Modular DC Interconnection Branching for Compact Fault Clearance
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Solution Overview
Problem
Conventional DC interconnection devices in electrical networks are expensive and occupy a large footprint, making them costly and inefficient for feeder interconnections.
Innovation Solution
A modular direct current interconnection device (MDCID) with at least three operation branches and one transient branch, along with a local controller, is introduced. The local controller manages fault clearance by determining operation and transient branches based on received fault information, utilizing mechanical switches, auxiliary breakers, and energy absorption devices to provide a transient DC current path during faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional DC interconnection devices are used, then reliability is maintained, but cost and footprint are high
Solution Approach 1:
The DC interconnection device is divided into multiple operation branches (at least three) that can independently connect different feeders. Each branch contains switching devices that can independently open or close, allowing selective disconnection of faulty feeders while maintaining connections for healthy feeders. This segmentation enables the system to maintain reliability by preserving functional branches while reducing the effective footprint by isolating only the necessary components during fault conditions.
Solution Approach 2:
The device incorporates dynamic switching capabilities with mechanical switches and auxiliary breakers in each operation branch. These switching devices can dynamically reconfigure the circuit topology based on fault conditions, transitioning from a static full-connection configuration to a dynamic selective-connection configuration. This dynamic reconfiguration maintains reliability by preserving alternative current paths while reducing the active footprint during fault clearance operations.
2Reliability
If conventional DC interconnection devices are used, then reliability is maintained, but cost increases
Solution Approach 1:
By segmenting the device into modular operation branches with standardized switching devices (mechanical switches and auxiliary breakers), the design enables easier manufacturing and assembly. Each branch can be independently manufactured and tested before final assembly, reducing overall production costs while maintaining the reliability required for DC feeder interconnection.
Solution Approach 2:
The device employs auxiliary breakers that can be replaced more easily and at lower cost compared to conventional DC interconnection device components. These auxiliary breakers serve as sacrificial protective elements that can be quickly replaced after fault events, reducing long-term maintenance and replacement costs while maintaining system reliability through the redundant operation branches.
3Area of stationary object
If transient branches are minimized, then footprint and cost are reduced, but fault clearance capability must be maintained
Solution Approach 1:
The operation branches serve multiple functions: they provide normal DC current transmission during healthy operation and simultaneously serve as transient current paths during fault clearance. By making the operation branches multi-functional, the device eliminates the need for separate dedicated transient branches, reducing footprint and cost while maintaining full fault clearance capability through the same operational infrastructure.
Solution Approach 2:
The switching devices in the operation branches enable continuous useful action by seamlessly transitioning between normal operation mode and fault clearance mode. The mechanical switches and auxiliary breakers can rapidly switch states to provide transient current paths when needed, ensuring that the same components serve both continuous transmission and intermittent fault clearance functions without requiring separate dedicated structures.
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 MDCID reduces costs, volume, and footprint by minimizing the number of transient branches, simplifying control complexity, and enhancing the reliability of the electrical network system.
Implementation Method 1
cause the energy absorption device in the determined transient branch to absorb electric energy in response to turning off the main breaker
Data Source
AI summary
Embodiments of a modular direct current interconnection device (MDCID) include at least three operation branches, at least one transient branch, and a local controller. Each of the operation branches includes a first terminal coupled to a common node and configured to transmit DC current in a normal mode. The transient branch is coupled between second terminals of different ones of the at least three operation branches and configured to provide a transient DC current path in a fault clearance mode. The local controller is coupled to the operation branches and the transient branch, and the local controller is configured to control operation of the operation branches and the transient branch.