基于发热—散热积累模型的牵引变压器过载保护应用

Application for Traction Transformer Overload Protection based on Heat Accumulation-omission Model

针对现有牵引变压器过载保护存在误动的问题,提出了基于发热—散热积累模型的牵引变压器过载保护新方案。该保护方案根据牵引负载时变特性和充分考虑牵引变压器的热积累现象,采用热传递微分方程建立了牵引变压器温升模型,通过求解暂态热平衡微分方程的方法,给出了新的牵引变压器过载保护判据和数字算法实现。为满足牵引变压器具有较强的过负荷能力,给出了依据满足典型负荷曲线的热过载保护整定方法。通过实测数据分析,验证了此新型保护即可满足充分利用牵引变压器过负荷能力的要求,又能可靠地保护牵引变压器免遭过热受损。

In view of the characteristics of high speed electric railway with heavy load and strong volatility, this paper establishes a mathematical model for the dynamic over-load protection, based on the heat balance different equation, to determine how temperature increases with the change of the protection traction transformer＇s current, and the intelligent traction transformer over-load protector are designed with the setting method based on typical load curve. Through the analysis of actual load of traction transformer, the results show that the method can make full use of the transformer overload capacity and reliably protect the transformer from insulation aging caused by overheating.