求翻译：本文首先从变电站接地系统的稳定性、有效性、经济性三个方面综合分析比较，其次从接地装置的阻值、均压、热稳定、防腐蚀、连接形式等方面，全面分析利用自然接地体、引外接地装置、深井接地、扩大地网面积、使用降阻材料以及局部换土等方法对常规变电站进行降阻改造，另外针对某些变电站的特殊地域情况重点分析了边角放射型地网，利用长垂直接地极与斜接地极相配合的立体型地网，还有利用架空地线引外接地网等降阻措施，运用这些有效的措施来解决典型变电站接地装置建设和改造的特殊问题。是什么意思？

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This article first from substation grounding system stability, effectiveness, and economic aspects of a 3 and the second from comparative analysis of the Ground Resistance value, pressure, heat, corrosion protection, such as forms, comprehensive analysis of use of natural earth, grounding, ground, d

This article first from substation grounding system of stability, and effectiveness, and economic sexual three a aspects integrated analysis comparison, second from grounding device of resistance, and are pressure, and hot stability, and anti-corrosion, and connection forms, aspects, comprehensive a