Xiamen Power Supply Bureau

Xiamen, China

Xiamen Power Supply Bureau

Xiamen, China
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Li T.,Fujian Electrical Power Co. | Xue Y.,China University of Petroleum - East China | Li J.,Xiamen Power Supply Bureau
IET Conference Publications | Year: 2013

The paper presents a new small current grounding fault location method applicable to distribution automation systems (DASs) using fault transient currents. The faulty section is identified by comparing the degree of similarity of transient currents of feeder terminal units (FTUs) (including faulty line selection device) at adjacent switches. If both transient currents are highly similar, then the section is regarded as the sound section, otherwise as the faulty section. The paper also analyzes the adaptability of the transient localization algorithm on DAS, as well as other key technologies such as time synchronization for FTUs, software and hardware processing ability, etc. The prototype system was installed in a typical distribution system in Xiamen Power Supply Bureau, State Grid Company of China. Dozens of grounding fault transients were captured with correct faulty line identification and faulty section localization. The method is reliable, free from the influence of arc suppression coil and easy to be implemented. It makes DASs function more complete, and helps to improve its overall performances.


Chen D.,North China Electrical Power University | Huang J.,North China Electrical Power University | Zhang L.,Xiamen Power Supply Bureau
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2010

As the excitation inrush is seriously distorted while the fault current is nearly sinusoid, a method is proposed to identify the excitation inrush current of transformer. Full-wave Fourier algorithm and half-wave Fourier algorithm are used to respectively calculate the imaginary part of fundamental differential current, and the normalized correlation coefficient between them is then deduced by correlation analysis, which is compared with a setting to identify the inrush current. Dynamic tests are carried out for four transformer operating conditions: energizing without load, inter-phase short-circuit, phase-ground short-circuit and energizing with fault. Experimental data are analyzed, which verifies the correctness and effectiveness of the proposed approach.


Chen D.-Z.,North China Electrical Power University | Zhang L.,Xiamen Power Supply Bureau
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2010

A new algorithm based on half-wave fourier and two points product method is presented for solving the mal-operation in transformer differential protection due to magnetizing inrush current. The method is based on the principle that the waveform of the inrush distorts seriously and even forms into vertex sharp wave, while the fault current keeps nearly sinusoid. Based on the half-wave fourier, this method samples currents with differential filter continuously, gets groups of square sum of two neighboring PI/2 currents using trigonometric theorem, then distinguishes inrush current by the ratios of neighboring groups of square sum. Theoretical analysis and dynamic simulation results show that the method is correct and effective under various fault conditions.


Zheng N.-Z.,Xiamen Power Supply Bureau | Zeng J.-S.,Xiamen Power Supply Bureau
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2010

The functions and hardware level of microprocessor-based relay equipments are highly uprated with the level of automatic system in substations. But the relay systems are working on asymmtric mode in many cases, for example, the secondary system plates are often changed with the operating mode of primary system. It will cause incipient fault when system is running and also bring much work to operators. Some misunderstandings will be discussed in this paper when microcomputer relay systems are running in different voltage levels.


Zeng J.,Xiamen Power Supply Bureau
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2012

The unbalanced voltage protection is designed based on the voltage drift of neutral point during capacitor faults to effectively isolate the asymmetric faults of capacitor, but it may refuse to act when the single-phase wire-breaking fault happens in the ungrounded star-connecting capacitor bank, which is pointed out by the theoretical analysis in principle. As there is negative-sequence current in such case, the negative-sequence current protection is proposed to prevent the improper behaviour of unbalanced voltage protection, which is verified by theoretical analysis.

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