Cable Tester With Separate Test Ground For In-Service Fault Detection

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Solution Overview

Problem

Existing cable testing methods are time-consuming and error-prone, especially for multi-pole cables, and require the cable to be unplugged, limiting their application to short lengths and only allowing testing outside of normal operation.

Innovation Solution

A cable tester comprising two units connected by a tester cable with a separate test ground, allowing for independent measurement of electrical variables without affecting system voltage or current, enabling testing during normal operation and supporting long cable lengths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the cable is unplugged for testing using traditional methods, then the individual conductors can be tested automatically, but the system operation is interrupted and only short cable lengths are possible

Engineering Contradiction:
Improvetesting accuracyVSAvoidsystem availability
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent introduces a separate test ground as an intermediary reference potential that is independent from the system ground. This allows voltage measurements on cable conductors during normal system operation without interference from system voltages or currents, enabling testing while maintaining system availability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent separates the test ground from the system ground, creating independent measurement reference circuits. This segmentation allows the testing function to operate independently from the system power supply, enabling continuous operation during testing

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If traditional testing methods are used with system ground, then the setup is simple, but system voltage or current loads the individual conductor making accurate measurement difficult

Engineering Contradiction:
Improvesetup simplicityVSAvoidvoltage measurement accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The separate test ground acts as an intermediary reference that isolates the measurement circuit from system voltage and current loads. This allows accurate voltage measurements on cable conductors without the interference that would otherwise occur when using system ground as reference

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the cable is unplugged for testing, then individual conductors can be accessed, but the testing process becomes time-consuming and error-prone

Engineering Contradiction:
Improvetesting reliabilityVSAvoidtesting time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent enables continuous testing during normal cable operation by maintaining the cable connected in the system. The separate test ground allows automated testing to proceed without interrupting system operation or requiring cable disconnection, eliminating time loss and reducing errors from manual reconnection

Inventive Principle:
Principle #20Continuity of useful action

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

Enables flexible and accurate testing of cables of various lengths without disrupting normal operation, allowing for both voltage and current measurements to detect faults reliably.

Implementation Method 1

a separate test ground that is different from the ground of the cable tester

Methodology Applied
Scientific EffectElectrical grounding: Earthing

Data Source

PatentEP3186648B1Cable tester and a method for testing an n-pole cable
Publication Date: 2018.08.01 AVL DITEST
  • EP3186648B1 patent drawingFigure 1
  • EP3186648B1 patent drawingFigure 2
  • EP3186648B1 patent drawingFigure 3

AI summary

To allow a cable (7) of almost any length to be tested even during normal cable (7) operation, it is suggested that an individual conductor (10) of said cable (7) is connected to a separate test ground (TGND) that differs from the electrical ground (GND) of the cable tester (1), and an electrical variable (UADC, IT) relating to said test ground (TGND) is measured in a first tester unit (2) or a second tester unit (3) and evaluated in order for testing to be carried out.