Lu Y.,Jiangsu Electric Power Research Institute |
Li W.,Nanjing Southeast University
ICHVE 2016 - 2016 IEEE International Conference on High Voltage Engineering and Application | Year: 2016
Through several similar failures caused by partial discharge of the converter transformer on the Zhengping converter station of Three Gorges-Changzhou HVDC project, and combined with partial discharge fault location and the insulation contaminated sites, it is concluded that the conservator of open type is the direct cause of the failure. The existing 12 sets of conservator in the converter transformer is no capsule structure, free breather. In the long run insulating oil easily oxidized, generate impurities and moisture. These impurities and moisture can penetrate into the transformer from the bottom of the tank, and when they accumulated to a certain extent, it will lead to partial discharge, then failure. Studies have shown that the starting and developing process of partial discharge under combined AC and DC voltage is worth in-depth study. And to carry out the condition assessment and maintenance technology is of great significance on improving the safety and reliability of the converter transformer. © 2016 IEEE.
Zou Z.,Nanjing Southeast University |
Zhou K.,Nanjing Southeast University |
Yuan X.,Jiangsu Electric Power Research Institute
Dianwang Jishu/Power System Technology | Year: 2011
Considering the randomness of wind power source and structural features of power network connected with wind farm, the main influences of connecting wind power system consisting of doubly fed induction generators (DFIG) to power grid on voltage stability of local power network neighboring to connection point are analyzed. The relationship between wind farm capacity being connected to power grid and voltage stability, transient voltage stability under large disturbance occurred in power grid and low voltage ride through of wind farm are expounded. Based on the analysis results, the measures to improve voltage stability are proposed. The improving effect of static synchronous compensator (STATCOM) on voltage stability and the selection of the capacity of STATCOM are researched. Above-mentioned issues are simulated on DigSILENT/Powerfactory platform. Simulation results show that too large capacity of wind farm being connected to power grid is adverse to voltage stability of local power network neighboring to the connection point of wind farm; to prevent voltage instability under power grid disturbance, generally wind power systems ought to possess the capability of low voltage ride through; appropriate local reactive power compensation contributes to improve voltage stability of local power network.
Li C.,Hunan University |
Zhou J.,Hunan University |
Cao Y.,Hunan University |
Zhong J.,University of Hong Kong |
And 3 more authors.
Applied Energy | Year: 2014
With global climate changing, urban microclimate is deteriorating at a faster rate than before in many cities. In this paper, the significant effect of the deterioration of urban microclimate on air-conditioning energy consumption (ACEC) is studied. Cumulative effect (CE) has enormous influence on ACEC and it can also strengthen the influence of urban heat island effect (UHIE), which has not been recognized by previous literatures. UHIE, temperature and humidity effect (THE) and CE are taken into consideration via revising perceived temperature to precisely estimate ACEC caused by urban microclimate. The result shows the ACEC estimated in this paper is much larger than that reported in previous literatures. Our study shows electric ACEC resulting from the comprehensive influence of microclimate accounted for 11.28% of total summer electricity consumption and this percentage reached 20.4% during the peak load period in Beijing in 2005. In turn, the increased ACEC contributes to the increase of urban heat island intensity. Based on the study, it's discovered that the interaction between urban microclimate and ACEC, which is a positive feedback with saturation and time-lag. © 2013 Elsevier Ltd.
Ni M.,MISO |
Yang Z.,Jiangsu Electric Power Research Institute
IEEE Power and Energy Magazine | Year: 2012
New wind power installations in china have doubled every year since 2004. By 2010, Chinas wind generation capacity of 45 GW ranked fi rst in the world. Figure 1 shows how the installed wind capacity in China grew from 20002010. A total of 30 of 31 provinces, municipalities, and autonomous regions have wind farms. (This article does not discuss wind power development in Hong Kong, Macao, and Taiwan.) The Inner Mongolia Autonomous Region leads the other provinces with 14 GW of installed capacity, followed by Gansu, Hebei, and Liaoning. © 2012 IEEE.
Li C.,Jiangsu Fangtian Power Technology Co. |
Yuan Y.,Jiangsu Electric Power Research Institute |
Lu Y.,Jiangsu Fangtian Power Technology Co. |
Ning Y.,Jiangsu Fangtian Power Technology Co.
