scholarly journals Study on the Application of Optical Current Sensor for Lightning Current Measurement of Transmission Line

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5110
Author(s):  
Jin-ming Ge ◽  
Yan Shen ◽  
Wen-bin Yu ◽  
Yue Han ◽  
Fang-wei Duan

Accurate and reliable lightning current data are the basis of lightning protection design. To measure lightning current data at different measurement locations in a transmission system, the limitations of traditional lightning current sensors are analyzed, and optical current sensing technology is adopted, which has the advantages of no magnetic saturation and no bandwidth limitation. Compared with traditional application environments, the sensing technology is used in special environments in transmission systems. This paper analyzes the influence of environmental factors on sensors, and combines the extreme environmental requirements, such as temperature and insulation requirements, to study the sensor. Starting from the sensitivity, the sensing characteristics of the sensor are analyzed. The sensor is designed according to three aspects: sensing material selection, spatial measuring position, and sensing material size optimization, such that it can satisfy the different measurement requirements of towers, overhead ground wires, and transmission lines, respectively. The experiments indicate that the developed sensors can meet the measurement sensitivity requirements of different types of lightning strikes. The experimental results of sensors exhibit a reasonable amplitude measurement accuracy, linearity, and waveform measurement capability. These results provide important theoretical and experimental bases for the application of optical current sensing technology to the measurement of the lightning current of transmission systems.

2018 ◽  
Vol 9 (5) ◽  
pp. 5432-5443 ◽  
Author(s):  
Dimitrios Tzelepis ◽  
Grzegorz Fusiek ◽  
Adam Dysko ◽  
Pawel Niewczas ◽  
Campbell Booth ◽  
...  

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 296 ◽  
Author(s):  
Jakub Furgał

The analysis of lightning overvoltages generated in electrical power systems has a great meaning for the designers and exploitation engineers because it creates bases for the optimization of construction overhead transmission lines and high voltage substations, reducing costs and increasing reliability of the transmission and distribution of electrical energy. Lightning overvoltages generated in electrical power systems with overhead transmission lines are a result of complex, nonlinear, and surge phenomena occurring in the structure of line towers and electrical substation when the lightning current is flowing through them. Methods of overvoltage stress analysis are intensely developed, and one of the directions is working out models of high voltage electrical devices and phenomena in electrical networks, which influence the shape and values of overvoltage risks. The model of lightning current has a significant influence on the courses of overvoltages in high voltage transmission systems. The paper is focused on the analysis of the influence of the model of lightning current making use of simulations of the shape, and maximal values of overvoltages generated in high voltage transmission systems during a direct lightning strike to the overhead lines. Two models of lightning current used in simulations with the Electromagnetic Transients Program/Alternative Transient Program (EMTP/ATP) were analyzed, i.e., the Heidler model and CIGRE (Conseil International des Grands Réseaux Électriques) model. The EMTP/ATP computer program is very often used in simulations of overvoltages in electrical networks. Unfortunately, the users get no information on the criterion to be used when selecting the model of lightning current used in the simulations. The analysis presented in the paper gives practical knowledge about the effect of the use of a particular kind of lightning current model on the results of simulations of lightning overvoltage propagation in electrical networks, overvoltage protection, as well as on theoretical and practical aspects of the insulation coordination in high voltage transmission systems.


Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1561
Author(s):  
Hao Chen ◽  
Zhongnan Qian ◽  
Chengyin Liu ◽  
Jiande Wu ◽  
Wuhua Li ◽  
...  

Current measurement is a key part of the monitoring system for power transmission lines. Compared with the conventional current sensor, the distributed, self-powered and contactless current sensor has great advantages of safety and reliability. By integrating the current sensing function and the energy harvesting function of current transformer (CT), a time-multiplexed self-powered wireless sensor that can measure the power transmission line current is presented in this paper. Two operating modes of CT, including current sensing mode and energy harvesting mode, are analyzed in detail. Through the design of mode-switching circuit, harvesting circuit and measurement circuit are isolated using only one CT secondary coil, which eliminates the interference between energy harvesting and current measurement. Thus, the accurate measurement in the current sensing mode and the maximum energy collection in the energy harvesting mode are both realized, all of which simplify the online power transmission line monitoring. The designed time-multiplexed working mode allows the sensor to work at a lower transmission line current, at the expense of a lower working frequency. Finally, the proposed sensor is verified by experiments.


Author(s):  
CH. CHENGAIAH ◽  
R.V.S. SATYANARAYANA ◽  
G.V. MARUTHESWAR MARUTHESWAR

The power transfer capability of electric transmission lines are usually limited by large signals ability. Economic factors such as the high cost of long lines and revenue from the delivery of additional power gives strong intensive to explore all economically and technically feasible means of raising the stability limit. On the other hand, the development of effective ways to use transmission systems at their maximum thermal capability. Fast progression in the field of power electronics has already started to influence the power industry. This is one direct out come of the concept of FACTS aspects, which has become feasible due to the improvement realized in power electronic devices in principle the FACTS devices should provide fast control of active and reactive power through a transmission line. The UPFC is a member of the FACTS family with very attractive features. This device can independently control many parameters. This device offers an alternative mean to mitigate transmission system oscillations. It is an important question is the selection of the input signals and the adopted control strategy for this device in order to damp power oscillations in an effective and robust manner. The UPFC parameters can be controlled in order to achieve the maximal desire effect in solving first swing stability problem. This problem appears for bulky power transmission systems with long transmission lines. In this paper a MATLAB Simulink Model is considered with UPFC device to evaluate the performance of Electrical Transmission System of 22 kV and 33kV lines. In the simulation study, the UPFC facilitates the real time control and dynamic compensation of AC transmission system. The dynamic simulation is carried out in conjunction with the N-R power flow solution sequence. The updated voltages at each N-R iterative step are interpreted as dynamic variables. The relevant variables are input to the UPFC controllers.


Ni-Co 2013 ◽  
2013 ◽  
pp. 201-209
Author(s):  
Rob Fraser ◽  
Tim Johnston ◽  
John Yesberg ◽  
Sebastien Nolet ◽  
Chris Boon

2013 ◽  
Vol 2013 (1) ◽  
pp. 000776-000781
Author(s):  
Evan Reutzel ◽  
Rengang Chen ◽  
Scott Ragona ◽  
David Jauregui

A lossless current sensing technique is proposed, which takes advantage of the on-resistance of the sync FET used in the buck converter to sense the current flowing through the device and to reconstruct an emulated version of the inductor current. The current sensing circuit is integrated into the MOSFET driver and co-packaged with a set of FETs in a stacked die arrangement with common lead-frame shared between driver and sync FET to enable accuracy equivalent to or better than DCR sensing. In addition to steady-state operation, modern multiphase controllers are required to drive the buck converter in other operating modes including: Diode Emulation Mode (DEM), body-braking, tri-state (phase off). These additional modes are also correctly emulated by the current sense logic.


1975 ◽  
Vol 12 (1) ◽  
pp. 78-87
Author(s):  
P. S. Barnett

Graphical methods of solution for networks containing transmission lines with attenuation but no distortion are presented. These are similar to those available for the solution of travelling waves on lossless transmission lines using the Schnyder-Bergeron method. The equations used are derived and are of the same form as those used in the method of Schnyder and Bergeron. Examples illustrating the graphical methods are given.


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