Modified stress grading system for a 13.8 kV inverter-fed rotating machine

Nonlinear field dependent conductivity dielectrics made of graphite nanoplatelets filled composites

“…Indeed, the increase of energy demand with the concomitant decrease of the size of electric devices implies additional electric stresses on voltage insulating systems [6][7][8]. This makes it ever more technically challenging to safely and durably provide an efficient insulation.…”

Power Density and Temperature Rise Estimation at End-turn Stress Grading System of Large Rotating Machines under PWM Waveform

“…INVERTER-fed medium-and high-voltage motors have been widely used for the high-efficiency operations and the low energy consumptions in the industrial field, such as rolling mills in the steel industry and compressors in pipelines. Compared to conventional AC-driven motors, the inverter-fed motors are unavoidably exposed to the high frequency and high voltage waveforms, so-called inverter surges, which may accelerate the degradation of the motor insulation systems, especially end-turn stress grading (SG) systems [1][2][3][4]. Figure 1 shows a typical structure and a cross section of the end-turn SG system of a form-wound rotating machine.…”

Graphite nanoplatelets filled silicone composites with novel electrical and dielectric properties

“…The increasing energy demand with the concomitant decrease of the size of the electric devices and the penetration of renewable energy sources such as wind farms and solar power systems in the distribution network, imply additional electric stress on voltage insulating materials [1][2][3][4][5][6][7][8][9][10]. Providing an efficient and safe insulation is therefore a challenge.…”

“…Fig 7. Relative permittivity and dissipation factor (tan δ) spectrum at room temperature for the pure PDMS matrix and a 4.5 wt.% GnP /silicone nanocomposite…”