Time filter

Source Type

Xie H.,North China Electrical Power University | Li J.,North China Electrical Power University | Li Y.,North China Electrical Power University | Wang Y.,Xingtai Power Supply Company | Wang D.,North China Electrical Power University
Asia-Pacific Power and Energy Engineering Conference, APPEEC | Year: 2010

Interval Analytic Hierarchy Process( IAHP) is widely used in order to solve the issue that how to identify strengths and weaknesses of each program in urban power system's planning and decision-making. With the application of IAHP, planning staff face with problems that how to calculate the integrative weight of interval verdict matrix accurately, reasonably arrange the interval layers in total sort, and choose the optimum consistency check to interval verdict matrix and so on. Therefore, this paper presents an approach based on linear programming(LP) and goal programming(GP). The LP model is established to calculate the weight of the interval verdict matrix and arrange the interval layers in total sort, while improving the LP model to construct the corresponding GP model to choose the optimum consistency check. So the improved IAHP has higher accuracy and adaptability. Case study shows that the optimization results are mush more scientific and effective. It could be feasible references for the system planning. ©2010 IEEE.

Zheng L.-Q.,Chongqing University | Zhao Y.-T.,Chongqing University | Zhao Y.-T.,Xingtai Power Supply Company | Shan G.-D.,Chongqing University
Dianji yu Kongzhi Xuebao/Electric Machines and Control | Year: 2011

A novel control strategy for matrix converter was proposed. Through effective changing the structure of SPWM wave, the SPWPM wave which makes transformer work in high-frequency state was obtained. After the conventional SPWM wave was intenerated, pulse-density modulation was adopted to synchronize the soft SPWM wave with the bipolar three-state SPWPM wave. And the positive and negative polarities modulated soft SPWM wave was treated by logic, to obtain gates drive signals of matrix converter. Through demodulating the SPWPM wave, the matrix converter recovers it into the conventional SPWM wave. The mathematical analysis of the output wave of the former high frequency inverter respectively working on SPWM and SPWPM stage proves that the SPWPM wave contains the whole component of SPWM wave except the modulated wave frequency. Therefore, the energy can be transmitted by high frequency transformer effectively. The adopted LCL third-order filter is better than conventional LC filter in the high harmonic attenuation. Experimental results indicate that the theoretical analysis is correct and the control strategy mentioned above is feasible.

Feng Y.,Xingtai Power Supply Company | Lin R.,Hebei Electrical Power Corporation | Song G.-Q.,Xingtai Power Supply Company
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2010

Through the study of telecontrol digital channel in Hebei South Power System, this paper puts forward the scheme of RS232/E1 interface and fiber communication technology, so as to interconnect RS232/E1 protocol convertor to RTU by RS232 interface and directly transmit the digital signal by using E1 digital interface of the SDH communication devices. The bit error rate of telecontrol channel transferring can be effectively reduced, the time of fault restoration and processing telecontrol communication fault is shortened, and online monitoring of telecontrol channel and condition-based maintenance of RTU device can be effectively improved.

Chen H.-B.,Handan Power Supply Company | Bu M.-X.,Handan Power Supply Company | Tan C.,Handan Power Supply Company | Zhang C.,Handan Power Supply Company | Feng Y.,Xingtai Power Supply Company
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2010

In this paper, a brief introduction is given to the hierarchical distributed network architecture of digital substation based on IEC 61850 protocols. And the differences of AC sampling systems for transformer protection are pointed out, which exist in the equipments compositions, information transmission modes and transmission medium between the traditional substation and digital substation. By taking the special operation mode when primary main equipments are in maintenance into comprehensive consideration, the reason for blocking problem happened in transformer protections is analyzed detailedly in digital substation. Finally, a modification scheme is proposed to solve this phenomenon for the transformer protections in digital substation, and the solutions have been applied in Mingfu digital substation project in Hebei power grid. According to the actual operation results, the validity and feasibility of the scheme have been proved.

Loading Xingtai Power Supply Company collaborators
Loading Xingtai Power Supply Company collaborators