Multi-Stage Fuse Layout for DC-Side Short-Circuit Isolation
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Solution Overview
Problem
Conventional energy storage systems face high maintenance costs due to the need to replace all fuses when a short circuit fault occurs on the direct-current side of the energy storage inverter, especially in large-capacity systems, which can lead to severe accidents and economic losses.
Innovation Solution
A multi-stage short circuit protection system is implemented, featuring N stages of fuse units where each battery pack is connected to a first-stage fuse, and the direct-current side of the power conversion device is connected through third-stage fuse units, with second- and fourth-stage fuse units arranged between battery packs and the power conversion device, ensuring that only the fuse units preceding and following the fault position are broken, minimizing maintenance costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aR fuses are connected to each battery pack and the direct-current side of the energy storage inverter, then short circuit protection is provided, but all fuses must be replaced after a short circuit fault occurs, resulting in high maintenance costs
Solution Approach 1:
The protection system is divided into multiple stages: first-stage fuses connected to individual battery packs, second-stage fuses in the combiner box, and third-stage fuses on the inverter's direct-current side. This segmentation allows localized fault isolation, so when a short circuit occurs, only the fuses at the fault location and adjacent stages need to be replaced, not all fuses throughout the system.
Solution Approach 2:
The second-stage fuses in the combiner box act as intermediaries between the battery packs and the inverter. When a short circuit fault occurs on the inverter's direct-current side, these intermediate fuses break to isolate the fault, preventing the need to replace all first-stage fuses connected to individual battery packs.
2Quantity of substance
If the number of battery packs is increased for large-capacity energy storage systems, then energy storage capacity is improved, but the complexity of short circuit faults increases and the potential loss from accidents increases
Solution Approach 1:
The multi-stage fuse system segments the large-scale battery system into smaller protected zones. Each stage protects a specific portion of the system, allowing faults to be isolated to localized areas even as the overall system capacity increases, thereby managing complexity through hierarchical protection.
Solution Approach 2:
Different stages of the system have different protection characteristics tailored to their specific requirements. First-stage fuses protect individual battery packs, second-stage fuses protect combiner sections, and third-stage fuses protect the inverter. This local differentiation of protection quality allows the system to scale while maintaining manageable fault complexity.
3Reliability
If conventional fuse protection is used on the direct-current side, then short circuit faults are protected against, but severe accidents and economic losses may still occur due to the scale of large-capacity systems
Solution Approach 1:
By dividing the protection into multiple stages, the system prevents uncontrolled short circuit currents from affecting the entire large-capacity system. When a fault occurs, the segmented protection isolates only the affected section, preventing severe accidents and minimizing economic losses that would otherwise result from system-wide failures.
Solution Approach 2:
The multi-stage fuse system provides beforehand cushioning by having multiple layers of protection ready in advance. When a short circuit fault occurs, the intermediate second-stage fuses break first to cushion the impact, preventing the fault from propagating to the entire system and reducing the severity of potential accidents.
Data Source
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AI summary
An energy storage system and a multi-stage short circuit protection system thereof are provided. The multi-stage short circuit protection system includes N stages of fuse units. Each battery pack is connected to a corresponding first-stage fuse unit, a direct-current side of a power conversion device is arranged with a third-stage fuse unit, and at least one second-stage fuse unit is arranged between multiple battery packs and the power conversion device. In a case that a short circuit fault occurs at a position on the direct-current side of the power conversion device, only a fuse unit at a stage preceding the position and a fuse unit at a stage following the position are broken, thereby avoiding a problem of a high maintenance cost in the conventional technology due to that all fuses are broken.