Abstract: Currently there is a way to use for energy storage: batteries for chemical energy storage, super for electric field energy storage, and flywheel batteries for mechanical energy storage. Flywheel energy storage has the advantages of high energy storage density, high efficiency, short charging time, no pollution, wide applicability, no noise, long service life, easy maintenance and continuous operation. Recently the most promising and competitive new energy storage technology - flywheel energy storage technology, relative to other forms of energy storage, by domestic and foreign experts unanimously optimistic. This paper will focus on the composition and operation principle of flywheel energy storage system, the classification of drive control strategy, charging control strategy, discharge control strategy and other aspects. Read More

Abstract: Aiming at the problems of unbalanced load distribution of feeders and low utilization rate of system resources in existing medium voltage(MV) distribution network planning, it is difficult to meet the requirements of future grid construction, Propose a grid planning method of MV distribution network including distributed generator(DG) based on timing characteristics. Firstly, based on the existing grid planning achievements and temporal characteristics analysis, the grid structure and planning strategy of the MV distribution network are formed. Secondly, based on the network planning strategy, establish a dual level planning model for both internal and external distribution networks. The inner model uses comprehensive performance indicators as fitness functions to solve the optimal division of the distribution network grid, while the outer model calculates the distributed power capacity configuration of each grid with the goal of maximizing the consumption of DG. Then, based on the established dual layer planning model for the distribution network, genetic algorithms and self programming algorithms are used to solve the model by interconnecting the internal and external layers. Finally, the practicality and effectiveness of the proposed model and method were verified through practical examples combined with evaluation indicators. Read More

Abstract: Compared with the conventional 24-pulse rectifier, the low-voltage winding of the rectifier transformer must be connected in the y and d modes, so that the voltage phase of the low-voltage side of the transformer is separated by 30° in sequence. This paper uses the phasor method to obtain a set of phase voltages that move towards 15° through the equivalent of three-phase voltages, so that the two sets of voltages produce a phase difference. Then, through decoupling and voltage reduction, the electrical quantity is converted into a signal quantity, the voltage level is reduced, and then the electrical quantity output is obtained to obtain the required voltage value. Finally, the required DC power is obtained through the rectification system. The effectiveness of the reverse model of this paper is verified by comparing the results and efficiency with the conventional 24-pulse rectifier. Read More

Abstract: With the continuous deepening of the Inner Mongolia Power Company's level of informatization and the continuous expansion of the scale of business and application system construction, the company will also enter the era of big data, and the amount of data will show an explosive growth trend. In order to solve the problems of massive data storage and data value mining faced by the enterprise during its development process, research on the application of storage resource pool technology has been conducted. Ultimately, the unified planning, allocation, and management of storage resources have been achieved, greatly improving the utilization efficiency of storage resources. Read More

Abstract: Accurate prediction of wind power is of great significance to reduce the impact of large-scale wind power connection and improve the security and stability of power grid. A short-term wind power forecasting method based on VMD-KPCA and CFSBOA-BiLSTM is proposed. Firstly, the key environmental factors restricting the volatility of wind power are fully considered, and the variational mode decomposition method is used to decompose the wind power and meteorological factors. Secondly, the kernel principal component analysis method is used to reduce the dimension and construct the sub-sequence characteristic data set. Finally, the multi-strategy improved butterfly algorithm is used to optimize the BiLSTM network hyperparameters and establish the CFSBOA-BiLSTM prediction model. The simulation analysis uses the measured data of a wind farm in northwest China. The experimental results show that the combined forecasting model can fully mine the hidden information of the data and improve the accuracy of short-term wind power forecasting. Compared with the BiLSTM model, RMSE, MAE and MAPE decreased by 60.37%, 66.6% and 67.59%, respectively. Read More

Abstract: As Xizang's economic development enters the new normal stage, the extensive and highly polluting production mode in the past no longer meets the needs of high-quality economic development in Xizang. Therefore, there is an urgent need to reduce the consumption of traditional fossil energy, develop low-carbon and clean green energy, optimize the energy structure, and promote green and sustainable economic development. Read More

Abstract: In this paper, the electrical test and relay protection of power transformer are deeply analyzed. Firstly, the purpose, classification and common methods of electrical test are expounded, and the processing methods of test results are discussed. Then, the basic principle, device classification and configuration method of relay protection are discussed. Furthermore, the relationship between electrical test and relay protection is analyzed, and their application and significance in power transformer protection are discussed. This paper aims to provide theoretical support for improving the operation safety and reliability of power transformers. Read More

Abstract: Flying cars are becoming a key technology in future transportation, because of their ability to travel fast and to reduce traffic jams. Air shuttles are an important application scenario of flying cars. They can carry 19 passengers, playing a similar role as medium on-road buses. However, it is still unclear which has a better performance on carbon emissions, air shuttles or road buses. Based on the analysis of the flying car’s flying process, lifecycle greenhouse gas emissions from flying cars which are used as air shuttles are calculated and further compared with on-road bus emissions. For thorough consideration, improvements in battery specific energy are considered, and different propulsion systems for buses are also calculated. The results show that at the current battery technology level (200 Wh/kg specific energy), air shuttles have much more emissions than all kinds of road buses. But if the battery technology progresses to the level of 2030 (400 Wh/kg specific energy as predicted), air shuttles will have a lower emission than fuel cell buses within the range of 250 km, and will be competitive with battery electric bus that carries an equal number of passengers. Read More

Abstract: BiFeO3-based lead-free ferroelectrics have attracted great interest in energy storage applications due to their high spontaneous polarisation strength, however, the high residual polarisation strength (Pr) has become a serious obstacle to their practical application. In this work, (1-x)Bi0.88Nd0.10Sm0.02FeO3-xBaTiO3+0.1 wt% MnO2 ceramics were designed by ion doping and solid solution modification strategies, where Sm3+ and Nd3+ promote ionic disorder and reduce leakage current, and the introduction of nano-BaTiO3 induces the crushing of long-range ferroelectric structure into polar nano-regions with enhanced relaxation. As a result, the ceramic is able to maintain a high maximum polarisation intensity while possessing a low residual polarisation.The recoverable energy density (Wrec) of the 0.50BSNF-0.50BT ceramic is as high as 3.61 J/cm3 with an efficiency of 70.11%. In addition, the 0.50BSNF-0.50BT has good thermal stability (Wrec variation <7%) at 25-120°C. In the charge/discharge test, the Wdis was 2.58 J/cm3 and the discharge time was 273 ns. These results indicate that the 0.50BSNF-0.50BT ceramic is an ideal candidate as a material for energy storage applications. Read More