## 4 Smart5 Grid NetApp Use Cases
### UC3--Millisecond-Level Precise Distributed Generation Monitoring
#### 4.3.3 Specific NetApps  
This UC's NetApp consists of two software components, namely the predictive maintenance enabler service and the real-time energy production monitoring service. Each one of these components is implemented as a different VNF, which are interconnected, interact with the inputs, and provide the necessary outputs to fulfill the functional requirements of this UC, as can be seen in Figure 11.  
As it can be observed from Figure 11, the predictive maintenance and the real-time energy production monitoring VNFs have an external connection point (CP), which receives field measurements via a SIM8200 EA-M2 5G HAT type module [39]. This module enables the 5G communication with a Raspberry Pi IoT device [40]. It is worth mentioning that many monitoring devices or measurement units for power grids  
Figure 11: NetApp architecture of UC3.  
today, including wind turbine technology, are not 5G-ready. As such, 5G-enabling interfaces might be needed to facilitate the communication between the field sensor devices and the Smart5 Grid platform.  
The main scope of the NetApp component that performs predictive maintenance is to enhance the awareness of the wind farm owner on the need to make changes in the operation of the wind farm or on the portfolio of the flexibility service it might offer in the real-time balancing market. Specifically, this NetApp component is leveraging the data measured from the sensors that exist in the wind farm, which are then forwarded through an open platform communications (OPC) server, located in the laboratory of one of the project's partners where the actual processing takes place. The data generation process is repeated in a Raspberry Pi, which possesses a 5G-HAT type module, those supporting 5G connectivity. OPC unified architecture (UA) [41], which is a machine-to-machine (M2M) communication protocol for industrial automation developed by the OPC Foundation [41], will be used as the communication protocol in the context of this use case. Afterwards, this component collects the data and executes an internal process to assess the wind farm operation to conclude whether any predictive maintenance action must be taken. Thus, wind farm owners receiving the input from that component increase their ability to more properly operate the asset.  
The second NetApp component implements the wind farm performance monitoring process. Specifically, key performance parameters (such as turbine rotation and vibration) are collected from field sensors. Moreover, environmental parameters (such as wind speed, humidity, and ambient temperature), along with electrical parameters (such as power output, grid frequency, and voltage), are also collected and processed.  
The real-time energy production monitoring, the second software component of UC3's NetApp, provides real-time data monitoring of the wind farm production on a millisecond basis to the owner of the wind turbine and to the system operator. The data collection process follows a similar approach as the previously described software component. Finally, the two software components have a management CP in order to grant access for configuration or debugging purposes.