Field test‐based research on current sharing characteristics of multicolumn parallel arresters

Abstract

Abstract A converter station is the hub of a High Voltage Direct Current (HVDC) transmission project, and the neutral bus arrester on its rectifier side has the most complex operation condition. The ideal operating condition of a multicolumn parallel arrester is the equipartition of energy generated when the system is impacted. When this condition is not achieved, individual arrester units with lower residual voltage absorb more energy than their tolerance level, which leads to breakdown failure of the arrester and forced outage of the DC system, resulting in significant economic losses. In this paper, the influence of the internal structure, assembly technology, and installation mode of a multicolumn parallel arrester on the operation status of an arrester is analysed, the quality control measures are summarized, and suggestions for site maintenance are given first. Then, the current sharing characteristics of large capacity multicolumn parallel arresters under different current waveforms, different current amplitudes and different temperatures are studied through experiments. The results show that the impact current waveform has little influence on the current non‐uniformity coefficient and generally does not exceed the standard value; under long duration current shock, the current deviation coefficient (CDC) may increase or decrease with increasing temperature. The above conclusions provide a practical basis and theoretical basis for the study of multicolumn parallel arrester operation condition monitoring methods, such as the selection of state characteristics and the formulation of monitoring criteria.

Keywords

• Reliability
• d.c. transmission
• Protection apparatus
• Power convertors and power supplies to apparatus