Strengthened Assembly is a technology in Clone Campaigns that can be researched at the Power Core in Tech Level 3. It costs 150 Carbon and 50 Ore, and gives +200 Hit Points to Power Cores and +40 Hit Points to Power Droids.
This technology makes Power Cores far more sturdy, particularly if combined with Power Core Shielding, or if the Power Core is located near a Shield Generator. This will make it harder for enemy strikes to deprive the player's buildings of power in order to slow down unit production.
"This Tech Level 3 technology makes your Power Cores considerably tougher, rendering them much more difficult to destroy. Strengthened Assembly also makes all your Power Droids more durable."
—Manual description