/usr/lib/linux-tools/4.15.0-30-lowlatency/cpupower is in linux-tools-4.15.0-30-lowlatency 4.15.0-30.32~16.04.1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/linux-tools/4.15.0-30-lowlatency/../../linux-hwe-tools-4.15.0-30/cpupower