Power Grid Structure Research Articles

Power grid fault diagnosis using polar PMU data plots

With the increasing complexity in power grid structures and fault characteristics, fast and accurate power grid fault diagnosis has become increasingly important for the safe and stable operation of power grids. Synchronous phasor measurement units (PMUs) are a promising approach to power grid fault diagnosis because of their synchronization, speed, and accuracy. In this study, PMU data are used as the source of fault information, and these data are transformed into polar plots. A power grid fault diagnosis method is proposed based on the polar PMU data plots and a convolutional neural network (CNN). The method is shown to reduce the computational cost and improve the efficiency of fault diagnosis. The method includes three steps. First, different types and quantities of electrical data were selected for identifying faulty equipment and fault types, and the corresponding PMU data were transformed into a polar plot using polar coordinates in different dimensions. Second, the faulty equipment detection model and the fault type classification model were constructed, and the faulty buses, lines and transformers were determined along with their various fault types based on the fault information features extracted by the CNN from the polar PMU data plots. Finally, a set of complete power grid fault diagnosis processes and a block diagram are proposed, and the validity and practicability of the proposed method are evaluated using actual measurement and simulation PMU data of the power grid.

Research on open source platform of digital power grid based on CEPH open source distributed storage technology

In order to ensure the operational quality of open source platform and improve the security of power grid information management, a research method of digital power grid open source platform based on CEPH open source distributed storage technology is proposed. The open source platform structure of digital power grid is optimized by using the operation of object to block mapping and human-computer interaction function of CEPH platform. CEPH open source distributed storage is used to optimize the information management function of digital grid open source platform and improve the effect of grid data and information sharing. An adaptive quantization strategy is designed to dynamically determine the load factor weightthe weighty of load factor of the digital grid open source platform and improve the resource storage performance of the platform. The test results show that the digital grid open source platform based on CEPH open source distributed storage technology has low memory occupancy, data processing of high efficiency and good system load balancing ability, which meets the needs of information security and data processing of the digital grid open source platform.

Research on Simulation of Distribution Network Engineering Scene Based on 3D GIS Technology

With the rapid development of the power system and the increasing complexity of the power grid structure, users’ demand for information-based management of the power distribution network is growing, and the need to improve various power production service standards is becoming increasingly urgent. Geographic information systems (GIS) are a natural combination of geographic and data attributes that are particularly well suited to the management of urban pipeline systems such as distribution and telecommunication networks. This paper discusses the current application characteristics and challenges of 3D GIS in the power system. A 3D graphic analysis model of the power grid and its realization method are proposed using 2D GIS and scene simulation technology combined with object-oriented design method. The problems that exist in current urban distribution facility management are solved in this paper through the effective integration of information construction and distribution facility management, and the goal of refined management is achieved on this basis. More and more complex 3D spatial data can be processed more realistically and intuitively with 3D GIS.

GIS-Analysis Of The Ural Power Grid Vulnerability To The Impact Of Sleet And Wind

In this paper, we describe an experiment of complex power grid structure and wind and sleet mapping of territory using two different network indices: standard edge betweenness centrality and new author’s index – electrical grid centrality. Such analysis of the network allows to identify power lines with high load which could be vulnerable elements of the power grid. It is very important for strategic planning of power grids to reduce the risk of accidents by distributing loads across several lines so that they will be able to reserve each other. As a case territory for this research, we took the Ural united power system in Russia which is greatly exposed to different sleet and wind according to the statistics of the power grid operator. The degree of natural hazard consequences could be compensated by the network structure through alternative paths of energy supply or vice versa – increased if they are absent. At the same time, in this paper we consider that power grids have their own features from the graph theory point of view, for example multiple (parallel) edges, branches, different types of vertices. The existing index of edge betweenness centrality does not perfectly cope with them. We compare two indices characterizing power line importance within the system – betweenness centrality and electrical grid centrality and analyze the network structure features together with the spatial distribution of sleet and wind. As a result, we could identify bottlenecks in the study network. According to this study the most vulnerable power lines were detected, for example 500 kV Iriklinskaya CHP – Gazovaya and 500 kV Yuzhnouralskaya CHP-2 – Shagol power lines, that supply big cities such as Chelyabinsk and Orenburg and a bunch of industries around them.

