## 1 Introduction  
With the increasing connection of distributed generators (DGs), the distribution system operation mode has witnessed some major changes in terms of the control mode when compared with traditional distribution systems [1; 2]. Due to its flexible operation mode, environmental friendliness, and high efficiency, DGs have effectively uplifted the efficiency of intelligent distribution system operation. Through the strategy of collaboratively controlling multiple DGs, the uninterrupted power supply of the distribution system can be ensured in the case of operation instability or fault, hence, helping realize the \"self-healing\" function of the distribution system [3]. To further promote the development of distribution system with multiple DGs, the Institute of Electrical and Electronic Engineers (IEEE) compiled the IEEE Std. 1547-2003 in 2003, encouraging the realization of island operation in multiple regions under fault through technical means [4]. In the modified standard IEEE 1547.4-2011, the definition of a microgrid was expanded to the distribution system with a relatively high penetration of DGs, believing that a future intelligent distribution system could be regarded as consisting of multiple microgrids with a collaborative control function [5]. The formulation of these standards indicates that when there is a fault in the future intelligent distribution system, island partition can be conducted according to an island zone partition or real-time operation status of the distribution system, so as to form multiple independently-running microgrid systems, realizing the autonomous operation of many islands in zones without fault, and ultimately ensure power supply stability and reliability. Experts at home and abroad have conducted in-depth research on island partitioning of distribution systems with multiple distributed generators. [PERSON] et al. [6] through assessing the operational status of DGs and the load in the case of a fault, proposed one type of self-adapting island partition strategy. Considering the DG capacity and distribution, [PERSON] et al. [7] transformed the island partition into a finite tree issue in graph theory. [PERSON] et al. [8] divided the island partition into two stages by constructing an initial island through the tree knapsack problem (TKP) method and then analyzed the generation and load status in the initial island, hence, realizing quadratic optimization. With a distribution system of microgrids as the research subject, [PERSON] et al. [9] proposed an energy risk evaluation-based island partition strategy considering the power supply and demand balance. With maximal power supply capacity and minimal energy consumption as target functions, [PERSON] et al. [10] established an island partition with load system operation constraint conditions by constructing a comprehensive learning particles swarm optimization (CLPSO). [PERSON] et al. [11] proposed fast greedy algorithm (FGA) and bloom algorithm, respectively, for island issues in small-scale and large-scale distribution systems, which uplifted the computational efficiency of the island partition algorithm under different distribution systems. [PERSON] et al. [12] proposed one type of preliminary island partition method in the distribution system under a short-term power constraint mechanism, and verified the validity of the algorithm in PG and E 69 and IEEE 118 node systems. With a distribution system with multi-point faults as the research subject, [PERSON] et al. [13] proposed one type of multi-stage stochastic programming model with minimal loss of load so as to realize the effective response of island partitioning against the power supply fault of the distribution system. The above references all used minimal island operation cost or maximal power supply capacity under a stable operational status as the target function for the solution of island partitioning and the optimization of solution efficiency.