Simulation Analysis of the Influence of Harmonics Current on the Winding Temperature Distribution of Converter Transformer

The converter transformer is directly connected to the main non sinusoidal power receiving equipment of the power network, the converter valve, which has a large harmonic content. The temperature rise is an important index to reflect the internal state and safe transmission capacity of converter transformer, so the influence of harmonics on the temperature rise of converter transformer winding is worthy of attention. Taking the actual converter transformer as an example, the magnetic field simulation model and heat flow simulation model of the converter transformer are established, and the variation of winding loss and winding temperature distribution under different harmonic content and harmonic frequency are simulated and studied. It is found that when the harmonic content increases, the harmonic current of the winding increases, so the resistance loss of the winding increases, and the hot spot temperature rise of the winding increases in a power function with the harmonic content; when the harmonic content increases, the equivalent resistance of the winding increases, so the resistance loss of the winding increases, and the hot spot temperature rise of the winding increases in an exponential function with the harmonic frequency. Finally, the quantitative relationship of winding temperature rise under different harmonic content and harmonic frequency is obtained.