202
1MRS751802-MUM
Protection Relay
Technical Reference Manual, Standard Configurations
REX 521
• In cases “Live-Dead”, “Dead-Live” and “Dead-Dead” no other conditions are
checked.
• In the case “Live-Live” also the following must be fulfilled:
•
∆
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 for example 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, for example 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.
11.1.4.
Connections
All the necessary settings for the connections and signal routings can be set via the
Relay Setting Tool or the local HMI.
11.1.4.1.
Protection signal routing
The settings for the protection signal routing can be implemented as described in the
second application example (see Section 9.2. Incoming feeder, Basic B01). 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.
11.1.4.2.
Indication and control connections
The connections for indication and control can be implemented as described in first
application example (see Section 9.1. Outgoing feeder, Basic B01), 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
REX 521 Operator’s
Manual
(see Section 1.5. Related documents).
11.1.5.
Implementations
In the sections below a few implementation examples for the standard configuration
H01 are presented.
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