Access impedance in Brazilian in-home, broadband and low-voltage electric power grids

An Analog Filter Bank-based Circuit for Performing the Adaptive Impedance Matching in PLC Systems

“…According to [28], [30], the data communication channel between two PLC transceivers become time-invariant during a period shorter than the so-called coherence time of PLC channel, T c . In addition, [31]- [33] states that the frequency response of any quantity can be constant in a frequency bandwidth shorter than the so-called coherence bandwidth. Assuming that T z ≈ T c , which is an acceptable assumption due to the intrinsic relationship among the scattering parameters and the value of the coherence bandwidth of the access impedance of electric power systems, it is easy to conclude that Z(f + ∆f, t + ∆t) = Z for 0 ∆f B z and 0 ∆t T z .…”

“…In this regard, it is necessary to know the values of access impedance values of electric power systems. According to [31], 90% of the input resistance values measured are between 25 Ω and 100 Ω and the mean value equal to 50 Ω. Therefore, three analog filters (M = 3) are designed with the input resistance equal to 25 Ω, 50 Ω, and 100 Ω.…”

“…When the constant γ = √ 2 applies, which represents −3 dB cut-off frequency, a ratio of 1 : 5.828 is obtained. However, this ratio between the output impedance Z L , which is fixed in 50 Ω, and the electric power system impedance Z S is not adequate because the value 1 : 5.828 results in an input impedance of Z S = 8.579 Ω, which is not a desired impedance value and outside the range of the desired access impedance value of electric power systems (i.e., between 25 Ω and 100 Ω, see [31]). In this sense, the low-pass irregular analog filter has been redesigned to obtain a ratio between electric power system impedance Z S and output impedance Z L equal to 1 : 2 and 2 : 1, as a consequence, to lock the input impedance of the low-pass irregular analog filter at 25 Ω and 100 Ω.…”

An Initial Discussion of an Adaptive Impedance Matching Circuit for PLC_ Systems

“…For an appropriate design of the impedance matching circuits bank (i.e., analog filter bank), it is necessary to know the input impedance values of electric power grids. According to [9], 90% of the input impedance values measured are between 25 Ω and 100 Ω with mean value equal to 50 Ω. Therefore, three analog filters (M = 3) are designed with the input impedance equal to 25 Ω, 50 Ω, and 100 Ω.…”

Medición y análisis de la impedancia en PLC de banda angosta en un ambiente universitario

“…Dado que la impedancia es el resultado de la topología de la red y del tipo y cantidad de cargas conectadas, su valor depende de la instalación particular, el tiempo y la posición, y puede ser menor a los valores considerados por equipos comerciales y notas de aplicación de fabricantes de circuitos integrados. Por esta razón, para diseñar correctamente el circuito de acoplamiento de un módem PLC, el valor de la impedancia debe ser correctamente evaluado [6], [7].…”