Intgration of Renewable Energies with high intermittency

The Power Generation by Renewable Energies integrated in Electric Grid is increasing day by day.
Therefore, the Utilities are demanding more accurate Control of the Generation Plant:
-MTR (Minimal Technical Requirements) in the POI (Point of Interconection):
- Access for the Utility interconection with the Plant, for knowing in every moment what is the situation, in terms of generation (Quality of Wave, assurance MTR) and the possibility for disconnection of the Plant, which can get serious damages for the complete Electric System, making a variation of the frequency in the Complete Electric System.
- Necessity for stablishing a PPC (Power Plant Controller) for getting the control of the plant, in terms of Voltage, Current and Power, having in consideration next points for non getting a disconnection of the Plant:

1. Issues coming from the Electric Network: *LVRT (Low Voltage Ride Through),  HVRT (High  Voltage Ride Through) and ZVRT (Zero Voltage Ride Through). This Issues can affect the connectivity of the Plant if the Issues are greater than a determinated time.
2. Power Control: Curtailment (Limitation of Power) and Ramp Rate (Variation of Geneation depending Wind or Sun).

For controlling all points commented it is necessary systems (software) which gives the possibility for controlling the plant, and not only for monitoring.

*LVRT (Low Voltage Ride Through): especially in Wind and PV farms, it is the ability to operate at low voltage levels, in terms of grid voltage supplying. It happens the same situation in big computer centers (Datacenter etc) which in cases of emergency (outages) are using UPS (Uninterruptible Power Supply).
Considering this low voltage operation (LVRT) in Wind and PV farms, it has the possibility to induce in the disconnection of the one complete Wind Farm and at the same time, it is able to induce one serious issue in the Operation of the Electric System, because the disconnection, it is able to induce in cascade (cascading failure) the disconnection of other wind and PV farms due to low voltage. 

PS: Consider forecasting systems of energy yield in Wind and PV Farm more necessary such as minimum condition, in terms of information, in point of interconnection in future, even being one condition in some states.

Figure 1_ Example of Wind Turbine in Tarragona_source: Javier Sanchez Rios