The 30th Army was a military formation of the People's Volunteer Army (Chinese People's Volunteers (CPV) or Chinese Communist Forces (CCF)) during the Korean War.
The 30th Army consisted of the 88th, 89th, 94th Divisions. It appears that the 30th Army did not fight in the Korean War as a unit though, as its Divisions were assigned to augment the 20th, 26th, and 27th Armies.
References
30th Army (People's Republic of China) Wikipedia(Text) CC BY-SA