主变中性点隔直装置在工程中的设计及应用

Design and Application of Neutral DC Blocking Device of Main Transformer

高压直流输电单极运行方式会在影响范围内的主变励磁电流中流入直流分量,从而导致主变出现直流偏磁现象,具体表现在变压器损耗增加、噪音增大、出口电压畸变及温度升高等方面,严重影响到变压器安全运行。通过在主变中性点接入隔直装置,可有效隔离流入变压器中性点的直流电流,确保主变的安全可靠运行。

The monopole operation of the HV DC transmission may allow the DC component to flow into the excitation current of the main transformer which is covered by the monopole operation. Accordingly, it results in occurrence of the DC bias in the main transformer. This DC bias is displayed in terms of the consumption increase of the main transformer, the noise increase, the outlet voltage aberrance and the temperature increase, etc. They seriously impact the safety operation of the main transformer. By application of the DC blocking device at neutral point of the main transformer, the DC current flowing into the transformer neutral point can be effectively blocked so as to assure the safe and reliable operation of the main transformer.