# Passive Power Line Communication Filter Design and Benchmarking Using Scattering Parameters
## 5 PLC Filter Design, Simulation, and Evaluation
### PLC Filter Design  
The filter was designed using the following requirements:  
* The filter should reach \(-120\) dB attenuation at 50 kHz because the maximum PLC signal level is 120 dBuV [16], thus blocking PLC signal passing through the filter;
* Filter power consumption at the mains frequency should be kept as low as possible;
* The filter saturation current should be at least 30 A, making it suitable for installation between SM and electrical installation of the building (i.e., main fuse);
* The filter input/output impedance in the NB-PLC frequency band must be as high as possible so that it does not affect the communication. As a minimum requirement, the impedance must be above 2 \(\Omega\) because the PLC modems are designed and tested to transmit on 2 \(\Omega\) loads [16];
* The filter design and component selection shall be conducted in order to ensure compliance with the tests described in Section 4 for additional testing.  
We have designed the 13 th order filter from Figure 14 in compliance with the requirements from the beginning of this section. The compliance and performance have been assessed in Section 5.3.  
Electronic component selection has an important role in the implementation of the filter, Table 1 is the bill of materials explaining our selection.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Component(s)** & **Part Descriptions and Use Case Explanation** \\ \hline \multirow{4}{*}{TMOV} & The filter incorporates a TMOV (thermally protected metal oxide varistor) from Little FuseTM \\  & TMOV20 RP460E [57]. The TMOV compared to traditional metal oxide varistors provides surge protection while ensuring that it will not conduct at mains voltage, thus overheating and ultimately catching fire [58]. The selected TMOV will start conducting at 460 V, thus safe operation of the filter is ensured during overvoltage V\({}_{(L-L)max}=438\) V. \\ \hline \multirow{4}{*}{R1, R2 and R3} & An array of three series connected resistors is used for passive damping of oscillations that might occur in the grid [59]. Surge safety resistors SSR300J10K0 TKZTB500 from FirstohmTM [60] were chosen. Series connection is preferred in order to ensure that there is no arching due to insufficient clearance and creepage distances [61]. \\ \hline \multirow{2}{*}{C1 and C5} & Polyester film capacitors capable of withstanding V\({}_{(L-L)max}=438\) V were used. Specifically in our design, JGCC series from JB\({}^{\text{\textregistered}}\)[62] were used. \\ \hline \multirow{4}{*}{L1 to L8} & The inductors were designed and built using a toroidal core made out of Sendust MS-184075-2 [63] manufactured by MicrometalsTM. Sendust is appropriate to be used in applications requiring high permeability, low coercivity, high resistivity, and high magnetization, such as inductors used in filtering applications [64]. In order to obtain L = 100 \(\mu\)H and a current rating of 40 A, N = 26 turns of 4 mm\({}^{2}\) stranded wire are used. \\ \hline \multirow{2}{*}{C2, C3, C4} & Polyester film capacitors capable of withstanding V\({}_{(L-L)max}=438\) V were used. Specifically in our design, JGCC series from JB\({}^{\text{\textregistered}}\)[62] were used. The value of the capacitors was adjusted to C = 2.2 \(\mu\)F based on simulation and calculation values in order to have a trade-off between power consumption, attenuation, and input/ output impedance. \\ \hline \hline \end{tabular}
\end{table}
Table 1: Filter comparison based on datasheet values.