Insulating Base for High Voltage Surge Arrester

Study creepage and clearance distance.

You can't.

You will need to hire an experienced designer. How will you ever get it insured if it is designed by an unqualified person such as yourself?

Augmenting the correct views of unredundant and lynlynch...

• What is the voltage level, nominal and peak, that you DON'T want the arrestor to work ?
• What are the minimum and maximum clamping voltage levels?
• What is the surge energy in Joules that needs to be handled?
• Is the surge arrestor based on open sparkgap, silicon carbide, metal oxide....what?

• What is the voltage level, nominal and peak, that you DON'T want the arrestor to work ?

Vnominal=198kV, Vmax=245vK

• What are the minimum and maximum clamping voltage levels?

Vclamping=494kV (8/20us-20kA)

• What is the surge energy in Joules that needs to be handled?

10.8kJ/kV

• Is the surge arrestor based on open sparkgap, silicon carbide, metal oxide....what?

ZnO, GAPLESS

Wow, that is very detailed and precise. i now hope that some real experts will help you. Good luck.

i expect you are already having lots of data, however, please check out the ABB link : abb XPS.pdf

An image of the 240kV version... (H = 2.8 m)

The only rational reason for inserting an insulating sub-base between the base of the arrester and ground is to ground the arrester through a discharge counter (to count the number of arrester operations) or, to monitor grading current (which may or may not be accurate). If the arrester housing is wet or contaminated, both external leakage and internal grading currents will flow through the milliammeter which I suppose could be used to determine when the arrester housing is contaminated and should be cleaned to prevent external contamination flashover.

All major arrester manufacturers have different types of insulating sub-bases for their arresters available. Take a look at one or more of them. Discharge counters are available with and without grading current meters.