Anti-islanding protection and islanding operation of grid-connected hydropower distributed generation

Salient issues associated with the connection of hydropower distributed generation (HPDG) into distribution networks include operation and voltage regulation, grid connection and control interaction, anti-islanding protection and islanding operation, and operation of protective devices. Better understanding of these issues and finding solutions to these problems are timely and important to the electricity industry. This paper has addressed islanding and anti-islanding issues of hydropower DG, and developed design criteria and solution for effective operation and control. A current control scheme based on microprocessor-based line-tracking system is proposed for HPDG operation with grid system. A technique is developed to use islanding detection and anti-islanding protection of HPDG. The paper has also proposed guidelines for islanding operation of HPDG to improve quality and reliability of power supply. Control of over- and under-generated islanded systems with hydropower DG have been explored and criteria for islanding operation and resynchronisation when mains return are discussed.