abstract
- We investigate how the chemical symmetry of adjacent semiconductive screens modulate space-charge formation and transport in Low-Density PolyEthylene (LDPE). Using the Pulsed Electro-Acoustic (PEA) method on 1 5 0 - ¿ m LDPE under 100 kV mm DC at 23 ± 2° C, we compare symmetric (OSL-LDPE-OSL) and asymmetric (ISL-LDPEOSL) stacks based on EVA/carbon-black screens. Symmetric screens markedly suppress space-charge accumulation-peak density 2. 3 8 ~ C · m-3 vs 2 9. 9 6 ~ C · m-3-and slow packet propagation-transit 900 s vs 500 s-with earlier onsets in the asymmetric case (150 s) than in the symmetric (450 s). Intermediate behavior appears for ISL-LDPE-ISL (9.38 C · m-3; 600 s) and OSL-LDPE-ISL (17.25 C · m-3; 600 ~s). PEA maps for symmetric stacks are broader and less skewed, consistent with more balanced injection barriers and more effective bipolar recombination. Without altering the polymer matrix, interfacial symmetry emerges as a simple, scalable lever to attenuate spacecharge accumulation and enhance dielectric reliability in medium-voltage cable insulation.