Toshiba GR200 Series Instruction Manual page 33

transient power system conditions, while the OST element initiates system separation by
tripping in the event that a severe power swing results in potentially irrecoverable loss of
stability in the power system. The PSB and OST elements are therefore completely separate
functions within the relay, with different characteristics, separate scheme logic and different
settings.
Concepts of carrier command protection (DISCAR/DEFCAR) function
1.1.6
DISCAR Command protection by the distance (ZS/ZG) protection
(i)
If information picked up in the distance protection (ZS/ZG) function located at the ends of the
protected line are exchanged mutually by means of the telecommunication, it is possible to
determine accurately whether a fault occurs within the protecting zone or not. Consequently,
at each ends, the trip command can be issued faster. The GR200 series can provide the
following carrier command schemes using the elements of the ZS/ZG function.
• Permissive underreach protection (PUP)
• Permissive overreach protection (POP)
• Unblocking overreach protection (UOP)
• Blocking overreach protection (BOP)
DEFCAR command protection by the earth fault (EF) protection
(ii)
Like in the DISCAR function, the DEFCAR function is designed to operate using the
directional characteristic of the earth fault protection (EF) function. The DEFCAR function
can provide the following carrier command schemes:
• Permissive overreach protection (POP)
• Unblocking overreach protection (UOP)
• Blocking overreach protection (BOP)
Operation with autoreclosing (ARC)
(iii)
The user should notice that the operation in respective command protections initiate the
operation of the autoreclose (ARC) for the circuit breaker very fast.
Tripping CB by the protection functions
1.1.7
After issuing the trip commands by the protection functions, the trip commands are grouped
within the trip circuit (TRC) function; then, the TRC function drives the binary output circuits
within the relay for transferring the trip commands to the CB. The TRC function can operate
for tripping single-pole or multi-poles. Before the protection functions is reset, the auxiliary
contacts of the CB must be derived to open; this is because, the protection function cannot
interrupt straightforward the current flowing on the tripping coil circuit of the CB.
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6F2S1914 (0.49)
GRL200 (Soft 033 & 037)