## 3 Noise in PLC Networks
### Noise Library for NBPLC-PRIME
#### 3.2.4 Noise Signals Measured in the Lab  
In addition to normative noise and the noise measurements taken in the field, noise measurements have been also gathered in a controlled environment such as the LINTER of Union Fenosa Distribucion [39]. This laboratory is equipped with around 100 smart meters and a few concentrators from the main manufacturers in the market [60], as well as with DG installations based on renewables  
Figure 11: Electronic ballast noise measured in the field. Figure 10: Water pump noise measured in the field. and EV charging spots. All the equipment is connected with low voltage cables of lengths ranging from 10 to 150 m and sections ranging from 4 to 35 mm\({}^{2}\). In this case the measurements have focused indeed on the noise introduced by the DG installations and the EV charging due to their relevance in low voltage networks both currently and even more in the forthcoming years. The equipment used for measuring the noise in this case is the HW/SW SpectraVue sniffer from Moetronix [61], which allows capturing instantaneous values and accumulated values of the frequency response of both noise and communications in a range that includes PRIME frequency band. The records are both CSV and JPEG images. The JPEG images include two lines: a green one representing the \"instantaneous\" noise, and a blue one, superior to the green one, which reflects the maximum level measured since the analyzer was switched on, which is the sum of the noise and the PRIME communications signal. The CSV records include the frequencies and amplitudes associated to the green line of the JPEG images (i.e., \"instantaneous\" noise). EV are elements that require a rapid charging process during which they can emit significant noise levels in PRIME communication bands. Figure 12 shows the setup and components used for measuring the EV charging noise at the LINTER. As it can be seen, three different models of EV were considered, namely Renault Twicy, Renault Zoe, and Nissan Leaf. Figure 13 shows the noise measured at the LINTER when charging a Renault Twicy. It can be seen that it introduces a remarkable peak at the very beginning of the PRIME frequency band. By analyzing the CSV records with MATLAB, it can be seen that such a peak reaches \(-30.28\) dBV at 48.29 kHz. Figure 14 shows the noise measured at the LINTER when charging a Renault Zoe. In this case, the measured noise is kind of colored, reaching levels up to \(-65\) dBV, i.e., lower than when charging the Renault Twicy. Figure 15 shows the noise measured at the LINTER when charging a Nissan Leaf. In this case, it can be observed that it is kind of colored with two main peaks at 54 and 82 kHz that reach \(-60\) dBV. Figure 12: Setup and components used for measuring the EV (Electric Vehicle) charging noise at the LINTER (Grid Interoperability Laboratory). Figure 14: Noise associated to charging a Renault Zoe. Figure 15: Noise associated to charging a Nissan Leaf. Figure 13: Noise associated to charging a Renault Twicy. It should be noted that, although these records are valuable to reproduce these noises in a controlled or simulated environment with the aim of evaluating their impact in different scenarios, the noise introduces by EV charging changes with time and also depends on the charging type (e.g., slow, semi-fast or fast, single-phase or three-phase) and on the state of charge of the battery. Regarding the inverters, they are elements that have not limited conducted emissions in the frequency bands below 150 kHz by regulation so far, so they can emit very relevant noise signals in PRIME communication band. The noise generated by inverters typically contains a series of peaks whose frequency is related to the working frequency of the inverter power electronics. In many cases the inverters are grouped by tens, reason why the accumulated noise in the installation is much bigger than the contribution of only one. Figure 16 illustrates the setup and components used for measuring the noise coming from inverters at the LINTER.