scholarly journals Signal power distribution in time delay in Tokyo City experimental sites

Radio Science ◽  
2008 ◽  
Vol 43 (3) ◽  
pp. n/a-n/a ◽  
Author(s):  
M. Hayakawa ◽  
D. Katz ◽  
N. Blaunstein
Keyword(s):  
Time Delay ◽  
Power Distribution ◽  
Signal Power

Protection Coordination of 33/11 kV Power Distribution Substation in Iraq

2021 ◽  
Vol 39 (5A) ◽  
pp. 723-737
Author(s):  
Yamur M. Obied ◽  
Thamir M. Abdul Wahhab
Keyword(s):  
Time Delay ◽  
Power System ◽  
Power Distribution ◽  
Software Package ◽  
Short Circuit ◽  
Distribution Network ◽  
Circuit Breaker ◽  
Short Circuit Current ◽  
Earth Fault ◽  
Current Characteristics

The coordination between protective devices is the process of determining the most appropriate timing of power interruption during abnormal conditions in the power system. The aim of this work is to coordinate the protection of the 33/11 kV power distribution substation in Iraq using the CYME 7.1 software package. In this paper overcurrent and earth fault relays are simulated in two cases, with time delay setting and instantaneous setting, to obtain the Time Current Characteristics (TCC) curves for each Circuit Breaker (CB) relay of Al-Karama substation (2×31.5 MVA, 33/11 kV) in Babil distribution network. The short circuit current at each CB is calculated and accordingly, the protection coordination for Al-Karama substation has been simulated. The TCC curves have been obtained in two cases for overcurrent and earth fault relays; in a case with time delay setting and in the case with the instantaneous setting. The setting takes into consideration the short circuit current at the furthest point of the longest outgoing feeder and the shortest outgoing feeder.

scholarly journals Evaluation of multifrequency range-imaging technique implemented on the Chung–Li VHF atmospheric radar

2015 ◽  
Vol 8 (9) ◽  
pp. 10097-10120 ◽  
Author(s):  
J.-S. Chen ◽  
S.-C. Tsai ◽  
C.-L. Su ◽  
Y.-H. Chu
Keyword(s):  
Time Delay ◽  
Power Distribution ◽  
Weighting Function ◽  
Imaging Technique ◽  
Pulse Length ◽  
Radar Data ◽  
Range Imaging ◽  
Vhf Radar ◽  
Two Factors ◽  
Cable Lines

Abstract. Multifrequency range imaging technique (RIM) has been implemented on the Chung–Li VHF-array radar since 2008 after its renovation. This study made a more complete examination and evaluation of the RIM technique to facilitate the performance of the radar for atmospheric studies. Various experiments of RIM with different radar parameters such as pulse length, pulse shape, receiver bandwidth, transmitter frequency set, and so on, were conducted. The radar data employed for the study were collected from 2008 to 2013. It has been shown that two factors, the range/time delay of the signal traveling in the media and the standard deviation of Gaussian-shaped range-weighting function, play crucial roles in ameliorating the RIM-produced brightness (or power distribution); the two factors are associated with some radar parameters. In addition to radar parameters, long-term RIM data show that the aging of cable lines or key components of the radar system may result in an increase of the range/time delay of signal. It is also found that the range/time delay was visibly different for the echoes from the atmosphere with and without the presence of significant precipitation. A procedure of point-by-point correction of range/time delay was thus conducted to minimize the bogus brightness discontinuity at range gate boundaries. With the RIM technique, the Chung–Li VHF radar demonstrates its first successful observation of double-layer structures as well as their temporal and spatial variations with time.

scholarly journals Jammers signal power modelling in the Wi-Fi band

2019 ◽  
Vol 252 ◽  
pp. 03016
Author(s):  
Dariusz Czerwinski ◽  
Slawomir Przylucki ◽  
Jaroslaw Nowak
Keyword(s):  
Power Distribution ◽  
Signal Power ◽  
Critical Importance

The distribution of the signal coming from jamming sources is an issue of critical importance to the security and jammer localisation. The paper presents the results of simulations of signal power distribution in the Wi-Fi band conducted for two commercially available jammers, CRJ4000 and CKJ-1502A12. Calculated distributions of signal power were compared with the results from the measurements. The comparison made it possible to assess the correctness of the designed models and out of the simulations. The paper presents the results of simulations and measurements for different scenarios of jammers settings.

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