Yang B.,Yancheng Institute of Technology |
Zhao Q.,Yangzhou Power Supply Company |
Zhang J.,Nanjing Southeast University
Chemical Physics Letters | Year: 2016
We report the temperature dependence of photoluminescent properties of Mn-doped nanocrystals (NCs) with different binding symmetry. The photoluminescence peaks of Mn2+ ions shift to shorter wavelength with increasing temperatures, resulting from the reduction of crystal field. Further evidence for temperature-dependent crystal field variety is demonstrated by electronic paramagnetic resonance (EPR) spectra. Additionally, the inflexion temperature of the excited state lifetimes increases from 170 K (Sample I) to 220 K (Sample IV), which is speculated to be resulted from the easily affected wave function overlap due to thermal lattice expansion in more symmetrical binding Mn-doped NCs. © 2016 Elsevier B.V. All rights reserved.
Fan Y.,Nanjing Southeast University |
Zhang L.,Nanjing Southeast University |
Xue Z.,Yangzhou Power Supply Company |
Zou Z.,Nanjing Southeast University
Dianwang Jishu/Power System Technology | Year: 2013
Reactive power compensation is one of the most effective measures to improve power quality and promote economic and efficient operation of power grid. Considering the possibility of applying vehicle to grid (V2G) technique in smart-grid environment, a V2G-based reactive power compensation technology is proposed. Based on structural features of existing V2G circuits and combining instantaneous reactive power theory with the principle of deadbeat control, the detection of instantaneous reactive power in the proposed model and the control of the compensation are analyzed. Finally, the feasibility of the proposed scheme is verified by both simulation and experiments. Verification results show that by means of V2G technique, the household load can be locally compensated by electrical vehicle (EV) used as reactive power compensator.
Gao L.,Jiangsu Electric Power Company |
Shi H.,Yangzhou Power Supply Company |
Yang Y.,Jiangsu Electric Power Company |
Cao W.,Nanjing Five C Smart Power Grid Technology Co.
Dianwang Jishu/Power System Technology | Year: 2014
The validity of substation configuration description (SCD) file is of crucial importance to the secure operation of the smart substation, especially the virtual terminal and the connection of virtual terminals relate to the tripping and sampling circuits of intelligent electronic devices (IED). The manage and control approach for the configuration file of smart substation is researched, and the management and control process of SCD files and corresponding technical means are expounded and the overall architecture and the construction of configuration file management and control system are presented. Using configuration file management and control system, the centralized management of SCD files of multi smart substations within the region can be implemented, in which a series management functions such as the file upload, storage, verification, comparison, visual display and the version tracing and so on are provided to conduct real-time supervision and control to ensure the safety, integrity and consistency of SCD files. ©, 2014, Power System Technology Press. All right reserved.
Yang G.,Hohai University |
Pan W.,Hohai University |
Liu M.,Hohai University |
Yang C.,Yangzhou Power Supply Company
Dianwang Jishu/Power System Technology | Year: 2016
Model of DFIG with crowbar protection is different from common asynchronous generator in those: firstly, DFIG rotor side is connected to converter; secondly, the converter is protected with crowbar. In calculation method, two generators also have corresponding differences. In term of short-circuit current calculation, national standard GB/T 15544. 1《Short-circuit current calculation in three-phase a. c. systems》 is adopted now in China. This calculation method does not consider crowbar resistance impact. Therefore, a new model of DFIG with crowbar protection was established to research practical calculation method of three-phase short-circuit current of DFIG with crowbar protection. Practical calculation method of three-phase short-circuit current was verified with PSCAD/EMTDC simulation. Comparison between national standard calculation method and practical calculation method with new model was performed. It demonstrates that practical calculation method of three-phase short-circuit current of DFIG with crowbar protection proposed in this paper is accurate and convenient. It is of great significance to electrical safety design of wind farm. © 2016, Power System Technology Press. All right reserved.
Ying Z.,Nanjing University of Science and Technology |
Chen Y.,Nanjing University of Science and Technology |
Tian Y.,Yangzhou Power Supply Company |
Wu J.,Nanjing University of Science and Technology |
Feng K.,Nanjing University of Science and Technology
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2013
The frequency detection reliability of active frequency shift method is easily influenced by the grid interferences, which may be wrongly taken as the occurrence islanding effect. The anti-interference six-point frequency detection algorithm is adopted in the active frequency shift method to avoid such misjudgement and quickly detect islanding, which applies the optimal interval of detection point and eliminates the frequency singularity to suppress the grid interference. The simulative research of islanding detection is performed according to the worst conditions stipulated by IEEE Std929-2000 and results show that, with fast response, the proposed method prevents the misjudgement and has no nondetection zone.
Lu S.-Z.,Yangzhou Power Supply Company |
Xue Z.-B.,Yangzhou Power Supply Company
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2014
To improve the efficiency of traditional relay protection setting value local modification, a setting value modified system based on EMS integration is presented. Based on the analysis of IEC104 expanding protocol, and on the basis of Yangzhou power dispatch automation OPEN-3000 system, the whole frame and software design of remote operation system are researched and proposed. To test the performance, the system is applied in Yangzhou 220 kV Guangling substation. The results show that the system can realize the setting value remote modification, the setting value zone remote switch and the soft plate control on-line, which improves the levels of dispatch management and operation management.
