## 5 Results
### Supraharmonics Emission
#### 5.2.2 Case Study 2--LED 7 W Lamp
The obtained results will serve for further studies like a deeper  
Figure 10: Zoom-ins on the dominant emission band of the LED 8 W lamp supraharmonic spectrum for various supply voltage values: (**a**) frequency range 9–15 kHz, (**b**) frequency 54–64 kHz, (**c**) frequency range 113–125 kHz [21]. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Supply** & **210** & **220** & \
\begin{tabular}{c} **230** \\ **Reference** \\ \end{tabular} & **240** & **250** &
\begin{tabular}{c} **Dominant** \\ **Frequency Band** \\ \end{tabular} \\ \hline Emission level U [dB\(\mu\)V] & 33.79 & 33.14 & 32.71 & 32.01 & 31.76 & \\ Difference in emission level \(\Delta\)U [dB\(\mu\)V] & +1.08 & +0.43 & 0 & \(-\)0.70 & \(-\)0.95 & 9–15 kHz \\ Dominant center frequency \(\mathrm{f}\) [kHz] & 11.80 & 11.80 & 11.80 & 12.00 & 12.00 & \\ Frequency shift level \(\Delta\)f [kHz] & 0 & 0 & 0 & +0.20 & +0.20 & \\ \hline Emission level U [dB\(\mu\)V] & 67.04 & 66.30 & 65.37 & 64.95 & 64.24 & \\ Difference in emission level \(\Delta\)U [dB\(\mu\)V] & +1.67 & +0.93 & 0 & \(-\)0.42 & \(-\)1.13 & 54–64 kHz \\ Dominant center frequency f [kHz] & 58.60 & 59.60 & 61.00 & 60.80 & 61.20 & \\ Frequency shift level \(\Delta\)f [kHz] & \(-\)2.40 & \(-\)1.40 & 0 & \(-\)0.20 & 0.20 & \\ \hline Emission level U [dB\(\mu\)V] & 46.84 & 46.14 & 45.34 & 44.99 & 44.41 & \\ Difference in emission level \(\Delta\)U [dB\(\mu\)V] & +1.50 & +0.80 & 0 & \(-\)0.36 & \(-\)0.93 & 113–125 kHz \\ Dominant center frequency f [kHz] & 116.80 & 119.00 & 121.80 & 121.20 & 122.20 & 113–125 kHz \\ Frequency shift level \(\Delta\)f [kHz] & \(-\)5.00 & \(-\)2.80 & 0 & \(-\)0.60 & +0.40 & \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Selected dominant emission bands for the LED 8 W lamp. analysis of the topology of the power supply circuits, including filters or power factor correction systems with which electrical loads are equipped. It is possible to assess the level of supraharmonic components by analyzing the emissions associated with the dominant frequency band. As an analogy to the total harmonic distortion factor, the total supraharmonic distortion factor is used to characterize the overall assessment of emissions across the entire supraharmonic range of 9-150 kHz. It is evaluated according to Equation (2) [20; 25]:  
\[TSHD=\sqrt{\sum_{B=1}^{705}\gamma_{B}^{2}} \tag{2}\]  
where \(B\) is the index of the RMS value \(Y\) of the 200 Hz frequency bin starting at 9 kHz. The _TSHD_ factor presents the entire supraharmonic emission in dBuV emitted by a EUT (Table 6). The tested lighting sources are supplied with varying voltage levels from 210 V to 250 V. The results show that the voltage level variation within the permissible tolerance \(\pm\)10% according to the standard EN50160 [14] affects the _TSHD_ factor. Contrary to harmonic emissions, the severity of supraharmonic emissions (in examined frequency ranges) increases for all EUT with the decreasing supply voltage level value from 230 V to 210 V. The maximum relative emission change is high circa 9.5% for the CFL lighting source supplied with the voltage 210 V compared to the emission generated by the same device supplied with the nominal voltage level. A decreasing tendency of the _TSHD_ index for the rising supply voltage level value from 230 V to 250 V can be observed numerically on the right side in Table 6 and graphically in Figure 11.