First of all install required package for running ppc:
sudo zypper install qemu-ppc
Download the ISO built for PowerPC architecture (ppc64le). E.g. openSUSE-Leap-42.3-NET-ppc64le-Build0130-Media.iso.
Create file which will contain disk image:
qemu-img create suse.img 10G
Now, start the ppc64le virtual and boot from cdrom:
qemu-system-ppc64 -boot d -cdrom openSUSE-Leap-42.3-NET-ppc64le-Build0130-Media.iso -m 1024 -hda suse.img
After the installation you can simply run the installed system:
qemu-system-ppc64 -m 1024 -hda suse.img
Note: -m 1024 stands for “memory 1 GB”