Credibility‐based secure distributed load frequency control for power systems under false data injection attacks

The safe and reliable operation of power systems is an important guarantee for the healthy development of the national economy. Industry and people’s lives are inseparable from electricity, so the safety and reliability of electricity supply is very important. The sudden interruption of power supply will not only bring serious economic losses, but also seriously affect people’s normal lives and even endanger social stability. False data injection attack (FDIAs) are a new type of power system network attack method. FDIAs are a new type of power system network attack method. It can successfully bypass the bad data detection mechanism, offset the power measurement data, and mislead the control center under extremely subtle conditions. Therefore, it poses a very serious threat to the stable operation of the power system. Therefore, this article first analyzes the principle of false data injection attacks, in order to provide a theoretical basis for subsequent attack detection. Then this paper constructs a detection method based on extreme learning from the perspective of optimizing learning efficiency. Based on the IEEE14-bus standard test system, the method is verified through simulation, which shows the feasibility of this method, which provides a direction for building a safe and stable smart grid.

Under the background of the construction of “three types and two networks”, the introduction of a large number of heterogeneous intelligent terminals, ubiquitous open networks, interactive real-time control services and wide area interconnected power systems have transmitted the network security risks to all aspects of the power system. The security defense capability of power system is not only the superposition of security defense equipment, but also the excellent network security team. The continuous improvement of the level of network security is inseparable from the accumulation of network security attack and defense technology and practical experience, as well as practical tools and equipment with the characteristics of the power industry. In order to meet the increasingly severe security protection challenges, actively implement the security protection requirements of the power information system, ensure the safe and stable operation of the power system, build a network shooting range suited to the attributes of the power industry, and continuously improve the ability of network security protection, consolidate the foundation of digital transformation to ensure the safe and stable operation of power system and reliable power supply.The safe and stable operation of the information system needs to carry out comprehensive and in-depth vulnerability troubleshooting. In view of the lack of power business loophole mining and security event verification shooting range environment, this paper studies the power security shooting range construction technology.

As power big data plays an increasingly important role in the operation, maintenance, and management of power systems, complex and covert false data attacks pose a serious threat to the safe and stable operation of the power system. This article first explores the characteristics of new power systems, and the challenges posed by false data attacks. The application of big data technology in power production optimization, energy consumption analysis, and user service improvement is then investigated. The article classifies typical attacks against the four stages of power big data systems in detail and analyzes the characteristics of the attack types. It comprehensively summarizes the attack detection technologies used in the four key stages of power big data, including state estimation, machine learning, and data-driven attack detection methods in the data collection stage; clock synchronization monitoring and defense strategies in the data transmission stage; data processing and analysis, data integrity verification and protection measures of blockchain technology in the third stage; and traffic supervision, statistics and elastic computing measures in the control and response stage. Finally, the limitations of attack detection mechanisms are proposed and discussed from three dimensions: research problems, existing solutions, and future research directions. It aims to provide useful references and inspiration for researchers in power big data security to promote technological progress in the safe and stable operation of power systems.

The condition monitoring and fault diagnosis of power transformers plays a significant role in the safe, stable and reliable operation of the whole power system. Dissolved gas analysis (DGA) methods are widely used for fault diagnosis, however, their accuracy is limited by the selection of DGA features and the performance of fault diagnosis models, for example, the classical support vector machine (SVM), is easily affected by unbalanced training samples. This paper presents a transformer fault diagnosis model based on chemical reaction optimization and a twin support vector machine. Twin support vector machines (TWSVMs) are used as classifiers for solving problems involving unbalanced and insufficient samples. Restricted Boltzmann machines (RBMs) are used for data preprocessing to ensure the effective identification of feature parameters and improve the efficiency and accuracy of fault diagnosis. The chemical reaction optimization (CRO) algorithm is used to optimize TWSVM parameters to select the optimal training parameters. The cross-validation (CV) method is used to ensure the reliability and generalization ability of the diagnostic model. Finally, the validity of the model is verified using real fault samples and random testing.

