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Multi-terminal flexible DC grid circuit breaker withstands multi-lightning strike analysis.
Yutao Tang1, Hongchun Shu1,2, Kai He2
1The State Key Laboratory of Collaborative Innovation Center for Smart Grid Fault Detection, Protection and Control Jointly, Kunming University of Science and Technology, Kunming, 650500, China.
Scientific Reports
|January 24, 2025
Summary
Multi-lightning strikes pose a significant threat to hybrid DC circuit breakers (DCCBs). While the energy-consuming branch shows tolerance, MOV failure during these events can cause severe overvoltages, necessitating careful DCCB design.
Area of Science:
- Electrical Engineering
- Power Systems
- High Voltage Engineering
Background:
- Lightning strikes are a major threat to power grids, with multi-lightning strikes being particularly hazardous.
- Hybrid DC circuit breakers (DCCBs) are crucial for power grid protection, but their insulation is vulnerable to lightning surges.
- Existing research extensively studies multi-lightning strikes, highlighting their severe impact on power infrastructure.
Purpose of the Study:
- To analyze the impact of multi-lightning strikes on a ±500 kV Zhangbei HVDC project DCCB.
- To investigate the energy absorption of metal oxide varistors (MOVs) within the DCCB under multi-lightning strike conditions.
- To assess overvoltage levels across different DCCB branches during multi-lightning strikes.
Main Methods:
- A simulation model of a DCCB was developed using a Real-Time Digital Simulator.
- The model was based on the parameters of the DCCB in the ±500 kV Zhangbei HVDC project.
- Lightning intrusive waves and MOV energy absorption were analyzed under simulated multi-lightning strike scenarios.
Main Results:
- The energy-consuming branch of the DCCB demonstrated a degree of tolerance to multi-lightning strikes.
- MOV failure within the energy-consuming branch under multi-lightning strikes can lead to critical overvoltage issues.
- Overvoltage levels in various DCCB branches were quantified under multi-lightning strike conditions.
Conclusions:
- The design and selection of DCCBs must account for the significant risks posed by multi-lightning strikes.
- Ensuring the robustness of MOVs in DCCBs is critical for mitigating overvoltage risks during severe lightning events.
- Further research into DCCB resilience against multi-lightning strikes is warranted for enhanced power grid reliability.
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