Distribution Network Voltage-Sag-Source Detection Method Based on Modified Incremental Impedance
Zhu Ke1,Wang Yixuan1,Liu Wenhua2
1. Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education Shandong University Jinan 250061 China; 2. Dongying Power Supply Corporation Dongying 257091 China
Abstract:For the voltage sag source locating method based on real-part of the incremental impedance, the positive sequence component changes, which is caused by some asymmetry voltage sag, are sometimes too small to accurately locate. In order to solve this problem, a modified incremental impedance method for voltage-sag-source detection is proposed according to different types of voltage sag sources. The paper starts with the voltage-sag-source detection theory based on the incremental impedance, and derives the locating criteria for different types of voltage sag sources according to neutral point operation modes of domestic distribution networks. The voltage-sag-source detection strategy for Chinese radial distribution network is then accomplished after the analysis of voltage sag ride-through capability of the distribution transformers. In addition, the paper analyzes the effect of the system transient process on the calculation of the incremental impedance. The method has clear physics concept, can be easily implemented, and is practical for both linear and nonlinear load. Theoretical analysis, simulations, and experiments can verify the effectiveness of the method.
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