The starbase is so strong that it kills all my fleet when i tried to follow the above steps. So, i may try killing the Starbase first with more Ogrov with more support ships. Presently, i have not set a fleet. I think a mixed fleet of bombers, support and capital ships may help..
Goa answered this correctly. Bombers is the best bet to kill a starbase, just remember if they have fighters which the AI typically does you can't go ALL bombers or they eventually wear down you bomber fleet.
There was a section at the end of that post detailing what works. A large mixed fleet can also brute force most starbases down as you discovered.
What kills starbases?
Vasari Star base ****
TEC Ogrov Torpedo Cruisers (with fighter/flak support) ***
Kortul (lvl 3+ with fighter/bomber support, against lower level star bases) **
Heavy Cruisers (works well against lower level star bases) **
LRM (works ok against lower level or deploying star bases) **
LF (works ok against deploying star bases or low level star bases with low hull) *
Advent Adjudicators (sorta, very weak and meant to attack multiple targets) *
You may be tempted to send your fleet directly against a star base. Don’t do it unless it is deploying or for the final kill! Don’t be the AI and suicide your fleet against it. Your also only helping to level up his capital ship by needlessly sacrificing LF/LRF. This also goes for your bombers, if his fighters outnumber your bombers don’t provide him the experience. Work for the upper hand first.
IMO Carriers and some flak should be your first priority against a star base. However, if they are using their defensive capabilities this may be more difficult than planned!