## 5 Example Analysis
### Results and Analysis of Siting and Sizing
#### 5.2.2 Scheme I: Power-Limited Mode of Gas Turbine
Similarly, based on the calculation of the electrical distance, we continued to choose nodes 2, 5, and 14 as ES connection points. When the output power of the gas turbine decreased by 30% and 70%, the distribution grid power currents per hour before and after the ES connection were calculated, respectively, and the results are shown in Figures 15 and 16. Figure 8.1 WT/PV planning results: (**a**) WT/PV planning results after 30% reduction in gas-turbine output power; (**b**) WT/PV planning results after 70% reduction in gas-turbine output power. Figure 8.2 Distribution of power flow in distribution network with gas-turbine output power reduced by 50%: (**a**) one-day total loss optimization; (**b**) voltage-fluctuation optimization. When the output power of the gas turbine decreased by 30%, the maximum values of node voltage before and after ES connection were 1.033 and 1.028 p.u., respectively, and the minimum values before and after ES connection were 0.954 and 0.96 p.u., respectively, as shown in Figure 8.3 The loss decreased from 53.5 MWh to 46.2 MWh and the total voltage fluctuation decreased from 7.58 to 6.17, as shown in Figure 8.4  
When the output power of the gas turbine decreased by 70%, before and after ES connection, the maximum values of node voltage were 1.069 and 1.049 p.u., respectively, and the minimum values were 0.942 and 0.951 p.u., respectively, as shown in Figure 8.5 The loss was reduced from 44.6 MWh to 35.1 MWh and the total voltage fluctuation was reduced from 9.57 to 8.18, as shown in Figure 8.6  
Figure 8.7 Distribution of power flow in distribution network with gas-turbine output power reduced by 70%: (a) before ES connection; (b) after ES connection. Figure 8.8 Optimization of ES connection when the output power of the gas turbine is reduced by 30%: (a) one-day total loss optimization; (b) optimization of total voltage fluctuation of all the nodes. Figure 8.9 Distribution of power flow in distribution network with gas-turbine output power reduced by 30%: (a) before ES connection; (b) after ES connection. Table 1 presents the results of various indicators before and after the connection of WT/PV ES. When the gas turbine output power decreased by 30%, the planning results of ES capacity were 7.6, 6.1, and 3.3 MWh, the power/capacity penetration was 55.43%, the energy penetration was 34.84%, and the stability indicator was 0.053. When the gas turbine output power decreased by 70%, the ES capacity planning results were 15, 15.2, and 6.3 MWh, the power/capacity penetration was 99.40%, the energy penetration was 61.10%, and the stability indicator was 0.073. It can be seen from the data in Table 1 that, compared with the original working condition, reducing the output power of gas turbine and incorporating renewable energy such as distributed WT/PV ES effectively improved the renewable power, the renewable capacity, and the renewable-energy penetration of the entire oil-gas platform, improved the power flow distribution in the distribution network, and enhanced the static voltage/power-flow stability of the distribution network. Moreover, the addition of WT/PV reduced the active power loss of the system, and the addition of ES in the sub-cluster further reduced the active-power loss and the voltage fluctuation, thereby improving the economy and reliability of the distribution network operation.