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Standalone multi‐energy hub is the next frontier of electric grid modernization. It is vital to optimize the standalone multi‐energy hub capacity configuration to enhance the hub reliability, economic efficiency, and sustainability. Therefore, this paper proposes a novel multi‐objective capacity configuration model for standalone multi‐energy hub considering electricity, heat and hydrogen energy uncertainty. First, the standalone multi‐energy hub model with electricity, heat, and hydrogen energy is established. It takes into account photovoltaic generators, wind generation, combined heat and power units, power to gas, gas boiler and hydrogen storage tank to meet the electrical, thermal and hydrogen energy demands. At the same time, in order to solve the influence of uncertainty on hub capacity configuration, the typical source‐load scenarios are established considering the uncertainty of wind speed, solar radiation and energy demands. On this basis, the objective functions and constraints of the capacity configuration model are presented. The improved hybrid multi‐objective particle swarm optimization algorithm and fuzzy membership function are used to solve the model. Finally, case studies verified the effectiveness and rationality of the proposed model.

The rapid development of renewable energy and the continuous growth of peak load bring new challenges to the dispatching capacity of generation side. In view of the possible mismatch between power generation of renewable energy and the load, we propose an integrated optimal dispatching strategy model of power generation and consumption interaction in this paper. Among them, the generation side resources include wind power, photovoltaic and battery energy storage and the load side dispatching resources include transferable load, interruptible load and electric vehicles. The model takes the benefits of generation side and the benefits of load side as objectives. Moreover, three different dispatching orders are put forward, which are random dispatching, interruption and transfer of load before electric vehicles charging and discharging, electric vehicles charging and discharging before interruption and transfer of load. In addition, we propose seven different dispatching combinations based on the optimal dispatching order to analyse the response ability of different load side dispatching resources. Multi-objective Genetic Algorithm and the method of technique for order preference by similarity to an ideal solution are applied in this study to obtain the optimal results. It can be identified that the response ability of different load side dispatching resources is different, and the overall dispatching can improve the benefits of generation side and the benefits of load side. Meanwhile, the proposed strategy considers the willingness of the load to the greatest extent and effectively improves the utilization rate of wind and solar power generation.

This paper focuses on the development of smart grid in the trends of the energy Internet, analyze the development situation of smart grid and studies the requirements for the construction of major advanced smart grid demonstration areas in China. Under this background, this paper proposes medium and long term China smart grid development strategies, key tasks, technical routes and implementation plans. And planning practices in typical regions are carried out to support the implementation of major national strategic decision-making deployments.

Aiming at the lack of top-level planning ideas and implementation schemes in the development of Ubiquitous Power Internet of Things, this article proposes the ideas named “around one goal, planning six areas, and creating eighteen key projects”. And the 18 key projects with " Energy business datamation, Energy data servitization, Energy service valuation, Energy value ecological cultivation, Energy ecological business updation” are proposed as the planning implementation path, they provide planning ideas and proposals for regional Ubiquitous Power Internet of Things planning and construction.

Smart meter is a digital meter capable of two-way communication between power supply companies and users, and it is able to manage and adjust the power consumption of users’ various electrical equipment automatically. As the eye and data source of the power grid, the smart meter is also the ports where grid companies interact with electric vehicle charging facilities. By expanding the functions of the smart meter, it can manage the charging facilities in the society effectively. It is playing an important role in optimizing the load characteristics of the power grid, improving the quality of power consumption, and increasing the economic benefits of power supply companies. This paper introduces the functions of smart meters when interacting with electric vehicle charging facilities, analyzes how power supply companies use smart meters to manage electric vehicle charging facilities, and discusses the deeper application prospects of the smart meter.

In order to promote the construction of the Ubiquitous Power Internet of Things scientifically and effectively, this paper considers the characteristics of each region comprehensively according to the needs of local and municipal companies, and forms three types of construction tasks with basic, improved and leading characteristics differentially. Key constructions in eight directions are defined, including production operations, customer service, construction management, energy ecology, enterprise intermediate platform, smart internet of things, basic support and technology research, etc. The objectives and effectiveness of twelve specific construction projects are cited as examples, which provide references for promoting the construction for prefecture-level power supply companies comprehensively.

