A New Control Method for Multiterminal HVDC Transmission Without Fast Communications Systems

A new control scheme (the 2-ACR method) for parallel multiterminal HVDC systems is proposed. The method does not require fast communication systems. Any terminal can be disconnected or connected to the system without power re-coordination, since a new stable operating point can be always determined automatically by control actions of each converter with two automatic current regulators and one constant voltage controller. A light duty dc circuit breaker can disconnect a fault line, and the remaining terminals can restore transmission power as fast as possible. The excellent performance of the proposed scheme has been demonstrated by digital simulations using EMTP.