Toshiba GR200 Series - 2.29.4 Multi-level overcurrent elements (OCMFS); (i) Characteristic of OCMFS

6F2S1914 (0.49)
GRL200 (Soft 033 & 037)
- 361 -
2.29.4 Multi-level overcurrent elements (OCMFS)
(i) Characteristic of OCMFS
A current fluctuates when there is a condition about out of step, so the function of multi-level
overcurrent elements (OCMFS) is provided in the FS function. That function includes seven
detectors placed at seven multiple levels.
I
0
LD1
LD2
LD3
LD4
LD5
LD6
LD7
D.O./P.U.=0.8
Figure 2.29-2 OCMF characteristics
Figure 2.29-2 illustrates that that OCMFS includes those current level detectors (LDs).
Table 2.29-2 shows a detector threshold between operating and resetting is fixed in each LD.
LD element starts operating if the current exceeds its operating threshold, and the LD will
reset its operation when the current is below 80% of the operating threshold.