考虑参数频变特性的电力电缆改进贝杰龙模型

Improved Bergeron Model of Power Cable Considering Parameter Frequency-dependent Characteristics

新型电力系统中电力电子设备、可再生能源机组和交直流电网间的相互作用会导致宽频谐振问题,而电力电缆作为新能源并网的关键环节,其不可忽略的分布电容会增加系统发生宽频谐振的风险。目前,对该问题的研究多使用时域仿真法、阻抗分析法等方法,但对电力电缆的建模多未考虑其分布参数特性及参数频变特性,由此会导致稳定性评估结果不准确及时域仿真效率降低、虚值振荡等问题。传统贝杰龙模型具有分布参数特性,但由于其未考虑参数频变特性,会造成高次谐波放大等问题。为确定适用于谐波频段内的电力电缆建模方法,该文根据电缆结构总结出简化的电力电缆谐波频段电气参数计算方法;在此基础上,深入挖掘贝杰龙模型优势,根据相关谐波频率修正电缆电气参数来改进传统贝杰龙模型;最后对比电力电缆电气参数简化计算方法得出的结果与PSCAD/EMTDC中计算得出的结果,同时对提出的改进模型进行时域仿真测试,验证其正确性和有效性。

The interaction between power electronic equipment,renewable energy units and power grids in the new power system leads to broadband resonance problems.Power cables are key links of renewable energy integration and their non-negligible distributed capacitance increases the risk of broadband resonance.The existing research mainly includes time-domain simulation and impedance analysis.However,the distributed parameter characteristics and frequency-dependent characteristics are ignored during the modeling,which leads to inaccurate stability assessment,lower efficiency of simulation and imaginary oscillation.The traditional Bergeron model fails to take the frequency-dependent characteristics into consideration,which causes problems like high-order harmonic amplification.In order to determine the modeling method suitable for power cables in the harmonic frequency range,the simplified calculation of power cable parameters is summarized according to the cable structure.On this basis,the advantages of Bergeron model are explored deeply,and the cable electrical parameters are modified according to the related harmonic frequency to improve the traditional Bergeron mode.Finally,the results obtained by the simplified calculation method of power cable electrical parameters are compared with those obtained by the calculation in PSCAD/EMTDC,and the proposed improved model is tested in time domain to verify its correctness and effectiveness.