Grid-side flexibility of power systems in integrating large-scale renewable generations: A critical review on concepts, formulations and solution approaches

Abstract

Though considerable effort has been devoted to exploiting generation-side and demand-side operational flexibility in order to cope with uncertain renewable generations, grid-side operational flexibility has not been fully investigated. In this review, we define grid-side flexibility as the ability of a power network to deploy its flexibility resources to cope with the changes of power system state, particularly due to variation of renewable generation. Starting with a survey on the metrics of operational flexibility, we explain the definition from both physical and mathematical point of views. Then conceptual examples are presented to demonstrate the impacts of grid-side flexibility graphically, providing a geometric interpretation for a better understanding of the concepts. Afterwards the formulations and solution approaches in terms of grid-side flexibility in power system operation and planning are reviewed, based on which future research directions and challenges are outlined.

Local flexibility markets: Literature review on concepts, models and clearing methods

“…in local markets. The optimization with uncertainties can be divided into two streams depending on the formulation of uncertain variables: stochastic programming and robust optimization [175].…”

Grid Integration Challenges of Wind Energy: A Review

“…Also, the coordination between the different reactive power sources associated with the wind turbine is essential to avoid instability problems. A wind turbine can contribute to the grid side flexibility by improving the voltage profile through the process of generating and absorbing reactive power [48] Maintaining the voltage within the operational limit is always considered as one of the critical issues, especially when introducing new technology associated with the load or power generation. For instance, the fluctuation of wind power output causes voltage fluctuations and flickers that depend on the variation of wind speed and type of generation system [49].…”

Power system flexibility: an overview of emergence to evolution

“…In such a case, by adjusting the physical characteristics of the power grid to control the power flow, grid side flexibility resources can provide additional operational flexibility. Grid side flexibility resources are categorized into discrete and continuous resources [128]. Transmission expansion planning [129,130] and line switching in operation [131,132] are typical discrete resources which change the power grid topology.…”