Weifang Power Supply Company

Weifang, China

Weifang Power Supply Company

Weifang, China
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Zheng T.,North China Electrical Power University | Pan Y.-M.,North China Electrical Power University | Wang Y.-N.,Shenyang Power Supply Company | Wang L.,Weifang Power Supply Company | Wang Z.-P.,North China Electrical Power University
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2014

In order to realize robust fault location and isolation of distribution systems under the condition of incomplete information, this paper proposes using the relevance among each phase of fault information, three-phase fault currents and both reported by each feeder switch after fault to amend the omitted and false fault information reported by terminal equipment. And then, a method is proposed to achieve rapid fault location of distribution system's fault section by analyzing the topology, dividing the system into independent minimum distribution area and combining the corrected fault information reported by the above minimum distribution area. The simulation results show that the algorithm can effectively correct the missing and false fault information in order to achieve rapid fault-tolerant location of distribution system's fault section.

Zhang G.,Xi'an Jiaotong University | Huang X.,Weifang Power Supply Company | Tian J.,Shenzhen Power Supply Bureau | Zhan J.,Xi'an Jiaotong University | And 2 more authors.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2013

Surface flashover phenomena in vacuum often occur along the insulator, with its onset flashover voltage much lower than the breakdown voltage of either the insulator or the vacuum gap with the same length, so it seriously limits the development of high voltage electro-vacuum devices. Introducing a kind of machinable ceramic (MC) with excellent machinable performance and good surface dielectrical capability into vacuum insulation system, and considering the commonly used insulation stack structure, multiple layers machinable ceramic samples were established. Their surface flashover voltage were investigated under nanosecond pulsed voltage in vacuum, and the surface electric field distributions and electron trajectory in different structure were simulated. The experimental results indicate that, the flashover voltage of multiple layer insulators is better than that of the cylinder, and it improves with the increase of ratio of insulation to metal (I/M), the radial electric field of multiple layer insulators decreases with the increase of I/M. The flashover stability of truncated cone MC multiple layer insulators is better than that of truncated cone MC with the same angle, and the electrons are not easy to impact the surface of samples. © 2013 Chin. Soc. for Elec. Eng.

Zhan J.-Y.,Xi'an Jiaotong University | Mu H.-B.,Xi'an Jiaotong University | Huang X.-Z.,Xi'an Jiaotong University | Huang X.-Z.,Weifang Power Supply Company | Zhang G.-J.,Xi'an Jiaotong University
Journal of Applied Physics | Year: 2013

Recently, the cathode-like luminescence phenomena are observed from the surface of solid dielectrics under steady-state high voltage excitation in vacuum, which is closely related to the self-stabilizing secondary electron emission (SSEE) occurring on insulator surface. In this paper, the theoretical analysis about surface charging based on the SSEE is made, and a one-dimensional Mont Carlo simulation on surface charge accumulation under DC voltage excitation is provided. The results reveal that surface charging process can be divided into three stages including initial accumulation, fast multiplication, and final stable stage. In the final stage, the SSEE phenomena are achieved and surface charges are invariable and reach up to a stable distribution. The simulated stable surface charge distribution is consistent with the theoretical deduction results, which confirms the existence of SSEE process. © 2013 American Institute of Physics.

Luo J.,Chongqing University | Ren C.-J.,Chongqing University | Feng S.-H.,Weifang Power Supply Company | Chen T.,Chongqing Electric Power Research Institute | And 2 more authors.
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2013

This paper presents a linear state-space equation for a single machine-infinite system based on Park model, which is used for the design of optimal excitation control law. Applying this equation on the basis of optimal control theory, a new excitation controller is designed, in which the terminal voltage, active power, reactive power, angular velocity and angle are the feedback. Load angle and reactive power are introduced to excitation control law, which are closely related to stability and quality. At the same time, in order to improve the terminal voltage regulation accuracy, the integral control is introduced to the excitation control law. The result of MATLAB simulation indicates that compared with other methods, the proposed excitation control can effectively improve the power system's stability in large and small disturbance, as well as voltage regulation precision.

