Conductor Cable Length Measurement via Electromagnetic Signal Transit

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Solution Overview

Problem

Existing methods for determining the length of conductor cables in overhead lines are either invasive, require additional sensors, or lack accuracy, particularly in measuring sag which can be affected by temperature and external factors like wind and ice loads.

Innovation Solution

A method and device that couple an electromagnetic signal into one end of the conductor cable, measure the transit time, and calculate the length without additional sensors, using either pulsed or frequency-modulated signals, allowing for precise measurement and integration with the existing infrastructure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If temperature sensors are attached directly to the conductor to measure sag, then temperature measurement capability is improved, but device complexity and invasiveness increase

Engineering Contradiction:

Improvetemperature measurement capabilityVSAvoidsensor attachment infrastructure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces physical temperature sensors attached to the conductor with electromagnetic signal-based measurement. Instead of using mechanical/thermal sensors that require direct contact with the conductor, the invention uses electromagnetic signals that propagate through the conductor to determine its length and infer sag, thereby eliminating the need for physical sensor attachments.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces electromagnetic signals as an intermediary medium to measure conductor properties. Rather than directly measuring temperature with sensors on the conductor, the invention uses electromagnetic signal propagation characteristics (transit time, frequency) as an intermediary to indirectly determine conductor length and sag, avoiding direct physical contact.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If additional sensors are installed on the conductor cable to measure length and sag, then measurement capability is improved, but ease of operation and installation difficulty worsen

Engineering Contradiction:

Improveconductor length and sag measurement capabilityVSAvoidinstallation and operation simplicity

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The conductor cable serves itself as the transmission medium for electromagnetic signals. The existing conductor infrastructure is utilized to carry the measurement signals without requiring separate sensing elements or additional hardware attached to the conductor. The conductor's own electrical properties enable the measurement function.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The conductor cable performs multiple functions: it serves both as the electrical transmission medium for power delivery and as the transmission medium for electromagnetic measurement signals. This multi-functionality eliminates the need for dedicated sensing infrastructure, simplifying installation and operation.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If conventional measurement methods are used that require sensors attached to the conductor, then measurement data can be obtained, but measurement accuracy under varying temperature and external conditions deteriorates

Engineering Contradiction:

Improvemeasurement data availabilityVSAvoidmeasurement accuracy under varying conditions

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent employs periodic electromagnetic signals (continuous waves or repeated pulses) to measure conductor properties. By using periodic signals with known frequencies and comparing the transmitted and received signals, the system can accurately determine transit time and frequency shifts, enabling reliable measurement of conductor length and sag under varying environmental conditions.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system uses feedback by comparing the transmitted electromagnetic signal with the received signal after propagation through the conductor. By analyzing the frequency shift, phase difference, or transit time of the returned signal, the system continuously monitors and determines conductor length and sag, providing reliable measurements that compensate for environmental variations.

Inventive Principle:

Principle #23Feedback

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 simple, accurate, and non-invasive measurement of conductor cable length and sag, with high measurement accuracy down to the centimeter range, facilitating real-time monitoring and load distribution control within the power supply network.

Implementation Method 1

coupling an electromagnetic signal into a first end of the conductor cable, receiving the coupled electromagnetic signal at a second end of the conductor cable

Methodology Applied

Scientific EffectElectromagnetic signal propagation: Electromagnetic Induction

Data Source

PatentEP2591306B1Method and apparatus for determining a length of a conductor cable fixed between pylons of an aerial line

Publication Date: 2020.04.15 SIEMENS AG

Figure 1~3
Figure 4~5

AI summary

A method for determining a length of a conductor cable of an overhead line has steps for injecting an electromagnetic signal into a first end of the conductor cable, for determining a propagation time of the signal in the conductor cable and for determining the length of the conductor cable from the determined propagation time.