Li P.,North China Electrical Power University |
Yang S.,North China Electrical Power University |
Wang Y.,Yangzhou Power Supply Company |
Yin Z.,North China Electrical Power University
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2014
Microgrid, which is an effective and feasible approach for scale application of new energy and renewable energy generation, integrates effectively the advantages of the distributed new energy and renewable energy generation. The various running modes and excellent electricity services of microgrid depend on the flexible and steady control frame, while the independent control of micro source active power output and reactive power output is a burning question. Considering the problem of power coupling, which was brought by the lines characteristics, a method of objective function diagonalization decoupling control of microgrid power based on relative gain analysis was proposed. Relative gain analysis was introduced for matching selection of power model of low voltage microgrid, which quantified the channel coupling degree. Based on this, the objective function diagonalization method was applied for power decoupling control. Finally, independent active and reactive power control of microgrid was realized. The simulation results show that the proposed decoupling method effectively eliminates the power coupling in microgrid and realizes the independent and flexible regulation of the microgrid active and reactive power. © 2014 Chinese Society for Electrical Engineering.
Li R.,North China Electrical Power University |
Lu F.,Guangzhou Electrical Power Design Institute |
Xu H.,North China Electrical Power University |
Zhang L.,Yangzhou Power Supply Company
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2010
The load structure and influencing factors are increasingly complex, and has become an important bottleneck for improving the precision of load forecast. Components decomposed by local wave can represent fundamental components of the load, and these components correspond the load information influenced by different factors. Simultaneously, approximate entropy is able to quantify the load characteristics, therefore, a new method for load analysis was proposed based on local wave and approximate entropy. First, the load sequence was decomposed by local wave to obtain the component and the remainder, which were able to reflect the load composition; Second, Hilbert transformation was conducted for each component to obtain the Hilbert time-frequency spectrum and the power spectrum, thus evaluate the contribution of each component to the overall load fluctuation. Approximate entropy was taken as the characteristic parameter for various components and the remainder to investigate the physical meaning of the components. Finally, the real-time climatic factor was used to analyze load components with different time interval of a day so as to analyze the influence of the meteorological factor on the load. The case study showed that this method is effective to analyze the load structure and influencing factors. © Chinese Society for Electrical Engineering.
Chen Q.,Jiangsu Electric Power Company |
Deng J.,Jiangsu Electric Power Company |
Pan J.,Jiangsu Electric Power Company |
Fan Y.,Yangzhou Power Supply Company
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2015
Inner-bridge configuration is a kind of main electrical connection widely used in 110 kV substations. This paper describes the protection action process during a circuit breaker fault on the low voltage side of the main transformer in a 110 kV substation with inner-bridge configuration. The long-term overheat made the button contact of the low voltage side circuit breaker of the transformer lose its elasticity. The contact fall off caused an interphase short circuit. Since the high voltage side back-up protection of the transformer failed to operate, the line protection and recloser of the superior 220 kV substation acted. And automatic switchover acted irrationally while the backup line put in. The circuit breaker was damaged by the rush more than once until the substation lost power. The fault is to a certain extent typical of a power system with problems in the design of its protection configuration. An overall analysis is made by the authors on the protection action process of the fault alongside suggestions and countermeasures for optimizing main protection configuration and setting, as well as operation and maintenance of inner-bridge configuration. ©2015 State Grid Electric Power Research Institute Press
Jun J.,Yangzhou Power Supply Company |
Yu W.,Yangzhou Power Supply Company
2010 China International Conference on Electricity Distribution, CICED 2010 | Year: 2010
State Grid Corporation of China(SGCC) proposed to build the unified strong smart grid with Chinese characteristics, that is the maintenance of electrical equipments has been gradually breaking human-controlled mode, transforming into smart mode and real-time monitoring of various equipments in substation. Besides, the condition intelligence judgment is one of center links. And the zinc oxide arrester is one kind of important overvoltage protector. Because of the superior nonlinear and protective value, it has been widely used in power system. However, the zinc oxide arrester doesn't have the discharge gap, the valve will gradually deteriorate in the effect of long-term running voltage or the arrester will be affected with damp for itself bad structure. These will cause the arrester's leakage current to increase, or cause the electric operational accident for the thermal runaway in critical condition. The traditional method is manual periodic patrol, inspection and transcript. It's not convenient to use and manage which makes operators to do much more and inefficient. What's more, it can't grasp the safe state of the arrester promptly and accurately. This article studies one kind of system to real-time acquire, transmit, preserve, manage and share the information such as the zinc oxide arrester's leakage current, the lightning frequency and timing. And form an information management system of the zinc oxide arrester's leakage current. All the related personnel can inquire the state of all the zinc oxide arrester, of course, it increases the work efficiency. Compared with other methods, this system has the simple structure and dependable performance, and can be used in the substation of strong interference of electromagnetic field. © 2010 Chinese Soc for Elec Eng.