Automatic Generation Control Frequency Research Articles

Optimal False Data Injection Attacks Against Power System Frequency Stability

The automatic generation control (AGC) is one of the core control systems in power grids that regulate frequency within the permissible range. However, its dependence on communication makes it highly vulnerable to cyber-attacks. An arbitrary false data injection attack (FDIA) on AGC frequency and tie-line flow measurements will likely be detectable by bad data detection methods; however, if an attack can be launched optimally, it often becomes stealthy. In this regard, we develop a framework of optimal FDIAs (OFDIAs) to demonstrate the feasibility of such attacks in the power system frequency control loop. We propose a linearized formulation of discretized power systems’ dynamics in an optimization framework to model OFDIAs that compromise the AGC system by corrupting tie-line flow and generators’ frequency measurements. Using the proposed formal modeling, we study the effects of two types of FDIAs, continuous and time-limited, on the frequency behavior in power grids. The results demonstrate that continuous OFDIAs can lead to severe consequences on a power grid’s performance, such as frequency instability. In contrast, the time-limited FDIAs can cause the frequency to fluctuate beyond the acceptable range, which may lead to the triggering of the frequency-based protection relays.

Comprehensive frequency regulation control strategy of thermal power generating unit and ESS considering flexible load simultaneously participating in AGC

The strategy for frequency modulation control of energy storage assisted AGC (automatic generation control) systems with flexible loads was looked into from the viewpoint of source charge interaction in order to optimize the problem of single cell storage with flexible loads on the load side with slower energy storage forces in less fluctuating grids. In order to take advantage of both system stability and energy storage safety, a battery energy storage system is configured on the power side, and a linear regression function model is used to characterize its maximum power constraint in different needs as well as different levels of charge. Upper and lower limits of the total controllable force were determined by simultaneously invoking flexible loads on the load side and polymerizing the material using a method under central control. In order to extend the useful life of energy storage while also solving the frequency problem more quickly and effectively, different regions are divided using the frequency deviation signal, which is regulated by various modes of action in various regions. Four frequency modulation scenarios with and without flexible loads and energy storage systems engaged in AGC frequency modulation were compared using MATLAB/SIMULINK for simulation validation. The findings demonstrated that the suggested control technique may improve frequency modulation performance and lower the lifetime loss of energy storage.

Double-layer AGC frequency regulation control method considering operating economic cost and energy storage SOC consistency

Aiming at the problem of power grid frequency regulation caused by the large-scale grid connection of new energy, this paper proposes a double-layer automatic generation control (AGC) frequency regulation control method that considers the operating economic cost and the consistency of the state of charge (SOC) of the energy storage. At the regional control level, an economically optimized dynamic frequency regulation responsibility distribution between the unit and the energy storage is realized, and the idle time of energy storage is fully used for SOC management to effectively suppress the fluctuation of the energy storage SOC. At the energy storage station level, the cooperative control algorithm is used to ensure that the output and SOC of each energy storage unit are consistent, respectively. The effectiveness of the method is verified by establishing the dynamic model of the unit-storage combined frequency regulation of the regional power grid for simulation and comparison experiments. The method proposed in this paper considers the influence of different disturbance conditions on the AGC frequency regulation responsibility distribution between the unit and the energy storage and fully uses the frequency regulation characteristics of the energy storage's rapid and flexible response. It effectively improves the service life of energy storage and the comprehensive operation efficiency of the system while optimizing the frequency regulation operation cost, improving the frequency regulation performance, and increasing the frequency regulation compensation income.

Multi-Objective Mayfly Optimization-Based Frequency Regulation for Power Grid With Wind Energy Penetration

With the continuous development of society and under the background of sustainable development and resource conservation, the proportion of renewable energy in the global energy structure is increasing. At the same time, wind power has been widely used in many regions of the world because wind power technology is more advanced and mature than other renewable energy sources. In addition, with a large number of wind turbines connected to the grid, it not only helps automatic generation control (AGC) of power systems but also brings new challenges and difficulties. In this study, a multi-source cooperative control model of wind power participating in AGC frequency regulation is established to solve the dynamic problem of power distribution from real-time total power command to different AGC units. This study presents an optimal AGC-coordinated control method based on the multi-objective mayfly optimization (MMO) algorithm, which makes the fitting degree of power command output and actual output curve high and the adjustment mileage payment minimum, so as to achieve the best AGC performance. Finally, the simulation results show that this method can effectively decrease the total power deviation and adjustment mileage payment in the multi-source-coordinated control of AGC.

Dynamic-Model-Based AGC Frequency Control Simulation Method for Korean Power System

To fulfill the need of operating power systems more effectively through diverse resources, frequency control conditions for maintaining a balance between generators and loads need to be provided accurately. As frequency control is generally achieved via the governor responses from local generators and the automatic generation control (AGC) frequency control of the central energy management system, it is important to coordinate these two mechanisms of frequency control efficiently. This paper proposes a dynamic-model-based AGC frequency control simulation method that can be designed and analyzed using the governor responses of generators, which are represented through dynamic models in the planning stage. In the proposed simulation model, the mechanism of the AGC frequency control is implemented based on the dynamic models of the power system, including governors and generators; hence, frequency responses from the governors and AGC can be sequentially simulated to coordinate and operate these two mechanisms efficiently. The effectiveness of the proposed model is verified by simulating the AGC frequency control of the Korean power system and analyzing the coordination effect of the frequency responses from the governors and AGC.

DECISION TABLE LOOKING UP APPROACH FOR FUZZY LOGIC CONTROL OF MULTI-AREA AGC SYSTEMS

A Decision Table looking up algorithm for Fuzzy Logic Controller (FLC) with Genetic Algorithm (GA) optimization for Automatic Generation Control (AGC) system is developed. The single-input single-output (SISO) cascade loop structure of the AGC system is analyzed first. Then the interaction between the fast Area Control Error (ACE) loop and slow inner Boiler-Turbine-Generator (BTG) loop is decoupled by the FLC Decision Table algorithm based on the Relation Matrix recursive algorithm. The outer AGC frequency loop is optimized for disturbance rejection, and inner BTG loop is tuned for tracking the AGC instruction with the FLC. The Decision Table algorithm for FLC with GA optimization is suitable for the nonlinear element in AGC, such as generator rate constraint (GRC) and saturation. Simulations have shown that the approach is available for the AGC system performance optimization.