空载线路合闸对发电机励磁回路的影响

Stresses on field circuit caused by energizing lines

通过分析空载长线路合闸过程中发电机励磁电流的暂态特性,解释了励磁电流出现过零趋势的原因,提出计及励磁主回路反向电阻的发电机暂态等值电路。对黑启动模式下发电机投空载长线进行仿真计算,结果表明:空载线路合闸过程中发电机励磁绕组可能会出现过电压,并可能比自励磁现象和线路末端过电压更容易发生;如果励磁回路有允许反向电流通过的能力,则能避免励磁绕组过电压。

The field current tran sient characteristics when a generator energizes transmission lines under no-l oad are studied in the paper.The tendency of reverse current induced in field circuit is explained.Taking into account the reverse resistance of exciting ci rcuit,a new transient equivalent circuit of generator is presented.A generat or energizing long lines under no-load is simulated with the EMTDC program.The simulation results demonstrate that the large reverse voltages may occur in fi eld circuit and happen easier than the phenomena of self-excitation and line ov ervoltages of receiving end,and that some excitation systems with Negative Cu rrent Logic can avoid the large reverse voltages.