## 2 Load Frequency Control and DoS Attack Models Based on ADES  
The development and popularization of distributed energy sources and power electronics techniques provide more flexible and efficient implementation methods for power grid frequency control [38]. The decentralized comprehensive energy utilization systems established in various regions compose an ADES system by integrating the power resources generated by different energy systems and transmitting them to large power grids [38].  
As shown in Figure 1, if power grids are divided into multiple subsystems containing ADES, each subsystem transmits power and exchanges data information through power transmission lines and communication networks. Each subsystem includes phase measurement units (PMUs), ADES, ADES controllers, synchronous generators, turbine governors, tie-line controllers, power electronics interface, and the load. Renewable distributed energy sources, such as the electricity generated by wind and photovolta are smoothly output and connected to power grids through energy storage systems.  
Due to disturbances, such as load changes, the power grid frequency fluctuates; therefore, the active power of synchronous generator sets is adjusted to control the power grid frequency based on the P-f droop control [44]. When the frequency deviation exceeds the set threshold range for the first time [45], ADES controllers are activated, and the battery energy storage system (BESS) is introduced to participate in the frequency adjustment process.  
From now on, BESS continues to run. BESS has the ability of fast power response and four-quadrant operation, which can inject enough active power for the fast frequency adjustment of power grids under the disturbances of load changes. Renewable distributed energy sources have three main characteristics, randomness, intermittency, and volatility. If large-scale and high proportions of renewable distributed energy sources are connected to power grids, huge peaks and frequency regulation pressured occur, which weakens the system moment of inertia and brings new challenges to power grids, such as balance adjustment and safe and stable operations [46].  
The proposed ADES-based strategy with BESS can realize the regional multi-energy aggregation mode in which the large-scale distributed energy resources are connected to power grids. There are two advantages to the ADES with BESS. First, the proposed strategy realizes the flexible control of large-scale distributed energy sources, and thus the scheduling of distributed energy sources can be processed as a whole.  
Second, the proposed strategy is conducive to the rational and optimal allocation and utilization of energy resources [47]. This paper adopts controllable inverters as the interface and aggregation techniques, which have fast response speed, can effectively suppress frequency deviation in a short time and provide sufficient control capacity under aggregation and BESS to prevent the instability of power grids.  
Each subsystem contains a local distributed ADES controller. When the subsystem ADES controller exerts a control function, the ADES controller first receives the PMU measurement data (the frequency and power deviation corresponding to the subsystem)  
Figure 1: Subsystem structure diagram.  
from both local and other remote subsystems at each discrete sampling moment and then uses them to calculate the control output. The ADES controller also sends the corresponding control command signals to local distributed energy sources and adjusts the output power of each distributed energy system in real time to resist both frequency deviations and power grid oscillations.  
DoS attacks occur in the information transmission process between subsystem \(i\) and subsystem \(j\) as shown in Figure 1. When DoS attacks occur, the information interaction between the two subsystems is cut off.