency conditions. We propose a setting of approximately 70% of
UBase.
The drop off time of 200 ms for dead phase detection makes it recommended to
always set SealIn to On since this will secure a fuse failure indication at persistent
Secondary system supervision
without the presence of the negative-
2
without the presence of the residual current 3I
0
Section 10
is a
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IP15000-1 v1
M13683-3 v5
M13683-9 v9
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