Portable Network Protector Isolation System for Safe Maintenance

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Solution Overview

Problem

Existing methods for isolating a malfunctioning network protector in electric power distribution networks are unsafe and disruptive, often requiring shutdowns of electric service and exposing workers to hazardous conditions, as they involve manual intervention and limited time frames for clearing faulty devices without interrupting load.

Innovation Solution

A remote-controlled, portable system for simultaneous three-phase isolation of a faulty backfed network protector, using temporary contactors to safely and quickly disconnect the defective unit from the network, allowing for automatic operation and reduced risk to workers and service continuity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual isolation methods are used to clear a malfunctioning network protector, then the faulty device can be opened for repair, but worker safety is compromised and electric service must be interrupted

Engineering Contradiction:

Improvesafe clearing of malfunctioning protectorVSAvoidworker exposure to hazardous conditions

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A portable isolation system with temporary contactors serves as an intermediary device between the malfunctioning network protector and the network. The contactors are connected to the protector terminals and can be remotely controlled to isolate the faulty device without requiring workers to physically handle energized components, thus eliminating direct worker exposure to electrical hazards while maintaining the ability to clear the protector for repair

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If manual isolation methods are used to clear a malfunctioning network protector, then the faulty device can be opened for repair, but electric service must be interrupted

Engineering Contradiction:

Improvesafe clearing of malfunctioning protectorVSAvoidelectric service continuity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The isolation function is segmented into separate controllable contactors for each phase, allowing selective isolation of the malfunctioning protector without affecting the overall network operation. The temporary contactors can be controlled independently to maintain service to other parts of the network while clearing the faulty device

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The portable isolation system is prepared and connected to the malfunctioning protector before isolation is required. The contactors are positioned and ready for remote operation, allowing quick isolation without interrupting service. The system enables preliminary setup so that when isolation is needed, it can be executed remotely and rapidly

Inventive Principle:

Principle #10Preliminary action

3Ease of repair

If existing isolation methods are used, then the malfunctioning protector can be cleared, but the process requires significant time and manual intervention

Engineering Contradiction:

Improveclearing of faulty deviceVSAvoidtime required for isolation and clearing

Core Design Contradiction:

Ease of repairVSLoss of time

Solution Approach 1:

The manual mechanical process of isolating a network protector is replaced with an automated electrical control system. Remote control switches and contactors enable electronic/isolated control of the isolation process, eliminating the need for workers to manually operate under time constraints and reducing the overall clearing time significantly

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

This solution enables safe and rapid isolation of malfunctioning network protectors without interrupting electric service, improving worker safety and reducing the time required for servicing or replacing faulty devices, while maintaining load and ensuring voltage overload protection.

Implementation Method 1

When large differences in voltage or phase angle are detected in paralleled network feeders, the network protector isolates the backfed transformer from the other transformers to which it is connected

Methodology Applied

Scientific EffectVoltage detection: Electric Field

Implementation Method 2

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS10277027B2Apparatus for isolating a network protector in an electric power distribution network

Publication Date: 2019.04.30 ELECTRICAL MATERIALS CO

AI summary

An apparatus for isolating a malfunctioning network protector from the power distribution network and for allowing the network protector to be safely reset. The apparatus includes: a 3 phase controller coupled by parallel single phase poles in plural contactors to the fuse link and adapted to receive an electric load current flowing in reverse through the network power transformer; a remote controlled switch coupled to the controller for switching the electric load current from the network protector via the controller to the network bus, with the controller then carrying the electric load current in parallel with the network protector fuse link; and visual indicators coupled to the controller for showing when the remote controlled switch has been activated to transfer the load current from the fuse links to the controller and when the electric load current has been transferred from the controller to the network bus.