A grounding grid plays the role of discharging current and balancing voltage to ensure the safety of the power system. However, soil corrosion can damage the grounding grid, which then can endanger the safe operation of power system. This paper reviewed recent research advances of soil corrosion of grounding grid. The cause, mechanism, types, and influencing factors of soil corrosion of grounding grids were summarized, and the corresponding detection technology and protective measures were also introduced. The paper pointed out that soil corrosion is a serious threat to the grounding grid system. Moreover, the impact mechanism of AC stray current, new corrosion detection technology, and better protective measures still need in-depth research.
A breakdown caused by the icing of power generation infrastructure is one of the serious disasters occurring in the power system. Slippery lubricant-infused porous surfaces (SLIPSs), whose ice adhesion strength is extremely low, have a promising application in the anti-icing field. In the present study, we fabricated SLIPSs with low ice adhesion strength by infusing silicone oil into an anodic aluminum oxide (AAO) substrate. In addition, the effects of the viscosity of silicone oil on the anti-icing properties and durability of the SLIPSs were investigated. The results show that a lower viscosity silicone oil brings about more slippery surfaces and lower ice adhesion strength. The ice adhesion strength was reduced by 99.3% in comparison with the bare Al alloy. However, low-viscosity silicone oil has worse de-icing resistance and heat resistance. Additionally, the porous films filled with low-viscosity silicone oil possess a better self-healing property after icing/de-icing cycles and followed by exposure to the atmosphere. When the viscosity of silicone oil is 50 mPa·s, the SLIPSs exhibit the best durability for anti-icing. Even after 21 de-icing tests or 168 h of heating at 90 °C, the ice adhesion strength still remains below 10% compared with that of bare Al. This work provides some useful advice for the design and fabrication of anti-icing SLIPSs.
Corrosive sulphur has been commonly regarded as an enormous threat to electrical power equipment in recent decades. Cuprous sulphide (Cu 2 S) deposition on the insulating oil and paper insulation caused by sulphur corrosion will bring about insulation deteriorations or failures in power transformers and shunt reactors. A large number of experiments have been carried out to investigate sulphur corrosion and some measures have been come up to solve this issue such as replacement of insulating oil, chemical removal of corrosive sulphur and the addition of passivator and so on. However, there has not been a perfect method to work out this problem completely, and the phenomenon of sulphur corrosion still occurs. This paper intends to provide thorough information of corrosive sulphur in power equipment and give detailed explanations about its corrosion mechanism, hazards and control measures, which is supposed to offer a reference for subsequent researchers.
The phenomenon of transformer failure caused by oil‐sulphur corrosion of oil₋paper insulation system has always been concerned by scholars. Irgamet 39 is the most used metal passivator for inhibiting sulphur corrosion. However, Irgamet 39 causes abnormal dissolved gas in oil during the process of exerting anti‐corrosion effect. Herein, the gas production mechanism of Irgamet 39 and its long‐term corrosion resistance were investigated. Compared with other metal passivators, the Irgamet 39 produces more dissolved gases in oil, especially H 2 , CO and CO 2 . The main sources of free radicals in the gas production process are from the branched chains of the Irgamet 39 structure (−CH 2 N(C 8 H 17 ) 2 and −CH 3 ). Furthermore, the ageing products of insulating paper and oil promote the cleavage of the chain in the Irgamet 39 molecule, which then causes Irgamet 39 to generate more dissolved gases. Irgamet 39 exhibits excellent long‐term corrosion inhibition properties,while it also leads to abnormal gases in the oil, which can affect the interpretation of the dissolved gas analysis data and thus interfere with the diagnosis. This work provides useful information for the practical application of Irgamet 39 and helps electrical workers make reasonable predictions for transformer problems.
As a typical failure phenomenon in transformers, sulfur corrosion has garnered significant attention in the field of high‐voltage engineering. Grain boundary character distribution (GBCD) copper windings have been introduced to enhance sulfur corrosion resistance by slowing down intergranular corrosion. In this study, the sulfur corrosion behaviour and mechanisms of the GBCD copper windings under various temperatures were experimentally and theoretically studied. Results show that GBCD can enhance the corrosion resistance of copper in liquid environments. With the increase in temperatures, the insulating properties of oil and papers in traditional copper windings experience notable degradation, while GBCD copper windings show more stable insulating behaviours. In addition, modelling of grain boundary energy indicates that the grain boundary structure of GBCD copper windings has a lower average interface energy of 0.170 eV/Å 2 . Calculations of reaction thermodynamics show that GBCD copper windings possess a higher failure temperature (135.2°C) and inhibition degree (activation energy) of the sulfur corrosion (32,557.62 J/mol), revealing the stability and enhanced sulfur corrosion resistance at elevated temperatures.