# Communication Architecture for Grid Integration of Cyber Physical Wind Energy Systems
## 4 Simulation Results
### Standalone Wind Turbine Results  
We considered four operation modes for a wind turbine, which are idle, start-up, power generation, and shutdown, as shown in Figure 7. Based on wind conditions, the WTC determines the turbine operation mode [8]. We assumed that the control center operator turned on a wind turbine for operation. The WTC first checked the condition of the wind turbine. If no faults were detected in the wind turbine system, the WTC activated the operation in the idle mode. During the idle mode, if the average wind speed was greater than the cut-in wind speed for a certain time, the WTC activated the start-up operation mode. During the power production mode, the WTC adjusted the blades' pitch \begin{table}
\begin{tabular}{c c} \hline \hline
**Information Types** & **Delay Requirements** \\ \hline Protection Information (high speed) & 4 ms \\ Analogue Measurement and Status Information & 16 ms \\ Meteorological data & 1 s \\ Audio and Video data stream & 1 s \\ Image files & 10 s \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Wind farm communication requirements based on the IEEE 1646 standard. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Scale** & **Level** & **Options** \\ \hline
1 & Standalone Wind Turbine & 10 Mb/s, 100 Mb/s \\
2 & Wind Farm & 100 Mb/s, 1 Gb/s \\
3 & Met-Mast & 10 Mb/s, 100 Mb/s \\
4 & Substation & 10 Mb/s, 100 Mb/s, 1 Gb/s \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Summary of simulation cases. angle and position of the nacelle in order to optimize the turbine operation. In case of higher wind speeds, which were greater than the cut-off, the WTC activated the shutdown mode. We classified the sensor nodes inside the wind turbine into four different categories: mechanical measurement (rotor speed, pitch angle, displacement, vibration, etc. ), electrical measurements (voltage, current, power, frequency, etc. ), meteorological data (wind speed, wind direction, temperature, humidity, etc. ), and foundation measurements, as shown in Table 9. Based on the turbine operation mode, the amount of monitoring data forwarded to the WTC was different. This classification meant that some of the sensor nodes were continuously working, while other sensor nodes were generating the monitoring data based on the turbine operation mode. The OPNET Modeler was used to simulate data transmission of condition monitoring system for a wind turbine during three operation modes (shutdown, idle, and operation). The nacelle dimension was configured as 12 m \(\times\) 4 m. The total number of monitoring parameters and sensors was 108. The height of the tower was configured as 85 m (distance between DCU and main ethernet switch). Based on the IEC 61400-25 standard, different profiles were defined, configured, and assigned to each LN. The simulation time was 20 min. Figure 8a shows the total received traffic at the WTC for different operation modes. The maximum received traffic was about 227,036 bytes/s (225,544 AM, 58 SI, and 1434 FOU) during turbine operation, while the received traffic was about 5808 bytes/s during the idle mode. The difference was due to the sensing data of the electric measurement (voltage, current, power, power factor and frequency), which were about 221,228 bytes/s. No traffic was received at the WTC while the turbine was in the shutdown mode. Figure 8b shows the end-to-end delay inside the wind turbine between sensor nodes and the WTC). The link capacities inside the wind turbine were configured with 10 Mbps and 100 Mbps. During the power production mode, the end-to-end delay was about 0.098 ms and 1.1 ms using link capacities of 10 Mbps and 100 Mbps, respectively. The received traffic from the pitch angel sensor, wind