Impedance of electrical loads and branching of lines have been found to be the main causes of impedance discontinuities in PLC channel networks. Therefore, the transmission line is modeled assuming a randomly distributed set of scavengers near the channel with a sufficient number of impedance discontinuity points. The model is based on the confirmation of the assumption of a randomly distributed set of scavengers in the vicinity of the channel, which only requires a sufficient number of impedance discontinuity points.
Therefore, only part of the signal sent at the transmitter reaches the receiver. Relative permittivity and permittivity are parameters of the insulating material of the transmission line.
Signal Attenuation
Figures 2.3-5 and 2.3-6 below show the attenuation (in dB/m) versus the characteristic impedance of a coaxial transmission line using polyethylene ( ) as the dielectric medium, which has a solid copper inner conductor of radius a = 2 mm and a copper outer conductor with inner radius b. 2.3-7 which shows that characteristic impedance increases when copper outer conductor with inner radius b varies from 4.5 to 10 mm. 2.3- 8 show the specific attenuation for coaxial transmission line with inner conductor with radius a = 0.8 mm and a copper outer conductor with inner radius b = 2 mm.
2.3-9, the specific attenuation for a coaxial transmission line with inner conductor of radius a = 2 mm and a copper outer conductor with inner radius b = 4.5 mm has the highest attenuation of 0.258 dB and the lowest of 0.23 dB. This shows that there is a higher conductor attenuation for a cable with an inner conductor with radius a = 0.8 mm and a copper outer conductor with inner radius b = 2 mm, than for a cable with an inner conductor with radius a = 2 mm and a copper outer conductor. with inner radius b = 4.5 mm.
Refractivity of a Metal
Theory of Dielectric Material
The parameters of greatest interest are the conductivity, σ, and the permittivity, ε, as these control the dielectric attenuation. Permittivity is a complex quantity whereby: 2.18) where is the electric flux density, the electric field strength, is the dielectric constant, (− ) is the permittivity of free space, is the relative dielectric constant,. The real and imaginary parts of the permittivity can be represented as a set of orthogonal axes as in fig.
Scattering parameters
The upper and lower bounds for the channel response at varying loads are also derived, resulting in a statistical characterization of the channel. The information provides a broad knowledge base for the design of the PLC channel modem that can be used for the practical implementation of the PLC channel data transmission systems. With different paths or lengths and end loads tapering to the main path, the PLC channel impedance varies significantly with frequency in the range of a few ohms to a few kilo-ohms.
Then, a suitable computer model of the corona noise was proposed that was consistent with the measurement results. The first output is the average RMS of the corona noise, which multiplies samples of the white noise.
Spread Spectrum Modulation
Multi Carrier Modulation
The characteristic of the standard (CENELEC, 1991) is the limitation of the maximum output voltage of the. The Philipps model was based on evolutionary strategy to get lumped circuit parameters from the SR load, but the model did not consider the length of the cable. The attenuation function is also given by Equation (3.7), where is the length of the cable.
The Philipps model was based on an evolutionary strategy to obtain lumped circuit parameters for the SRC load, but the model did not consider the length of the cable. Once we have all parameters for the branch, we use equations (3.20) and (3.22) to generate the transfer function of the transmission line using the MATLAB tool. The lower the length of the line, the higher the resonant frequency as shown in Fig.
Currently, there is no universal model for the powerline transfer function because there are many parameters that must be known or measured before the transfer function can be determined. Proceeding of the 1998 International Symposium on Powerline Communications and its Applications (ISPLCA '98), Tokyo, Japan, March, p. In this chapter, we investigate the effect of the number of branching nodes in the PLC network and derive a scattering distribution model for PLC channels.
The model is based on the assumption of a randomly distributed set of scatterers near the channel, which only requires a sufficient number of impedance discontinuity points [Sabih Güzelgöz, (2011)]. Multipath propagation of a power line (PLC) communication channel results from the presence of multiple branches and impedance mismatches that cause multiple reflections. Here, we note that the reflection factor of the first arrival path consists only of the transmission coefficients experienced along the direct path arising from the impedance discontinuities at the branch nodes.
Thus, its calculation is sufficient to characterize the reflection factor of the first arrival path. Note that the phase term of the reflection factor is 0 for this particular case since it cannot be a complex number.
