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Development Of Power Interference Suppression Applied In Secondary System Of Power Plant And Substation

Posted on:2008-03-20Degree:MasterType:Thesis
Country:ChinaCandidate:C Y SunFull Text:PDF
GTID:2252360218953126Subject:High Voltage and Insulation Technology
Abstract/Summary:PDF Full Text Request
At present, arresters aren’t installed to protect the secondary sides of power transformers in most substations; besides any lightning protection measure isn’t adopted. Apparently, lightning interference has influence on the whole power source system with low voltage of the power plants and substations. In virtue of the abundant insulation margin of the mentioned low voltage sides, the insulation isn’t breakdown easily. However, the lightning over-voltage, or so-called strive power source surge induced by low power source system, can be several kilovoltage sometimes when transmitted to the microcomputer system, since the presented reason, the lightning over-voltage can’t be limited effectively, so as to make the weak insulation part of low power source system breakdown. The weakest part of insulation is electronic component of the computer system, in which the power source module is most sensitive to electromagnetic interference, which makes it easy to be breakdown and damaged. So it’s necessary to research on the power resource interference of the secondary system of power plants and substations, and to develop the means to be restrained. Main research content in this paper is as follows:The first part is to analyze the interference mode and the coupling means of lightning surge, especially on the inrush approach, indicating the damage on power source system by lightning surge.Contemporarily, the frequency spectrum characteristics of some lightning waveforms are analyzed, which gives reference to develop suppressor based on the frequency spectrum of lightning waveforms.The second part is the research on power interference suppression (PIS). A brief introduction is given on essential requirements of PIS, analyzing the basic protection principle, particularly on the principle analysis of varistor +LC type filtering function. ATP is adopted to simulate the power anti-interference circuit ofΓtype filter and LC type filter respectively, and then compare their protection effect. Based on it,the main circuit structural of PIS can be determined. The analog and digital techniques are used to design the auxiliary system—alert and account system. The parameters of varistor, capacitor and inductor are set by theoretic calculation, and ATP simulation software is used to certify the effectivity. The results from experiment show that PIS can protect electron devices effectively.The third part is the protection characteristic analysis of PIS. The simple model of single-phase low voltage distribution system is used to analyze cable with different length and different load, in which case certain reflection and oscillation can be observed. Take the pure resistance load, pure capacity load and Resistance-Capacitance load as example, when the length of connecting cable is different, the voltage wave is output from the two sides of PIS. It can be clearly shown from the result of simulation analysis that, the accrual endured surge voltage of load has close relationship with load type and the length of cable that connected to the PIS, which means the lower cable length, the better protection effect of PIS.
Keywords/Search Tags:secondary system, electromagnetic compatibility, lightning surge, power interference, power interference suppression, ATP simulation
PDF Full Text Request
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