考虑负荷不平衡分布的低压配电网线损实用计算策略

低压台区线制特殊,单相负荷与三相负荷混合,三相不平衡情况普遍且严重,引起较为严重的不平衡附加线损.各相负荷大小、空间分布的不同使低压台区内不平衡情况差异较大,对线损的影响不容忽视.为了提高低压台区线损计算的准确度,基于前推法构建考虑三相负荷不平衡分布的线损计算模型,并提出考虑负荷分布的不平衡修正系数表征三相不同分布对线损的影响.为了便于应用,以4种典型负荷分布为基础,将模型进行等效简化,提出适用于两类典型负荷分布场景的,考虑三相负荷不平衡分布的线损计算方法.算例验证了所提方法的准确性与可行性,能够为提高低压台区线损计算准确度提供参考依据.

Practical calculation strategy for low-voltage network line loss considering unbalanced load distribution

The single-phase load and the three-phase load in the low-voltage station area are mixed and the wiring system is special. The three-phase unbalance is common and serious, causing more serious unbalanced additional line loss. The difference in the load size and spatial distribution of each phase causes the imbalance in the low-voltage station area to be great different, and the impact on the unbalanced line loss cannot be ignored. In order to improve the accuracy of the line loss calculation in the low-voltage station area, a three-phase unbalanced line loss calculation model that considers the load distribution based on the forward method is constructed, and an unbalanced correction coefficient considering the load distribution to characterize the effect of the three-phase distribution on the line loss is proposed. In order to facilitate the application, based on the four typical load distributions, the model is equivalently simplified, and a three-phase unbalanced line loss calculation method that is suitable for two types of typical load distribution scenarios and considering the load distribution is proposed. The calculation example verifies the accuracy and feasibility of the method, and can provide a reference for improving the accuracy of line loss calculation in the low-voltage station area.