It depends on the specific device you have. If it’s a Z-Wave power outlet, then typically they have configuration parameters that control the reporting interval and (power delta) reporting threshold, which you would want to tweak. Check your product manual.
Changing the parameters would need to be supported by the device handler you’re using though. If not, you could try my Z-Wave Tweaker tool. However, if you’re using the official SmartThings power outlet, I think it’s actually a Zigbee device, so what I’ve said won’t apply.