Review of Grid Codes and Implementation for Wind Farm Frequency Regulation

With the increase of wind power and the construction of UHVDC transmission, the wind turbines must actively participate in the system frequency regulation through inertia response and primary frequency regulation to ensure the safe and stable operation of the power system. However, the wind power penetration rate and the grid structure of each regional power grid are different, so that the corresponding power grid codes are also slightly different. Firstly, this paper introduces the specific requirements of wind power grid guidelines in typical countries and regions, and with reference to the experience of international frequency regulation codes, it puts forward the proposed implementation mode of active support new energy frequency regulation suitable for domestic power grid, and the recommended parameter for wind farm frequency regulation. Secondly, this paper summarizes the frequency modulation implementation schemes of the main wind turbine manufacturers in the world, and demonstrates the potential frequency modulation capability of the wind turbine. Finally, the challenges and realizable solutions of virtual inertia and primary frequency regulation of wind farms are prospected, and some suggestions are given.

Impacts of Grid Structure on PLL-Synchronization Stability of Converter-Integrated Power Systems

Small-signal instability of grid-connected power converters may arise when the converters use phase-locked loops (PLLs) to synchronize with a weak grid, i.e., operating in grid-following mode. Commonly, this stability problem (referred to as PLL-synchronization stability in this paper) was studied by employing a single-converter system connected to an infinite bus, which, however, omits the impacts of the power grid structure and the interactions among multiple converters. Motivated by this, we investigate how the grid structure affects the PLL-synchronization stability of multi-converter systems. Moreover, we provide guidelines on how to improve the PLL-synchronization stability of multi-converter systems by PLL-retuning, proper placement of converters, or enhancing some weak connections in the network. Finally, we validate our findings with simulation results based on a 39-bus test system.

Review of MVDC Applications, Technologies, and Future Prospects

This paper presents a complete review of MVDC applications and their required technologies. Four main MVDC applications were investigated: rail, shipboard systems, distribution grids, and offshore collection systems. For each application, the voltage and power levels, grid structures, converter topologies, and protection and control structure were reviewed. Case studies of the varying applications as well as the literature were analyzed to ascertain the common trends and to review suggested future topologies. For rail, ship, and distribution systems, the technology and ability to implement MVDC grids is available, and there are already a number of case studies. Offshore wind collection systems, however, are yet able to be implemented. Across the four applications, the MVDC voltages ranged from 5–50 kV DC and tens of MW, with some papers suggesting an upper limit of 100 kV DC and hundreds of MV for distribution networks and offshore wind farm applications. This enables the use of varying technologies at both the lower and high voltage ranges, giving flexibility in the choice of topology that is required required.

Research on Matter Element Model in Power Grid Analysis

With the increasing complexity of power system grid structure and development environment, the dimensions and factors that need to be considered in the power grid statu analysis also become complex. It is necessary to judge the aspects of power grid that need to be improved through the analysis results. This paper constructs an evaluation index system of power grid, including safety reliability, operation efficiency, operation margin of power grid, power grid structure and equipment level. Based on the index system, an evaluation model combining matter-element model and entropy weight method is proposed. Matter element model can not only quantitatively judge the development level of power grid, but also find out the weakness of power grid and put forward the direction of its improvement. Finally, a case study is proposed to show that the matter element model analysis in power grid comprehensive evaluation is feasible and has a good evaluation accuracy.

The Vulnerability of the Power Grid Structure: A System Analysis Based on Complex Network Theory.

The safety and reliability of the power grid are related to national power security, economic development and people’s daily life. The occurrence of extreme weather changes the external environment greatly. Including generators and transmission lines, many power grid units cannot resist such a huge attack and get damaged easily, which forces units to quit from the power grid running system for a while. Furthermore, if the number of influenced units is high enough, the whole power system will be destroyed by cascading failure caused by extreme weather. Aiming at dealing with the cascading failure emergencies, this paper is trying to improve the traditional power structural vulnerability model so that it can be used to discuss extreme weather and propose a theoretical topological model to help scholars measure the damage caused by extreme cases. Based on previous research in this field, this paper utilizes complex network knowledge to build the power grid topology model. Then, considering extreme cases and the three attack modes simulation process, this paper makes use of the characteristic parameters of the power grid topology model and designs an algorithm, according to the realistic situation of the propagation mechanism of cascading failure of the power grid model as well as extreme weather research. Finally, taking IEEE-30 and IEEE-118 node bus system as examples, which shows that the structural vulnerability method proposed in this paper can properly address the mechanism of unbalanced load of cascading failure of power grid units under extreme conditions and can provide theoretical reference for preventing and reducing the impact of extreme cases on power grid which improves the reliability of the power grid.

