# Performance Analysis of Quantum Key Distribution Technology for Power Business
## 3 Performance Characteristics of Power QKD System
### Simulation Environment Test  
Figure 3 shows the topology of test system. In this experiment, the quantum channel was tested using simulated fiber channels and actual fiber channel. In the simulation of the optical fiber line test, the quantum link uses different kilometers of fiber optic disks as the transmission medium. In the actual fiber-optic line test, the quantum link uses the buried optical cable in the actual environment. The hardware equipment is shown in Table 3. The following describes the use cases of this experiment. (1) Distance loss test--tests the secret key rate under 10 km, 20 km, 30 km, 40 km and the actual link. (2) Galloping loss test--tests the key rate of 10 km, 20 km, 30 km and 40 km under different wind scale. (3) Splice loss test--detects the effect of splice loss on secret key rate (wavelength: 1550 nm). \begin{table}
\begin{tabular}{c c} \hline \hline
**Wind Scale** & **Wind Speed (m/s)** \\ \hline Calm & 0–0.2 \\ Light air & 0.3–1.5 \\ Light breeze & 1.6–3.3 \\ Gentle breeze & 3.4–5.4 \\ Moderate breeze & 5.5–7.9 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Wind scale and wind speed list. Figure 2: Evaluation indicators of power QKD system. (4) Encryption algorithm test--tests the impact of different encryption algorithms on secret key rate. (5) Data traffic test--tests the impact of data traffic on the secret key rate and the maximum traffic supported by QVPN. (6) Stability performance test--tests the secret key rate of the actual link under light breeze. Table 4 shows some experimental results of distance loss test and gallop loss test. As the length of quantum channel increases, the line distance loss increases, and the quantum key rate decreases. The secret key rate of the quantum device fluctuates greatly in the light breeze and gentle breeze. The moderate breeze blows up the optical fiber to reduce the swing amplitude and increase the secret key rate. The 40 km optical fiber is affected by the dual effects of line attenuation and swing, and the secret key rate drops sharply. Based on the analysis of results, the distance loss greater than 6 dB causes the secret key rate of the overhead line to drop sharply. When there is no wind disturbance, \begin{table}
\begin{tabular}{c c} \hline \hline
**Name of Equipment** & **Model of Equipment** \\ \hline QKD terminal A \({}^{\ddagger}\) & QKDM-POL40A-24G4 \\ QKD terminal B \({}^{\ddagger}\) & QKDM-POL40B-24G4 \\ Quantum key management service system & NF-5270 M3 \\ Quantum network management system & NF-5270 M3 \\ Video telephone server & eSpace U1910 \\ Quantum VPN & SJJ1529 IPSee VPN-Q \\ Switch & s5700 \\ Video telephone & espace8950 \\ Network performance tester & N11U \\ Optical time-domain reflectometer & FTB-200 \\ Optical fiber power meter & JW3116/JW3216A \\ Digital anemometer & HT-628 \\ Optical fiber tray & 2\# (10 km), 3\# (10 km), 6\# (20 km) \\ Fused fiber & 1\textasci{e}, 2\textasci{e}, 3\textasci{e}\) \\ \hline \({}^{\dagger}\) QKD terminal is introduced at [[http://www.quantum-info.com/English/product/2017/0901/324.html](http://www.quantum-info.com/English/product/2017/0901/324.html)]([http://www.quantum-info.com/English/product/2017/0901/324.html](http://www.quantum-info.com/English/product/2017/0901/324.html)). \\ \end{tabular}
\end{table} 
Table 3: Experimental equipment. Figure 3: The network topology of the test environment. the quantum key generation terminal meets the code limit (average secret key rate \(\geq\) 2 Kbps). When the line is disturbed by wind, the quantum key generation terminal cannot be coded. Therefore, the anti-interference ability of the equipment and the application of quantum relay technology need to be considered in actual engineering. The connection loss is not only affected by the splicing of different spliced optical fibers, but also by the number of spliced nodes. The increase in the number of nodes leads to an increase in the degree of light scattering during transmission, and the connection loss also increases.