## 3 Problem Description
### Analysis of PV Influence on Distribution Network
#### 3.2.1 The Impact of Access Location  
Case a. Not connected to PV power supply. Case b. Connected to a PV power supply with a capacity of 144 kW and a power factor of 0.95 at node SS3. Case c. Connected to a PV power supply with a capacity of 144 kW and a power factor of 0.95 at node TS. By comparing theoretical calculation values with actual simulation results, the effectiveness of the method was verified. The error between the two remains within 1%. Figure 7a-c show the unit voltage values of the bus node when the PV with the same capacity is connected to different positions. The data as shown in Table 1. Combining the analysis in Section 3.1, it can be clearly determined that the integration of PV will increase the voltage of the integration nodes. Furthermore, for PV power generation of the same capacity, the closer the integration location is to the end of the system wiring, the more significant its ability to increase voltage becomes. The voltage rise caused by case c is 200% of that caused by case b. Figure 7d illustrates the voltage rise comparison of different nodes under three cases. It is evident that due to the distance from the power source, the voltage drop and rise at the end of the feeder are more pronounced. Under the same operating conditions, the voltage rise of bus SS3 is only 60% of that of TS. When integrating PV with the same capacity into the system, it is apparent that the system voltage is more likely to exceed the limit when integrating at the end of the feeder. When the voltage of bus TS in case c reaches 104.5% of the rated value, the voltage of bus TS in case b is only 101.5%. Figure 8a-c show the voltage deviation of the bus node when the PV with the same capacity is connected to different positions. The data as shown in Table 2. Previous analysis has shown that the integration of PV can affect the voltage of nodes, thereby leading to changes in voltage deviations. Observing the curves, it can be found that in case b, the voltage deviation of node SS3 has significantly improved, decreasing by 25% compared to case a. It can be inferred that adjusting the reasonable capacity and integration location of the PV can improve the voltage deviation situation of any node in the system. Figure 8d illustrates the voltage deviation comparison of different nodes under three cases. It demonstrates a phenomenon where the integration of the PV improves the voltage of nodes, but when the PV capacity is too large, the voltage condition of system nodes deteriorates. Comparing case a with case b, the voltage deviation of the system after integrating PV shows some improvement. Even in case c, high-capacity photovoltaics only increase the voltage deviation of SS3 and TS by 20%. In practical applications, this scenario that balances system stability and PV energy-saving characteristics is very meaningful. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Voltage** & \multicolumn{2}{c}{**MS1/MS2**} & \multicolumn{2}{c}{**SS3**} & \multicolumn{2}{c}{**TS**} \\ **(p.u.)** & **Theory** & **Simulation** & **Theory** & **Simulation** & **Theory** & **Simulation** \\ \hline a & 1.0 & 1.0 & 0.995 & 0.99 & 0.99 & 0.9875 \\ b & 1.0 & 1.0 & 1.005 & 1.0075 & 1.01 & 1.015 \\ c & 1.0 & 1.0 & 1.02 & 1.025 & 1.0375 & 1.045 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Node Voltage Data Sheet: The Impact of Access Location. Figure 8: _Cont_. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Deviation** & \multicolumn{2}{c}{**MS1/MS2**} & \multicolumn{2}{c}{**SS3**} & \multicolumn{2}{c}{**TS**} \\
**(\%)** & **Theory** & **Simulation** & **Theory** & **Simulation** & **Theory** & **Simulation** \\ \hline a & 0.0 & 0.0 & 0.5 & 1 & 1 & 1.25 \\ b & 0.0 & 0.0 & 0.5 & 0.75 & 1 & 1.5 \\ c & 0.0 & 0.0 & 2 & 2.5 & 3.75 & 4.5 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Node Voltage Deviation Data Sheet: The Impact of Access Location. Figure 7: The impact of PV access location on node voltage: (**a**) nodes MS1 and MS2; (**b**) nodes SS3; (**c**) nodes TS; (**d**) comparison of node voltage curves.