Phase-Selective Fault Isolation With Loop-Free Power Restoration

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Solution Overview

Problem

Power distribution networks often interrupt power for all customers on a transmission line due to single-phase faults, even when only one or two phases are affected, leading to unnecessary outages and inefficiencies.

Innovation Solution

A system and method for controlling power distribution networks that identifies subsets of affected and unaffected phases, sends open and close commands to isolation devices to isolate faults and restore power using tie-in devices, while avoiding loop configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If all three phases are isolated in response to a detected fault, then system reliability is improved by ensuring complete fault isolation, but unnecessary power outages occur for customers on unaffected phases

Engineering Contradiction:
Improvefault isolation completenessVSAvoidunnecessary power outages
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent segments the fault isolation process by phase, allowing independent identification and isolation of only the affected phases rather than isolating all three phases simultaneously. The system divides the power distribution network into phase-specific control units that can independently determine which phases require isolation based on fault detection signals.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by treating each phase differently based on its specific fault status. Instead of applying a uniform isolation action to all phases, the system applies isolation only to the specific phases where faults are detected, while allowing uninterrupted power supply to phases that remain healthy.

Inventive Principle:
Principle #3Local quality

2Productivity

If tie-in isolation devices are closed to restore power, then productivity is improved by restoring power to non-affected portions, but loop configurations may be created causing system instability

Engineering Contradiction:
Improvepower restoration speedVSAvoidsystem configuration stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary action by detecting and preventing potential loop configurations before they are formed. The system proactively identifies when closing a tie-in isolation device would create a loop and takes preventive action by blocking the close command, thereby avoiding system instability before it occurs.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms that continuously monitor the network configuration state and provide information to the control system. This feedback allows the system to detect when closing a tie-in device would create a loop configuration, enabling real-time adjustment of restoration commands to prevent instability.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3944442B1Single phase fault isolation and restoration with loop avoidance for multiple tie-in devices
Publication Date: 2026.04.01 G & W ELECTRIC CO
  • EP3944442B1 patent drawingFigure 1
  • EP3944442B1 patent drawingFigure 2
  • EP3944442B1 patent drawingFigure 3

AI summary

A method for controlling a power distribution network includes receiving, via an electronic processor, a fault indication associated with a fault from a first isolation device of a plurality of isolation devices. The processor identifies a first subset of a plurality of phases associated with the fault indication and a second subset not associated with the fault indication. The processor sends a first open command to each member of a set of downstream isolation devices for each phase in the first subset. The processor identifies a plurality of tie-in isolation devices to be closed to restore power. Responsive to identifying a first potential loop configuration, for each of the plurality of tie-in devices, the processor sends a close command to the tie-in isolation device for each of the plurality of phases and sends a second open command to the associated downstream isolation device for each phase in the second subset.