Analysis of Surface White Frost on LSZH Cables and Quality Improvement Study

The precipitation of white frost on the surface of low-smoke halogen-free (LSZH) cable sheaths not only affects product appearance but also adversely affects the electrical and mechanical properties of the cable, thereby shortening its service life and seriously affecting the long-term safe and reliable operation of power supply lines. The white frost substances on the sheath surface were systematically analyzed using Fourier transform infrared spectroscopy (FTIR), gas chromatography-mass spectrometry (GC-MS), scanning electron microscopy-energy dispersive spectrometry (SEM-EDS), and other analytical techniques. The results showed that, in addition to the matrix materials ethylene-vinyl acetate copolymer (EVA) and aluminum hydroxide, the white frost substances also contained components such as antioxidant 1010 and antioxidant 246. The mass fraction of C in the white frost area (48.69%–49.76%) was higher than that in the normal area (44.95%–47.07%), while that of O in the white frost area (37.16%–42.38%) was lower than that in the normal area (38.34%–46.09%). Based on these findings, improvements were made through material formulation optimization, processing technology improvement, and enhanced management of storage and service environments. As a result, no white frost precipitated on the cable surface, and the insulation resistance increased to 4.35 MΩ·km. The tensile strength and elongation at break reached 14.2 MPa and 235%, and the property retention rates after aging were significantly higher than those obtained before improvement.