Optical Branching Unit Thyristor Arc Prevention
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Solution Overview
Problem
Existing submarine optical telecommunication branching units face issues with arc formation and uncontrolled relay activation during power-up and fault conditions, leading to potential detrimental arc transfers and equipment damage.
Innovation Solution
Incorporation of a bidirectional triode thyristor in the sea earth circuit, which remains untriggered during switching to prevent discharge to sea earth and arc formation, and is only triggered upon complete switch-over of relays, ensuring controlled connection to the sea earth and preventing high surge-induced arc formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If relays are used to connect terminals to sea earth during power-up and fault conditions, then electrical continuity and power distribution are achieved, but arc formation and uncontrolled relay activation occur leading to equipment damage
Solution Approach 1:
A bidirectional triode thyristor is introduced as an intermediary device between the relay contacts and the sea earth circuit. The thyristor remains untriggered during relay switching operations, acting as an isolating barrier that prevents arc formation. It is only triggered after complete relay switch-over, ensuring controlled connection to sea earth while blocking harmful surges and arcs during the critical switching phase.
Solution Approach 2:
The system performs preliminary configuration of relays to establish proper terminal connections before triggering the thyristor for sea earth connection. This sequential operation ensures that all relay switching is completed and stabilized before the thyristor becomes conductive, preventing uncontrolled activation and arc formation during the power-up and fault response phases.
2Object-affected harmful factors
If additional discharge steps are performed at land stations to prevent arc transfer, then arc formation is reduced, but system complexity and operational procedures increase
Solution Approach 1:
The bidirectional triode thyristor provides automatic protection against arc formation and surge damage without requiring manual discharge procedures at land stations. The device self-regulates by remaining non-conductive during relay switching and automatically triggering only when proper connection conditions are met, eliminating the need for complex manual intervention and simplifying operational procedures.
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
The solution effectively prevents arc formation and relay activation issues during power-up and fault conditions, maintaining controlled operation and reducing the risk of equipment damage, thereby enhancing the reliability and safety of the branching unit.
Implementation Method 1
a first bidirectional triode thyristor (13) having a first main terminal (13') connected to the fourth terminal (5) and a second main terminal (13'') connected to the sea earth circuit (9), the first bidirectional triode thyristor being in a forward blocking state during the complete switch-over of the at least one relay of the group consisting in the first, second and third relay
Implementation Method 2
a driving circuit (19) configured for triggering the first bidirectional triode thyristor (13) in a conduction state only upon complete switch-over of one relay of the group consisting in the first, second and third relay
Implementation Method 3
a first switch (12') having a first contact (10') belonging to a first termination line (4'), a second contact (11') belonging to a second line (16) and a third contact (12') belonging to a third earth line (9''') of the sea earth circuit (9), and a first actuator (12'') configured for actuating the first switch (12') depending on a current along the first termination line (4')
Data Source
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AI summary
A branching unit (1) for an optical telecommunication link (100), the unit comprising a first (2), a second (3) and a third terminal (4) for termination of conductors of respective branch cables in use, a fourth terminal (5) for connection to a sea earth (6) in use, and a circuit (8) comprising a plurality of relays comprising at least a first, a second and a third relay associated to respectively the first, second and third terminal, the circuit being structured for connecting together two terminals out of the first, second and third terminal and for connecting the remaining terminal to the fourth terminal, depending on a sequence of power feeding at the first, second and third terminals, in use, wherein the circuit (8) comprises a sea earth circuit (9) terminated at one end to the fourth terminal and a bidirectional triode thyristor (13) placed along the sea earth circuit, a driving circuit (19) being provided for driving the bidirectional triode thyristor so as to trigger the bidirectional triode thyristor in a conduction state only upon complete switch-over of one relay of the group consisting in the first, second and third relay.