A positive and negative sequence current measuring device and method based on an electric energy metering platformXia, Wu; Liu, Youqiang; Tian, Xianggui; Qin, Xiankun; Shen, Diqiu
doi: 10.1088/1742-6596/2503/1/012068pmid: N/A
At present, the current positive and negative sequence extraction methods are all based on high-performance analog-to-digital converters and need high-performance microprocessors. Or the negative sequence current measurement circuit is constructed using an analog operational amplifier, and the phase shifting method is used to achieve the measurement purpose. The above methods need to be implemented by chips with high computing power. They even need to build an additional positive sequence current measurement circuit, which makes the circuit more complex and cost-effective. This paper proposes a positive and negative sequence current measuring device and method based on the electric energy metering platform. Through the external phase, the current access device is to be measured using the power measurement value formed by the voltage channel, current channel, and multi-function measurement channel corresponding to the single-phase metering chip of the measurement unit, the included angle of phase current can be calculated, thus realizing the calculation of positive and negative sequence current. It avoids using high-performance analog-to-digital converters, effective value, frequency tracking, phase measurement, and other complex algorithms, reduces the computational requirements for MCU master chip, and reduces the development difficulty and cost.
Optimal Dispatching Method of Integrated Energy System of Electrothermal Interconnection Based on Energy FlowQian, Kejun; Liu, Yi; Li, Yafei
doi: 10.1088/1742-6596/2503/1/012021pmid: N/A
Aiming at the problem that the total amount of coal consumption and the abandoned wind is too high in the actual operation of the current integrated energy system of electric heating and interconnection, this paper studies the design of the optimal dispatching method of the system from the angle of energy flow. The potential energy dissipation rate of the heat source, heat exchanger, heat pipe network, and other structures in the system is described in mathematical form, and a complete system energy flow model is constructed by combining them. On this basis, the heat load of system users is analyzed and predicted from the angle of energy flow. Finally, the system is divided into power and gas grid variables, optimized to realize distributed multi-objective optimal scheduling. By comparing the operation of the system before and after the optimal scheduling, it is found that the total coal consumption and the total abandoned wind during the system operation are reduced after the optimal scheduling, which proves that the optimal scheduling method has a very high practical application value.
Research on Levitation Force Control of an Axial-flux Hybrid-Excitation Generator with PI-Based Torque DistributionChen, Jiming; Xu, Chongwang; Zhu, Jingnan; Liu, Jing
doi: 10.1088/1742-6596/2503/1/012033pmid: N/A
An asymmetric-primary axial-flux hybrid-excitation generator (APAFHG) has already been proposed to improve the starting performance of vertical axis wind turbines. However, the double-stator single-rotor structure causes a problem: different torque proportions create different rotor maglev forces, which will cause fluctuation and negatively impact the rotor bearing and even the operation of the wind power generation system. Therefore, a mathematical model considering the double-stator single-rotor structure and a proportional integral-based torque control strategy considering double-stator distribution are proposed in this paper to help APAFHG offer a good starting performance in vertical-axis wind power generation system and to stabilize maglev force generated by double-stator quadrature axis current simultaneously. Finally, the cooperation control of the maglev force and torque distribution is realized in MATLAB/Simulink, and the rotor maglev force will be relatively stable despite mechanical torque changes, which is a basis for the wind turbine to stably operate as the wind constantly fluctuates in vertical axis wind power system.
Research on A Fast Recognition System for Abnormal Harmonic Amplification Caused by Centralized Connection of Multiple Wind Power PlantsYuan, Ye; Zhu, Daming
doi: 10.1088/1742-6596/2503/1/012023pmid: N/A
This paper introduces the abnormal harmonic current amplification phenomenon that occurred in the electric transmission lines, which is caused by the centralized join-up of multiple wind farm plants, by collecting and analysing the voltage, current, and active power indicators data of harmonic amplification phenomenon, to realize the classification and statistics of abnormal indexes variation trend during the harmonic amplification phenomenon. In this paper, the abnormal indexes are classified by different working conditions, such as normal operating state and harmonic amplification phenomenon, thus the recognition index of harmonic amplification is compared and summarized. After screening the most obvious changed part of the index under two kinds of working conditions, nine feature indexes are chosen to be embraced into the recognizing system. Finally, this method is used to analyse the harmonic amplification events in other moments of transmission lines, and all the harmonic amplification phenomena are identified successfully, which proves the feasibility and accuracy of this method.
Design and Test of Control System of RF Ion Source Test Platform Based on Industrial PLCDuan, Lian; Liu, Zhimin; Li, Yibin; Song, Shihua
doi: 10.1088/1742-6596/2503/1/012082pmid: N/A
Combined with the experimental operation requirements of the radio frequency ion source test platform, a set of the control system is designed with S7-1200 series PLC which is based on TIA Portal and WinCC configuration software. It realizes the monitoring and management of the RF ion source performance test experiment. In order to visualize the operation of the test platform, a fully graphical monitoring interface is designed. And the system has functions such as timing control, real-time status monitoring, parameter setting, data acquisition and recording, historical data query, and alarm recording. After experimental testing, the system meets the control requirements of the ion source performance testing platform and is of great significance for the fault diagnosis and safe operation of the test platform system.