Scattering Points Approximation Model
In [Papaleonidopoulos (2002), Sabih Güzelgöz (2011)], the estimation of the road amplitude distribution is done using Log-normal distribution with two parameters, and. We note that the fitted results of the values show dependence on the number of branching nodes. In this section, we investigate the effect of the number of branches and the number of reflections that occur at each node.
In the example, (N-1) degrees of freedom are used to determine the significance level of the preferred model. On the other hand, it shows the closeness of the proposed specific damping model with the theoretical model. The non-linearity of cable resistance and conductance causes the specific attenuation to be non-linear as a function of frequency.
In Figure 4.3-8, where the frequencies used are 10, 16.7, and 21.7 MHz, respectively, the number of branch nodes is used in the estimation of and through a regression fitting procedure. 4.5-3, and the segmented section of the cable is modeled as a four-terminal network, represented by an ABCD matrix as shown in Figure. And the equivalent of the transfer function of the network is the inverse of A in [T], [Tsuzuki et al., (2002)].
The analytical models of the attenuation constant and the phase constant are derived in Sections 4.3 and 4.4, while they are derived in Section 3.2. We also developed a power-law model that relies on knowing the number of branch nodes in the network, and thus the attenuation can be predicted from this model. Finally, the analytical models of the attenuation constant and the phase constant derived in Sections 4.3 and 4.4 and derived in Section 3.2 were used in the two-port model to simulate the channel frequency response.
Yamada, (2002) "A transfer function evaluation method of internal power line ducts for Japanese houses", in Proc. Yamada, "A Transfer Function Evaluation Method of Internal Power Line Ducts for Japanese Houses," Proc.
Oscilloscope
This is a general purpose network analyzer with extended functionality to support network and impedance measurements for electronic devices from LF to RF, with the following features:
Signal Generator
The type of cable measured was CABTYRE CABLE- FLEXIBLE CABLE (300/500 V) and the dimensions of the cables are: in. In order to determine the characteristic impedance of the power line cable from the measured data, the input impedance was measured when the end of the cable was open and then when it was short-circuited. The input impedance should be measured with the cable end open and shorted.
The measured time difference between the sending end and the receiving end of the sine wave signal was 750 nS. The snapshot in Figure 5.3-3 below shows the sending end and the receiving end of the signal. The velocity of propagation can also be written as a function of the speed of light as.
5.3-5, the effects of the impedance mismatch, which causes more reflections in the cable, can be seen. When the load is not connected and the end of the cable is open, it can be written using equation (5.1). The maximum value of the open circuit impedance is 11 Ω at 10 MHz, while the minimum value is 0 Ω at 80 MHz.
Similarly, when the end of the cable is shorted, this means the equation for the input impedance given in equation (5.2) above. The characteristic impedances of the power cables used for measurements are low compared to those of conventional cables used for data transmission, and this is due to the dimensions of the conductor compared to the insulation layer. In general, characteristic impedances are between 5 and 50 ohms, and depend on the type of cable and signal coupling used.
Attenuation Measurements
The simulation and measurement of channel transfer responses of the two branch point transmission line is shown in Figure 5.5-1 Figure 5.5-2 below. In addition, Figure 5.5-2 shows the simulation and measurement of phase shifts of the two branch point transmission line with no load at the branch point. We therefore conclude that the models developed do not require knowledge of the link topology or -70.
Therefore, this chapter has been useful in the discussion of the measurements with respect to the analytical model thus developed for powerline parameters, especially S and Z. The attenuation of the signal in the PLC channel is determined by cable characteristics, cable length, network topology and electrical devices connected to the network. A comparison between the measured values and the simulation results of the frequency response shows a very good agreement.
Thus, we conclude that the developed models do not require knowledge of link topology or cable models, but require a large-scale measurement campaign. The transmission line parameters of the cables were determined from the measurements and the attenuation results obtained were very close to those obtained by the analytical model. In the 10 MHz - 100 MHz frequency band, the main loss mechanism of the low voltage power cable is the dielectric loss of the PVC insulation material used.
In the studied frequency range of 10 MHz – 100 MHz, the attenuation of the signal in the PLC channels increases for the measurements carried out due to increasing cabling losses. Thus, standing waves are formed which can be noticed in the frequency responses of the power line channels as frequently repeating notches and peaks. Wang, (2011), “For the grid and through the grid: the role of power line communications in the smart grid”, Proceedings of the IEEE, vol.
