ZIP load modeling for single and aggregate loads and CVR factor estimation

Yiqi Zhang, Yuan Liao, Evan Jones, Nicholas Jewell, Dan Ionel

Research output: Contribution to journalArticlepeer-review


ZIP load modeling has been used in various power system applications. The aggregate load modeling is common practice in utility companies. However, little research has been done on the theoretical formulation of the aggregate load and on various factors that affect accurate estimation of the parameters. This paper proposes new methods to systematically formulate the aggregate ZIP load model using the single ZIP load model and comprehensively examines the factors that may affect aggregate ZIP load estimation. Moreover, novel analysis of reactive power ZIP parameter calculation considering different compensating device modeling is presented. ZIP parameter estimation methods including least squares method, optimization method, and neural network method have been used in this paper to estimate ZIP parameters. The proposed new method was illustrated using the IEEE 13-bus and 34-bus systems built in OpenDSS. In addition, the ZIP parameter estimation is also performed using field data, and the conservation through voltage reduction (CVR) factor is further computed based on the estimated ZIP load model. The results provide guidance on calculation and interpretation of CVR estimates. Note that this paper was first presented at PAC world conference 2021 which provides no published conference proceedings.

Original languageEnglish
Pages (from-to)839-858
Number of pages20
JournalInternational Journal of Emerging Electric Power Systems
Issue number6
StatePublished - Dec 1 2022

Bibliographical note

Publisher Copyright:
© 2022 Walter de Gruyter GmbH, Berlin/Boston.


  • ZIP load model
  • conservation through voltage reduction
  • optimization
  • parameter estimation

ASJC Scopus subject areas

  • Energy Engineering and Power Technology


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