Ablation Monitoring - Hitachi Relion 650 Series Technical Manual

Section 12
Monitoring
The arcing time extension is limited by MaxReStrikeCorr or MaxArcTime whichever is reached first.
The extension value for the target arcing time is given as output ADAPTOPLX and also added to the
predicted electrical operating time and predicted arcing time in the next controlled opening operation.
12.18.7.14

Ablation monitoring

During CB opening, plasma from switching arcs in the circuit breaker will erode both the metallic
contacts and the teflon nozzles of the interrupter. This process is called interrupter wear or contact
ablation in the document.
Figure 141
and to endure 10000 mechanical operation cycles. For every value of interrupted current, the graph
tells how many operations at that current the CB can perform before the interrupter needs overhaul.
It is divided into three parts:
• Interruptions of low currents below IntTh1 are considered mechanical operations.
• Interruption of higher currents (between IntTh1 and IntTh2) causes non-negligible ablation,
which reduces the number of remaining operations till end of life.
• Currents beyond the IntTh2 limit should never occur in service, as they exceed the equipment
rating and may lead to CB failure.
IEC19000922 V1 EN-US
Figure 141: Example of electrical life curve of a circuit breaker
306
shows a typical electrical life curve of a circuit breaker rated to interrupt maximum 63 kA
© 2021 Hitachi Energy. All rights reserved.
1MRK 511 557-UEN Rev. A
GUID-15EA8332-353C-45B7-B9DF-8C605EF31150 v3
1EC19000922-2-en.vsdx
Technical Manual