Indices System and Improvement Measures of Distribution Network Equipment Utilization Rate Considering PV ConnectionZhang, Wencheng
doi: 10.1088/1757-899X/452/3/032001pmid: N/A
With the expansion of China’s power system and the advancement of the power market, more and more extensive attentions have been paid on the issue of equipment utilization. The number of distribution equipment accounts for a large proportion, but the utilization of equipment is limited by many factors and distribution utilization is rather low. However, the PV penetration in distribution networks has been increasing in recent years, which changes the way distribution system operates. Therefore, it is necessary to study the distribution equipment utilization considering the PV connection. This paper summarizes the impact factors of the utilization and analyzes the impact of PV on the distribution equipment utilization. An evaluation index system for the utilization is proposed with the consideration of PV connection, which includes electric utilization indices, quantity utilization indices, life-cycle utilization indices, system-coordination indices. In addition, a typical distribution system is established analyzed to explore the impact of PV capacity and location on utilization. And the effect of several technical strategies for utilization improvement is compared and analyzed to guide the actual work of the distribution network.
Design of Improving Bus Short Circuit Residual Voltage Based on Reactive Power Regulation of Synchronous MotorMeng, Xiangfei; Liu, Huikang
doi: 10.1088/1757-899X/452/3/032002pmid: N/A
When a short circuit fault occurs in a power system, the short circuit current value in the short circuit increases greatly, and at the same time, it will reduce the voltage in the power network, even 60 percent to 70 percent of the original voltage, then the power of some users was destroyed. In order to make the system work properly, it is important to analyse the cause of bus voltage drop. The traditional solution is to increase reactive power by using external equipment, such as static capacitor or STATCOM device, but the cost of the above two devices is too high. And each bus bar lower end of the load is connected with synchronous motor in Xindu Chemical 110kv Substation. When a short circuit fault occurs in the system, the synchronous motor can be excited in a short time to reduce the voltage drop, which is economical and fast. In this paper, four excitation modes of synchronous machine are analysed in detail, including constant excitation current, constant reactive power excitation, constant power factor excitation and constant active power excitation. Finally, the constant active power excitation model is chosen to solve the problems encountered. Finally, the short circuit current is judged quickly, so that the short-circuit fault can be judged quickly according to the change rate of the current in the system.
Multi-Population Artificial Bee Colony (MPABC) Algorithm for Numerical OptimizationZhao, Ming; Wang, Peihong
doi: 10.1088/1757-899X/452/3/032003pmid: N/A
This paper aims to propose a variant artificial bee colony algorithm (ABC), called multi-population artificial bee colony (MPABC) algorithm so as to optimize numerical functions with single and/or multiple solutions where the global optimization can be achieved. In MPABC, the solution space (i.e., food source) is partitioned into some subspaces in which a subpopulation of bees are parallel produced and employed to search the local optimization. Among these local optimizations, the ones with highest adaptability are taken as the global optimizations in each iteration step, and the corresponding local solutions are thus the global solutions. With a reasonable partition of solution space, all the global optimization and all the associated global solutions can be found by using MPABC. This property can not be committed by the ABC, as the ABC is interested in finding the global optimization with one solution in one running time. In addition, the MPABC holds higher abilities on convergence speed and accuracy than the ABC. Some experiments were conducted with some numerical functions so as to validate such conclusions.
Optimization of installing angles of photovoltaic panels to maximize solar radiation by simulated annealing algorithmZhou, Li; Yang, Liu
doi: 10.1088/1757-899X/452/3/032004pmid: N/A
In this study, simulated annealing (SA) algorithm was used to optimize the installing angles, specifically the tilt angle and surface azimuth angle, to maximize the solar radiation on photovoltaic (PV) panels in Wuhan, China. The KT model was adopted to calculate the monthly average solar radiation on the tilt PV panels and the SA algorithm was chosen to do the optimization. The optimized installing angles obtained by the KT method was compared with those obtained by the experimental solar radiation information, and the results agreed quite well. It is found that the summer in Wuhan has the largest monthly solar radiation. The optimized tilt angle varies in different months but the optimized surface azimuth angle is approximate 0 degree. It is implied that the tilt angle is the key parameter in the PV installation rather than the azimuth angle. For the yearly total solar radiation, the optimized tilt angle is 15°, which is about 15.52° less than the latitude.