Aiming at the lack of regional overall planning and reasonable construction schemes in the development of the Ubiquitous Power Internet of Things, based on the form and planning boundaries of the current development, this paper proposes a planning about "aiming at one goal, planning six areas and creating eighteen key projects". About the 18 key projects, the overall technical architecture are about six major areas, including "application innovation, platform construction, communication network, information perception, security protection, business development". And the planning implementation path is "Energy business datamation, Energy data servitization, Energy service valuation, Energy value ecological cultivation, Energy ecological business updation ". They provide technical framework and planning proposal suggestions for regional Ubiquitous Power Internet of Things planning and construction.

The power terminal communication access network is an important part of the power communication network and an extension of the power backbone communication network. With the rapid development of communication technology, the technology applicable to the terminal communication access network is diversified. The most suitable communication access technology for different power terminal communication services is the prerequisite for improving communication efficiency and ensuring communication service quality. This paper designs the communication technology optimization matching algorithm based on subjective preference and objective mathematical analysis. The algorithm weighs the preference of the business to the attributes and the importance of each attribute itself, and finally derives the most suitable communication technology for different power communication services, which fundamentally improves the performance of the terminal communication access network.

The development of power wireless private network planning work has very important guiding significance for realizing wireless network coverage in the target area and optimizing construction investment. However, the power wireless private network has the characteristics of limited base station location, fixed service terminal location, and access priority. The existing wireless public network planning and location strategy is not applicable to the background of the power wireless network. This paper analyzes the power wireless private network access service, and gives the overall plan process. Before establishing the modified model, some calibration requirements, continuous wave(CW) test steps and data processing are put forward.

Based on the propagation model correction technique, this paper establishes the model of the influence degree of terrain, obstacles and human environment on the path loss in radio wave propagation. After completing various steps, such as project establishment, transmitter setting, data collection and processing, K-factor correction, and result verification in the calibration software, a general propagation model suitable for the region is obtained. Furthermore, the wireless private networks planning expected value can be achieved.

Aiming at the existing problems in power communication network and communication management project, based on the planning forecasting strategy of business priority and the evaluation index system of planning effectiveness, the overall structure of power communication network considering global information fusion is constructed. And the whole process information system platform of power optical transmission network is built. Relying on the platform of communication planning system, the weaknesses of provincial power communication network in China are analyzed, and the provincial and prefectural target network frame of 13th Five-Year Plan in China (2016-2020) communication network is constructed. The technology supports the construction of provincial backbone communication network project and the planning of power wireless private network project.

This paper reviews the development of power communication network, followed by the situation and demand that power communication network is facing. Aiming at the problems, such as lack of global planning platform for power optical transmission network, lack of precise planning for power wireless private network and lack of whole process connection for planning information, the planning forecasting strategy and planning effectiveness evaluation index system based on business priority are put forward. The whole process information management system structure is constructed, which is composed of the whole process information organization module, the technology module and the collaboration module, etc. It will cover three major stages of power communication network in an all-round way (communication network planning, construction and post-evaluation stage), and form the "headquarters-provinces-municipalities-counties" four-level linkage scientifically.

Power communication network is an important supporting network of smart power grid. According to the complex characteristics of power communication network to identify the structural vulnerability of power communication network, how to carry out comprehensive and effective assessment of its vulnerability, this paper proposes an effective assessment method based on the vulnerability loss of power communication network. Firstly, the topology modeling of power communication network is carried out. According to the static parameter characteristics of the network and the static statistical characteristics of the network, the typical model corresponding to the complex network is pointed out, and its characteristics are summarized and verified. Secondly, considering the physical layer and the network layer comprehensively, the importance loss of the physical layer and the maximum connectivity rate of the network layer are defined, and then the vulnerability loss of the network is finally obtained by giving the corresponding weight value respectively, which is used as the vulnerability evaluation index of the power communication network. Finally, based on the simulation background of the actual power communication network in a province, the effectiveness of the method in this paper is proved by comparing the vulnerability loss of different curves.

Distribution transformer is the basic unit of power grid operation and the carrier of data in power grid construction. In real life, heavy overload of equipment in the distribution network will damage the equipment and affect the power supply demand and normal production and life of the distribution area. In response to this problem, this paper applies machine learning and neural network models to the heavy-overload estimation of main equipment in the distribution network. First, select nine machine learning and neural network models such as the SVM algorithm to apply to equipment heavy overload estimation, and use the K-Means clustering algorithm to define the classification of heavy overload tags; then extract the feature variable set from the data set, and select the Apriori algorithm to perform Frequent pattern mining, derive heavy overload association rules. After comparing the accuracy and loss changes of each training model, the optimal SVM algorithm is selected to adjust the parameters based on cross-validation and grid search, and the accuracy is increased by 2.6% compared to the previous one.

