Study on the measurement method of power frequency impedance parameters of multiple-circuit transmission lines on the same tower

2014 ◽  
pp. 125-129
Author(s):  
W Gu ◽  
Y Zhao ◽  
J Yin ◽  
J Zhao ◽  
N Fan ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Measurement Method ◽  
Power Frequency ◽  
Impedance Parameters

scholarly journals A Novel Synthetization Approach for Multi Coupled Line Section Impedance Transformers in Wideband Applications

2022 ◽  
Vol 12 (2) ◽  
pp. 875
Author(s):  
Nan Zhang ◽  
Xiaolong Wang ◽  
Chunxi Bao ◽  
Bin Wu ◽  
Chun-Ping Chen ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Return Loss ◽  
Circuit Simulation ◽  
Characteristic Impedance ◽  
Fractional Bandwidth ◽  
Coupled Line ◽  
Variable Parameters ◽  
Line Section ◽  
Original Topology ◽  
Impedance Parameters

In this paper, a novel synthetization approach is proposed for filter-integrated wideband impedance transformers (ITs). The original topology consists of N cascaded coupled line sections (CLSs) with 2N characteristic impedance parameters. By analyzing these characteristic impedances, a Chebyshev response can be derived to consume N + 2 design conditions. To optimize the left N − 2 variable parameters, CLSs were newly substituted by transmission lines (TLs) to consume the remaining variable parameters and simplify the circuit topology. Therefore, there are totally 2N − N − 2 substituting possibilities. To verify the proposed approach, 25 cases are listed under the condition of N = 5, and 7 selected cases are compared and discussed in detail. Finally, a 75–50 Ω IT with 100% fractional bandwidth and 20 dB bandpass return loss (RL) is designed and fabricated. The measured results meet the circuit simulation and the EM simulation accurately.

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.

An Electroscope System Based on Electric Field Measurement Method for UHV Transmission Lines

2009 ◽  
Vol 10 (2) ◽  
Author(s):  
Fan Yang ◽  
Wei He ◽  
Tao Chen ◽  
Xiaochu Luo ◽  
Yongchang Fu
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Transmission Lines ◽  
Field Measurement ◽  
Measurement Method ◽  
Electric Field Measurement ◽  
Set Up ◽  
Global Regularization ◽  
Uhv Transmission Lines ◽  
Internet Network

The paper describes an electric field measurement method based electroscope system to check the electrification state of ultra-high voltage transmission lines, which is composed of three parts: 1) Measuring terminal; 2) Central sever; 3) GPRS and Internet network. The measuring terminal was used to measure the electric field and the location of the measuring points, then the measured data was sent to the central sever by GPRS and Internet network, and requested for an electricity state confirmation.When the sever received a request from a terminal, the electric fields and locations of the measuring points were obtained first, then according to the location of the measuring points, the server searches the corresponding objective transmission lines in the database and read their parameters. According to the parameters of the measuring points and transmission lines, a calculation would be carried out to confirm the electrification state of the transmission lines. For the confirmation calculation, equations for the electric field inverse problem of the transmission lines were set up first, then global regularization and damped Gauss Newton (DGN) method were used to solve the inverse problem.A 500kV double loops transmission line was taken as an example to verify the validity of this method. The electric field and location of 11 measuring points were measured by the measuring terminal firstly, and then sent to the central sever. Electrification state was confirmed by the central sever.

Researches on Reactive Compensation for Long-Distance and Highcapacity Hybrid Submarine Cable Lines

2012 ◽  
Vol 433-440 ◽  
pp. 2406-2410
Author(s):  
Dong Mei Sun ◽  
Jun Wen
Keyword(s):  
High Voltage ◽  
Transmission Lines ◽  
Reactive Power ◽  
High Capacity ◽  
Reactive Power Compensation ◽  
Submarine Cable ◽  
Long Distance ◽  
Power Frequency ◽  
Electro Magnetic ◽  
Cable Lines

In order to balance reactive power, reduce line losses, prevent excessive power frequency and switching over-voltage and adjust and control the line voltage etc. The long-distance and high voltage transmission lines are needed reactive power compensation. High voltage overhead transmission lines and high voltage submarine cable (including mixed-submarine) transmission lines are different, for example, the capacitance in the submarine cable lines is larger than in the conventional overhead lines. Therefore, the reactive power compensation on the EHV transmission lines which contains submarine cable lines is focus on the compensation of submarine cable lines. The reactive power compensation in 500 kV AC submarine cable interconnection project for Hainan power grid and Guangdong power grid[1], which is the first 500 kV long-distance and high-capacity sea trails interconnection project in China and which is just completed soon, is researched by Electro-Magnetic Transient Program——PSCAD/EMTDC (Power System Computer Aided Design/ Electro Magnetic Transient in DC System in this paper). The simulation results verifies that the role of shunt reactor which could absorb charging power and suppress the power frequency overvoltage for the long-distance and high-capacity hybrid submarine cable lines. The conclusions can offer references to suppress power frequency overvoltage and the reactive power compensation in extra high voltage transmission lines which is the mixed mode of overhead transmission lines and submarine cables.

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