It's not uncommon for this to happen The key is timing and your abilities
When under Tractor Beam, Viral Matrix/Photonic Shockwave, THEN 3 Heavy Plasma Torpedoes hit you... it's a near guarenteed KO, even at higher ship tiers.
Even so, there are a number of ways to prevent this.
First is distance. Tractor Beam can only be done within 5K, while Viral Matrix can only be done within 7K (and Photonic Shockwave only reaches 3K, I think). If you keep your distance, you can focus on the torpedoes.
Polarize Hull negates Tractor Beam, and gives you Damage Resistance (which will help you survive). Eng Team gets rid of Viral Matrix, while Photonic Shockwave can't be guarded against (but it's disable is brief). Beam: Fire At Will and Cannon: Scatter Volley can also work against the torpedoes
Plus, Gravity Well does great work of dispatching them
But if you can't avoid being hit, hit every single Damage resistance ability you have before impact (Transfer Shield Strength, Hazard Emitters, Emergency Power to Shields, etc), plus any other helpful abilities like Tac Team. The stronger your resistance, the less damage it'll do.
Last post missed Brace for Impact. Big one, there, on normal you should be able to survive them comfortably with brace for impact and emergency power to shields. On advanced in an escort I've managed to eat all three torpedoes with a a couple extra buffs (the subspace field modulator from the Devidian episodes helps here, too), though I wouldn't recommend trying on elite.
I jsut hat ethe fact that warbirds can shoot off not 1 but 3 Heavy Plsma Torps....and we can't..even as part of a set bonus..like the reman set perhaps...would actually make it worth my time to collect all the data logs and get something better than a +15% passive plasma HYT damage increase.
dont use them until the ship tractors you and fires the three heavy plasma.
voila. you're safe from this tactic.
Usually. Don't get me wrong, I use this method myself, but it's not entirely foolproof - if the warbird zaps you with Viral Matrix prior to the tractor beam, it's possible to have your Auxiliary abilities - including Repulsors - offline when you need 'em.
Beam Fire at Will, assuming a beam build, will help if this happens. But it's not 100% guaranteed to hit all three torps before they impact so a proper AoE like Repulsors is better, just don't expect it to always save you.
A photonic shockwave of your own will also destroy the heavy torps, as will Gravity Well. If you can manage to position it in their flight path, Eject Warp Plasma also stops them but I wouldn't want to rely on that!
I had real trouble with the named warbirds in the Romulan campaign until I switched to these tactics, even on Normal. Now on Advanced, it's very rare for me to die to a warbird (usually only if the mission lets them get the drop on you).