Li N.,Shandong Electric Power Research Institute | Zhang M.,Weifang Power Supply Company | Wang X.,Shandong Electric Power Research Institute | Wu J.,Weifang Power Supply Company | Liu C.,Weifang Power Supply Company
Dianwang Jishu/Power System Technology | Year: 2015

Aimed at accurate GIS fault identification and automatic power supply restoration, a new bus protection principle is presented. GIS equipment fault location is accurately identified based on region differential principle. When fault is between line side CT and breaker, breaker in fault bay trips to isolate fault point; when fault is between bus side CT and breaker, isolating switch in fault bay is opened up and other normal bays continue operating without interruption; when fault is between bus side CT of bus I(II) and bus tie breaker, breakers of bus I(II) trip to isolate fault point and bus II(I) continue operating without interruption; when bus fault cannot be isolated, breakers of the fault bus trip to isolate fault point. The principle effectively solves the problem of power outage cascading when faults in single bay and bus tie breaker region occur, thus accurate GIS fault identification and automatic power supply restoration are realized. Theoretical analysis and practical application cases verify validity and feasibility of the new principle. ©, 2015, Power System Technology Press. All right reserved.

Tang K.,Chongqing University | Kang L.,Chongqing University | Yin J.,Chongqing Electrical Power Corporation | Feng S.,Weifang Power Supply Company
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2014

The immeasurable variables of synchronous generator model make its parameter identification difficult. Based on Park model, a parameter identification model only with measurable state variables is derived for synchronous generator, based on which and according to the two-step strategy, the generator parameters are identified by applying the direct integral least square principle. With the proposed model and algorithm, all state variables are directly obtained by integration and the complex differential equations are avoided, which simplifies the parameter identification, improves the identification efficiency and decreases the impact of noise on identification results. Case simulation is carried out on MATLAB and the comparison among the proposed model, Park model and a reference model shows that, the proposed model and algorithm are correct, simple and more accurate.

Wu J.,Weifang Power Supply Company | Gao J.,Weifang Power Supply Company | Zhang S.,Weifang Power Supply Company
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2012

Logic of conventional backup power switchover unit (BPSU) is merely adapted to the inner bridge connection or sectionalized single-bus configuration. When the operation mode changes in double-bus scheme, the logic has obvious defect, causing the locking pattern and abnormally complex functions of relay protection. According to the changes in BPSU function and actual operation mode of double-bus scheme, the special problem that logic of conventional BPSU cannot adapt to double-bus scheme is analyzed. The solution is put forward. Independent from changes of operation mode, locking relations between differential protection of bus bars and conventional BPSU can be simplified, reducing the risk of relay protection operating frequently and ensuring the accuracy of locking logic of BPSU. © 2012 State Grid Electric Power Research Institute Press.

Wu J.,Weifang Power Supply Company | Gao J.,Weifang Power Supply Company | Zhang S.,Weifang Power Supply Company
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2012

The operating and manipulating provisions for on-duty operators are discussed when the distance protection loses voltage. Via analyzing general principle of the microprocessor-based protective relaying device, the necessary measures adopted when AC voltage circuit is abnormal are put forward. Proposals are presented for strengthening the protection configuration and preventing electrical equipments in operation from losing protection. Accordingly, the annotations to the involved new provisions are given. © 2012 State Grid Electric Power Research Institute Press.

Hou M.,Shandong University | Gao H.,Shandong University | Lu Y.,Shandong University | Zhang Y.,Weifang Power Supply Company | And 2 more authors.
Asia-Pacific Power and Energy Engineering Conference, APPEEC | Year: 2010

Islanding detection is an important issue for distributed generation operating with main network. To solve the problem of reliability and sensitivity of conventional vector shift method, this paper presents a composite islanding detection method utilizing both angle change and frequency variation derived from distributed generator terminal voltage. The method consists of main criterion and auxiliary criterion, each one having its own setting and calculating algorithm. The establishment and working principle of the proposed method are described in detail. PSCAD/EMTDC based simulations on a test system are conducted and analyzed. Simulation results show that the composite method is sensitive and reliable. ©2010 IEEE.

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