This is the 8961st most frequent Japanese word.
永続
"永続" means "permanence" or "continuity."
永続的 in this sentence means 'continuous or permanent' in describing the nature of the system's operation.
このシステムは永続的な運用が可能です。
This system is capable of continuous operation.
永続する here means 'everlasting or enduring,' describing the enduring nature of love.
永続する愛を信じています。
I believe in everlasting love.
永続させた means 'sustained,' referring to an action enabling the continuation of success.