Voltage — Reactive power control in renewables power plants: Technical requirements applied in the Romanian power grid

The presence of a significant proportion of renewable power plants in the Romanian National Power System has led to the need for renewable generation to contribute more significantly to power system voltage and reactive power control. This paper has theoretical and practical contributions on the operation in a complex, interconnected power system through secondary voltage-reactive power (U-Q) control requirements for renewable power plants. These conditions are gathered in a set of regulations proposed by the National Transport System Operator (TSO) and were implemented successfully on subsystems that include distributed energy resources. Several tests were done on wind power plants connected to the grid. The U-Q control regulations were based on a systemic approach of the substations where wind or photovoltaic are connected to the national power grid.