661 / 2022-03-31 10:43:33

Study on the Influence of Harmonics on the Distribution of Sound Pressure Field of 500kV Connected Transformer

connected transformer,high-order harmonic,Noise Estimation

Purpose/Aim

In recent years, the application of power electronic devices in flexible DC project makes the harmonics of power system present new characteristics of high frequency and wide frequency domain. High frequency harmonics will be transmitted through overhead lines, which will affect the primary equipment in a wider range. Therefore, it is of great significance to study the possible adverse effects of harmonics on the operation of transformers, and to formulate effective countermeasures to ensure the reliable operation of power system.

Experimental/Modeling methods

In this paper, the coupling simulation model of structural force field and sound pressure field is established. Through the step-by-step simulation idea of ‘strong coupling’ and ‘weak coupling’, the noise generated by core vibration and its propagation process inside and outside the transformer are obtained.

Results/discussion

The results show that the influence of harmonics on the noise propagation in the external space of the transformer is small, but it can significantly improve the maximum sound pressure level. The noise increases about 23dB inside the transformer and 13dB in the external space. At the horizontal position 5m away from the transformer, the harmonic condition can still produce more than 60 dB noise, which will bring some noise pollution.

Conclusions

Harmonic injection will have a great impact on the distribution of sound pressure field of transformer, so it is necessary to take measures to reduce noise. According to the simulation results, it is feasible to install sound insulation boards on the left and right sides and above the transformer for noise reduction.