The variability and intermittency of renewable energy and power load bring great pressure to the dispatch of Micro-Grid, especially intra-day dispatch. In order to reduce the intra-day dispatch pressure, this paper proposes a data-driven two-stage day-ahead dispatch model for islanded Micro-Grid. The first stage dispatch model considers multiple demand responses, and applies phase space reconstruction and machine learning to predict renewable energy output and power load. Multi-objective particle swarm optimization algorithm is used to solve the first stage dispatch model. For the obtained Pareto Front, weight multiple objectives by entropy weight method to get the optimal solution. Since the deviation between the predicted value and the actual value can lead to renewable energy curtailment or load loss, the role of the second stage is to predict the renewable energy curtailment and load loss after the first stage dispatch. Firstly, extreme gradient boosting is used to predict when renewable energy curtailment and load loss occur. Secondly, extreme learning machine is used to predict the amount of renewable energy curtailment and load loss at the corresponding time points. Finally, linear programming and mixed integer linear programming are used to solve the second stage dispatch model. By comparative cases analysis, simulation results show that the enhancement of demand response to system efficiency is at the cost of increasing dispatch cost and reducing reliability. In contrast, the proposed two-stage dispatch method using regulation reserve capacity not only reduces dispatch cost, but also improves system efficiency and reliability.

With the continuous integration of the power grid and the information network, the vulnerability analysis of cyber-physical system considering the interaction between networks become more important. Based on the complex network theory, a topology model of power cyber-physical network is established, and improved structural entropy is proposed, which considering node differences, edge differences, and node dependency differences. Taking the Hunan Electric Power Cyber-Physical System as an example, the simulation results show that the improved structural entropy can identify important nodes in the power grid. the dependent network is more vulnerable than a single network, nodes with high-degree and high-betweenness play a key role in maintaining the operation of the system, and the robustness of system will also be reduced when a few nodes with low-degree and low-betweenness fail.

This work introduces the dynamic economic dispatch of the micro-grid considering the uncertainty of the renewable energy. Firstly, this paper applies scenario analysis method to deal with the uncertainty of the renewable energy. After scenario generation and scenario reduction, the most representative scenario is selected. Secondly, the integrated optimal dispatching model of the micro-grid is established on the basis of considering the economy and the environmental friendliness. Finally, a case study is carried out in selected scenarios, using differential evolution algorithm to solve the integrated optimal dispatching model of micro-grid.

with a large number of uncertain distributed power supply access to the distribution network, increasing multiple uncertainties in distribution networks brings new challenges to its planning. Considering the uncertainty of load and wind speed, this paper proposes a robust planning method considering multiple uncertainties for distribution network. Firstly, based on life cycle cost and robust optimization, a two- layer robust planning model considering multiple uncertainties is constructed. Then the upper planning scheme is verified with the worst scenario. Finally, the IEEE33 node is used for simulation analysis. Simulation results based on standard example verify the rationality and effectiveness of the proposed method.

Traditional power grid has become an obstacle for society to promote low-carbon economy due to fossil energy abuse. In order to deal with this crisis, a large amount of distributed energy resource is connected to the distribution network, so as to improve the single energy structure. However, the planning technology of traditional distribution network has been unable to meet the requirements of power supply security and stability after multiple distributed energy resources are connected to the distribution network. Based on the above situation, this paper summarizes the planning technology of active distribution network, describes the difficulties and problems frequently encountered in the planning technology of active distribution network. In the end, this paper presents the summary and outlook for the planning technology of active distribution network.

In order to investigate the impact of electric vehicles’ charging-discharging behaviour and demand side response resources on the economic operation of photovoltaic grid-connected microgrid system, a multi-objective model of microgrid economic dispatching with electric vehicles, transferable load and other distributed generations (diesel engines and energy storage unit) is proposed in this paper. The model takes the comprehensive operating cost of microgrid, the utilization rate of photovoltaic energy and the power fluctuation between the microgrid and main grid as objectives. Moreover, four different cases of microgrid economic dispatch considering electric vehicles and transferable load are put forward, which are electric vehicles’ orderly charging and discharging and transferable load participating in demand response in Case 1, electric vehicles’ charging randomly and the transferable load participating in demand response in Case 2, electric vehicles orderly charging and discharging and transferable load not participating in demand response in Case 3, electric vehicles’ charging randomly and the transferable load not participating in the demand response in Case 4. Multi-objective Seeker Optimization Algorithm and the method of fuzzy membership function are applied in this study to obtain the optimal results. The simulation analysis shows that the orderly charging-discharging behaviour of electric vehicles and the participation of transferable load can effectively improve the economic costs, efficiency and security of microgrid economic operation.