The electric power system is one of the indispensable infrastructures in modern society, and its stable operation is crucial for guaranteeing economic development and social security. By calculating the correlation coefficient and drawing the correlation heat map, we find that there is a correlation between the voltage at each location and the occurrence of electrical faults, and at the same time, there is also a certain correlation between various types of electrical faults and the voltage at each location. These results indicate that there are complex and close interrelationships between different locations and between different types in the power system. In order to better identify and classify different types of electrical faults, we used the random forest model for prediction. The model is used to classify whether an electrical fault occurs or not and to determine its category. The prediction results show that the Random Forest achieved 99.63% in classifying whether an electrical fault occurred or not, and 91.26% in classifying the category of electrical faults. This shows that the Random Forest algorithm model is able to detect electrical faults well, as well as judge the category of electrical faults. In summary, this paper provides insight into the operation of the power system by studying the correlation between the voltage at various locations in the power system and the different types of electrical faults and using the random forest model to make predictions. These findings are of great significance in ensuring the stable operation of power systems.

Modern power system is a typical cyber-physical system (CPS). The stable operation of the modern power system relies increasingly on the well-functioning cyber system. Therefore, it is important to include the possible effects of the cyber system as we assess power system stability. Since our main purpose of considering the cyber system is to study its possible effect on power system operation, and cyber system mainly affect the physical system through affecting the information flow, we mainly focus on the information flow as we model the cyber system. In the proposed model, the details in cyber system operation is not considered to reduce redundant calculation burden. Instead, cyber elements and cyber contingencies are classified and modeled based on their effect on the information flow, reflecting their possible effect on the operation of the power system. We can simulate the CPS by integrating the proposed cyber system model with the power system model and conducting mixed simulation. Case study is carried out in the AVC system in the IEEE-14 bus power system. The result shows the proposed cyber system model and CPS simulation method can be used to analysis the possible effect of cyber contingencies on the power system.

Due to its vulnerability to a variety of cyber attacks, research on cyber security for power systems has become especially crucial. In order to maintain the safe and stable operation of power systems, it is worthwhile to gain insight into the complex characteristics and behaviors of cyber attacks from the attacker's perspective. The consensus-based distributed state estimation problem is investigated for power systems subject to collaborative attacks. In order to describe such attack behaviors, the denial of service (DoS) attack model for hybrid remote terminal unit (RTU) and phasor measurement unit (PMU) measurements, and the false data injection (FDI) attack model for neighboring estimation information, are constructed. By integrating these two types of attack models, a different consensus-based distributed estimator is designed to accurately estimate the state of the power system under collaborative attacks. Then, through Lyapunov stability analysis theory, a sufficient condition is provided to ensure that the proposed distributed estimator is stable, and a suitable consensus gain matrix is devised. Finally, to confirm the viability and efficacy of the suggested algorithm, a simulation experiment on an IEEE benchmark 14-bus power system is carried out.

In order to alleviate the serious pollution problems caused by traditional thermal power generation, it is an inevitable trend to incorporate clean and renewable energy sources such as wind power into power system dispatching. However, the unpredictability and volatility of wind power posed enormous challenges for the stable operation of power systems. Therefore, it is a popular research topic to improve the traditional scheduling strategy and maintain the stable economic operation of the power system. This paper studied the joint optimization scheduling problem of power system with wind power, hydropower and thermal power, and discussed the effect of hydropower on system scheduling with different adjustment capabilities.

