Submarine Cable Insulation Evaluation Using Dielectric Loss Correction
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Solution Overview
Problem
The existing methods for evaluating the insulation performance of submarine cables, particularly those using the polarization-depolarization current (PDC) method, face inaccuracies due to the large dielectric loss values measured, especially in longer cables with increased capacitance, leading to unreliable insulation performance evaluations.
Innovation Solution
A method and apparatus for evaluating the insulation performance of submarine cables by obtaining measured dielectric loss values, current-limiting resistances, and insulation resistances, and then calculating an actual dielectric loss value using a preset expression that includes a product calculated by a Debye model, thereby correcting for the inaccuracies in the measured values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the PDC method is used to measure dielectric loss value in submarine cables, then the insulation performance can be evaluated, but the measured dielectric loss value becomes too large due to cable capacitance, leading to inaccurate evaluation results
Solution Approach 1:
The patent extracts and removes the capacitive component from the measured dielectric loss value through mathematical calculation. By separating the capacitive effect (which causes the overly large measured value) from the actual insulation loss, the method obtains an accurate insulation performance evaluation free from capacitive interference.
Solution Approach 2:
The patent transforms the measurement approach by changing from direct measurement to calculated derivation. Instead of directly using the measured dielectric loss value, the method calculates the actual insulation loss by subtracting the capacitive component (determined through voltage and current relationship analysis) from the total measured loss, thereby obtaining an accurate insulation parameter.
2Productivity
If a voltage approximately step signal is applied to the submarine cable, then the dielectric loss value can be obtained, but the voltage becomes approximately exponential signal due to large cable capacitance, causing significant deviation in evaluation results
Solution Approach 1:
The patent introduces a feedback mechanism where the measured voltage and current signals are continuously monitored and used to calculate the capacitive component. This feedback loop allows the system to dynamically determine and remove the capacitive effect from the dielectric loss measurement, ensuring reliable evaluation results even when the voltage signal deviates from the ideal step signal due to cable capacitance.
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 approach ensures a high-precision insulation performance evaluation by accurately calculating the actual dielectric loss value, thereby overcoming the limitations of previous methods and providing reliable results.
Implementation Method 1
the first product is calculated by a preset model in an nth-order situation, the nth-order situation represents that there are n branches in the submarine cable
Implementation Method 2
When evaluating the insulation performance of the submarine cable based on a dielectric loss value of the submarine cable
Data Source
AI summary
Provided are a method and apparatus for evaluating insulation performance of a submarine cable, and a medium. The method includes: obtaining a first measured dielectric loss value, first current-limiting resistance, and first insulation resistance of a submarine cable; substituting the above parameters into an expression of the first measured dielectric loss value to calculate a first actual dielectric loss value, where the expression of the first measured dielectric loss value is calculated based on a preset expression of a total dielectric loss value, and the expression of the total dielectric loss value includes a first product and the to-be-solved first actual dielectric loss value; and evaluating insulation performance of the submarine cable based on the first actual dielectric loss value to obtain an insulation performance evaluation result. The present disclosure can solve a problem of low reliability of the insulation performance evaluation result of the submarine cable.