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Yang Z.,Changzhou Power Supply Company | Xu X.,Taizhou Power Supply Company | Xu S.,Nanjing Southeast University | Zhao J.,Nanjing Southeast University
Asia-Pacific Power and Energy Engineering Conference, APPEEC | Year: 2010

To eliminate common-mode voltage (CMV) of cascaded multi-level inverter, a novel strategy is carried out respectively in the point of 2-level SVM and 3-level SVM, which can be easily applied in cascaded high voltage (HV) inverters by sampling time staggered technique. The concept of left-and-right leg groups is proposed for the special structure of 2-level SVM, and the phase difference between two reference vectors is set to be 2π/3 to suppress the CMV. On 3-level SVM mode, as each one cascade can generate three levels, only zero-CMV vectors are selected for modulation in order to decrease the CMV. Applying the above two SVM strategies to cascaded HV inverters by sampling time staggered (STS) technique, the CMV can be completely eliminated theoretically. Experimental results testified the effectiveness of the above two methods. ©2010 IEEE.


Ge L.,Nanjing Institute of Technology | Yang Z.,Nanjing Institute of Technology | Hu B.,Suzhou Wujiang Power Supply Company | Zhu H.,Changzhou Power Supply Company | And 2 more authors.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2013

Based on the veracity, cost, and reliability problems of the on-line monitoring device for the transmission line safety evaluation, a novel method of the line ontology structure safety evaluation is proposed, which works by checking the operating stress of the components and their actual strength. By applying reductionism and inversion theories, a multimode line mechanical model is developed under complex conditions, and the calculating formula of the stress for the corresponding components is derived. By taking the influencing factors of long-term operation and the uncertainty of the experts' knowledge of the evaluations into consideration, a fuzzy comprehensive evaluation model is built. On the basis of the J2EE struts-spring-hibernate (SSH) three-tier architecture, the corresponding software system is designed and realized. Examples are given to prove the validity and reliability of the system. The results provide the scientific decision basis to the power-grid for safety measures and pre-control. State Grid Electric Power Research Institute Press.


Yang Z.,Jiangsu Electric Power Company | Yang Z.,Changzhou Power Supply Company | Xu S.,Jiangnan University | Xu X.,Jiangsu Anfi Electrical Technology Co.
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2011

The circuit structure of present high-voltage large-capacity D-STATCOM is analyzed and the features of link structure are compared between Δ-type and Y-type. A Y-type back-to-back H-bridge inverter is constructed, which has some advantages: bidirectional energy flow, DC-link voltage controlled individually by H-rectifier, adaptive to n+1 redundancy, easy extension to high-voltage and large-capacitance, etc. The Ip-Iq current compensation strategy based on α-β coordinates conversion, the fault-tolerant control of faulty link bypass and its correlative CPS-SPWM adjustment algorithm to avoid the minimum sampling interval between different phases are proposed. The asymmetric load compensation experiment and the link-bypass fault-tolerance experiment are carried out with a 1.14 kV/100 kV · A prototype of 5 serial links and the experimental results testify the validity and effectiveness of the proposed structure and algorithm.


Yang Z.-Y.,Changzhou Power Supply Company | Xu S.,Jiangnan University | Xu X.-T.,Taizhou Power Supply Company
2010 China International Conference on Electricity Distribution, CICED 2010 | Year: 2010

In view of analysis and comparison of present high-voltage large-capacity D-STATCOM circuit structure, especially advantages and disadvantages of Δ-cascaded structure and Y-cascaded structure, then it proposes and describes a Y-cascaded structure, the link of which is composed of two back-to-back H converters. Current compensation algorithm based on coordinate αβ conversion, fault links bypass tolerance, and its correlative CPS-SPWM are proposed respectively, the experimental results of 1.14kV/100kVA prototype testify the validity and the effectivity of the proposed structure and algorithm. © 2010 Chinese Soc for Elec Eng.


Li C.,Huazhong University of Science and Technology | Shen W.,Changzhou Power Supply Company | Ding H.,Huazhong University of Science and Technology | Wen J.,Huazhong University of Science and Technology
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2011

One cycle control technique is applied in cascaded multilevel converter to improve its performance. Based on the theoretical analysis, a cascaded multi-level DC/AC converter control model with one cycle control is proposed and four simulation examples of three-phase cascaded H-bridge multilevel converter are built. The output AC phase-voltage of converter is 1268 V and its output line-voltage is 2193 V when the switching frequency is 2500 Hz, the filter inductance is 4 mH, the filter capacitor is 14μF and the DC-side voltage of each H-bridge is 500 V with fluctuation under 10%, and the output voltage is stable. Four examples indicate the voltage THD is less than 5%. Theoretical and simulative results show that, the cascaded multilevel converter with one cycle control has the advantages of simple control circuit, good control effect and stable output voltage.