In recent years, Japan has rapidly extended its use of electricity obtained via photovoltaic (PV) generation. When the proportion of PV in the generation mix was small, its unpredictable output fluctuations had little effect on the supply and demand operation. However, as the role of PV in grid supply grows, predicting these fluctuations becomes increasingly necessary to ensure stable and economical operation of the electric power system. In this study, we discuss the current approaches of estimating and forecasting the PV output. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Multi-objective optimal load dispatch of microgrid with stochastic access of electric vehicles

For the past century, electric power systems have primarily been bulk power systems consisting of generation, transmission, and distribution networks. Now the rapid expansion of distributed renewable power sources (RESs) and the shift from large, conventional synchronous machine resources to smaller-sized resources with diverse generation characteristics become the most significant change in modern power systems. With the increasing penetration of RESs, which are inverter-based resources (IBRs), it is important to develop interconnection standards that define performance and capability criteria for these IBRs. This is necessary to ensure the stable and reliable operation of power systems. This report summarizes the standards for IBRs interconnection in North America.

Line Commutated Converter High Voltage Direct Current (LCC HVDC) technology’s controllability has provided considerable flexibility for System Operators to maintain the stable and reliable operation of the modern power systems. This paper, based on the Kazakhstan power system, provides a detailed assessment of the impacts from LCC HVDC on the transient stability of the AC system. Different control modes of LCC HVDC have been assessed and the best combination has been proposed and tested in the detailed Kazakhstan power system model. Dynamic simulation studies are carried out for different fault conditions and comparisons are made with the case where AC transmission line is installed instead of DC. Test results are used to show that HVDC links improve the transient stability in comparison to the case with AC transmission line when fault is located at rectifier side or in the middle of the parallel AC line.

Currently, traditional electricity consumers are now shifting to a new role of prosumers since more integration of renewable energy to demand side. Accurate short-term load demand forecasting is significant to safe, stable, and reliable operation of a renewable energy-dominated power system. In this paper, a short-term load forecasting model based on a bidirectional long short-term memory network (Bi-LSTM) using kernel transfer operator is proposed to achieve short-term load demand forecasting. To consider the influence of seasonality, holiday effects and weather on load demand forecasting, and simultaneously to improve the accuracy and performance of the forecasting model, this paper implements the dimensionality reduction of the input data by introducing an improved kernel transfer operator based on the Perron-Frobenius method. On this basis, a Bayesian Bi-LSTM for short-term load demand forecasting is formulated to obtain the probability prediction interval of load demand. To verify the validity of the proposed method, the actual historical load demand in a certain region in China was used for model training and verification. The forecasting results are compared with several conventional load demand methods using probability prediction technics. Simulation analysis shows that the proposed method can effectively reflect the short-term uncertainty of load demand, and is superior to the conventional methods in terms of forecasting accuracy and computational performance.

The increasing level of wind power integration using doubly fed induction generators (DFIGs) has implications for local frequency support as a consequence of decoupling between DFIG rotor speed and grid frequency. To ensure reliable and stable power system operation with DFIG integration, supplementary inertial control strategies are required. Conventional inertial control algorithms which use the rate of change of frequency (RoCoF) and frequency deviation loops (droop loop) require great effort to determine appropriate gains suitable for all power grid and wind speeds. In this paper, the influence of supplementary inertial control loop parameters on the inertial response and power system frequency are analysed. An active control strategy is proposed for frequency regulation using variable gains in the frequency deviation loop for the inertial controller. The variable gain control approach is shown to actively respond to system changes to improve the performance. The controller is compared with the widely used PID method. The proposed method is shown to enhance the frequency nadir and guarantee steady DFIG operation.

In a modern power system, stable operation of the electrical system is a major concern. For the stable operation of power system, it is desirable to access the effect of unforeseen events and identification of more sensitive nodes. The most outstanding job of distribution engineers is to simulate the power system for corrective action. Probabilistic power flow (PPF) is a tool that can effectively access the performance of power system network over most of its working conditions taking into account the unforeseen events. In this paper, a new PPF model is developed to evaluate power system network taking into account the uncertainty with input random variables, such as wind energy, loads, generation outage, and branch outage. This model is based upon the two well-known methods, Monte Carlo simulation (MCS) and point estimation method (PEM). For the sake of, computational efficiency and results accuracy Box-Muller sampling equation was used with MCS and $2m+1$ concentration scheme was used with PEM. The proposed model was investigated by using modified IEEE 14-bus standard test system.