A generalized voltage stability indicator based on the tangential angles of PV and load curves considering voltage dependent load models

Mariana Kamel, Fangxing Li, Siqi Bu, Qiuwei Wu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

7 Citations (Scopus)

Abstract

The majority of traditional techniques for voltage stability assessment do not account for load power-voltage characteristics and assume a constant PQ load model, which is proven unreliable especially if the system load contains a large percentage of induction motor loads. This work presents a generalized voltage stability index which has two important features. First, it is applicable to general load models including ZIP, exponential, and induction motor loads. Second, it can be used for both measurement-based and model-based voltage stability assessment. The key idea of this index is that at the collapsing point, the system P-V curve and the load P-V curve share the same tangent line. Thus, the tangential angle between the two curves is an appropriate indicator of proximity to voltage collapse when voltage-dependent loads like ZIP and motor are considered. The performance of the proposed index is tested on both the IEEE 14-bus system and the 181-bus WECC system. The results show that the proposed index gives a good and reliable assessment of system stability. In addition, it demonstrated a consistent behavior, always reaching a value of 0.0 at the stability limit which enables the definition of a threshold for taking corrective measures.

Original languageEnglish
Article number106624
JournalInternational Journal of Electrical Power and Energy Systems
Volume127
DOIs
Publication statusPublished - May 2021

Keywords

  • Composite load
  • Induction motor
  • Voltage collapse
  • Voltage stability
  • ZIP load

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering

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