Effect of Ionic Conductors on the Suppression of PTC and Carrier Emission of Semiconductive Composites

Yingchao Cui,Shiyi Zhao,Xiangjin Guo,Qingquan Lei,Guochang Li,Zhaoliang Xing,Meng Xin,Chuncheng Hao,Yanhui Wei,Hongxia Yin

doi:10.3390/app10082915

Abstract

The positive temperature coefficient (PTC) effect of the semiconductive layers of high-voltage direct current (HVDC) cables is a key factor limiting its usage when the temperature exceeds 70 °C. The conductivity of the ionic conductor increases with the increase in temperature. Based on the characteristics of the ionic conductor, the PTC effect of the composite can be weakened by doping the ionic conductor into the semiconductive materials. Thus, in this paper, the PCT effects of electrical resistivity in perovskite La0.6Sr0.4CoO3 (LSC) particle-dispersed semiconductive composites are discussed based on experimental results from scanning electron microscopy (SEM), transmission electron microscopy (TEM) and a semiconductive resistance test device. Semiconductive composites with different LSC contents of 0.5 wt%, 1 wt%, 3 wt%, and 5 wt% were prepared by hot pressing crosslinking. The results show that the PTC effect is weakened due to the addition of LSC. At the same time, the injection of space charge in the insulating sample is characterized by the pulsed electroacoustic method (PEA) and the thermally stimulated current method (TSC), and the results show that when the content of LSC is 1 wt%, the injection of space charge in the insulating layer can be significantly reduced.

Highlights

High-voltage direct current (HVDC) transmission plays a significant role in the power system [1,2,3,4,5].In particular, high-voltage direct current (HVDC) cable transmission is feasible over long distances and large capacities due to the absence of reactive power and low transmission losses [6,7]
It is observed that there are no impurity peaks from the X-ray Diffraction (XRD) pattern, and the XRD diagram of LSC shows the characteristic of sharp peaks, indicating fromThe theXRD
In order to compensate the net electric imbalance, imbalance, oxygen vacancy will be generated in the lattice to bring many holes to achieve the oxygenbalance, vacancyand willoxygen be generated latticeto totransfer bring many holes achieve the charge balance, charge vacancyinisthe allowed through thetoperovskite lattice

Summary

Introduction

High-voltage direct current (HVDC) transmission plays a significant role in the power system [1,2,3,4,5].In particular, HVDC cable transmission is feasible over long distances and large capacities due to the absence of reactive power and low transmission losses [6,7]. Typical medium and high-voltage power polyethylene (PE)cable cross-sectional constructions include: (1) conductors, (2) conductor shield,. In the construction of high-voltage power cables, the semiconductive layer can suppress the injection of carriers from the metal electrode into the insulating layer and can effectively prevent local electric field distortion between the conductor and the insulating layer. The electrical resistance of the semiconductive layer can suddenly increase to 90 ◦ C, which causes the cable to heat up and leads the interface to partially melt. This phenomenon is called the positive temperature coefficient (PTC) effect [9]. The amount of CB added to the semiconductive shielding layer affects its

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Discussion

Conclusion