For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/KDE:Frameworks5:LTS/openSUSE_Tumbleweed/KDE:Frameworks5:LTS.repo
zypper refresh
zypper install plasma5-openSUSE
For openSUSE Leap 42.3 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/KDE:Frameworks5:LTS/openSUSE_Leap_42.3/KDE:Frameworks5:LTS.repo
zypper refresh
zypper install plasma5-openSUSE
For openSUSE Leap 42.2 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/KDE:Frameworks5:LTS/openSUSE_Leap_42.2/KDE:Frameworks5:LTS.repo
zypper refresh
zypper install plasma5-openSUSE
For KDE Qt56 openSUSE Leap 42.1 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/KDE:Frameworks5:LTS/KDE_Qt56_openSUSE_Leap_42.1/KDE:Frameworks5:LTS.repo
zypper refresh
zypper install plasma5-openSUSE