Resonance Analysis: Tips and Techniques for Cable Line Optimization

 

In the present industrial stage, the inspection and performance of wire systems, particularly those which are used as cables for the control and instrumentation applications is critical for the safety and proper functioning. The challenge of aging of wire systems is growing across oil & gas, transportation, and some defense sectors. The nuclear industry is an example of the extended lifetime that cables are required to uphold, which is often offered above 40 years. Nevertheless, the challenges of harsh environmental circumstances and correcting by-pass impedance are still to be addressed leading to the development of the more sophisticated techniques such as Cable Line Impedance Resonance Analysis (CLIRA).

 

Understanding CLIRA: A Comprehensive Measure Proposal

 

Cable Line Impedance Resonance Analysis (CLIRA), also linguistically the same with Line Resonance Analysis (LIRA), is now being used as a method to monitor cable status. The CLIRA (a short- for “Cable Linear Interaction and Response Analysis”) tool employs

transmission line theory to carry out a cable behaviour study under diverse conditions. First, CLIRA examines the complex cable impedance spectrum, allowing to recognize such insulation imperfections like thermal degradation and mechanical damage.

 

Key Principles of CLIRA:

 

Transmission Line Theory: The transmission line theory from the CLIRA places emphasis on how the action of the cable depends on the sizes of the signal's wavelength and the cable's length.

Characterization Parameters: In its performance CLIRA uses the skin effect resistance (R), the sheathing inductance (L), the cable capacitance (C) and insulation conductivity (G) as the parameters to evaluate the cable behaviour.

 

Impedance Spectrum Estimation: CLIRA software utilizes the institution of their own algorithms which determine the comprehensive layout of the cables and then estimates both local and global degradation.

 

Tips for Effective Cable Line Optimization:

 

Baseline Measurements: First of all, you have to define your initial scope of the measurements, for it will allow to understand the state of the system after the tests and analysis.

 

Damage Detection: Engage the use of CLIRA together with other techniques, including TDR, for reliably detecting the impact. Despite the fact that TDR is an extremely accurate method to determine the exact wiring defects, CLIRA provides a picture of a cable’s overall health.

 

Custom Algorithms: Features such as custom algorithms within CLIRA for precise parameter determination like phase velocity, not dependent on cable length or load attributes made possible.

 

Continuous Monitoring: CLIRA should fit in a multiparametric monitoring system and augment material screening for the continuous evaluation of cable health, with special attention given to nuclear power plants operating environment.

 

Ultra-sonic and other Non-Destructive Testing of cables that are tested without the need of energising the cables with high voltages. More likely to be used in a ‘high risk’ scenario than other methods

 

LIRA has been made as small as to be placed on electrical cables up to few hundred kilometres long and is gradually evolving as a condition monitoring or fault locating tool in the distances (like, for instance, a submarine cable that connects an off-shore platform to the grid).

 

Through IRLA, it is possible to test for and to find the various types of flaws and faults in insulation such as temperature and radiation damage, moisture intrusion fluid as well as mechanical impact being a fair sample.

 

LIRA makes use insulation conditions to impose a relationship between which and capacitance and therefore calculates the impedance spectrum (amplitude and phase) as the applied signal increases over the wide frequency band.

 

The capacitance of a cable changes as a function of changes in the cables permittivity and changes in the cable’s radius, as shown below:The capacitance of a cable changes as a function of changes in the cables permittivity and changes in the cable’s radius, as shown below:

 

 

 

R = series resistance
L = series inductance
G = parallel conductance
C = parallel capacitance

 

The changes in the permittivity and radius determined the neighboring impedance. Impedance mismatches show up exactly where immunancies are the most - specifically, it is when the cable ends. LIRA will generate standing wave patterns on short open circuits by comparing them to existing ones and promptly informing the system operators of slow impedance value changes.

Features and Benefits

LIRA can be applied to cables hundreds of kilometers long, in contrast to VLF associated with the use of the latter being restricted to the cables with a length of maybe 10km.

Useful for cable testing where hazard of applying energy to fully working voltage range exists.

 

With this technology you may apply fingerprinting used as your initial tool that allows you quickly to distinguish between the good cable and the bad one. This strategy showed the best outcomes.

 

Precise evolution of the impedance value will reliably demonstrate the presence of the anomaly.

Faults are isolated into a section located within 0.3% of the cable system.

precisely pinpoint sources of joints that are typically impossible to recognise.

 

LIRA can detect the following phenomena:

●     Global insulation degradation

●     High Temperature damage

●     Moisture ingress

●     Radiation damage

●     Mechanical effects/defects

 

 

*Note: When the highest sensitivity is the goal, expect a slight loss of signal at the multiple impedence changes so it is recommended to test from both ends. However, this does not need to be done.

 

Maximizing Sensitivity and Efficiency:

 

In order to achieve most sensitivity and be able to test signal gain at each location of impedance changes, it is highly recommended to conduct LIRA testing from both ends of the cable. However, it is not a formal requirement yet which gives priority to achievement of detection accuracy and efficiency, particularly, in sophisticated cable networks.

 

Conclusion:

 

We conclude that the Best Cable Line Impedance Resonance Analysis technique, is a very safe, reliable, and highly effective method for diagnosing line deterioration and may be performing necessary maintenance during the process of a line performance enhancement. It is the most advanced non-destructive technology known for comprehensive fault detection, accurate localization and being environmentally non-invasive that is the best solution for ensuring safety and reliability in modern industrial technology.