## 4 Smart5 Grid NetApp Use Cases
### UC4--Real-Time Wide Area Monitoring
#### 4.4.3 Specific NetApps  
The NetApp of this UC consists of three software components--the vPDC, the monitoring service, and the advisory provisioning service, as can be seen in Figure 13. Each one of these components is implemented as a different VNF, which is interconnected and interacts with the rest of them. Firstly, the _vPDC VNF_ has an external CP for the arrival of the input measurements of the PMU. Then, after the processing of the data, the output will be forwarded to the next blocks via the internal CPs. Next, the _Monitoring VNF_ has an internal CP where the input from the vPDC arrives, as well as one CP to communicate with the advisory VNF. Finally, the _advisory VNF_ has two internal CPs for the input given from the other two VNFs and an external one to provide the advice messages to the TSOs. All three components have a management CP in order to grant access for configuration or debugging purposes. For the monitoring VNF, the management CP will also be used for the RSC (owner and administrator of the NetApp) to have access to the visual representations, as elaborated in the section below. The _vPDC service_ will include several functional requirements to preserve the standards and constraints implied by the application of WAM, as dictated by the IEEE C37.244 standard [42]. These are summarized as follows:  
_Data aggregation with time alignment to relative time_: The PDC aligns data received from PMUs/PDCs and transmits the combined data in one or more output data streams to other PDCs or applications, such as archiving, visualization, or control. The PDC latency starts  
Figure 13: NetApp architecture of UC4. when the first complete data message with a given timestamp arrives at the PDC. The worst-case PDC latency is the time of egress of the output data minus the time of the first data arrival at the PDC. This latency will approximately be the relative wait time plus the PDC processing time. Any data that arrives later than the end of the relative wait time is discarded. _Data validation_: A PDC may perform basic data validation and check for the data arriving at the PDC. It includes checking the data status flags and time quality of all PMUs and performing data integrity checks on all received data. _Data transfer protocol support_: PMU data may be available in different synchro phasor data transfer protocols, such as IEEE Std C37.118-2-2011 [43], IEEE Std C37.118-2005 [44], IEEE Std 1344-1995 [45], IEC 61850-90-5 [46], and new standards as they become defined. This requirement will be valid when more than one data transfer protocol, that is, incompatible PMUs from different vendors, are used in the demonstrators. _Output data buffering_: A PDC may buffer output data to reduce data losses in case communication to other PDCs or applications is interrupted. This function affects PDC memory requirements. _Configuration_: Configuration management is designed to assure the availability of appropriate data for the local functions of the PDC as well as other applications that receive data from the PDC. Configuration information is sent by the data source to the data destination ahead of the actual data to permit the data destination to interpret the data as soon as it arrives. The configuration information may be sent unsolicited or on explicit requests. _Performance monitoring_: A PDC may have performance monitoring functions to monitor the quality of data and communication with other PMUs and PDCs. Performance monitoring includes errors, events, and overall system operation. _Cyber security_: Cyber security will be evaluated at all PDC interfaces while maintaining the reliability of the PDC. PDC cyber security likely goes beyond simply securing synchro phasor communications and includes security for all communications and access to the PDC. Security practices that are poorly applied to PDCs may degrade PDC performance and/or functionality. The _WAM service_ will demonstrate several status indicators and visualization features of the PMUs.