Impact of cyber-attack on coordinated voltage control in low voltage grids

Power grid is facing several challenges such as voltage violation, power losses, and power quality issues due to the high integration of renewable energy sources such as solar and wind. One of the several strategies to overcome the voltage violation problem is the provision of reactive power from wind and solar power plants. Local controller of these plants coordinates with the controller to generate the reactive power. The coordinated controller performs its function based on the information obtained from the whole grid via communication network. Communication network infrastructure has high responsibility to ensure secure and stable services in order to provide reliable voltage control in distribution grids (DGs). Unstable or insecure communication networks can lead to several problems in the power system, such as increased power losses and in worse case blackouts. Therefore, this paper analyses the impact of cyber-attacks on the voltage quality control supported by the reactive power generation of PV plants in DGs. Two cyber-attack scenarios are demonstrated via a voltage coordination scenario based on a real distribution grid in Northern Denmark. Simulations are done in a Simulink model of Thy Mors Energi Grid, Denmark. A cyber control block is implemented within the coordinated controller in order to mitigate the effect of cyber-attack. Experimental results show that it is possible to detect and mitigate a cyber-attack such as denial of service and integrity attack before sending a control signal thus contributing towards a secure, stable, and resilient power grid.