Connections; 1.Protection Signal Routing; 2.Indication And Control Connections; Implementations - ABB REX 521 Technical Reference Manual, Standard Configurations

REX 521
11.1.4.
11.1.4.1.
11.1.4.2.
11.1.5.
11.1.5.1.
170
Protection Relay
Technical Reference Manual, Standard Configurations
∆
• U< dU setting
∆
• f< df setting
∆
ϕ< dphi setting
•
Before the function block allows the CB closing, it ensures that the phase difference
will remain within the setting range until the CB closes.
The command mode is used as a basic control principle of the synchro-check
function. In command mode, the synchro-check function directly uses the output
signal to close the circuit breaker. The close command e.g. from the HMI is
connected to the synchro-check function. When the close command is activated, the
synchro-check function checks the closing criteria and if they are fulfilled, it will
route the command to the output relay of the protection relay. In this application
example the close signal is connected to the power output PO3.
The command mode principle means that the interlocking logic related to the control
functionality will affect the synchro-check function as well. If blocking is needed it
can be carried out by using the ready-made interlocking logic, e.g. in a case where
the phase-to-phase voltage is missing from either side of the circuit breaker because
of the open miniature circuit breaker (MCB) of the measurement circuit.

Connections

All the necessary settings for the connections and signal routings can be set via the
Relay Setting Tool or the local HMI.
Protection signal routing
The settings for the protection signal routing can be implemented as described in the
second application example (chapter 9.2.). In this application two different trip
signals are used: Trip 1 for opening of the circuit breaker of the incoming feeder and
Trip 2 for opening of the circuit breaker of the transformer feeder. In this application
separate power output relays are used for Trip 2 and CBFP (circuit breaker failure
protection) function.
Indication and control connections
The connections for indication and control can be implemented as described in first
application example (chapter 9.1.), except the signals for the open and close buttons
that in this example are disconnected. Local control can be executed by HMI
according to the instructions in Operator's Manual (1MRS 751107-MUM).

Implementations

In the sections below a few implementation examples for the standard configuration
H01 are presented.

Blocking principles

The blocking principles presented in the application example 11.2. are applicable,
but different overcurrent protection stages have been used.
1MRS 751802-MUM