A properly designed stand-alone surge suppressor should have a design topology that includes a 'Positive Shutdown Circuit'. This is basicly an internal testing circuit that will disconnect the load in the event that a surge enters the device that is beyond the capacity of the surge suppression circuit. This is a specific equipment protection feature. Our ZX-5000 Surge Suppressors have a 'Positive Shutdown Circuit'. If a critical surge circuit component fails, or if a surge enters the device that is beyond it's suppression capability, the ZX-5000 Surge Suppressor's protected load will be disconnected.
Electrical surges are by far the most destructive electrical event.
Our UPS systems have many safeguards built-in to protect the UPS and to protect your equipment from a surge event, including the most substantial surge circuit in the industry today. From the description of the electrical events, it sounds like your UPS has been exposed to frequent brownouts and follow-on surges. This is one reason why I do not recommend the use of a Standby stepped wave UPS for use in areas where frequent brownouts are likely. The Standby stepped wave UPS units are the cheapest ones available, but not the best buy, in my opinion. The battery sub-stage is also very reliable, and likely to last 5 years or more.