高精度高效非标准变比变压器模型研究

High accuracy and high efficiency model of non-standard ratio transformer

电力变压器分接开关位置调整是电力系统调压的一种重要手段。当分接开关不在标准档位时,变压器工作在非标准变比条件下,其运行电气参数偏离额定参数。现有非标准变比变压器模型难以同时保证高精度和高计算效率。针对此问题,利用电路网络等值变换,提出改进Π-1型非标准变比变压器等值电路模型,该模型具备精确T型非标准变比变压器模型高精度的优点,且无需增加额外节点,计算效率高。为进一步提升应用于前推回代潮流计算的收敛特性,基于Y-△阻抗网络等值变换推导出改进Π-2型模型,增加模型的实用性。基于简化两节点、修正IEEE 9和IEEE 300测试算例进行对比分析,验证了所提模型在计算精度、速度和收敛性能方面的有效性和优越性。

The position adjustment of power transformer tap changer is an important means of voltage regulation in the power system.When the tap changer is not in the standard gear,the transformer works under non-standard ratio conditions,and its operating electrical parameters deviate from the rated parameters.The existing non-standard ratio transformer model is difficult to guarantee high accuracy and high calculation efficiency at the same time.Aiming at this problem,an improvedΠ-1 type non-standard ratio transformer equivalent circuit model is proposed by using the equivalent transformation of the circuit network.The proposed model has the same accuracy as the accurate T-type non-standard ratio transformer model.And it avoids the disadvantage of increasing the number of equivalent nodes which guarantee high computational efficiency.In order to further improve the convergence characteristics of power flow calculation for backward/forward sweep method,an improvedΠ-2 model with better practicability is derived based on Y-△impedance network transformation,which increases the practicability of the model.Based on the comparative analysis of simplified 2-bus,modified IEEE 9 and IEEE 300 test cases,the validity and superiority of the proposed model in terms of calculation accuracy,speed and convergence performance are verified.