In this paper, a series of laboratory experiments are conducted to investigate the effect of momentary small variations in the transformer operating temperature on the dissolved gas analysis (DGA) measurement. With the increased penetration level of renewable energy sources of intermittent characteristics into electricity grids, operating power transformers are expected to experience frequent temperature variations. Sampling transformer oil during such temperature variation leads to inaccurate diagnosis. Experimental results reveal that gas evolution in transformer oil is greatly affected by the small variations in the operating temperature. Such small variation can be a result of the intermittent generation characteristics of renewable energy sources. Hence, false analysis may be reported if oil is sampled during generation or load fluctuation events. Experimental results are explained through chemical equilibrium constant theory, which indicates that dissolved gases reflect the change in aging rate of the transformer oil-paper insulation system. These results suggest a new paradigm for DGA process through correlating measurements with the transformer operating temperature through the generation and load profiles at the instant of oil sampling.

中文翻译：

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分布式可再生发电系统中电力变压器的溶解气体分析


在本文中，进行了一系列实验室实验来研究变压器工作温度的瞬时小变化对溶解气体分析（DGA）测量的影响。随着间歇性可再生能源在电网中渗透率的提高，运行中的电力变压器预计会经历频繁的温度变化。在这种温度变化期间对变压器油进行采样会导致诊断不准确。实验结果表明，变压器油中的气体析出量受工作温度的微小变化影响很大。如此小的变化可能是可再生能源的间歇性发电特性造成的。因此，如果在发电或负载波动事件期间对油进行采样，则可能会报告错误分析。实验结果通过化学平衡常数理论进行解释，表明溶解气体反映了变压器油纸绝缘系统老化速率的变化。这些结果通过油样采样时的发电和负载曲线将测量值与变压器工作温度相关联，为 DGA 过程提供了一种新范例。