Chance-constrained optimization of storage and PFC capacity for railway electrical smart grids considering uncertain traction load

Yinyu Chen, Minwu Chen, Lie Xu, Zongyou Liang

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)
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To foster the utilization of regeneration braking energy and suppress voltage unbalance (VU), a railway electrical smart grid (RESG), intergraded with power flow controller (PFC) and energy storage (ES), is proposed as an important part of next-generation electrified railways. However, under the uncertain traction load, how to design the optimal size of PFC-ES is a challenge during the planning period. Hence, this paper proposes a chance-constrained two-stage programming approach. The first-stage aims to minimising the overall cost of RESG’s devices. The second-stage aims to arrange the energy flow of the PFC-ES with the objective of minimising the expected operation cost under the dynamic VU restriction, and the stochastics characteristics of traction load are transformed into a chance constraint by using a scenario approach. Then, traction power predictions are combined with multivariate Gaussian Mixture Model (multi-GMM) model to generate correlated traction power flow scenarios and to assess VU probabilistic metrics distribution with different confidence levels. Finally, a novel algorithm is designed to select the confidence level and violation probability so that the capacity planning results can ensure the high-efficient and high-quality operation of the RESG. Case studies based on an actual electrified railway demonstrate that the proposed PFC-ES sizing approach can reduce the overall cost by up to 13%.
Original languageEnglish
Article number3276198
Pages (from-to)286-298
Number of pages13
JournalIEEE Transactions on Smart Grid
Issue number1
Early online date15 May 2023
Publication statusPublished - 1 Jan 2024


  • general computer science
  • chance constraint
  • two-stage programming
  • probabilistic forecasting
  • load modeling
  • costs
  • traction power supplies


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