【摘要】 针对直流输电系统处于单极大地回路运行方式时对交流电网运行带来的噪声、谐波、振动等不利影响,比较全面地对各种抑制地中直流影响的措施进行了对比分析。基于地中电流的成因与流散规律分析,提出了采用直流接地极与交流变电站选址优化、无接地极运行或多极共址运行方式、合理结构型式变压器的选择等主动防范措施减小地中直流的影响。结合作者的研究成果,就国内外目前抑制变压器中性点直流采取的注入反向电流、中性点串入电容、中性点串入电阻等措施进行了对比分析。通过分析串电阻措施的关键问题,认为该方案结构简洁,长期运行可靠性高,不会产生谐振,成本低廉,建议在现场使用。该研究成果为解决交直流电网并列运行安全稳定运行提供了有益的建议。更多还原

【Abstract】 The influences, such as sharp rising of the audible noise, harmonic and oscillation, will be found in the power system and transformer, where the HVDC transmission system operated in ground return mode. Based on the analyzing of the characteristics of the DC current distributed under ground and in the AC network, some useful measures, such as the optimization of the location of the substation and the DC grounding system, being operated with additional metal return wire, several HVDC substations sharing one grounding system, suitable structure selection of transformer, were put forward. Some measures to decrease the neutral current, such as the injection of reverse DC current, blocking capacitor and blocking resistor, were compared. Moreover, the resistor blocking solution was recommended, and some useful conclusions were drawn.更多还原