Adaptive Distribution Grid Protection via Area Segmentation
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Solution Overview
Problem
Existing protection systems for active distribution networks, particularly those with distributed energy resources, face challenges in dynamically adjusting to changing operating conditions, leading to inadequate fault detection and unnecessary tripping due to their centralized control and fixed settings, which are not suitable for large-scale networks with complex topologies.
Innovation Solution
A decentralized protection method that divides the distribution network into multiple protection areas, each with a local logic controller that evaluates and adapts short circuit levels and protection settings based on changes in feeder lines, loads, or generators, allowing for dynamic adjustments without requiring complete system topology knowledge and reducing communication load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a centralized protection system with fixed settings is used, then the system structure is simple, but the system cannot adapt to dynamic operating conditions in active distribution networks with DER
Solution Approach 1:
The protection system is divided into multiple autonomous protection areas, each managed by a local logic controller that independently evaluates short circuit levels and adapts protection settings. This segmentation enables local adaptability without requiring a complex centralized system, as each area operates semi-independently based on its own conditions and received information from neighboring areas.
Solution Approach 2:
The protection settings are made dynamic through continuous re-evaluation of short circuit levels by local logic controllers. When topological changes occur (such as DER connection/disconnection or switching operations), the system automatically updates protection parameters in real-time, transitioning from fixed settings to adaptive settings that respond to changing network conditions.
2Reliability
If a centralized system monitors and controls all protection devices, then coordination is centralized, but communication load increases significantly in large-scale networks
Solution Approach 1:
The network is divided into protection areas with local logic controllers that make autonomous decisions within their areas. Each controller only communicates essential information (such as short circuit level contributions) with neighboring areas, dramatically reducing communication load compared to a centralized system where all data must be transmitted to a central controller.
Solution Approach 2:
Local logic controllers autonomously evaluate short circuit levels, determine protection settings, and coordinate with neighboring areas without requiring continuous central controller intervention. This self-service capability reduces communication infrastructure load while maintaining reliable coordination through distributed decision-making.
3Loss of energy
If protection areas are divided and managed locally, then communication load is reduced, but system-wide coordination becomes more complex
Solution Approach 1:
All protection areas use the same evaluation methodology and communication protocols, with local logic controllers performing identical functions (evaluating short circuit levels, determining protection settings, exchanging information with neighbors). This homogeneous approach simplifies distributed coordination compared to heterogeneous systems, as each area operates according to the same rules regardless of its specific location or configuration.
4Measurement precision
If fixed protection settings are used, then device complexity is low, but fault detection sensitivity and speed decrease in tapped DER connections
Solution Approach 1:
Protection settings are dynamically adjusted based on real-time evaluation of short circuit levels by local logic controllers. In tapped DER connections, the system continuously monitors changes in network topology and DER status, automatically updating protection parameters to maintain high fault detection sensitivity and speed despite the complexity of distributed energy resource configurations.
Data Source
AI summary
Method of protecting a distribution network with a line interconnecting busbars, each busbar being connectable, by means of switching devices adjacent to the busbar, to the line and to loads and/or generators. The method divides the distribution network in multiple protection areas, each comprises a busbar, a protection device and an area controller. Upon a change in connect status of a distribution feeder line, load or generator connectable to one of the busbar, the logic controller in this protection area re-calculates the short circuit level of the areas. Based on the recalculated short circuit levels, the protection settings of the areas may be adapted. The embodiment also provides a system and computer program product adapted to perform the method.