Back-fed Arc Fault Circuit Interrupter for Distributed Generation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional residential net metering solar systems lack protection against arc faults and ground faults in the wiring between the inverter and the home power distribution system, and existing remotely located arc fault and ground fault protection devices are difficult to access, maintain, and reset.

Innovation Solution

A system that back-feeds an arc fault circuit interrupter (AFCI) with a line side terminal coupled to a voltage source and a current source, providing arc fault and ground fault protection for distributed generation sources such as photovoltaic systems, wind power systems, and hydroelectric systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If arc fault and ground fault protection devices are remotely located near distributed generation sources, then protection coverage is improved, but accessibility for maintenance and resetting deteriorates

Engineering Contradiction:

Improveprotection coverageVSAvoidaccessibility for maintenance and resetting

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent inverts the conventional approach by back-feeding the AFCI device with current from the distributed generation source rather than requiring utility power at the remote location. This allows the AFCI to be installed near the DG source where protection is most needed, while the inversion of power flow enables the device to operate autonomously without compromising accessibility

Inventive Principle:

Principle #13The other way round (Inversion)

2Ease of manufacture

If conventional circuit breakers are used in distributed generation systems, then simplicity and ease of installation are maintained, but arc fault and ground fault protection is lost

Engineering Contradiction:

Improvesimplicity of installationVSAvoidarc fault and ground fault protection

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent makes the circuit breaker multi-functional by integrating both conventional overload/short-circuit protection and arc fault/ground fault protection capabilities into a single device. The back-fed AFCI circuit breaker performs multiple protection functions simultaneously, eliminating the need for separate protection devices while maintaining ease of installation

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If arc fault and ground fault protection is integrated into remotely located distributed generation sources, then wiring protection is improved, but device maintenance and replacement difficulty increases

Engineering Contradiction:

Improvewiring protectionVSAvoidmaintenance and replacement difficulty

Core Design Contradiction:

ReliabilityVSEase of repair

Solution Approach 1:

The patent applies the inversion principle by reversing the conventional power flow direction to back-feed the AFCI device. This allows the device to be located near the DG source for optimal wiring protection while operating independently of utility power, enabling easier maintenance and replacement by technicians who can access the device without requiring complex utility power connections at remote locations

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentEP2596560B1Systems and methods for providing arc fault and/or ground fault protection for distributed generation sources

Publication Date: 2014.10.01 SIEMENS INDUSTRY INC

Figure 1~2
Figure 3
Figure 4A

AI summary

A system is provided including: an arc fault circuit interrupter AFCI (12) having a line side terminal (L,N,G) and a load side terminal (L',N',G'), wherein the line side terminal is coupled to a voltage source (16 '), and a current source (20) coupled to the load side terminal to backfeed the arc fault circuit interrupter.