Influence of Repetitive Square Voltage Duty Cycle on the Electrical Tree Characteristics of Epoxy Resin

Abstract

The application of wide band-gap power electronic devices brings more challenges to insulating packaging technology. Knowing the influence of applied voltage parameters on insulation performance is helpful to evaluate the insulation condition of electric power equipment. In this paper, the effect of repetitive square wave voltage duty cycle on the growth characteristics of electrical trees in epoxy resin was studied. The experimental results show that the square wave voltage duty cycle has a significant influence on treeing features. The electrical tree proportion initiation has shown a decreasing trend, and the shape of the electrical tree changes from pine-like to branch-like by increasing the duty cycles. The length and damaged area of electrical tree increased with the increase in the duty cycle up to 10% and then decrease by increasing the duty cycle higher than 30%. It indicates that a low duty cycle will enhance the electron injection and accumulate space charges and thus accelerate electrical tree development. Under short duty cycles, the electric field due to the shielding effect near the needle tip suppresses the electrical tree growth, which results in treeing growth stagnation. The obtained results are helpful to keep these parameters in mind during the design of epoxy-based insulation such high-voltage rotating machines and power electronic device packaging.

Charge vibration behaviour in polyimide under the pulse voltage with different rise and fall times

“…Power electronic equipment is generally operated under high-frequency pulse voltages for long periods. On the one hand, the power electronic technology, such as pulse width modulation (PWM), is applied to realise flexible control of electronic equipment by subjecting to a high-frequency pulse voltage [3,4]. For example, the power electronic transformer is a new type of transformer that combines the power electronic technology with a high frequency transformer.…”

Transient electric field of the combined insulation structure under positive periodic square waveform voltage: Analytical analysis and application

“…In experimental studies, extensive efforts have been made to obtain the partial discharge characteristics of power electronics [9,10], the surface charge characteristics [11][12][13], the streamer characteristics [14], accumulation and dissipation of the space charge characteristics [15,16] of engineering insulation materials. Significant progress has been achieved to investigate the dependence of waveform parameters of the PPSW voltage on space charge accumulation characteristics [17], partial discharge characteristics [18], surface discharge characteristics [19], and electric tree characteristics [20,21] of insulation materials. Besides, polarisation characteristics of double-layer composites under the square waveform voltage with only one single cycle were also studied [22].…”

Steady-State Conduction Current Performance for Multilayer Polyimide/SiO2 Films

“…Over the last decade, nanodielectric insulating materials have received a lot of attention in the global market [19][20][21][22]. Several published studies proclaim that polymers and their derived nanocomposite insulating materials can enhance the dielectric properties for electrical applications [23][24][25][26][27][28][29]. In another study, fluorine-coated PI films have shown promising improvements in results by applying a thin layer of conductive surface coating on the top and bottom of these films [30,31].…”