145
6
F
2
S
0
8
5
0
Long Time Inverse
t = T
×
120
(I/Is)
−
1
Standard Inverse
t = T
×
0.14
(I/Is)
0.02
−
1
Very Inverse
t = T
×
13.5
(I/Is)
−
1
Extremely Inverse
t = T
×
80
(I/Is)
2
−
1
where,
t = operating time
I = fault current
Is = current setting
T = time multiplier setting
2.16.7 Thermal Overload Element
Thermal overload element operates according to the characteristics defined in IEC60255-8. (Refer
to Figure 2.6.1 and Appendix P.)
2.16.8 Out-of-Step Element OST
The OST element detects the out-of-step by checking that the voltage phasor VB of the remote
terminal transits from the second quadrant (
α
-zone) to the third quadrant (
β
-zone) or vice versa
when the voltage phasor VA of the local terminal is taken as a reference.
Figure 2.16.8.1 Out-of-Step Element
VB is further required to stay at each quadrant for a set time (1.5 cycles) to avoid the influence of
any VT transient.
Positive phase voltages are used and valid for VA and VB when their amplitudes are larger than
1V.
α
-zone
VB
β
-zone
1V
VA
www
. ElectricalPartManuals
. com
Summary of Contents for GRL100-701B
Page 329: ... 328 6 F 2 S 0 8 5 0 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 339: ... 338 6 F 2 S 0 8 5 0 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 351: ... 350 6 F 2 S 0 8 5 0 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 381: ... 380 6 F 2 S 0 8 5 0 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 413: ... 412 6 F 2 S 0 8 5 0 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 417: ... 416 6 F 2 S 0 8 5 0 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 453: ... 452 6 F 2 S 0 8 5 0 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 457: ... 456 6 F 2 S 0 8 5 0 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Page 473: ...w w w E l e c t r i c a l P a r t M a n u a l s c o m ...