HVDC Link Protection Using Optical Breaker Blocking Signals
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Solution Overview
Problem
In HVDC grids, existing fault detection methods suffer from latency and incorrect tripping of breakers, leading to potential network blackouts due to the propagation of fault currents and transient waves, making it difficult to isolate faulty links quickly and accurately.
Innovation Solution
The method involves an HVDC node with link modules equipped with fault sensing devices and optical transceivers, allowing for immediate detection of faults and transmission of breaker disabling requests through optical fibers, enabling swift isolation of faulty links without latency and minimizing unnecessary breaker tripping across the network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If fault detection is performed using transient wave propagation at link edges, then fault detection speed is improved, but false tripping of breakers on remote lines occurs causing network blackout
Solution Approach 1:
The patent introduces an intermediary communication system (optical transceivers and communication lines) that mediates between fault detection and breaker tripping. When a fault is detected on one link, the system sends disabling requests through this intermediary channel to prevent breakers on other links from tripping, thus resolving the contradiction between fast detection and false tripping
Solution Approach 2:
The system implements feedback by monitoring breaker status and sending disabling requests back to breakers on other links. The communication system provides feedback information about which links are affected by the fault, enabling the breakers to adjust their tripping behavior accordingly and avoid false operations
2Measurement precision
If double-ended method is used to exchange information at both ends of the line, then fault location accuracy is improved, but latency increases causing breaker to dimension for higher current
Solution Approach 1:
The system performs preliminary action by pre-configuring the communication channels and breaker control logic before faults occur. When a fault is detected, the disabling requests are immediately sent through the pre-established communication paths, eliminating the need for real-time negotiation and reducing latency while maintaining accurate fault location
3Ease of manufacture
If single end method is used to compare measurement levels with predetermined levels, then implementation simplicity is improved, but difficulty in defining thresholds for every fault type increases
Solution Approach 1:
The communication-based disabling request system provides a universal solution that works for all fault types and locations without requiring different threshold configurations. A single mechanism (sending disabling requests through communication channels) handles various fault scenarios, eliminating the need for complex threshold definitions while maintaining implementation simplicity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for rapid isolation of faulty links at low current levels, reducing the risk of network blackouts and simplifying threshold settings by ensuring only the affected link is broken, while maintaining network stability and enabling quick recovery for subsequent faults.
Implementation Method 1
transferring, if a fault is detected by the first link module, a first breaker disabling request through each optical transceiver of second link modules of the HVDC node that are different from the first link module
Data Source
AI summary
The present invention concerns a node of an HVDC grid composed of HVDC nodes and of a plurality of links interconnecting the HVDC nodes, each HVDC node being interconnected to at least one HVDC node of the HVDC grid by a link composed of conductive cables for high voltage direct current transportation and one optical fiber, at least one HVDC node being interconnected to at least two HVDC nodes, each HVDC node comprising, for each link connecting the HVDC node to the at least one other HVDC node, a link module comprising a fault sensing device, a breaker, and an optical transceiver for communicating through the optical fiber of the link.