Research and engineering verification of high-voltage cable laying method under complicated working conditionsHe, Guanghua; Zhang, Zhijian
doi: 10.1088/1757-899X/452/3/032005pmid: N/A
In the light of the characteristics of the cable construction model under complicated working conditions, it is found that there is no engineering experience to calculate the traction force of the stay tube section and the arc high drop section. This paper establishes the corresponding engineering mechanics models according to the construction site environment, which determines the engineering calculation formulas by theoretical deduction and the on-site industrial test verification, thus realizing the safe, economical and efficient laying of high-voltage cables under complex working conditions. Finally, the 220kV East Traction Station project is taken as an example to verify the proposed construction scheme. The results show that the laying and bending tasks can be successfully completed and all the indicators are in perfect conformity with the technical specifications.
Exploration of Combining Innovation Effect of Industry, University and Research Institute Based on Utility TheoryLiu, Huazhi; Wang, Lin
doi: 10.1088/1757-899X/452/3/032006pmid: N/A
To explore the industry, university and research institute collaborative innovation mechanism from the perspective of utility theory, the main utility demand was evaluated through factor analysis method and analytic hierarchy process (AHP). In addition, the subjective and objective utility demands of each subject were analysed. Moreover, through system dynamics method, the relationship between innovation subject effectiveness and collaborative innovation mechanism effectiveness was verified. First of all, on the basis of collaborative innovation subject effectiveness and collaborative innovation interest, the preliminary screening of index was conducted by questionnaire survey. Secondly, the hierarchy model was established and the AHP was used to determine the subjective and objective utility demand of subjects and analyse the differences between objective and subjective utility demands. Finally, the method of system dynamics was introduced and the system dynamics model including the industry, university and research institute subject effectiveness sub-system, output subsystem, long-term effective subsystem and industry, university and research institute collaborative innovation mechanism subsystem were constructed based on the utility theory. The results demonstrated the relationship between the industry, university and research institute collaborative innovation subject effectiveness and collaborative innovation mechanism effectiveness. To sum up, the mechanism has quite high effectiveness so that it can be applied to various production fields.
Fault Diagnosis of Wind Turbine Based on Empirical Mode DecompositionWang, Jing
doi: 10.1088/1757-899X/452/3/032007pmid: N/A
The structure of the gearbox of wind turbine is complex. The working environment is bad and the load is heavy which results in frequent failure of the gearbox parts and huge economic losses. In this paper, the signal processing method combined with empirical mode decomposition and improved bispectrum is used to diagnose the gearbox of wind turbine and the condition of wind turbine is monitored by a portable inspection. The feasibility and applicability of this method in the fault diagnosis of wind turbine gearbox are checked by an example.
An SVM-Based Recognition Method for Safety Monitoring Signals of Oil and Gas PipelineChen, Yang; Zhao, Jianhui; Li, Fan
doi: 10.1088/1757-899X/452/3/032008pmid: N/A
An SVM-based recognition method for the safety of oil and gas pipeline was proposed due to limitation of the traditional learning methods based on empirical risk minimization. The vibration signals along the pipelines are obtained with the distributed optical fiber vibration sensor on the basis of Mach-Zehnder optical fiber interferometer theory. The wavelet packet threshold denoising is used to preprocess the signal. Then the eigenvectors of vibration signals were extracted through the energy-pattern method based on wavelet packet decomposition. At last the vibration signals were recognized by support vector machine (SVM) through the eigenvectors with a view to detecting whether abnormal events happened along the pipelines.
Multithreading-Based design and implementation of distributed file transfer systemLi, Xianhui; Xu, Zengrong; Gong, Changping
doi: 10.1088/1757-899X/452/3/032009pmid: N/A
File is an important form of data exchange in application system, but It is restricted by the file size and the network environment between application systems, lacks of effective technical solutions for efficient and stable transmission of files, we consider the design principles of loose coupling, scalability and high availability, design a distributed file transfer system based on multithreading; The scheme designs the module of API, Broker, NameServer, contacts moudles by the way of Socket connection, forms a complete file transmission channel in the application system, and provides convenient and abundant file transfer process information to help application system know file transfer process, at the same time, adopts key technologies such as multithreading, distributed architecture, breakpoint renewal and so on, guarantees file transmission efficiency, satisfies the needs of file exchange between application systems better.
A distributed storage method for real-time database System designLi, XianHui; Zhou, Chun
doi: 10.1088/1757-899X/452/3/032010pmid: N/A
With the rapid development of network technology, the amount of data generated by real-time system is increasing exponentially. Business applications are putting forward more and more high demand on the management and real-time requirement. As the traditional stand-alone RTDB technology has met the needs with difficulty, the distributed thinking is introduced into the RTDB field, mainly studied from the Data distribution mode, Data redundancy backup, Data consistency and other aspects, Propose a design of data distributed storage in real-time data system. This design can provide technical support for current RTDB scalability and reliability.