非有效接地配电系统接地故障相主动降压安全运行的基础理论研究

Grounding fault treatment is a hot and challenging issue in the research of high rating generator and smart distribution system. For the neutral ineffectively grounded distribution system, it is acceptable to operate with grounding fault in a short time, which may result in over-voltage in non-fault phases, fault residual current and hidden danger for human safety and equipment security. They will limit the operation time with grounding fault. However, the fault clearing mode with power cut reduces the reliability of power supply. This project plans to carry out the following researches. Firstly, the distribution system safety operation theory and method with grounding fault will be proposed, which can actively reduce fault phase voltage, eliminate fault current and restrain the transient over-voltage by injecting zero sequence current. Secondly, the optimization and evaluation method will be researched for the step-down voltage value of fault phase and the operation time with the grounding fault. Thirdly, the chipping sensor based on tunneling magnetoresistance (TMR) will be developed, and then the fault elimination method based on damping ratio will be invented. A novel idea of fault clearing with manual, safety and no power outages will be put forward by controlling the fault point voltage to zero. Finally, the continuous control method of faulted phase voltage in the full frequency-domain and its dual-loop smooth control strategy will also be proposed. A new flexible control device will be developed for grounding fault phase voltage. This project will build a novel method of grounding fault treatment based on active fault current elimination and fault safety clearing with no power outages. It is expected to realize the rapid suppression of fault transient voltage in the full frequency-domain, expand the safe and reliable operation time for generators and distribution systems with grounding fault.

接地故障处理是大型发电机与智能配电网研究的一个难点和热点问题，现有中性点非有效接地配电系统采用短时带接地故障运行模式，存在非故障相过电压、故障残流和人身设备安全隐患等难题，限制了带故障运行时间；且采用的停电清除故障模式降低了供电可靠性。为此，项目计划：1）研究基于注入零序电流主动降低故障相电压、消除故障电流、抑制暂态过电压的配电系统接地故障安全运行理论与方法；2）研究故障相降压值和带故障运行时间的优化与评估方法；3）研究基于隧道磁电阻的暂态电流芯片传感器和基于阻尼率的故障电流消除辨识方法，将提出基于故障点零电位控制的故障不停电人工安全清除方法；4）提出全频域故障相电压连续控制方法和双闭环平稳控制策略，研发接地故障电压柔性控制装置。项目将最终构建主动消除故障电流和安全清除故障的配电系统接地故障不停电处理新模式，有望实现接地故障电压全频域快速抑制，提升发电机和配电网带接地故障安全可靠运行时间。

现有中性点非有效接地配电系统采用短时带接地故障运行模式，存在非故障相过电压、故障残流和人身设备安全隐患等难题，限制了带故障运行时间；且采用的停电清除故障模式降低了供电可靠性，难以满足电网公司“瞬时故障安全消弧，永久故障快速隔离”的迫切需求。.针对非有效接地配电系统接地故障快速安全处理难题，项目构建了主动消除故障电流和安全清除故障的配电系统接地故障不停电处理新模式，完成了项目计划：1）研究了基于注入零序电流主动降低故障相电压、消除故障电流、抑制暂态过电压的配电系统接地故障安全运行理论与方法；2）研究了故障相降压值和带故障运行时间的优化与评估方法；3）研究了基于隧道磁电阻的暂态电流芯片传感器和基于阻尼率的故障电流消除辨识方法，提出了基于故障点零电位控制的故障不停电人工安全清除方法；4）提出了全频域故障相电压连续控制方法和双闭环平稳控制策略，研发了接地故障电压柔性控制装置。取得的研究成果为：1）提出了接地故障相主动降压消弧控制理论，巧妙利用非有效接地系统电源、负荷三角形接线天然优势，在接地故障后，灵活调控零序电压，控制故障点电压低于电弧重燃电压，强迫故障电弧熄灭，故障抑制率由70%提升到100%；2）创建了降压安全运行域，提出不同类型接地故障的降压消除方法；3）提出了馈线对地绝缘参数（阻尼率、介损等）实时精确测量技术和高阻接地故障灵敏感知技术，故障检测能力由1kΩ提升至20kΩ；4）建设了国内外特有大规模10kV真型试验场；装置已通过了中国电科院等权威部门检测，结果显示装置能灵敏感知并可靠抑制16kΩ高阻接地故障，补偿后故障相电压降到300V以下，接地点残流为mA级，有效消除触电及山火隐患。.子成果分别获日内瓦国际发明专利金奖、湖南省科学技术创新团队奖、湖南省科技进步一等奖、云南省技术发明一等奖和中国电力技术发明一等奖；多项专题成果被鉴定为国际领先水平；授权专利43项（含美国、欧盟等国际专利6项），申请待批准发明专利20项；发表高水平论文41篇，撰写标准3项，学术专著2部；承办国际会议4次；培养国家百千万人才工程1人、湖南省杰青1人、湖南芙蓉学者1人、湖湘青年英才1人，出站博士后1人，毕业博士3人，在读博士9人，毕业硕士20人；装置已在湖南、广东、云南、四川、浙江等电网企业成功运行150余台套，破解了接地故障引发的过电压、触电、起火和停电等行业痛点，社会经济效益显著。