Functional Diagrams; Functional Diagrams For Protection - ABB RELION 615 Series Applications Manual

Section 3
REG615 standard configurations
3.4.3
3.4.3.1
72

Functional diagrams

The functional diagrams describe the default input, output, alarm LED and function-
to-function connections. The default connections can be viewed and changed with
PCM600 according to the application requirements.
The analog channels have fixed connections to the different function blocks inside the
protection relay's standard configuration. However, the 12 analog channels available
for the disturbance recorder function are freely selectable as a part of the disturbance
recorder's parameter settings.
The phase currents to the protection relay are fed from a current transformer. It is
assumed that the core balance CT is provided both on line and neutral side of the
generator and are connected such that the differential residual current is fed to the
protection relay.
The terminal side phase voltages to the protection relay are fed from a voltage
transformer. The residual voltage to the protection relay is fed from either residually
connected VTs, an open delta connected VT or internally calculated.
The protection relay offers six different setting groups which can be set based on
individual needs. Each group can be activated or deactivated using the setting group
settings available in the protection relay.
Depending on the communication protocol the required function block needs to be
instantiated in the configuration. The Application Configuration tool also includes
fixed Boolean signals TRUE and FALSE which can be used according to the
application needs.

Functional diagrams for protection

The functional diagrams describe the protection functionality of the relay in detail and
according to the factory set default connections.
Three non-directional overcurrent stages are offered for detecting phase faults in
generators. In addition to overcurrent stages, one instance of voltage dependent
overcurrent protection is also provided which can be used as a backup protection
against phase faults. During certain conditions, fault current for three phase faults may
be less than full load current of the generator. This may not get noticed by phase
overcurrent protection, but the fault will cause generator terminal voltage to drop.
Voltage dependent overcurrent protection can be used to detect and operate such
faults.
1MRS758272 B
REG615
Application Manual