Setting Guidelines; Meshed Network Without Parallel Line - ABB RER670 Applications Manual

Section 8
Current protection
8.1.3
8.1.3.1
158

Setting guidelines

The parameters for instantaneous phase overcurrent protection PHPIOC are set via
the local HMI or PCM600.
This protection function must operate only in a selective way. So check all system
and transient conditions that could cause its unwanted operation.
Only detailed network studies can determine the operating conditions under which
the highest possible fault current is expected on the line. In most cases, this current
appears during two-phase fault conditions. But also examine single-phase-to-earth
condition.
Also study transients that could cause a high increase of the line current for short
times. A typical example is a line with a power transformer at the remote end,
which can cause high inrush current when connected to the network and can thus
also cause the operation of the built-in, instantaneous, overcurrent protection.
Common base IED values for primary current (IBase), primary voltage (UBase)
and primary power (SBase) are set in the global base values for settings function
GBASVAL.
GlobalBaseSel: This is used to select GBASVAL function for reference of base
values.
Operation: Set the protection to On/Off.
IP>>: Set operate current in % of IB.
IP>>Max and IP>>Min should only be changed if remote setting of operation
current level, IP>>, is used. The limits are used for decreasing the used range of
the IP>> setting. If IP>> is set outside IP>>Max and IP>>Min, the closest of the
limits to IP>> is used by the function. If IP>>Max is smaller than IP>>Min, the
limits are swapped.
IP>>MinEd2Set: Minimum settable operate phase current level in % of IBase, for
IEC 61850 Ed. 2 settings.
IP>>MaxEd2Set: Maximum settable operate phase current level in % of IBase, for
IEC 61850 Ed. 2 settings.

Meshed network without parallel line

The following fault calculations have to be done for two-phase and single-phase-
to-earth faults. With reference to Figure 47, apply a fault in B and then calculate
the through-fault phase current I
minimum source impedance values for Z
values for Z in order to get the maximum through fault current from A to B.
B
. The calculation should be done using the
fB
and the maximum source impedance
A
Railway application RER670 2.2 IEC
1MRK 506 375-UEN A
IP14979-1 v1
M12915-4 v9
M12915-9 v8
Application manual