This technology uses local relay modules at each AC circuit breaker to continuously monitor voltage and current parameters along a hybrid HVDC transmission line, which integrates both cable and overhead sections. The system detects characteristic low-frequency (~10 Hz) oscillations that indicate pole-to-ground faults at distinct terminals—voltage oscillations at the cable end and current oscillations at the overhead line. For pole-to-pole faults, a high current threshold identifies the terminal closest to the fault, triggering a controlled breaker reclosure based on local logic. This approach eliminates the need for long-distance communications by relying solely on real-time, local measurements.
Description
What differentiates this method is its innovative communication-less strategy that precisely distinguishes between transient overhead line issues and permanent cable faults. By leveraging predetermined oscillation characteristics and voltage thresholds, the system ensures rapid fault section identification and avoids inappropriate reclosure attempts. This targeted approach enhances system reliability and recovery efficiency by tailoring responses locally, even in complex Modular Multilevel Converter and VSC-HVDC environments, addressing limitations traditionally encountered in fault location techniques.
Applications
- Fault localization in HVDC
- Cable and overhead fault management
- Rapid system restoration process
- Communication-less fault detection
- Local measurement-based protection
Advantages
- Eliminates dependency on long-distance communication by relying solely on local relay measurements.
- Differentiates fault types accurately, distinguishing between permanent cable faults and transient overhead line faults.
- Enables rapid fault section identification for prompt and appropriate system restoration.
- Prevents unnecessary breaker reclosures for permanent cable faults while allowing controlled reclosure for transient faults.
- Enhances overall system protection and recovery through intelligent, local decision-making.
IP Status
https://patents.google.com/patent/US10732214B2
