DC T&D System Fault Isolation via Current Sensors
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Solution Overview
Problem
High voltage direct current (HVDC) transmission and distribution systems face challenges in rapidly isolating electrical faults due to the nature of DC power, which increases the risk of arcing and reduces the service life of mechanical isolation devices, and existing systems lack efficient methods for selective isolation and rapid restoration.
Innovation Solution
The implementation of a DC transmission and distribution system that includes a plurality of current sensors and processors to regulate DC current through DC-to-DC converter devices, allowing for real-time monitoring and control of electrical parameters, and the use of mechanical isolation devices that can operate under near-zero loads to isolate faults quickly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical isolation devices are opened under load to isolate electrical faults in DC T&D systems, then fault isolation is achieved, but the risk of arcing increases and service life of contactor portions decreases
Solution Approach 1:
The system performs preliminary action by detecting DC current excursions and opening mechanical isolation devices before the fault can cause significant damage. The rapid detection and isolation capability (within 5 milliseconds) prevents the fault from escalating, allowing the mechanical devices to open under near-zero load conditions rather than sustained load, thereby reducing arcing risk and extending service life
Solution Approach 2:
The patent replaces traditional mechanical circuit breakers with a hybrid system that uses electronic detection (current sensors) and control systems to identify faults, then actuates mechanical isolation devices only when necessary and under optimized conditions. This substitution of electronic monitoring for purely mechanical operation allows for more precise control of the isolation process, reducing unnecessary arcing events
2Reliability
If mechanical isolation devices are opened under load to isolate electrical faults, then fault isolation is achieved, but service life of contactor portions decreases
Solution Approach 1:
The system performs preliminary action by detecting DC current excursions and opening mechanical isolation devices before the fault can cause significant damage. The rapid detection and isolation capability (within 5 milliseconds) prevents the fault from escalating, allowing the mechanical devices to open under near-zero load conditions rather than sustained load, thereby reducing arcing risk and extending service life
Solution Approach 2:
The patent changes the operational parameters of mechanical isolation devices by ensuring they open under near-zero load conditions rather than under full load. This parameter change (from opening under load to opening under near-zero load) significantly reduces the stress and arcing experienced by contactor portions, thereby extending their service life while maintaining fault isolation capability
3Reliability
If traditional circuit breakers are used for fault isolation in DC T&D systems, then fault isolation is achieved, but isolation time is excessive
Solution Approach 1:
The system performs preliminary action by continuously monitoring DC current through sensors positioned throughout the T&D system. This continuous preliminary detection allows the system to identify current excursions and initiate isolation procedures within 5 milliseconds, dramatically reducing the total fault isolation time compared to traditional breaker operation times
Solution Approach 2:
The patent replaces traditional mechanical circuit breakers with a hybrid system that uses electronic detection (current sensors) and control systems to identify faults, then actuates mechanical isolation devices only when necessary and under optimized conditions. This substitution of electronic monitoring for purely mechanical operation allows for more precise control of the isolation process, reducing unnecessary arcing events
Data Source
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AI summary
A direct current (DC) transmission and distribution (T&D) system (300) includes a plurality of DC-to-DC converter devices (310) defining a plurality of isolatable portions of the DC T&D system (300). The DC T&D system (300) also includes a DC T&D control system (200) coupled to the DC-to-DC converter devices (310). The DC T&D control system includes a plurality of current sensors (334). At least one of the current sensors is positioned at one of the DC-to-DC converter devices. The current sensor is configured to transmit signals representative of a value of DC electric current transmission through the DC-to-DC converter device. The DC T&D control system (200) also includes a plurality of processors (336). At least one processor (336) is coupled to the current sensor (334) and the DC-to-DC converter device (310). The processor (336) is configured to regulate DC current transmission through the DC-to-DC converter device (310) as a function of the value of DC current transmission through the DC-to-DC converter device (310).