Process and tools for optimising wind power projects connected to weak grids

Abstract

Integration of wind power plants (WPPs) into weak electric grids has gained a lot of interest in recent years due to an increase in sites with low short-circuit power at the point of connection. In response to this reality, wind turbine (WT) manufacturers have been working on developing suitable technical functionalities. However, it can be argued that technology is not the only challenge faced during the interconnection of WPP to a weak grid. This study aims at proposing and demonstrating the application of a process that can be applied to optimise many aspects of such projects and outlines the tools needed to do so. Outcomes and experiences from applying this process and its tools to a real project including steady-state and time-domain simulation results are also presented. It is shown that, in order to successfully interconnect WPPs into weak grids without putting power system safety and reliability at risk, strong collaboration between project developers, network operators, consultants and WT manufacturers is crucial. The proposed process will greatly support all stake holders involved in developing the market of WPPs connected to weak grids.

Impedance-Based Interactions in Grid-Tied Three-Phase Inverters in Renewable Energy Applications

“…If the grid impedance is low, then the PCC voltage is in phase with the grid voltage. In case of weak grid [45][46][47][48][49][50][51][52][53][54], the grid impedance can be rather high, which changes the phase of the PCC voltage to deviate from the phase of the grid voltage depending on the level of the power supplied by the inverter [51][52][53]. In practice, this means that the inverter seems to supply reactive power into the grid even if the inverter output power is pure real power at PCC [53].…”