Identification of Lightning Strikes on Transmission Lines Based on Integral Method and Wavelet Analysis

2014 ◽  
Vol 936 ◽  
pp. 2190-2195
Author(s):  
Hong Wei Yan ◽  
Yong Li Zhu ◽  
Guo Chen Fan ◽  
Xi Xiong
Keyword(s):  
Transmission Lines ◽  
Short Circuit ◽  
Transient Current ◽  
Scale Transformation ◽  
Current Waveform ◽  
Lightning Strikes ◽  
Multi Scale ◽  
Measuring Devices ◽  
The Time Domain ◽  
Short Circuit Fault

Transient signals caused by lightning strikes on transmission lines may interfere with the distance measuring devices relying on traveling wave. A synthesized method based on the additional components of disturbed current is proposed to distinguish between lightning interference, lightning fault and short-circuit fault. Firstly, since the disturbed current waveform generated by lightning interference and faults are distinct in the time domain, transient current components over and below timeline are respectively integrated to identify lightning interference from faults. And then, due to the distribution differences of current in the frequency domain, multi-scale transformation of wavelet is adopted to analyze the energy spectrum of transient current generated by short-circuit fault and faults of lightning. Numerous PSCAD simulation results demonstrate the proposed method is valid and correct.

scholarly journals Study on the Power-Frequency Waves Distribution Characteristics for Half-Wavelength Transmission Lines Based on the Frequency-Length Factor

2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Chang Chen ◽  
Xiaoyang Ma ◽  
Honggeng Yang ◽  
Weikang Wang ◽  
Yilu Liu
Keyword(s):  
Transmission Lines ◽  
Short Circuit ◽  
Distribution Characteristics ◽  
System Parameters ◽  
Frequency Resonance ◽  
Fault Resistance ◽  
Maximum Value ◽  
Half Wavelength ◽  
Power Frequency ◽  
Short Circuit Fault

To analyze the distribution characteristics of voltage and current along half-wavelength transmission lines (HWTLs) in the cases with or without short circuit in the steady state, the method based on the frequency-length factor (FLF) for lossy lines is proposed. Firstly, according to the pole condition of the FLF, the distribution characteristics of power-frequency waves along HWTLs are analyzed. Then, the comprehensive effects of the system parameters and fault resistance are explored, revealing the mechanism of the power-frequency resonance caused by nonmetallic short circuit. Meanwhile, unbalanced short-circuit fault is studied by exploiting additional impedance. The results show that the distribution of the maximum value of power-frequency resonance voltage is related to the system parameters but not to the fault impedance. When a HWTL is short circuited at 2640 km∼2930 km, the resonance voltage can reach to 21 p.u. In relation to symmetrical short circuit, the resonance voltage appears at 1469 km from the short-circuit point, while the position moves towards the short-circuit point with the increase of additional impedance in asymmetrical short-circuit conditions. Additionally, the model theoretically proves that the power-frequency overvoltage induced by short circuit does not appear on a line whose length is less than 1469 km. Finally, cases are studied on PSCAD to verify the accuracy of the model.

The Comparative Analysis of SVC and STATCOM on Subsynchronous Oscillation Mitigation

2013 ◽  
Vol 756-759 ◽  
pp. 245-249 ◽  
Author(s):  
Jian Zhang ◽  
Xiang Ning Xiao ◽  
Ben Feng Gao ◽  
Chao Luo
Keyword(s):  
Short Circuit ◽  
Time Domain Simulation ◽  
Subsynchronous Oscillation ◽  
Damping Coefficients ◽  
Torque Coefficient ◽  
Electrical Damping ◽  
The Time Domain ◽  
Generator Terminal ◽  
Short Circuit Fault ◽  
Signal Method

The methods for subsynchronous oscillation mitigation based on SVC and STATCOM are analyzed in this paper. According to the IEEE first benchmark model, the electrical damping coefficients respectively provided by SVC and STATCOM connected at the generator terminal, as well as positive damping condition, are deduced by complex torque coefficient approach. Correlative factors which influence the two positive dampings are compared. The analysis results indicate that the positive damping provided by SVC is proportional to the size of system voltage. The positive damping provided by STATCOM is not affected by the size of system voltage, which is mostly proportional to the subsynchronous voltage produced itself. The controllers of SVC and STATCOM are designed and the positive dampings separately offered by SVC and STATCOM are optimized by phase compensation with test signal method. The time domain simulation reveals that STATCOM has stronger damping ability than SVC in the case of short circuit fault.

The UHVDC Transmission Line Lightning Disturbance Identification Based on the Morphology

2014 ◽  
Vol 1008-1009 ◽  
pp. 603-609
Author(s):  
Rui Rui Cao ◽  
Ju Rui Yang
Keyword(s):  
Transmission Lines ◽  
Short Circuit ◽  
Low Frequency ◽  
Transient State ◽  
Spectral Energy ◽  
Complex Signal ◽  
Main Criterion ◽  
Lightning Stroke ◽  
Multi Scale ◽  
Overhead Transmission Lines

Research and identify overhead transmission lines’ transient characteristic which was caused by lightning stroke is significant to develop the protection and improving its reliability based on transient state. A complex signal can be resolved into several parts which have respective physical meanings by mathematical morphology’s multi-scale decomposition and this can reveal the local features of waves. Therefore, the transient current of ±800 kV UHVDC transmission lines, caused by the non-fault lightning stroke, fault lightning stroke and other line short circuit, can be decomposed by the multi-scale morphology decomposition to extract the spectral energy from the high and the low frequency bands, and the ratio of those two spectrum energy forms main criterion to realize the identification between lightening disturbance and the fault states. According to the ratio of the maximum of the current’s amplitudes of decomposition waveform of the first head of current’s second scale and sixth scale, to further distinguish the lightning stroke fault from the line short circuit. Extensive simulations show that the approach is correct and effective.

Fault Section Location in Distribution Network with DG Based on Voltage Sag Correlation Coefficient

2013 ◽  
Vol 787 ◽  
pp. 902-908 ◽  
Author(s):  
Xin Du ◽  
Min Fang Peng ◽  
Hong Mei Zeng ◽  
Liang Zhu ◽  
Hong Wei Che ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Distribution System ◽  
Fault Location ◽  
Short Circuit ◽  
Distribution Network ◽  
Voltage Sag ◽  
Search Range ◽  
Actual Distribution ◽  
Measuring Devices ◽  
Short Circuit Fault

A fault location method based on correlation coefficient was proposed in the paper for the distribution system with distributed generation (DG). At first, by acquiring the Thevenin equivalent parameters of each DG to establish simulation model of the actual distribution network. Then voltage sag feature vectors of each bus would be obtained by simulating short-circuit fault at the location of each bus, respectively. Afterwards, by calculating and analyzing the correlation coefficient between each bus and the actual fault node,, suspicious fault sections can be determined. Finally, the fault section was identified by utilizing the associated node of every suspicious fault section .The method could reduce the fault search range obviously, without a massive requirement of measuring devices, and the required data can be obtained easily. Simulation results of a 10kV distribution network with DG showed that the proposed method was accuracy and effective.

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