Current differential protection is widely used as the main protection in UHV/EHV (Ultra/Extra High Voltage) transmission lines with advantages of simple principle, high reliability and inherent phase-selection capacity. However, as the voltage level and line length increase, the performance of the current differential protection is severely restricted by distributed capacity current. Aimed at this problem, a rapid extraction method of single-phase active current is proposed in this paper. The method first uses single PLL (phase-locked loop) to track the phase of the corresponding fundamental voltage. Then the current signal is transformed from the abc static coordinate system to the pq rotating coordinate through transformation matrix. By filtering out the high-frequency AC signal on p axis with low-pass filter, the active current component remaining being in the same direction with voltage phase can be obtained. On this basis, a novel active current differential protection method is proposed, with the advantages of high sensitivity and strong capacity of enduring transition resistance without requirement for the acquisition of line impedance parameters. Finally, the proposed method is tested by a series of dynamic simulations through PSCAD and experiment. The simulation results show that the method has merits of effectiveness, robustness and rapidity.

The purpose of this paper is to provide a hierarchical and active fault location method in neutral point non-effectively grounded loop distribution network. It analyzes the distribution of loop closing zero-sequence current with single-phase grounding (SPG) fault occurring in two different topologies. According to the variations characteristics of steady loop closing zero-sequence current, fault section can be determined. Then precise SPG fault position can be got using Discrete Wavelet Transform (DWT) and Support Vector Machine (SVM) technology. Even if the fault point cant be located at the first time, the method can still work by repeating the process till the accurate fault position is located. More than 115,200 study cases are simulated on the simulation platform built on PSCAD/EMTP. The results indicate that the proposed fault location method is effective and robust for neutral point non-effectively grounded loop distribution network.

To realise the accurate and real-time compensation of the harmonics of a power system, this study proposes a novel control strategy for shunt active power filter (SAPF), adopting the composite strategy of neural network proportional-integral (PI) control and dual-repetitive controller (DRC). In DRC, one repetitive controller is used to ensure current tracking accuracy and the other one is used to enhance dynamic response. The neural network PI control is adopted to improve response speed by turning the PI parameters adaptively and setting optimisation parameters online. Through the optimisation of this approach and the rational configuration of the hardware and software systems, the SAPF could achieve rapid dynamic response with high tracking accuracy and excellent compensation performance. A 100 kVA industrial prototype active power filter has been developed by using this control strategy. System compensation could effectively reduce the total harmonic distortion values from 26 to 27.7%, 27.6 to 4.25% and 4.57 to 4.35% for each phase of the current. The full response time of the system is < 10 ms.

This paper presents a novel current differential protection scheme for UHV/EHV transmission lines. This method is based on active current component extraction using instantaneous power theory, which is also called ip-iq method, and it has been widely used in APF (active power filter). Adopt three digital PLL (phase-locked loop) to get the positive voltage’s angle and active current containing DC and AC components can be obtained by using dq transformation. The average filter is employed to filter the AC active current component out. This algorithm can eliminate the influence of distributed capacity current fundamentally. Compared to compensation methods, it requires no heavy computation, line parameters and voltage information transmission. Compared to other differential protection methods, it has the advantages of clear physical meaning and simple operation. Simulation results show that the novel protection method is effective and robust, providing a new perspective on transmission lines’ protection.

This paper analyses the configuration characteristics of the shunt active power filter (SAPF) and introduces a novel dead time control strategy in combination with three dimensional space-vector modulation (3D-SVM) strategies. The steps for the 3D-SVM implementation are identified. The switching vectors, 3D-SVM diagram and duty cycle calculation in abc coordinates, as well as the selection of the tetrahedron are discussed in detail. Moreover, based on the analysis of the APF’S dead-time effect with 3D-SVM control, a novel predictive direct current control algorithm is used for the APF’s inverter control. Experimental results together with different control strategy are presented to validate the proposed SVM control strategy for three-phase four-wire system. The experimental results verify the correctness and validity of the proposed 3D-SVM scheme.