052D air defence is quite weak actually:
-Can only intercept fighter jet upto 150km.
-Can only intercept AshM upto 70km, if the missile is sea skimming, then the interception range is shorter!
- Su-30MK2 can track a big ship like 052D from over 150km away when flying high.
- The Su-30MK2 can guide missiles to the target from over 150KM away.
- When missiles like the KH-35 approaches near 60km of the target, it switches it's active radar on to home into the target.
-This means the Su-30MK2 and Molniya has a safe standoff range to fire their missiles.
- With its air search and targeting radar off (it can use Su-30 radar), the small Molniya is nearly invisible from 052D's radar when >130KM away.
-If fired in a salvo of +16 (or 32) sea-skimming missiles, the 052D will have a very hard time.
The only defence against Su-30MK2 and Molniya are fighters, not the 052D.
But the Spratlys are far away from Chinese airbases. And the SCS is huge, it will be very expensive and hard work for PLAAF to give full air coverage 24/7 over the Spratlys area.
But China can use their ballistic missiles to take out the Viet airbases and naval ports.
So how VN gonna use their Su-30MK2 and Molniya then?