基于电流相位估计的三相不平衡条件下配变损耗计算

Calculation of distribution loss under three-phase unbalancebased on current phase estimation

在配电网节能改造中因地制宜地更换高损耗配电变压器尤为重要,计算实际负荷条件下的配变损耗是变压器选型技术经济的关键之一。在低压三相四线制系统中,负荷不平衡往往造成了配变三相电流不对称。文中首先讨论了三相不平衡条件下变压器损耗计算模型,然后面向现有配变低压侧用采系统数据缺失电流相位的情况,提出了变压器低压侧电流相位估算方法,从而建立了三相不平衡条件下基于配变电流相位估算的损耗计算模型,解决了实际工程中因缺失相位数据而无法计算的难题。最后,通过仿真和试验分别对Yyn0和Dyn11这2种常用配变的电流相位估算和损耗计算模型进行了验证。

It is particularly important to replace high-loss distribution transformers according to local conditions in the energy-saving transformation of distribution networks.Calculating distribution transformer losses under actual load conditions is one of the key points of transformer selection technology and economy.In low-voltage three-phase and four-wire system,unbalanced load often results in asymmetrical distribution and transformer three-phase current.The loss calculation model of transformer under three-phase unbalance condition is discussed at first,and then the current phase estimation method of transformer low-voltage side is put forward in view of the fact that the current phase of existing distribution transformer low-voltage side mining system data is missing.Thus,the loss calculation model based on distribution transformer current phase estimation under three-phase unbalance condition is established,which solves the problem that cannot be calculated due to missing phase data in actual engineering.Finally,the current phase estimation and loss calculation models of Yyn0 and Dyn11 commonly used transformers are verified by simulation and experiment respectively.