The user-side controllable load dispatching is flexible and has little impact on users' comfort level

and it has great potential to participate in the system scheduling after aggregation

which has become a world research hotspot. The necessity of load aggregation is expounded by proceeding from the purpose of load aggregation and a description of four kinds of passive load aggregation methods. The results of active load aggregation are summarized in the classification and control mode of active aggregation objects

aggregation modeling and aggregation scenarios. The direction of further research is discussed in three aspects including uncertainty quantization of load aggregation

load dynamic aggregation modeling and control instruction decomposition of the load aggregation model.