Sensitivity Analysis of HVDC-LCCs Affected by Voltage Unbalance Generated by Electric Trains

Troels Jakobsen, Morten Vadstrup, Jakob Harder Poulsen, Maria Eli Stenseth, Richard Mushimiye, Filipe Miguel Faria da Silva

Research output: Contribution to book/anthology/report/conference proceedingArticle in proceedingResearchpeer-review


An increasing number of single-phase loads are being connected to the Danish transmission grid due to electrification of the Danish railway, which consequently results in the need to estimate the effects of the introduced voltage unbalance. The tendency of having more power generated by units mechanically decoupled from the grid, which reduces the short-circuit power of the system, makes the grid more vulnerable to unbalanced loads. High-voltage direct current line commutated converters (HVDC-LCCs) can be negatively affected by voltage unbalance, in the form of commutation failure. The impact of the voltage unbalance on a HVDC-LCC is tested through electromagnetic transient simulations in DIgSILENT PowerFactory, where variations in the voltage unbalance are implemented as steps and approximated ramps. The worst point of wave to energise the single-phase loads, corresponding to the trains, is investigated and implemented in the simulation. The simulations show that if the HVDC LCC is operating at the maximum firing angle, steps of voltage unbalance can cause commutation failures in the HVDC-LCC. For the more realistic electric train scenario, where the voltage unbalance is simulated as an approximative ramp, no commutation failures were observed due to the control system of the HVDC-LCC’s ability to decrease the firing angle.
Original languageEnglish
Title of host publicationProceedings of 2018 53rd International Universities' Power Engineering Conference (UPEC)
Number of pages5
PublisherIEEE Press
Publication dateSep 2018
ISBN (Print)978-1-5386-2911-6
ISBN (Electronic)978-1-5386-2910-9
Publication statusPublished - Sep 2018
Event2018 53rd International Universities Power Engineering Conference - Glasgow, United Kingdom
Duration: 4 Sep 20187 Sep 2018


Conference2018 53rd International Universities Power Engineering Conference
CountryUnited Kingdom


  • Voltage unbalance
  • commutation failure
  • railway electrification
  • electromagnetic transient study

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