Research on Power Line Extraction and Modeling Technology Based on Laser Point CloudYu, Yongrui; Shi, Lei; Ran, Zhihong; Qiu, Shi; Ou, JinYong; Wu, Shan
doi: 10.1088/1742-6596/2503/1/012044pmid: N/A
For the operation and maintenance management of Power Lines, this paper uses laser scanners to collect data from the research lines, and proposes a method combining random sampling consistency with Euclidean clustering to extract the traverse point cloud data. Firstly, the idea of random sampling consistency is used to eliminate a large number of ground points unrelated to target points. Secondly, Euclidean clustering is used to extract traverse and tower points, and then the tower and traverse are divided by combining tower coordinates and threshold. Finally, the polynomial model is used to construct a fitting traverse. The results show that this method can effectively extract the traverse points and accurately fit the traverse model, and it has certain applicability.
Fracture Propagation Mechanism of Radial Well-Guided Preflush Fluid Acid Fracturing under Injection Discharge ControlGan, Junchong; Qi, Ning; Shen, Yuyang; Zhang, Zhenjun
doi: 10.1088/1742-6596/2503/1/012038pmid: N/A
In view of the low availability of carbonate reservoirs, a radial well-assisted preflush acid fracturing technology is proposed to help communicate oil and gas reservoirs in non-principal stress directions. The acid fracturing model of the auxiliary preflush in the radial well is established by using the extended finite element and the two-scale continuous model. The mechanism of fracture directional propagation under the control of injection discharge is analyzed, and the deflection coefficient is introduced to characterize the guiding effect quantitatively. The effects of different in-situ stress differences and injection discharge on the guiding effect and guiding mechanism of radial wells are studied emphatically. The results show that the induced stress field caused by radial wells and the high-pressure gradient at the end of fractures are the main reasons for the directional propagation of fractures. Horizontal in-situ stress difference is the main factor, which influences the guiding effect by controlling the induced stress field and pressure gradient. The radial well can effectively guide fracture propagation when the local stress difference is less than 3 MPa. The preflush fluid discharge and acid discharge are important factors affecting the guiding effect. The preflush fluid discharge affects the guiding effect by controlling the induced gravitational field and pressure gradient. The preflush fluid discharge between 2.5-3.5 m3·min-1 is most conducive to the directional expansion of acid fracturing cracks. The acid discharge affects the guiding effect by controlling the pressure gradient: the smaller the acid discharge, the more unfavorable the directional expansion of the acid fracture. Compared with the preflush fluid discharge, the influence of the acid discharge is smaller. The theoretical basis can be used in the field application of radial well-assisted preflush fluid acid fracturing technology through the article.
Numeerical Calculation and Test of the Influence of Environmental Vibration on Coriolis FlowmeterLian, Mingming; Zheng, Jin; Li, Zhen; Huang, Dongkui; Xue, Qingfeng; Zhou, Zhaoming
doi: 10.1088/1742-6596/2503/1/012080pmid: N/A
Coriolis mass flowmeters are resonant meters. In this paper, the intrinsic mode of the CMF300 model Coriolis flowmeter under fluid-structure interaction is calculated numerically, and the excitation mode and Coriolis force mode of the Coriolis mass flowmeter in the working state are analyzed. According to the results of modal analysis, the harmonic response analysis of the flowmeter was carried out, and the displacement, stress, and strain response curves of CMF300 under the action of excitation force of different frequency loads were obtained. It provides ideas for the modeling and design of Coriolis mass flowmeters in the future.
Study on the Coupling System of Building Flexible Energy and Energy Storage on Power Grid Operation PerformanceBian, Jiayu; Wang, Yong; Zhang, Zhiyu; Du, Wenhan; He, Yahui; Chen, Weiwei
doi: 10.1088/1742-6596/2503/1/012001pmid: N/A
The flexible building energy storage coupling dispatching framework and optimal dispatching model have been established in this paper by using the multi-levels network dispatching analysis method of the grid system. It would include solving the optimization model with the objective function having the minimum standard deviation and the constraint conditions of charging and discharging power and capacity. Second, a simulation analysis who used an example is implemented based on the typical daily load of a Tianjin district. The findings indicate that: energy storage, construction, and flexible energy use The joint optimization’s respective standard deviations are 1.40, 1.59, and 1.24. The system’s power storage, peak-clipping, valley-filling, and other features have a greater impact than the flexible energy use of a standard structure. The building’s flexible energy use has a good peak shaving effect, which can compensate for the problems caused by the general battery energy storage system’s power and capacity limitations during the generation capacity period. In addition, the battery energy storage system can use the valley time to charge, resolving issues with valley filling optimization and the lack of flexible energy use in buildings. From this, it can be seen that the power storage system and the building’s flexible energy use jointly regulate the overall energy use performance of the structure, which not only achieves good peak load cutting and valley filling effect but also controls other issues such as frequent load fluctuations, large load peak valley difference, and other issues, ultimately leading to high energy utilization in China.