5 Topic: Reclosers (15m)
Instructions:
- Cover the following content as a group (either reading out loud or independently) then give an opportunity to answer any questions.
- Have students do the review questions independently, then take up answers.
Reclosers are sometimes referred to as an OCR (oil circuit recloser), Intellirupters, or NOVAS. Reclosers are used in both single phase as well as three phase applications . They are designed to shut a line off that is seeing a permanent fault automatically based on an overcurrent event.
A permanent fault is caused by a primary powerline coming into contact with a direct path to ground that cannot be cleared, that in turn causes the recloser to operate. Permanent faults may be caused by equipment failure due to storms, animals that come into contact with primary voltage equipment that provide a path to ground and short out the equipment as well as various other reasons. Reclosers are also designed to clear temporary faults.
For example, if a small tree branch comes into contact with an energized line the OCR would see that fault, trip off momentarily, and if the branch had burnt clear of the energized line, would re-energize, and stay on. If a permanent fault has occurred, after repairs have been made, reclosers can be closed either manually or if equipped, remotely.
Review Questions: Reclosers (15m)
1. ( True / False ) Reclosers clear permanent faults.
2. ( True / False) Reclosers isolate temporary faults.
3. ( True / False) Reclosers can only be operated manually.
4. ( True / False) Animals can cause an OCR to operate.
5. ( True / False) Storm damages can cause an OCR to operate.
Answer Key
- F
- F
- F
- T
- T