Summary
Voltage Sourced Converter (VSC) based High Voltage Direct Current (HVDC) technology has become prominent in recent years due to increasing need for flexible, efficient, and controllable power transmission over long distances. Among the different VSC-HVDC topologies, rigid bipole configuration is widely adopted due to its simplicity and cost-effectiveness. However, unlike full bipole configurations, with a dedicated metallic return, rigid bipole DC neutral buses can often lack a direct electrical reference to ground, making it particularly sensitive to unbalanced pole loading, fault conditions and switching operations.
Read more Read lessThis paper investigates the impact of converter neutral grounding, with particular focus on resulting Transient Over-voltages (TOVs) and Transient Recovery Voltages (TRVs), of rigid bipole VSC systems. These phenomena are critical in defining insulation coordination margins, footprint of surge arresters and circuit breaker performance. The method of converter neutral grounding plays an important role in controlling the transient performance during disturbances caused by faults. The rigid bipole VSC-HVDC system can be grounded at one end only or can be grounded at both ends. Low impedance grounding of rigid bipole results in reduced TOVs but higher currents during disturbances. Conversely ungrounded DC neutral buses lead to decreased fault current and increased TOVs. A balance between the two can be achieved by grounding via an impedance.
Through detailed electromagnetic transient (EMT) simulations of a ±525 kVdc 2 GW Bipole
VSC-HVDC interconnector, this paper examines the effects of each grounding configuration on TOV and TRV profiles under a range of fault scenarios and including the effect of transformer saturation.
Additional informations
| Publication type | Session Materials |
|---|---|
| Reference | B4_10561_2026 |
| Publication year | |
| Publisher | CIGRE |
| Country | India |
| Study committees | |
| File size | 1 MB |
| Price for non member | 30 € |
| Price for member | 30 € |
Authors
SINGH* Amit - GE Vernova, INDIA; SHARMA Nikhil - GE Vernova, INDIA; CAWTHORNE James - GE Vernova, United Kingdom; PASHAEI Afshin - National Grid, United Kingdom; MORALES Javier Antolin - National Grid, United Kingdom
Keywords
