Resarch on coordinative optimal dispatch of interruptible load on multi time scale

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

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.

The damage of arc to gas insulation protection will affect the safe and stable operation of power system seriously in the field of high voltage insulation. Therefore, it is a great theoretical value and practical significance to study the mechanism of gas discharge and find out the law of gas discharge under different conditions for ensuring the safe and stable operation of power system. In order to study the variation law of arc channel complexity under different voltage levels, this paper adopts the discharging experiment of needle-plate electrode, adds different high voltage to the needle-plate electrode under other conditions unchanged, carries out many experiments, and collects five groups of discharging channel plans of needle-plate gap under different voltage. The are discharge channel image in the experiment is restored to the three-dimensional image from the space angle, and the fractal dimension of arc discharge channel under different voltage pressure is calculated by box dimension method of fractal dimension. The results show that the complexity of discharge channel decreases with the increase of voltage level, that is, the lower the voltage level and the larger the fractal dimension.

In the distributed load frequency control (DLFC) scheme, the compromised areas by attackers may endanger the stable and reliable operation of the entire power system. A credibility‐based secure DLFC strategy is in this work proposed to sustain the stable operation of the power system under false data injection attacks. In this secure DLFC method, the gradient‐variation‐based credibility metrics are defined to detect potential attacked measurements. Then, the communication isolation decisions are made based on the adaptive thresholds. To compensate the impact of the communication isolation of misbehaving areas, predictions of future measurements by using the average gradient variation of stored healthy data are feeded back to the area controller. Simulation results of a four‐area power system show the proposed secure DLFC can identify and cut off the communication of the misbehaving areas and still maintain the stability of the power system.

To ensure the safe and stable operation of the power system in the power market environment, a transaction model of power reserve ancillary services oriented to interruptible loads is constructed. By analyzing the benefits of interruptible users and power grid enterprises, a transaction model of interruptible load is established based on it. After obtaining the value of the minimum cost of power system to purchase interruptible load, the capacity cost, opportunity cost and standby use cost of power reserve are calculated respectively. The objective function of auxiliary power reserve service transaction model with interruptible load is established and the constraint conditions are set, and then the transaction result of auxiliary power reserve service is obtained by solving the objective function of the model. The experimental results show that the model can effectively calculate the power interruption compensation price of user interruptible load, and obtain the interruptible load transaction results according to the rapid capacity quotation, power quotation, etc. At the same time, the model has the lowest cost of reserve capacity and reserve use cost in a certain period of time, and the application effect is good.

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.

This paper proposes an optimal dispatching model for inter-regional wind power consumption based on gird-wide coordination and multi-time scale. In the space dimension, the tie lines is made full use to adjust the flowing power to realize the gird-wide coordination. In the time dimension, multi-time scale is established to realize the dispatching deviation correction of the next time scale to the previous time scale. To certificate the flash point of our proposed models, we have solved our models with an interconnected regional power grid. It is observed from the experiment that the established models can eliminate the influence of the random fluctuation of wind power on the power grid dispatch. In addition, the model takes the maximum comprehensive benefit of the inter-regional power grid as the objective function, as well as introducing a dynamic abandoned wind penalty factor to arrange the priority of wind power rationally. In consequence, our models improve the capacity of wind power consumption while giving consideration to the economic and environmental revenue of the power grid.

Research on multi-time scale integrated energy scheduling optimization considering carbon constraints

With the increase of capacity and the improvement of economy, doubly‐fed induction generator (DFIG) is gradually becoming the most widely used wind power generator in the world. DFIG has different characteristics of transient operation from the synchronous generator and its short‐circuit current is affected by the converter control mode, thus when there is a voltage sags occurs, the short‐circuit current of the wind farm may contain a certain amount of two harmonic. Power transformer is one of the most important power equipment in power system and the normal or not of transformer protection determines the safe and stable operation of power system. At present, the main protection of transformer is longitudinal differential protection. In order to correctly identify the inrush current, it is usually equipped with two harmonic braking measures to ensure the reliable operation of differential protection. Therefore, when the transformer failure occurs in wind farm, the protection may refuse to operate due to the reason that the short‐circuit current contains a certain amount of two harmonic. Focused on the large‐scale application of DFIG and the lack of the short‐circuit current harmonic characteristics analysis, this work is devoted to the study of two harmonic characteristics and their influence on transformer protection when the grid voltage occurs in a non‐depth drop. Through the analysis of the short‐circuit current, harmonic components under different control modes of converter research the characteristics and production mechanism of the two harmonic currents of the doubly‐fed wind power generator. This also lays a solid foundation for the improvement of transformer protection. Finally, the correctness of the analysis is verified by the experiments of short‐circuit and time‐domain simulation.

