# Analysis of Plasma Reactor Interaction with the Power Grid Depending on the Power Supply Design
## 5 Test Results  
To begin, the power supply units were tested for interaction with the grid under conditions when the outputs of the power supply units were not loaded. Measurements were carried out in the measurement system shown in Figure 6. The PR plasma reactor was disconnected from the circuit, leaving the output terminals of the L\({}_{1}\), L\({}_{2}\), L\({}_{3}\), L and N power supplies free. The measurements of the electrical quantities taken from the grid by the power supply units are shown in Table 4. The table gives the rms values of the phase voltages \(U_{1}\) feeding the power supplies, the currents taken by the power supplies from the mains \(I_{1}\), the active power \(P_{1}\), reactive power \(Q_{1}\) and complex power \(S_{1}\) taken, power coefficients cos\(\varphi\), and the harmonic content factors in the voltage \(U_{\rm 1 THD}\) and current \(I_{\rm 1 THD}\). The TPS power supply has the lowest grid power consumption, with a complex power consumption of 8.58 VA. Simultaneously, this power supply has the best power factor of all the power supplies tested (0.926) and has low harmonic content ratios in voltage and current of 2.45% and 34.63%, respectively. The IFCTPS power supply performs slightly poorer in terms of the aforementioned parameters. The ITPS is the worst performer. In idle operation, it takes 712.04 VA from the grid with a power factor of just 0.095. In contrast, the PCS power supply has the highest harmonic content in current at 87.22%. This power supply also takes the second highest power from the grid at 582.77 VA. From the comparison presented, it is apparent that plasma reactor power systems using conventional \begin{table}
\begin{tabular}{l l l l l l} \hline  & & **ITPS** & **TPS** & **IFCTPS** & **PCS** \\ \hline \(U_{1}\) & V & 237.4 & 238.3 & 234.4 & 234.9 \\ \hline \(I_{1}\) & A & 0.998 & 0.012 & 0.068 & 0.826 \\ \hline \(P_{1}\) & W & 67.61 & 7.95 & 14.11 & 335.41 \\ \hline \(Q_{1}\) & Var & 707.24 & 3.27 & 37.71 & 476.63 \\ \hline \(S_{1}\) & VA & 712.04 & 8.58 & 41.92 & 582.77 \\ \hline cos\(\varphi_{1}\) & \(-\) & 0.095 & 0.926 & 0.341 & 0.572 \\ \hline \(U_{\rm 1 THD}\) & \% & 2.54 & 2.45 & 2.68 & 1.93 \\ \hline \(I_{\rm 1 THD}\) & \% & 51.60 & 34.63 & 41.9 & 87.22 \\ \hline \end{tabular}
\end{table} 
Table 4: Operating parameters of power supplies in no-load condition. Figure 7: Plasma gas supply system, PR—plasma reactor, G—plasma gases, F—flow regulators, C—regulator setting and control system. transformers, with a typically chosen operating point on the magnetisation characteristic, provide the best interaction with the grid. The most important factor in the operation of the power supplies is their response under the load of the plasma reactor in which the arc discharge is burning. Example waveforms of single-phase voltages and currents at the inputs and outputs of power supplies loaded with an operating plasma reactor, obtained from oscilloscope measurements, are shown in Figures 8-11. The waveforms were obtained for a discharge burning in argon, whose volume flow through the plasmotron nozzle was 2.8 m\({}^{3}\)/h. Figure 8: Current and voltage waveforms of the TPS power supply, 1—input voltage, 2—input current, 3—output voltage, 4—output current, plasma gas: argon, flow: 2.8 m\({}^{3}\)/h. Figure 9: Current and voltage waveforms of the ITPS power supply, 1—input voltage, 2—input current, 3—output voltage, 4—output current, plasma gas: argon, flow: 2.8 m\({}^{3}\)/h. The voltage and current waveforms at the output of the TPS, ITPS and IFCTPS power supply shown in Figures 9-11 are typical of arcs burning in a three-phase system at low current and cooled intensively [30; 31]. Of the gases used in measurement, argon provides the best conditions for ignition and development of a discharge in the reactor over the entire range of its flow control, and over the entire range of control characteristics of the electrical parameters of the power supplies.