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Zhou H.,Zhejiang University | Zhang X.,Weifang Electricity Bureau | Zhao B.-C.,Weifang Electricity Bureau | Chen J.-M.,Hangzhou Electric Power | And 2 more authors.
Gaodianya Jishu/High Voltage Engineering | Year: 2010

To calculate the secure distance of quadruple-circuit transmission lines on the same tower with horizontal arrangements passing over buildings, power-frequency electric field distortion on the roof and the balcony is calculated and analyzed with CDEGS when 500 kV quadruple-circuit transmission lines pass over the building. And the secure distance between conductors and building is proposed based on distorted electric field, including minimum vertical secure distance and minimum horizontal secure distance. The results show that distorted electric field is the most important constraint factor for determining secure distance between transmission lines and buildings; the secure distance recommended by existing regulations cannot satisfy the requirements of quadruple-circuit transmission lines cross the buildings; the secure distance is decided by the factors such as line voltages, height of the buildings and tower structures. In the end, the secure distance of 110 kV, 220 kV quadruple-circuit transmission lines and 220 kV/110 kV, 500 kV/220 kV mixed-voltage quadruple-circuit transmission lines across buildings is also calculated. The conclusion provides reference to design transmission lines crossing buildings for the practical engineering.

Zheng F.-P.,Jiaxing Electrical Power Bureau | Yu G.-C.,North China Beijing EHV Power Transmission Company | Zhang Z.-Y.,Xinjiang Changji Electrical Power Bureau | Bai N.,Suide County Electrical Power Bureau
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2011

Aiming at methods for the calculation of voltage stability critical parameters, this paper proposes a new changeable step integration strategy for determination of critical parameters of static voltage stability based on load admittance model, which integrates dynamic step characteristic progress and asynchronous continuation characteristic progress.Firstly, maximal power point closest to critical point is calculated in the first progress quickly, namely, tracing calculation of the Thevenin's equivalent impedance during increasing the loads, then, the corresponding admittance is used as the load admittance value for next calculation.Thus, the transition from initial point to the maximal power point is completed with quick unequal step.The second progress successes after the first progress for transition from unequal steps to equal and exact determination of critical parameters by equal step, namely, the maximum power point can be used as the beginning to compute critical parameters of voltage stability via increasing or reducing the load admittance by equal step.Directional determination factor (DDF) is created to achieve reasonable transition between two progresses, which makes the calculation speed and accuracy organically coordinated.Examples of IEEE30, IEEE118 show the validity and accuracy of the strategy, which can supply a new tool for real-time analysis of voltage stability.

Yuan J.,Jiaxing University | Shou J.,Jiaxing Electrical Power Bureau | Zha L.,Jiaxing new energy sources electronic technology Co.
Advanced Materials Research | Year: 2012

This paper presents a controller design based on PIC24 single chip microcomputer, applied to a small independent wind-solar hybrid power generation system. The system's characteristics are analyzed and the complementary charging algorithm for the battery is studied. The PIC24MCU's internal resources are made full use of in the controller design, especially the multiplex PWM output and A/D input, thus the hardware circuit is simplified. The controller can not only realize the hybrid of wind generator and solar cell for charging the storage complementary, but also provide a constant current control function for the DC load. © (2012) Trans Tech Publications, Switzerland.

Tu Y.-W.,Jiaxing Electrical Power Bureau | Xia Q.-F.,Jiaxing Electrical Power Bureau
Gaoya Dianqi/High Voltage Apparatus | Year: 2012

Understanding voltage and electric field distribution of an insulator string is important for its insulator design and operation. In this paper, a three-dimensional electric field model is established with the finite element method to calculate and analyze the electric field of the porcelain insulator string according to its real structure and working conditions. The results show that the umbrella arris of insulator and lightning conductor exert a little impact on the space electric field, while the umbrella arris has clear influence on the surface electric field. Tower type, wire type and split, insulator string type, and insulation state of insulator surface all impose certain effects on the space electric field. They hence need to be considered in simulation analysis of the space electric field distribution of the insulator strings.

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