Busbar Protection

Question 1

What is ARC protection

Answer 1

3 Flash light sensors at the CB, Termination, and BB chamber to protect from flashover

Question 2

33kV panels with ARC protection

Answer 2

ABB
Siemens
Energoinvest
GEC Alstom
Tamco
Merlin Gerin
Koncar

Question 3

Operation considerations of ARC protection switchgear

Answer 3

Inadvertent operation during earth switch closing so arc prot. to be kept out by DPM

Question 4

Principle of VEM ARC Protection

Answer 4

• Mechanical protection
• 3 limit switches at Termination, BB chamber, and CB compartment
• Limit switch operated by pressure

Question 5

Differential principle in BB protection

Answer 5

Kirchhoff’s current law (comparing vector sum of current entering and leaving)
The difference is the magnitude of the fault current

Question 6

Zone Protection in Busbar

Answer 6

Discriminating Zone
Check Zone

Question 7

Features of Discriminating Zone

Answer 7

One zone per busbar
Each feeder has a separate CT
Checks vector sum of entering and leaving

Question 8

Features of check zone

Answer 8

One for the whole busbar
Each feeder has a separate CT
Used to avoid unwanted tripping

Question 9

When does the Busbar Trip?

Answer 9

When signal is received from both discriminating and check zone

Question 10

What are the Mechanical Relays in the Network?

Answer 10

Buchholz
Oil Temp.
Winding Temp.
PRV

Question 11

What are the Electrical Relays in the network?

Answer 11

OC
EF
REF
SBEF
PWP
DIFFERENTIAL RELAY
ARC PROTECTION
SEF
CHECK ZONE
DISCRIMINATING ZONE