变压器直流偏磁的仿真研究及限制措施

对高压直流输电系统接地极电流对中性点接地变压器的影响进行了研究。以实际工程中广泛应用的Jiles-Atherton铁磁磁滞原理为基础建立变压器模型进行电力变压器直流偏磁的仿真研究,结果较好地反映了励磁电流波形和幅值的变化对变压器的不利影响;提出了在变压器中性线串联电容器并设置其旁路电路等措施,分析说明该措施能有效地限制直流偏磁现象。文中介绍的模型和措施可分析处理变压器直流偏磁导致的铁耗、铜耗以及噪声增大等问题,实例的仿真结果证明了该方法的正确性。

DC Magnetic Bias Induced Current Effects on Transformer and Restricting Methods

This paper proposes a study of the influence of the HVDC(High Voltage Direct Current transmission) ground electrode current on neutral grounding transformer.According to the ferromagnetic hysteresis theory established by Jiles-Atherton,a new transformer model has been built.At the same time the model is applied in the simulation of direct current magnetic bias on transformer.The simulation results commendably reflect the disadvantageous influence on the transformer,which caused by the distortion of the waveform and the amplitude of the exciting current.On the basis of these researches,solutions of restricting transformer direct-current magnetic bias,such as installing a bypassing device in parallel with the capacitor installed in the neutral and so on are introduced.The problems caused by the direct current magnetic bias,e.g.transformer's copper loss,iron loss and noise increment,can be analyzed and solved by adopting the model and methods mentioned above.The application of the proposed algorithm to a test system shows its validity.