Research on Improving Flexibility of Thermal Power Units by Flue Gas-water Heat Exchanger

The proportion of renewable energy in the power supply structure of Shandong power grid is increasing day by day. Thermal power units inevitably face deep-peak shaving and frequent-peak shaving. The problem of thermal power contradiction is prominent when thermal power units are heating in winter, which has a negative impact on the security and stability of power grid and the consumption of renewable energy. Traditional thermoelectric decoupling technology has some problems such as narrow load adjustment range and poor overall energy utilization efficiency. A scheme of adding flue gas-water heat exchanger is proposed to supplement the traditional IP cylinder extraction technology for heating. According to the calculation, the minimum electric power of flue gas heating mode is significantly lower than that of traditional heating mode under small heating demand, and the maximum and minimum electric power of hybrid heating mode are better than that of traditional heating mode under the same heating demand, and the maximum heating capacity under the mixed heating mode is significantly increased, which can improve the operation flexibility of the unit and enhance the thermoelectric decoupling ability of the unit.

Research on Collaborative Planning Technology of New Energy Power System

In this paper, the collaborative planning technology of new energy power system was intensively studied, and the model of collaborative planning of new energy power system was established after considering the power structure, power distribution, coordination and optimization of power grid, limited resources, peak load regulating of power system and access of new energy. The results of numerical examples show that this model can guarantee the safe and stable operation of the power system, reduce the cost of investment, and improve the capacity of the power system to absorb new energy.

Research on the Whole Model Splicing Problem of the Provincial and Regional Power Grid Based on Dispatching and Control Cloud

With the increasing expansion of power grid scale and the increasing complexity of power grid structure, the integration of power network is becoming more and more obvious. The existing real-time model of power network can no longer meet the requirements of network analysis and calculation. In order to improve the accuracy of online analysis and application function of power grid, a whole model splicing method of the provincial and regional power grid is proposed, and the modeling method of boundary equipment, boundary splicing method and processing of boundary T connection lines are studied. By applying the whole model splicing scheme on Tianjin Power Grid, and validating the result, the method can improve the accuracy and rationality of the result for whole model splicing of the provincial and regional power grid, at the same time meet the requirements of various network analysis and calculation.

Study of offshore wind power penetration rate in gas turbine generator platform power grid

Because of the energy supply of the offshore oil platforms mainly relies on the supply of gas turbine, the development of renewable energy will become a rich energy supply for offshore oil platforms and a reliable way to improve the stability of the grid of the platforms. This paper developed the simulation model of offshore oil gas turbine platform power grid, simulated the hybrid power grid structure, the energy storage of frequency regulation, high wind power penetration rate, wind power and gas turbine power frequency stability and fault treatment. The method of increasing renewable energy penetration rate was proposed, and the hybrid energy coordinated control strategy of offshore oil platform was also carried out. Based on the weakly connected distributed offshore oil platform power grid project, this paper studied the influence of wind power and turbine power penetration rate on the power grid, in order to explore, determine and verify the limit of high wind power penetration rate under the condition of “large generation machine and small grid”. The simulation experiment of high wind power penetration rate under the condition of different load conditions and different wind speed limits were discussed, on the basis of research the influence degree of the stability of power grid frequency of low wind power swings, as well as to the wind power is given priority to with gas turbine mainly in both cases the advantages and disadvantages of the grid system, and attempt to put forward the corresponding switch control strategy.

DNN-Based Distributed Voltage Stability Online Monitoring Method for Large-Scale Power Grids

With the increase of power load demand and the complexity of power grid structure, the problem of voltage stability is becoming more serious, and it is urgent to study the countermeasures. In this paper, a DNN-based distributed voltage stability online monitoring method for large-scale power grids is proposed. Unlike the traditional load margin methods, the proposed method uses a local index load impedance modulus margin (LIMM) index to determine the optimal installation locations of PMUs, which is more efficiently. Moreover, the DNN is applied to learn the nonlinear relationship between the power system operation state and its corresponding LIMM. By this way, the corresponding LIMM value can be predicted through the state variables of nodes from the installed PMUs. This method can greatly improve the calculation speed of LIMM and assess the system voltage stability level in real-time, which help the system operator to judge the operating state and take measures in time. Finally, the proposed method is tested on the 14-bus system and then on the 118-bus system respectively, and the simulation results verify the effectiveness and correctness of the proposed method.

Study on Life-Cycle Energy Impact of New Energy Vehicle Car-Sharing with Large-Scale Application

Based on the life cycle assessment theory, the system of energy impact assessment is established relying on the demonstration project of new energy vehicle (NEV) car-sharing in Wuhan, Hubei province in China. The energy impact caused by NEV car-sharing is quantitatively analyzed. The results show that the NEV car-sharing business model needs to meet some operating conditions to obtain energy benefits. According to the operation scale of 3,000 vehicles, this demonstration project will lead to a decrease of annual gasoline consumption by 1,853t, while the power consumption will increase by 3.36GWh. The key factors affecting the energy benefit of NEV car-sharing include the average daily mileage of vehicles, energy consumption per 100km, operation period, vehicle class, power grid structure, and other aspects. Operators can improve energy benefit from two aspects: vehicle model selection (Class A0 and Class A00 should be preferred) and operating intensity (increasing the average daily mileage and operation period).

