直流机电暂态与电磁暂态模型在低频振荡分析中的比较

对交直流混合运行系统进行低频振荡分析时，直流系统通常采用机电暂态仿真模型。介绍了直流系统的机电暂态和电磁暂态两种仿真模型，在电力系统全数字仿真装置（ADPSS）平台上建立了EPRI36系统和某实际电网系统的机电暂态模型和机电-电磁暂态混合仿真模型，分别用于低频振荡分析。采用基于总体最小二乘-旋转不变技术的信号参数估计（TLS-ESPRIT）算法，分析故障后的振荡功率信号。提取低频振荡主导振荡频率、阻尼比等信息进行模态分析，并对分别利用两种仿真模型进行仿真得到的低频振荡分析的结果进行比较。结果表明，直流线路分别采取两种仿真模型时，仿真结果较为吻合，低频振荡分析的结果基本相同，机电暂态模型具有较高的实用价值。

Comparison between electromechanical transient model and electromagnetic transient model of DC in low frequency oscillation analysis

For AC and DC operating system Low Frequency Oscillation (LFO) Analysis, DC system usually adopts electromechanical transient model. This paper introduces the DC electromechanical transient and electromagnetic transient model, and then establishes the electromechanical transient model and the electromechanical-electromagnetic transient hybrid simulation model on the Advanced Digital Power System Simulator (ADPSS) platform for the LFO analysis respectively. Adopting the total least squares method-rotational invariance techniques of signal parameter estimation (TLS-ESPRIT) algorithm, the oscillation power after failure is analyzed. After extracting the LFO dominant oscillation frequency and damping ratio for making the modal analysis, it compares the LFO analysis results of the two simulation models. Results of the EPRI36 standard test system and a practical power system simulation show that the simulation results of two simulation models are tallied, besides, the LFO analysis result is basically the same. The electromechanical transient model has a high practical value.