The development of power dispatch services to ensure power supply has put forward new requirements for the digitalization, intelligence and servitization of the dispatching system. Based on the data of power dispatch and control, the characteristics of power dispatch services to ensure power supply, and research on intelligent technology of dispatching and control to ensure power supply based on multivariate information, by establishing the data model of power supply services, and applying forms of expression such as knowledge graph, with deep neural network and rule learning technology, this paper explores and develops an intelligent robot of dispatching and control to ensure power supply based on multivariate information, which realizes the functions of interface integration of various service platforms, visualized monitoring of power supply information, and release and submission of power supply information, etc. By building intelligent applications according to the requirements of power dispatch services to ensure power supply, it effectively improves the risk prevention and control level and emergency response capacity of power system to ensure power supply, and comprehensively upgrades the safe and stable operation of power system to ensure power supply.

With the progress and development of domestic power system, the automation, intelligence and informatization of power system have made great progress. However, as an important carrier of national information security and residents' electricity demand, how to ensure the safe and stable operation of power system has become a hot topic. The real-time monitoring of alarm information of power system monitoring system is the basic work of substation, converter station and monitoring center. The traditional way of listing information one by one has been difficult to meet the needs of monitoring center for a large number of substations. This paper analyzes the problems existing in the current monitoring of converter station equipment, introduces 5g high-speed wireless sensor network, optimizes the form of alarm window and abnormal information processing to ensure that the alarm information is effectively monitored.

As the key equipment of power transmission and transformation system, the reliability of power transformer is directly related to the safe and stable operation of power system. In recent years, sulfur compounds in mineral insulating oil makes the transformers in high risk, since these sulfur compounds can react with copper windings to produce semi-conductive Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> S species. This work mainly involved with the study of adsorption removal of sulfur compound from insulating oil by metal modified γ-Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> molding powder. The adsorption mechanism explained by TPD experiment suggested that the activation energy of DBDS desorption from modified γ-Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> was much higher than that of active carbon.

The short-term intermittency evaluation of distributed photovoltaic power

High voltage three-phase three-element combined transformer, widely used in power systems of 10kV, 35kV and the like, is important in guaranteeing the safe and stable operation of power system, and ensuring the fair and equitable metering of electric power. At present, when verified by single-phase verification method, combined transformer exposed to the situation which doesn’t match its actual operation situation, as a result, verification results can’t reflect the true error characteristics of combined transformer. So, it is suggested to adopt three-phase verification method to verify combined transformer. However, when combined transformer is verified by three-phase verification method, it has not been clear yet that what influence electric field generated by voltage has on current error. In this paper, through current error test on combined transformer with three-phase verification method at different voltage, it is discovered that electric field has a larger influence on current error at lower current (especially at 1% rated current),with the increase of current, the influence of electric field on current error decrease gradually till negligible. The use of three-phase verification method and appropriate modification of current error limits are recommended when combined transformer is verified.

It is of great significance for the safe and stable operation of power system to master the fluctuation characteristics of wind power output. On the basis of analyzing a large number of field measured data, a weighted mixed Gaussian probability model is proposed to simulate short-time wind power fluctuation characteristics of wind farm cluster, that evaluation indices to reflect the short-time maximum fluctuation of wind power output and maximum likelihood estimation algorithm based on Expectation Maximization (EM) to estimate model parameters are put forward. This model is compared with various other kinds of probability distribution model and the simulation results show that the weighted mixed Gaussian probability model possesses the highest precision, so as the effectiveness of the weighted mixed Gaussian probability model is verified.