Benchmarking power station voltage dip performance to meet the grid code requirements

Abstract

This study examines the bearing of a retrospective regulatory framework that requires power-generating units to have a degree of resilience to disturbances that originate in an integrated power system (IPS). Such frameworks are important to prevent interruptions of plant processes that can result in the interruption of power-generating capacity. The regulatory framework requirements of the South African National Grid Code form the background to the study. Typical power plant design and operating philosophy, the available technology and the literature examined in the study enriches this background. Included in the technology review and literature study are the characteristics of the disturbances that can originate in an integrated power system and how these disturbances come into play within the electrical reticulation system of the power plant. The literature study evaluated potential inherent power plant design disturbance resilience, historical and current means and measures implemented. The South African Grid Code in terms of GCR 9 requirements was benchmarked with other available countries' grid codes or similar network governances to identify resultant problems that affect the degree of resilience of power plants to disturbances that originate in an integrated power system (IPS). The research process involved a comparison between power plant design voltage operating limits and international standards applicable to the equipment used at power plants. The assessment of the international standards, the grid code voltage operating limits and the power plant design parameter provided the first indication of GCR 9 compliance and revealed additional problem areas. The analysis was conducted using historical and current means and measures implemented at power-generating units that provide resilience to typical characteristically defined disturbances. The study resulted in the identification of a specific problematic area that has resulted in power-generating capability interruptions. The subsequent process involved the investigation, definition, design, testing and implementation of a solution. The study revealed that power-generating units designed prior the existence of the national grid have a high degree of resilience to disturbances that originate in an integrated power system (IPS).