## 3 Experimental Analysis of the Reactive Power in Nowadays Power Distribution Lines
### Experimental Analysis of the Reactive Power in PDL Loaded by Diode Rectifier Supply-Side Devices
Figure 9: \(lg\Phi\) at the point of connection of the single-phase diode rectifier supply-side device to the PDL as a function of DC circuit capacity value, in case of internal parameters of PDL-connected \(R_{\text{PDL}}=0.82\)\(\Omega\), \(\omega L_{\text{PDL}}=0.2\)\(\Omega\). see in the current waveform at C = 23 \(\upmu\)F (Figure 11). With a larger capacity of the DC circuit, charging takes place aperiodically, and the oscillations do not occur, as we see in other current waveforms. Experimental Analysis of the Reactive Power in PDL Loaded by LED Light and Diode Rectifier Supply-Side Devices  
A photograph of the experimental setup is presented in Figure 11.  
The experimental setup, for the reactive power provided or drawn out by LED light and diode rectifier supply-side devices analysis, consists of (Figure 13):  
1. PDL connection switcher;
2. METREL MI 2892 power quality analyzer;
3. Diode rectifier;
4. Capacitors bank;
5. DC circuit voltage measuring device;
6. Ohmic load
7. 18 W LED light bulb;
8. 15 W LED light bulb;
9. 15 W LED light bulb;
10. 15 WK LED light bulb. The experimentally taken results of power analysis are presented in Figure 14.  
As can be seen from the diagrams in Figure 14, the reactive power of the PDL depends on the size of the DC circuit capacity of the diode rectifier supply-side device and the number of LED devices connected. By varying the DC circuit capacity value, the diode rectifier supply-side device can fully compensate the reactive power provided by the LED. In this particular experimental case, the size of the capacitors connected in the DC circuit was sufficient to compensate the reactive power provided by the two LEDs (32 W). This is  
Figure 11: Time and phase diagrams of the current at the point of connection of single-phase diode rectifier supply-side device to the PDL in the case of different DC capacitance value. Figure 12: Time and phase diagrams of the current at the point of connection of single-phase diode rectifier supply-side device to the PDL in the case of different PDL internal resistance and inductivity. shown in the diagrams in Figure 14a,b. In this case, for two LEDs, increasing the capacity of the DC circuit, the reactive power changed from negative to positive, and there is a point in the diagram where the reactive power is zero and the power factor is equal to one. The phase diagrams in Figure 14a,b show that the current leads against the PDL voltage at the minimum capacitor capacity used (\(C_{\text{DC}}\) = 23.5 uF). It can also be seen that the current lags behind the PDL voltage at the maximum capacitor capacity (\(C_{\text{DC}}\) = 1123 uF) used in the experiment. The diagrams in Figure 14c,d show that after connecting the four LED devices (62 W), the maximum DC circuit capacitance used in the experiment is not sufficient to compensate for the reactive power provided by the LEDs. The reactive power remains negative, and the current leads against the PDL voltage. Experimental Analysis of the Reactive Power in PDL Loaded by Diode Rectifier Supply-Side Variable Frequency Drive  
A photograph of the experimental setup is presented in Figure A9. The experimental setup, for the reactive power provided or drawn out by diode rectifier supply-side device analysis, consists of (Figure 15):  
1. PDL connection switcher;
2. METREL MI 2892 power quality analyzer;
3. Siemens Micromaster 420 variable frequency drive;
4. Induction motor connected to VFD;
5. Mechanically connected to induction motor DC generator;
6. Ammeter for DC generator load current measurement;
7. DC generator loading lamp bulbs;  
The aim of this experimental study was to determine the value and type of the reactive power provided or drawn out by a single-phase diode rectifier supply-side VFD. A laboratory workbench with the components described above was used for this purpose. As can be seen from the diagrams in Figure 16, this standard VFD provides leading reactive power over the entire frequency range of the induction motor.