Application of Artificial Intelligence Technology in Power Grid Enterprises based on Enterprise Architecture Method

The rapid development of contemporary new information technology provides new opportunities and challenges for power grid enterprises. As a new technology with rapid development, artificial intelligence technology has begun to play an important role in related fields. Because of the complexity of power grid enterprise structure, how to realize the in-depth implementation of artificial intelligence has become the current concern of power grid enterprises. In order to solve the problem, the enterprise architecture method is used to deeply analyse the power grid enterprise architecture, and the application of artificial intelligence is clearly planned according to the architecture system level. Based on the planning of business category, application category, technology category and data category, artificial intelligence can be applied to complex power grid structure more thoroughly. Successful application cases of artificial intelligence in power grid enterprise are be used as an example analysis. The application of artificial intelligence technology in power grid enterprises, the efficiency and ability of enterprises, and the pace of energy transformation will be improved.

Application of Matter Element Analysis in Power Grid Development Diagnosis

The structure and form of modern power grids are becoming more and more complex, and there are many indicators and factors that need to be considered to evaluate the development status of the power grid. In order to diagnose the development level of power grid, the index system is reconstructed, which includes seven dimensions: the coordination of power grid development speed, the coordination of power grid development scale, the coordination of power grid structure, the security and reliability of power grid, the level of equipment, the utilization efficiency of power grid and the development benefit of power grid, the construction principle and index selection basis are given. When dealing with contradictory problems in reality, methods combining quantitative and qualitative can be applied to study. The matter element analysis method is applied to power grid development diagnosis, and a model of power grid development diagnosis based on matter element analysis is established, the model can not only diagnose the development level of power grid, but also determine the key factors that affect the diagnosis results, and give suggestions for improvement. The practical example verifies the feasibility and rationality of the method, which has good evaluation accuracy and prediction effect.

Research on terrain aerodynamics analysis of power grid structure at different temperature

The distribution of near-surface meteorological elements will be greatly affected by topography and other factors, such as wind, which making the dynamic structure of the micro-topography area passed by the power transmission and transformation equipment more susceptible to micro-topography climate. The single hill is one of the typical topography in the micro-topography. This paper studies the variation of buoyant flow and temperate circulation in a typical long hilly terrain. Integrating factors such as buoyancy, turbulence and micro-topography, the separation vortex simulation technology is adopted to the special conditions of microtopography climate. The effect of different surface temperatures on the wind field of the power grid is described in detail. Experiments in the thesis show that the difference in surface temperature will directly affect the speedup ratio. Compared with the change of air temperature, when the surface temperature is higher, the acceleration effect is less obvious, but when the surface temperature is lower, the acceleration effect is more obvious.

Research on Multi-level Distribution Strategy Based on Energy Internet

Smart city energy Internet is to comply with the trend of sustainable energy development, urban power energy as the center, comprehensive utilization of all kinds of energy, especially renewable energy, to achieve interconnection and common optimization. Based on the background of distribution network in Disney Park, this paper studies the regulation, operation and management strategy of distribution network of smart city energy Internet. This paper describes the characteristics of the energy Internet, and then analyzes the key technologies that affect power grid regulation, operation and management. The paper investigated the distribution network construction in Shanghai Disney Park under the background of urban energy Internet pilot region to understand the allocation of distributed energy in the park grid. Through simulation calculation and analysis, this paper puts forward a distribution network regulation and management scheme suitable for the characteristics of energy Internet. In this paper, the study found that with the rapid development of power grid, especially all kinds of distributed energy access, the new lines are becoming more. In a wide range of power grid structure is becoming more and more complex, in order to ensure the reliability of power supply and power supply quality, scientific regulation under the background of urban energy Internet development mode, enhancing the management level of power grid is the inevitable developing trend of power grid.

Technology Research on Panoramic Situation Awareness of Operation State of Smart Distribution Network

With the increasing complexity of power grid structure, operation scheduling becomes more difficult, and the risk of blackout is also increasing. Therefore, it is particularly important to be able to timely and effectively perceive the security situation of smart power grid. The panoramic situation awareness technology of smart distribution network operation state mainly includes situation detection technology, situation perception technology and situation prediction technology. In the stage of situation detection, the collection and storage points of power big data are analysed from two aspects of internal and external factors, and the security situation evaluation system of power grid is constructed. In the phase of situation perception, HDFS, Hadoop, Hive and other technologies are used to obtain the security situation assessment value of smart grid to realize the comprehensive evaluation of the security situation of power grid. In the phase of situation prediction, a deep neural network model is constructed to complete the panoramic situation prediction of smart grid operation state.