How DPA (Decentralised Parallel Architecture) provides high availability

The DPA technology available from UPS Ltd is an advanced parallel redundant architecture which has been in successful operation for nearly ten years. It has proven to be of very high reliability and resilience.

Every UPS module in a DPA system has its own independent Parallel Control Logic and Parallel Regulation Logic as well as its own static switch. This decentralisation removes all single points of failure from the UPS configuration, making it a highly reliable solution. The Parallel Control Logic supervises the operation of all the parallel UPS modules, of which one is the Master while the remainder are Slaves. If one develops a fault then it is automatically isolated from the critical load. This load can then be shared by the remaining healthy modules, provided the UPS system was configured for redundancy. If the failed module was the Master then the next module in line switches from Slave to Master mode until the original Master is restored.

If the critical load is too great for the remaining modules and the system is synchronised, then all of the modules, including the faulty one, will transfer their load to the standby mains using their internal static switches. If the system is not synchronised, the UPS modules will not transfer; instead they will attempt to support the overload for as long as possible before shutting down to protect themselves.

The Parallel Regulation Logic provides a load sharing function. Perfect load sharing is maintained so that each module inverter supplies the same amount of current to the load. This eliminates currents circulating between the inverters.

The PowerWAVE 9000DPA Series modules feature hot swappability as part of their DPA architecture. This means that modules can be removed from or added to the 9000DPA rack without switching to bypass or interrupting power to the load. Recent developments in DPA technology have increased the number of DPA modules or cabinets that can be paralleled together, with configurations of up to ten DPA modules now possible.