The PLAN currently only operates 2 modern ships (052) with towed VDS sonar of French origin. There has been no other modern PLAN ships with towed sonar that I'm aware of, except for Jianghu-IV with SJD-7 VDS. From the photos avail, I don't think the 054A has aft deck space allocated for ASW equipment. But that's just my unprofessional opinion.
To improve its ASW capability, the PLAN could reverse-engineer the DUBV-43 (ESS-1), or import towed sonar from Russia. If we look at the latest 1,900 ton Russian ASW Corvette, Project 20380 Stereguschyy, the ship is equipped with 2x4 P-800 Yakhont AshM, hull mounted sonar, towed sonar array, "anti-diver sonar system", ASW helicopter, and a 6-cel Medvedka-VE (RPK-9) system:
If you look at the aft photo of the ship, there's a big hole where towed sonar equipment will go. The Russian navy has ordered 4 of these ships. The PLAN could import the same Russian towed sonar equipment.
The Medvedka-VE is an improved, VLS version of the old RPK-9:
The older system resemble quad-tube torpedo launchers. I don't have specs for the new system, but the old one is listed as 12,000 kg for 4-tube and 19,400 kg for 8-tube system. Each missile weights 800kg and is 5.5 meters long and 400mm in diameter. The RPK-9 (SS-N-29) ASW missile has range to 20km, which is a bit short, but the system can be easily bolted onto existing ship's deck. The newer VLS system might have improved range and performance.
The primary Russian navy long-range ASW missile is still the RPK-6 Vodopod (SS-N-16), with claimed range up to 100km-120km:
This is a much larger and heavier missile, said to be 6.5 meters in length, 650mm diameter, and 2,150 kg weight. Heavier than the Chinese C-803 or YJ-62, but still lighter than the P-800 Oniks/Yakhont (3,000 kg) AShM. The latest 91RE2 (Klub-N) ASW missile is lighter at 1,300 kg, but with shorter range at 40km.
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If I were modernizing PLAN's fleet for better ASW capability, I'd import the following systems from Russia:
* UDAV-1 ASW system
* RPK-9 short-range ASW missile
* 91RE2 (Klub-N) medium-range ASW Missile
* RPK-6 long-range ASW missile
* Bow/hull/towed/VDS sonar & technology
The UDAV-1 ASW system includes dept charge rockets, anti-torpedo proximity mine rockets (torpedo defense), and acoustic decoy rockets. If the PLAN already has something just as good, then imports is not necessary. This system is used as a last-ditch defense against submarines and torpedos.
The RPK-9 short-range ASW missile can be equipped on small sub chasers, or refit to existing ships to add better ASW capability.
The 91RE2 ASW missile will be the standard ASW missile on ASW Frigates. They could also be added as a refit on existing ships, replacing some AShM's.
The RPK-6 is quite large and would prolly only be used on a new class of ASW Destroyers, should the PLAN decide to build them.