The fear that conditioning will kill your strength keeps a lot of powerlifters from doing any. The reality is that conditioning and strength can live together, and a lifter with some conditioning is usually a better lifter. The trick is balancing them so each supports the other instead of competing.
Strength Comes First
Be clear about your priority. You are a powerlifter, so strength is the main job and conditioning is the support. That means your heavy lifting gets the best of your energy and recovery, and conditioning fits around it. Never let conditioning leave you too tired or sore to attack your main lifts. When you have to choose, the heavy work wins.
Separate the Hard Efforts
The biggest key to balancing them is not stacking hard conditioning on top of hard lifting for the same muscles. Keep intense conditioning away from your heavy lower body days so your legs get to recover. Put easy steady cardio on rest days or after upper body work where it does no harm. Spreading the hard efforts out lets you do both without one burying the other.
Match the Dose to the Season
How much conditioning you do should shift with your training. In the off-season, when you are building, you can carry more conditioning and use it to build work capacity and stay lean. As a meet approaches and strength becomes the whole focus, pull the conditioning back so your recovery goes toward peaking. The balance is not fixed, it moves with your goals.
Keep strength first, separate your hard efforts, and adjust the conditioning dose to the season. Done that way, conditioning makes you a healthier, better recovered, more capable lifter instead of a threat to your numbers.