Rated switching sequence according to IEC, O – t – CO – t’ – CO. (cf. opposite diagram):
O – Represents opening operation
CO – Represents closing operation followed immediately by an opening operation
Three rated operating sequences exist:
- Slow: O – 3 min – CO – 3 min – CO
- Fast 1: O – 0.3 s – CO – 3 min – CO
- Fast 2: O – 0.3 s – CO – 15 s – CO
NOTE: Other sequences can be requested from manufacturer.
Close/Open cycle
Assumption: O order as soon as the circuit breaker is closed

.
.
Automatic reclosing cycle
Assumption: C order as soon as the circuit breaker is open, (with time delay to achieve 0.3 s or 15 s or 3 min).

SOURCE: Schneider Electric – Medium Voltage Technical Guide
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Edvard Csanyi
Hi, I'm an electrical engineer, programmer and founder of EEP - Electrical Engineering Portal. I worked twelve years at Schneider Electric in the position of technical support for low- and medium-voltage projects and the design of busbar trunking systems.I'm highly specialized in the design of LV/MV switchgear and low-voltage, high-power busbar trunking (<6300A) in substations, commercial buildings and industry facilities. I'm also a professional in AutoCAD programming.
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Which on is better for 4000A ACB (Main LT Panel)
Please can you share with me the short circuit calculation guide for the protection relays
Thank you
Hello Sir!
Please explain Auxiliary Contacts State (OW-OD-C) what mean by (OW, OD).
Also help how ti analysis of timing graph of High voltage Breakers.
Thanks!
Hello Sir,
We have this rated operating sequence O-0.3s-CO-3min-CO VCB but our available unit have this rated operating sequence O-0.3s-CO-15s-CO.
Is it OK to use?
Please help.
Thank you.
I suppose,
Requirement is O-0.3s-CO-3min-CO. And available VCB is O-0.3s-CO-15s-CO.
15s VCB is suitable for autoreclosing application while 3 min VCB can’t.
Although 15s VCB can be used in place of 3 min VCB with suitable delay timer in circuit of breaker.
I hope it is the answer of your question.
Regards
Kamal
The article is quite not clear, i want a detailed explanation on this and where could i find articles or features or details about VCB’s. pls help
Try here: http://bit.ly/ZfTVfx Scroll down to title ‘Operating sequences and requirements’.
Hope this helps!