## 2 SOP Siting Based on the Characteristics of a Snowflake-Shaped Grid Structure  
The snowflake-shaped grid structure is based on a 10 kV ring cage, which serves as the core node. This is composed of eight 10 kV lines originating from four substations (or six lines from three substations), which form an independent feeder cluster. The purpose of this cluster is to provide power to the enclosed power supply area. Each substation is equipped with two 10 kV outgoing lines, each with one inter-station and one intra-station connection. These lines operate in an open-loop configuration. Eight (or six) lines are enclosed to form a snowflake-shaped area. The structural design of the snowflake-shaped grid embodies the concept of combined planning, which is consistent with the Constructive Law.  
The schematic diagram of the four-station snowflake-shaped grid is presented in Figure 1. The snowflake-shaped grid comprises four inter-station contact points and four intra-station contact points. The inter-station contact points are defined as key nodes, marked with red dots. The internal contact points are defined as secondary key nodes, marked with green dots. The other ring network nodes are defined as general nodes, which together with the 10 kV lines form the edges of the snowflake-shaped grid.  
Figure 1: _Cont._  
The traditional 10 kV grid structure is oriented towards a singular line and lacks an analytical focus on the network constituted by the lines. The snowflake-shaped grid introduces the concept of a feeder cluster, which is defined as a collection of multiple 10 kV lines connected through specific relationships. In terms of its physical configuration, each line is connected to two other lines, and the network structure is characterized by a high degree of simplicity and clarity and a lack of redundancy. In terms of functionality, each line is capable of transferring a load through the other seven lines. The grid structure is safe, reliable, and flexible in operation, making it a highly inclusive and adaptable power grid structure.  
In regions with elevated expectations regarding the dependability of the power supply, it is likewise feasible to reinforce the interconnection between feeder clusters, facilitate the load transfer between feeder clusters, construct a more substantial resource allocation platform, and establish a vast snowflake-shaped grid structure comprising small snowflakes as the fundamental unit, as illustrated in Figure 2.  
The preceding analysis demonstrates that the snowflake-shaped grid exhibits enhanced stability and reliability compared to the traditional 10 kV distribution network. Its distinctive grid structure endows it with robust load transfer capabilities, enabling it to effectively adapt to a high proportion of flexible resource access [5]. To date, the snowflake-shaped grid has been implemented in a number of demonstration areas, including the High-End Equipment Industrial Park in Beichen District, Tianjin, the Hexi National Game Village, and the Binhai New Area Ecological City Tourism Zone.  
Figure 1: Schematic diagram of 10 kV snowflake-shaped grid structure. (**a**) Electrical schematic diagram. (**b**) Simplified schematic diagram.  
Figure 2: Grid wiring with 10 kV snowflake petals as the basic unit.  
SOP is capable of achieving rapid and dynamic control of active and reactive power flows; therefore, its site selection must take into account the characteristics and requirements of the power flow within the power grid [14]. In light of the aforementioned analysis of the snowflake-shaped grid structure, it can be concluded that the inter-station connection nodes in the snowflake-shaped grid serve as the hub for the power flow between different lines, thereby meeting the site selection conditions of SOP. The installation of SOP at inter-station communication nodes serves to balance loads and optimize system voltage distribution.