Control and protection system ABB has its own powerful, flexible and reliable control and protection system which uses state-of-the-art computers microcontrollers and digital signal processors connected by high-performance industrial standard buses and fiber-optic communication links. The system is called MACH (Modular Advanced Control for HVDC and SVC) and is designed specifically for converters in power applications. All critical parts of the system have inherent parallel redundancy and use the same switch over principles that have been used by ABB for HVDC app cations since the 1980s.