2013年第7卷第6期 2013 Vol. 7 No. 6
南方电网技术
SOUTHERN POWER SYSTEM TECHNOLOGY
文章编号：1674-0629(2013)06-0063-04
中图分类号：TM411
高压直流输电 HVDC Transmission
文献标志码：A
穗东站换流变压器本体油位异常分析及带电处理
杨荆林，谢超，李乾坤，石延辉
（中国南方电网超高压输电公司广州局，广州510163）
摘要：云广直流稳东站一台换流变压器在行中本体油位偏高。透值迎峰度夏，云广直流满负荷运行，不可能停电处理。如果油位继续偏高则会带来严重的后果。研究了在带电的情况下该换流变压器油位高的处理。在带电情况下，由于负荷的变化，变压器内油温会持续发生史化，而温度场的变化是个缓慢的动态过程。在此动态过程中由于换流变箱体结构，油流循环，及油温油位传感器的住置等因素的影响，本体油位计显示油位与油温计的显示油温与呈非线性，且存在滞后。传统的方法不能适用于动态过程中油温油位的计算。固此，建立了在动态过程中的油温油位模型，并根
据模型确定了放油量，放油之后的稳态数据表明了模型的准确性。关键词：油位；变压器；油温计；油住计
Analysisof theOilLevelAbnormityofConverterTransformerBodyatSuidong
SubstationandItsOn-lineDisposal YANG Jinglin, XIE Chao, LI Qiankun, SHI Yanhui
(Guangzhou Bureau，EHV CSG Power Transmission Company,Guangzhou 510163，China)
Abstract: The oil level of a converter transformer in Suidong Station of Yun-Guang HVDC became abnormally high. Since the power load was very high in summer, it was impossible to shut down the converter transformer for this abnormity. If the oil level rises high er, serious consequences may follow. In this research, the high oil level abnormity is analyzed during the running of the converter transformer. When the converter transfomer is energized, the oil temperature would vary with the change of transformer power load. The change of oil temperature could be described as a slow dynamic process. Due to the structure of transformer oil tank, oil re-cycling and the location of oil temperature meter and oil level meter, the reilationship between the oil level and temperature displayed in the meter is nonlinear and there are time-delay between the displayed oil level and oil temperature, It is impossible for traditional method to describe this complex dynamic process. Thus in this research, a dynamic model is developed and the oil volume is calculat-
ed based on the model. The measurement after disposal shows the accuracy of the model. Key words: oil level; converter transformer; oil level meter; oil temperature mete
±800kV云广直流输电工程是世界上第一条特高压直流输电工程，分双极四端运行，满负荷容量 5000MW，送电规模占南方电网西电东送总容量的1/4，对南方电网的运行有极重要的影响[1-6]。
2011年7月，云广直流工程穗东站一台换流变压器在运行中发出本体油位限制报警，就地控制面板显示本体油位高达90%。如果本体实际油位确实持续高位运行，可能引起油枕中间法兰处或变压器箱体中的薄弱环节渗漏油。如果本体实际油位继续升高，油压进一步增大，会引起变压器箱体变形，严重时会引起压力释放阀动作喷油甚至爆炸，直接导致该换流变压器跳闸，至时云广直流极Ⅱ高端闭
万方数据
锁，直接损失功率1250MW，对南方电网网架安全将造成很大的影响。
为解决换流变压器本体显示油位过高的问题，首先确认真实油位，排除油位计显示假油位的现象，之后通过计算确定变压器油温和本体油位的变化模型，最后根据模型计算达到本体安全油位需要的放油量。处理的难点在于换流变压器带电运行，无法近距离或通过U形管确认实际油位。其次由于换流变压器箱体结构，油流循环，及油温传感器的位置等因素的影响，本体油位计显示油位与油温计的显示油温与呈非线性，且存在滞后。由于滞后效应的影响，在油温变化时，油位表的显示并不能反