Application; Setting Guidelines - ABB Relion 670 Series Applications Manual

Section 7
Current protection
7.11.2

Application

In a breaker-and-a-half switchyard the line protection and the busbar protection normally have
overlap when a connected object is in service. When an object is taken out of service it is normally
required to keep the diagonal of the breaker-and-a-half switchyard in operation. This is done by
opening the disconnector to the protected object. This will, however, disable the normal object
protection (for example the distance protection) of the energized part between the circuit
breakers and the open disconnector.
Stub protection STBPTOC (50STB) is a simple phase overcurrent protection, fed from the two
current transformer groups feeding the object taken out of service. The stub protection is only
activated when the disconnector of the object is open. STBPTOC (50STB) enables fast fault
clearance of faults at the section between the CTs and the open disconnector.
ANSI05000465 V2 EN-US
Figure 82: Typical connection for STBPTOC (50STB) in breaker-and-a-half arrangement.
7.11.3

Setting guidelines

The parameters for Stub protection STBPTOC (50STB) are set via the local HMI or PCM600.
The following settings can be done for the stub protection.
GlobalBaseSel : Selects the global base value group used by the function to define ( IBase ), ( VBase )
and ( SBase ).
Operation : Disabled / Enabled
EnableMode : This parameter can be set Enable or Continuous . With the Enable setting the function
is only active when a binary release signal ENABLE into the function is activated. This signal is
normally taken from an auxiliary contact (normally closed) of the line disconnector and connected
to a binary input ENABLE of the IED. With the setting
independent of presence of any external release signal.
176
Continuous the function is activated
1MRK 511 358-UUS A
M12904-3 v5
M12909-3 v5
Application manual