# Supply Systems of Non-Thermal Plasma Reactors. Construction Review with Examples of Applications
## 5 Selected Issues of Designing Power Systems for NT Plasma Reactors
According to previous studies, this leakage reactance should be 30-40% of short-circuit reactance for integrated power supply transformers [43; 75; 76; 78]. Similar leakage reactance values are required in power supplies based on a five-column transformer [44]. This value is higher than in classic power transformers and lower than in arc welding power supply systems. Such a value of leakage reactance is difficult to obtain in constructions of coaxial windings, where it does not exceed 15%, or in structures with separated windings, where it is over 60%. The leakage reactance of the windings supplying the working electrodes of GAD reactor is shaped by appropriate allocation of the primary and secondary windings on the transformer columns. The highest value of leakage reactance is obtained in the case of disk windings. When there is one primary winding disc and one secondary winding disc, the leakage reactance is so high that in conventional transformers it causes an unacceptably high voltage loss. By changing the number of discs, one can change the value of reactance within wide limits while in concentric windings, can influence to some extent the value of leakage reactance by introducing spatial asymmetry of the windings. Implementation of the matching HV and HF transformer to the pulse push-pull powers supply should assume the use of a core material that will be able to transfer frequencies in the range from (10-200) kHz, while frequencies in the range (10-25) kHz transfer most of the energy from the primary to the secondary in the form of a square wave. The ability to distribute high frequency pulses to the secondary side is only maintained because of the support of the reactor ignition by using commutation overvoltages. Many power ferrite powders are able to provide these parameters. The 3C90 core material was chosen for use in the push-pull power supply [45; 59; 64] whose own resonance frequency allows operation in a transformer up to 0.2 MHz. Impulse transformers made on the ferrite powder's core allow achieving magnetic flux density B exceeding 0.3 T. Moreover, the transformer for the NTP power supply is not a typical device, because of the high-voltage secondary coil, which requires special electrical insulation strength. Additionally, high voltage requires the use of a core forming a large window in relation to the small cross-sectional area of the column to house windings. Primary and secondary windings should be placed on separate columns, which minimizes the risk of high voltages being transferred to the inverter side. Schematic structure of the secondary winding of the high frequency HV transformer is depicted in Figure 24A, while HV transformer picture is presented in Figure 24B [45; 64]. Figure 24: (**A**) Schematic structure of the secondary winding of the high frequency transformer, where a) total windings’ cross-section with the core, b) enlarged section fragment with one coil, c) layer  
diagram, where 1--core, 2--carcass 3--insulation coil, 4--winding wire, 5 and 6--interlayer insulation, (**B**)--picture of the HF transformer [45; 64]. Other issues related to the design of transformers for plasma reactor power systems do not have special features.