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Xie H.,Xian Jiaotong University | Bie Z.,Xian Jiaotong University | Dong P.,Xian Jiaotong University | Zheng C.,China Electrical Power Research Institution
IEEE Region 10 Annual International Conference, Proceedings/TENCON | Year: 2016

The commutation failure is a common fault in line-commutated converter (LCC) based high-voltage direct current (HVDC) transmission system. The commutation failure is modeled and its influence on reliability of HVDC transmission systems is studied in this paper. First, the commutation failure mechanism of LCC-HVDC transmission systems is analyzed. Then, the commutation failure criterion is presented based on the concept of commutation area. Moreover, a concise equivalent reliability model of the commutation failure is built. The corresponding evaluation method is proposed based on Monte Carlo simulation. Furthermore, the impacts of commutation failures on reliability are studied by introducing the reliability model into the F&D approach in HVDC reliability evaluation. Extensive studies are conducted on a CIGRE benchmark system, which validate the presented methods. The evaluation results show that the commutation failures influence the reliability of HVDC system obviously. After the consideration of commutation failures, the energy unavailability of the HVDC transmission system increases more than 9%. © 2015 IEEE. Source


Guan Z.,Tsinghua University | Li J.,Tsinghua University | Zhou J.,China Electrical Power Research Institution | Wang L.,Tsinghua University
Gaodianya Jishu/High Voltage Engineering | Year: 2012

According to the urgent needs of the investigation of the outdoor insulation performance in high altitude for the power transmission from west to east and Tibet interconnection, we summarize the research works on the contamination performance of insulators under low pressure both in home and abroad, and emphatically introduce the recent research achievements in the field in China. It is found that the influence of pressure on the contamination flashover voltage can be evaluated by aexponent n. A statistic analysis shows that the average value of n is 0.49 for suspension insulators and 0.48 for post insulators under AC condition while the corresponding values are 0.27 and 0.42, respectively, under DC condition. A further discussion about the mechanism of pollution flashover voltage decrease under low pressure is presented. It is believed that the decrease of AC U-I characteristic and the arc bridging among sheds are the main reasons for the decrease of the voltage. Then, the physical meanings of the characteristic parameters n and K which demonstrate the influence of pressure and altitude are discussed. It is concluded that the parameter K has a definite physical meaning. Finally, the degrees of altitude affecting the corona inception voltage, air gap breakdown voltage and pollution flashover voltage are compared, and the results show that the decrease degree of pollution flashover voltage is not the most serious if the shed profile is reasonable. Source


Tan X.,Wuhan University | Di L.,George Mason University | Deng M.,George Mason University | Fu J.,China Electrical Power Research Institution | And 6 more authors.
Sustainability (Switzerland) | Year: 2015

Since the Open Geospatial Consortium (OGC) proposed the geospatial Web Processing Service (WPS), standard OGC Web Service (OWS)-based geospatial processing has become the major type of distributed geospatial application. However, improving the performance and sustainability of the distributed geospatial applications has become the dominant challenge for OWSs. This paper presents the construction of an elastic parallel OGC WPS service on a cloud-based cluster and the designs of a high-performance, cloud-based WPS service architecture, the scalability scheme of the cloud, and the algorithm of the elastic parallel geoprocessing. Experiments of the remote sensing data processing service demonstrate that our proposed method can provide a higher-performance WPS service that uses less computing resources. Our proposed method can also help institutions reduce hardware costs, raise the rate of hardware usage, and conserve energy, which is important in building green and sustainable geospatial services or applications. © 2015 by the authors. Source


Kang C.,North China Electrical Power University | Zhang J.,North China Electrical Power University | Sheng W.,China Electrical Power Research Institution | Li E.,China Electrical Power Research Institution | Chang F.,China Electrical Power Research Institution
Proceedings of the 5th IEEE International Conference on Electric Utility Deregulation, Restructuring and Power Technologies, DRPT 2015 | Year: 2015

Serve as one of the most important equipments in power distribution system, conditions of switch cabinets are closely connected with safety and stability of distribution network and exert great influence on power quality used by customers. But the information applied in the current research of distribution switch cabinet is not comprehensive enough, and the assessment model is not dynamic enough, because of this, a distribution vacuum switch cabinet dynamic condition assessment model based on multi-source information fusion is proposed in this paper. The vacuum switch cabinet is divided into three parts-vacuum circuit breaker, buses and cable outlets. The information used to assess these three parts' conditions concludes ultrasonic results, TEV results, infrared temperature measurement results, vacuum degree, insulation resistance and mechanic parameters. Moreover, environment information, operation information and position information of the switch cabinet are also taken into consideration. Membership functions and scale models are used in the condition assessment. Thus, the historical conditions of the switch cabinet in the past 5 years can be obtained, and Bayes conditional probability model is used to fuse these condition assessment results. In the meantime, the corresponding examples are given to prove the validity of the models proposed in this paper. © 2015 IEEE. Source


Zhang X.,State Grid Corporation of China | Zheng Y.,China Electrical Power Research Institution | Geng J.,China Electrical Power Research Institution | Huang L.,China Electrical Power Research Institution | And 2 more authors.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2016

As the first technical supporting platform for the whole business procedure of direct trading between electricity users and power generation enterprises in China, the design objective of the platform is introduced. The architecture design is described from the following four aspects: business architecture, application architecture, data architecture and technical architecture. The transaction management of multiple varieties, same-schedule rolling compilation of generating planning, unified settlement of multiple components of electricity quantity, data platform based on dimension decomposition and other key techniques are also analyzed. The platform has been practically applied in the building of state grid unified national electricity market, supporting the direct trading for large-power-end users in more than twenty provinces, including Shanxi, Anhui, Gansu and other pilot provinces. © 2016 Automation of Electric Power Systems Press. Source

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