Time delay along a chained lumped-circuits: for the physical analogy of half-wavelength power transmission lines

2017 2nd International Seminar on Advances in Materials Science and Engineering

Zhan, Rongrong^1 ; Li, Yurong^2 ; Jiao, Chongqing^2 ; Yu, Yue^1 ; Meng, Jiangwen^1 ; Wang, Bei^2

State Key Laboratory of Power Grid Safety and Energy Conservation, Relay Protection Research Department, China Electric Power Research Institute, Beijing

100192, China^1

State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing

102206, China^2

关键词: AC transmission;    Equivalent lumped circuits;    Half wave-length AC power transmissions;    Half wavelength;    Lumped-circuit;    Power frequency;    Relative errors;    Wave frequencies;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/231/1/012044/pdf
DOI  :  10.1088/1757-899X/231/1/012044

来源: IOP

【 摘 要 】

Half-wavelength AC power transmission (HWACT) technology is a kind of three-phase AC transmission technology, which can transmit electric power over a distance close to half power-frequency wavelength, i.e. 3000 km (50Hz) or 2500 km (60 Hz). In order to implement physical analogy of HWACT lines, in general, the equivalent lumped-circuits consisting of some chained π-type circuits or T-type circuits are used in laboratory. The number of the chained circuits is the most key parameter to establish good equivalence between the lumped-circuits and the transmission line. In this paper, the time delay of the chained circuits, which is defined as the time of a sine wave propagating from the sending end to the receiving end of the chained circuits, is calculated for different number of the chained circuits and different wave frequencies. Good equivalence requires the time delay equal to 10ms (the time of electromagnetic waves propagating along 3000km). It is shown that the time delay is dependent on the number of the chained circuits, as well as the wave frequency. For 50Hz, 4 chained π-type circuits can ensure that the relative error of the time delay is less than 2.6% and the sending-to-receiving voltage ratio is approximately 1. For frequencies below 400Hz, 30 chained π-type or T-type circuits can ensure that the relative error of the time delay is less than 3.2% and the sending-to-receiving voltage ratio is approximately 1. These works are instructive for the physical analogy of HWACT lines.