Generation dispatch with large-scale photovoltaic systems

Abstract

There is a widespread adoption of stability strategies that employ power system voltage, rotor angle and frequency control techniques for dealing with the impacts of large-scale PV systems on sub-transmission and transmission power system networks. However, generation dispatch strategy which is equally vital for solving operational challenges presented by non-conventional sources such as large-scale PV systems remain under-utilized. The list of well-known operational challenges associated with large-scale PV systems include load-following and spinning reserve requirements, load frequency excursions and system stability, amongst others. Generation dispatch is the aspect of control strategy that takes into account the intermittent nature of non-conventional sources and relies on the adjustment of power output from other generating units in the entire generation mix consisting of both non-conventional and conventional sources to maintain balance between generation and load. These entails fulfilling numerous operational requirements such as holding dispatchable sources in the form of both spinning and non-spinning reserve, optimal economic dispatch and unit commitment. Opportunity for further research lies in the application of generation dispatch strategy to solving some of the operational challenges posed by the integration of the large-scale PV systems in the sub-transmission and transmission system networks.

The role of generation dispatch strategy is to maintain a generation and load balance despite the intermittent nature of large-scale PV systems based on economic dispatch as well as spinning and non-spinning reserves techniques. This can be achieved by employing short and long-term forecast techniques for PV power output and working out the cost effective deployment methods of all the other generating units while taking into account prevailing transmission and operational constraints.