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.

Analysis of Power System Short-Circuit Fault and its Computer Simulation

2012 ◽  
Vol 614-615 ◽  
pp. 1318-1327
Author(s):  
Yu Ren Zhou
Keyword(s):  
Power System ◽  
Simulation Experiment ◽  
Short Circuit ◽  
Fault Simulation ◽  
Complex Model ◽  
Fault Current ◽  
Single Source ◽  
Source Power ◽  
System Parameters ◽  
Short Circuit Fault

The analysis and calculation of short-circuit fault of power system is an important task for the programming, designing and running of power system. With the rapid growth of power system, the traditional ways and means can not satisfy the needs of power system, so it is necessary to use computer to simulate and calculate. Firstly this paper analyzes all kinds of short-circuit fault of a single source power system and then this paper simulates this system, sets the system parameters and fault types, finally calculates the fault current and voltage by MATLAB and the results of the simulation verifies the correctness of analysis above. It avoids the commonly programmable language to set a complex model ,making the fault simulation experiment and data analysis fast and accurate.

scholarly journals An improved Bergeron differential protection for half-wavelength AC transmission line

2021 ◽  
Vol 257 ◽  
pp. 01016
Author(s):  
Pengfei Shao ◽  
Yu Li ◽  
Ruiming Fang ◽  
Xinghua Guo
Keyword(s):  
Transmission Line ◽  
Short Circuit ◽  
Differential Protection ◽  
Protection Scheme ◽  
Transmission Distance ◽  
Half Wavelength ◽  
Current Differential Protection ◽  
And Performance ◽  
Ac Transmission ◽  
Short Circuit Fault

Half-wavelength AC transmission line has the characteristics of long transmission distance and high voltage level, and its fault characteristics are significantly different from conventional transmission line. In order to reduce the interference of distributed capacitive current on half-wavelength AC transmission line on the calculation of current differential protection, this paper proposes a new current differential protection scheme based on Bergeron model. In order to solve the problem of small differential current located at the midpoint when a short circuit fault occurs, a solution using different methods to calculate setting value in different areas is proposed. The protection can move quickly near the terminal and delay to act in the middle area. After simulation and verification on the PSCAD experimental platform, it is found that when there is a fault at both terminals of the line, the protection can quickly operate in about 10 ms; when fault occurs in the middle area, the protection can delay its operation. The experimental results show that the various actions and performance of the protection device can meet the requirements of safe operation of half-wavelength transmission line.

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