Experimental-based improvements of the flexibility of RES and energy storage plants

So far, the main fact is that RES plants have to operate at the maximum possible output whenever technically possible. However, in energy markets which consist of many different (flexible) power generation sources, this fact has led to the violation of the maximum overvoltage limit at the Point of Common Coupling (PCC) and maximum short-circuit power at many HV/MV substations, hindering the penetration of other Renewable Energy Sources DGs. Taking also into account that in microgrids with R/X ratio higher than 2, the voltage level depends on the active power balance, a new microgrid control approach is also necessary. In this paper, the pseudo-State of Charge concept is introduced to improve energy storage management. Additionally, a non-invasive to the inverter, PV-plant control technique, based on remote control of PV-strings actuators, is presented. Both of these approaches are associated to a new iterative control algorithm of a microgrid and applied on a microgrid-based smart grid topology, improving power supply and demand-side management of traditional P-f and Q-V approaches.