配电网最大供电能力与N-1安全校验的对比验证

最大供电能力(TSC)是配电系统一个新的重要指标,但目前TSC计算结果是否准确、如何衡量TSC的准确性,这一基础性问题尚未解决。文中采用与传统的N-1安全校验对比来验证TSC准确性。首先,介绍了目前主要的TSC计算方法以及主变压器N-1安全校验方法;然后,设计了对比验证的指标与方案;为便于衡量误差,给出了一种N-1安全校验和TSC计算相结合的逼近法。大量算例对比验证发现,目前文献给出的供电能力计算方法均存在一定误差。通过分析误差规律发现,未将负荷细分到馈线且假设主变转带负荷连续可分是造成误差的主要原因。

Comparative Research Between Total Supply Capability and N-1 Security Verification for Distribution Networks

The total supply capability(TSC) is an important new index for distribution systems.However,such fundamental problems as whether the TSC calculating algorithms are accurate or not and how to evaluate the accuracy of TSC results are yet to be solved.This paper performs a comparative research between TSC algorithms and traditional N-1 security verification.Firstly,both TSC calculating methods and the transformer N-1 security verification are treated.Secondly,the indices and scheme of the comparative study are designed,in which a hybrid approximation method of calculating TSC is presented.Finally,case studies show that the current TSC algorithms are not free from errors.By analyzing the error forming process,it is found that there are two main causes for their formation.One is the assumption about the transferring load being continuous and divisible;the other is considering the transformer load instead of feeder load.