Fu Y.,Shanghai University of Electric Power | Wei C.,Shanghai University of Electric Power | Li Z.,Shanghai University of Electric Power | Jiang Y.,Changzhou Power Supply Company
Communications in Computer and Information Science | Year: 2014

Active distribution network (ADN) is an indispensable content of smart distribution network under smart grid framework. On the basis of integration modes study, an economy optimal model of DG integration from a DSO perspective is proposed and two DG integration indexes are defined, respectively, integration ratio and GC ratio. The hourly sequential model is adopted to simulate load and DG uncertainties and a method of DG optimal integration based on stochastic optimal power flow(S-OPF) is presented. Monte Carlo Simulation aiming to get expected value and variance of network parameter precisely is used in stochastic power flow. The influence of integration indexes on economy in two scenarios is analyzed and some useful conclusions are achieved. © Springer-Verlag Berlin Heidelberg 2014.


Xu S.,Taizhou Teachers College | Yang Z.,Changzhou Power Supply Company
Diangong Jishu Xuebao/Transactions of China Electrotechnical Society | Year: 2012

A sort of cascaded H-bridge distribution static synchronous compensator (DSTATCOM) based on current separation compensation is proposed in this paper. A three-phase 4-quadrant VSR united with the DC-side capacitor serves as the independent DC power supply for the H-bridge inverter in the power units of the DSTATCOM. Especially, the VSR provides the whole or a part of the fundamental wave positive-sequence reactive current, and contrarily, the H-bridge inverter only undertakes a part of the reactive compensation tasks besides the fundamental wave negative-sequence and harmonic currents. Thus, the compensation capacity of the DSTATCOM will get optimized distribution and the performance price ratio will also be improved. This paper, firstly introduces the mainly work principle of this device. Secondly, the energy operation rules between the DC and AC side of the power units are analyzed in detail. Moreover, the DC mathematic model is established so as to instruct the researches of the control arithmetic and circuit parameters. Then, this paper sets forth briefly the control system, and on this basis, several critical control methods are analyzed, such as reactive compensation synchronization control technology of every power units. At last, a great deal experiments are made to validate these conclusions mentioned in this paper.


Yang Z.-Y.,Changzhou Power Supply Company | He Z.-X.,Changzhou Power Supply Company | Yu C.-Y.,Changzhou Power Supply Company
Gaoya Dianqi/High Voltage Apparatus | Year: 2010

To remove SF 6 leakage of a 220 kV GIS in 500 kV Jinling substation, the damaged GIS was overhauled by the manufacturer. One month later, the manufacturer and the user investigated the cause of leakage together. Then, a voltage-withstand test based on LC resonance over-voltage principle was conducted by Jiangsu EPRI. After the test, the out-service GIS was returned to operation. The adverse influence on the local gird is discussed during the out-service period of bus I and II in Jinling substation.


Wei C.,Shanghai University of Electric Power | Fu Y.,Shanghai University of Electric Power | Li Z.,Shanghai University of Electric Power | Jiang Y.,Changzhou Power Supply Company
Neurocomputing | Year: 2016

Active distribution network (ADN) is an indispensable content of smart distribution network under smart grid framework. On the basis of integration modes study, an economy optimal model of DG integration from a DSO perspective is proposed and three DG integration indexes are defined, respectively, integration ratio, GC ratio and adjustable power factor. The hourly sequential model is adopted to simulate load and DG uncertainties and a method of DG optimal integration based on stochastic optimal power flow (S-OPF) is presented. According to different integration modes, the principle of initialization and conversion of DG bus type in optimal power flow calculation is discussed. Monte Carlo Simulation aiming to get expected value and variance of network parameter precisely is used in stochastic power flow. Combining actual connection mode of Shanghai distribution network, a Shanghai 48 bus test system is built for ADN research. The influence of integration indexes on economy in two scenarios is analyzed and some useful conclusions are achieved. © 2015 Elsevier B.V.


Li C.,Shanghai University of Electric Power | Yang X.,Shanghai University of Electric Power | Zhang M.,Shanghai University of Electric Power | Wang H.,Shanghai University of Electric Power | And 2 more authors.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2013

As one of the important development directions of energy storage technology, the hybrid energy storage system of super-capacitors and batteries combines the advantages of power-type energy storage elements and energy storage components while avoiding the inadequacy of a single energy storage technology. For energy storage applied on high-power, high-capacity and strong volatility occasions, on the basis of analyzing the demand of the load characteristics, a way of configuring the total storage capacity is given and a hybrid configuration scheme for the super-capacitors and batteries program based on cost analysis is proposed. The example has proved the effectiveness of the proposed method. © 2013 State Grid Electric Power Research Institute Press.

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