Nowadays, in low voltage electric distribution networks, the distribution network operators are encountering a high number of connected small-scale distributed generation units, mainly photovoltaic prosumers. The
In the literature, there are various strategies for controlling RP proposed as solutions for increasing the voltage of the distribution network. These techniques are classified as follows: fixed power factor (FPF) type control;
The increasing number of megawatt-scale photovoltaic (PV) power plants and other large inverter-based power stations that are being added to the power system are leading to changes in the way the
The proposed grid-forming controller is designed to maintain the PV output voltage close to the constant voltage region and prevent a dc-link voltage collapse, using a single-loop voltage control with overcurrent limiting.
Voltage regulation actions: the PV power plant is required to help maintaining the grid voltage level. A minimum reactive power capability of the PV power plant is established. Additional ancillary equipment, as FACTS devices, can help to reach the capability limits.
Current power systems are not designed to support the massive integration of PV and to respond to the grid codes. The application of intelligent and online control methods for better coordination between all parts of modern electrical systems is very important.
However, should regulation be conducted with the voltage-power control technique of the photovoltaic smart inverter mentioned, the mains voltage Vgrid would increase to the root-mean-square value of 220 V (1 p.u.), which would maintain the mains voltage at a stable value.
Then, the voltage-power control technology was added to the grid-connected photovoltaic inverter. When the grid voltage p.u. value is between 1.0 and 1.03, the smart inverter starts voltage-power regulation, reducing the real power output to 1440 W, and absorbing the system’s reactive power to 774 VAr.
By implementing the flexible power control strategies with necessary support, the PV systems can produce smooth power to the grid, if required, to handle the environmental intermittency and non-dispatchability (uncertainties).
The arrangement of the various section contents is as follows: Section 2 describes the maximum power point tracking algorithm for the photovoltaic system and the circuit design of the boost converter. Section 3 describes the smart inverter control architecture, including DC-link voltage control, output power control and voltage-power control.
