GE LPS-O Instruction Manual page 66

2.3 PROTECTION SETTINGS
2
1401: USE_OST - Select OST
Set USE_OST = YES if out-of-step tripping is to be used, otherwise set USE_OST = NO.
1402: NUMBRCHAR - Select Number Of Characteristics
Depending on the application, it may not be possible to use all three of the characteristics, and the MIDDLE
characteristic must be bypassed. If only two characteristics are to be used (MIDDLE characteristic bypassed),
set NUMBRCHAR = 2, otherwise set NUMBRCHAR = 3.
1403: TRIPIN_OUT - Trip Enter Or Leaving Inner
The OST function can be set so that tripping will be initiated shortly after the impedance enters the inner char-
acteristic (pickup time of TLOS3), or it can be set to trip shortly after the swing leaves the outer characteristic
(dropout time of TLOS1). This setting is determined by the capability of the breakers used in the power system:
1. If the circuit breaker is capable of interrupting when the systems are approximately 180° apart (around
twice voltage across the breaker contacts) set TRIPIN_OUT = IN.
2. If the circuit breaker is not capable of interrupting when the systems are nearly 180° apart, set
TRIPIN_OUT = OUT.
1404: FWDREACH - OST Forward Reach
For the simple system shown above in Figure 2–13: OST REACH CHARACTERISTIC, set the forward reach
long enough to include the line plus the source at the remote end of the line; that is,
FWDREACH > Zb + Zc
1405: REVREACH: - OST Reverse Reach
For the system shown above in Figure 2–13: OST REACH CHARACTERISTIC, set the reverse reach to
include the source behind the LPS-O system; that is,
REVREACH > Za
2-
26
Za Zb
LPS-O
X
Zf
Zc
Zb
C
B
Zr
Za
Figure 2-3
Figure 2–13: OST REACH CHARACTERISTIC
LPS-O Line Protection System
2 CALCULATION OF SETTINGS
Zc
A
Zload
D
R
GE Power Management