Parallel Operation of Nelson River HVDC Bipoles 1 and 2 Control System - Simulator Studies

The paper describes the control and protection system provided in the Nelson River HVDC scheme for paralleling, parallel operation, and deparalleling of Bipoles 1 and 2. The distance between the paralleled rectifiers is about 40 km. Although the paralleled inverters are located on the same site, the control system developed is such that it can also tackle parallel operation of inverters remote from one another. This feature will be useful for the parallel operation of Bipoles 2 and 3 in the distant future. The scheme is unique in the sense that a bipole with mercury-arc valves will operate in parallel with another bipole with thyristor valves.