Dianwang Jishu/Power System Technology | Year: 2014
The transfer method of sampled data in process-level network of smart substation is one of key technical problems in smart substation. At present, there are two sampled data transferring methods, namely the point-to-point transferring and networking transferring. The system structure can be simplified when networking transferring is used, however its operation depends on global synchronization system, so the failure in global synchronization system leads to the whole system out of service, so the networking transferring of sampled data should not depend on global clock. A new local synchronization scheme, in which the margin unit is used as local master clock and the protection, measuring and control devices as slave clocks, is proposed, and there are many slave clocks in a single measuring and control device, which are locally synchronized with local master clock in margin unit. By means of optimizing the clock selection and tracking mechanisms of IEEE1588, and utilizing interpolation the synchronous data sampling is implemented, and the dependence on global synchronization system is effectively avoided. Main advantage of the proposed scheme is that the networking transferring of sampled data is implemented without global synchronization system. Results of applying the proposed scheme to engineering practice show that the proposed scheme is more reliable and practicable than traditional networking scheme.
Zhang X.,Nanjing University of Science and Technology |
Li Q.,Jiangsu Electric Power Research Institute |
Yin M.,Nanjing University of Science and Technology |
Ye X.,Nanjing University of Science and Technology |
Zou Y.,Nanjing University of Science and Technology
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2012
To avoid oscillations of rotor speed at maximum power points (MPP) and to overcome wrong searching directions for MPPs due to the turbulence of wind speed, an improved hill-climbing searching (HCS) method for maximum power point tracking (MPPT) was proposed. It not only inherits the advantage of the variable-step HCS method so that MPP can be rapidly reached, but also introduces the mechanisms of detection and halt at MPP. Thus, the mechanical damage to wind turbines around MPP, resulted from rotor speed oscillations can be effectively reduced. Moreover, following the halt of HCS, the disturbance to determinations of searching directions caused by wind speed variations was resolved and as a result more wind energy was captured. Based on a simplified model of the wind energy conversion system, simulation studies were presented to verify the effectiveness and advantage of the improved method. © 2012 Chinese Society for Electrical Engineering.
Nan Y.,Jiangsu Electric Power Research Institute
Sensors and Transducers | Year: 2013
This article designed and had completed a digital image gathering system by the means of the ARMS3C44B0X processor and CMOS image sensing component. Considering the superiority of the ARM technology and the CMOS image sensing technology, the system combined the image gathering with the imagery processing recognition function in a module and had the advantages of rich function, strong handling ability, nimble connection and convenient expansion. The characteristic system was that it constructed the image gathering hardware platform on the base of S3C44B0X, studied and transplanted the Bootloder vectoring procedure and the uClinux operating system and can realize the real-time and multi-duty processing, thus enhanced the manageable capacity of the system largely. © 2013 IFSA.
Zhang Q.,Jiangsu Electric Power Research Institute |
Wang H.,Jiangsu Electric Power Research Institute |
Xie Z.,Jiangsu Electric Power Research Institute
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2011
The intermittent nature of wind power challenges the generation expansion planning based on deterministic methodology. By utilizing probabilistic methodology and software, this paper discusses the issue of generation expansion planning with large-scale wind power integration into Jiangsu power grid. System adequacy analysis and optimal generation mix are studied together with the discussion of proper parameters of peak-valley regulation capacity demand for wind power in the optimization. Considering the intense constrains between the source and demand of peak-valley regulation capacity, sensitivity analysis of the capacity between wind power, unclear and pumped storage are carried out. The statistics of power flows across Yangtze River are also calculated to analyze the proper generation location in Jiangsu. ©2011 State Grid Electric Power Research Institute Press.
Bian C.,Jiangsu Electric Power Research Institute |
Chen S.-B.,Jiangsu Electric Power Research Institute
Gaoya Dianqi/High Voltage Apparatus | Year: 2010
A novel approach of anti-interference used in PD detection based on pulse current waveshape is introduced in this paper. This novel anti-interference technique is composed of the equivalent time-frequency parameters extraction for pulse current sequence and the Fuzzy C-means (FCM) unsurprised clustering analysis. Simulation test result and PD signals extraction of corona discharge from on-filed GIS test show that this anti-interference technique proposed is feasible and practical, which provides a good approach to extract PD signals form GIS.
Xu H.,Jiangsu Electric Power Research Institute
Dongli Gongcheng Xuebao/Journal of Chinese Society of Power Engineering | Year: 2010
Three sects of domestic 1 000 MW ultra-supercritical pressure once-through boilers were introduced. The causes for failure of water-wall with vertical tube panels of ultra-supercritical pressure once-through boilers were analyzed. Results show that the direct cause for failure of water-wall with vertical tube panels is that the throttles located at entrance of water-wall have been blocked by deposits of magnetite pollutants. While the fundamental cause is the high content of forenoon at the inlet of economizer caused by poor all volatile feedwater treatment. Efficient anti-explosion strategies are put forward. Once overheating phenomenon of water-wall occurs, which indicates that serious blocking of throttles might exist, tube cutting inspection should be taken as soon as possible. Local cleaning should be carried out for the throttles by a special chemical cleaning procedure. And the feedwater should adopt oxygenated treatment.