Transmission Line TEM Sensing for Repeated Deep Subsurface Imaging
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Solution Overview
Problem
Conventional transient electromagnetic (TEM) surveys are limited by the need for expensive, specialized equipment and are difficult to conduct in urban or residential areas, and they struggle to detect deep subsurface features.
Innovation Solution
Utilizing pre-existing power transmission lines as a source of energy to generate subsurface images by detecting transient events such as lightning strikes or load switching, and employing a sensor array to capture induced electromagnetic signals, combined with machine learning models to process the data and generate images without the need for aerial platforms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional TEM surveys use specialized equipment and aerial platforms, then subsurface imaging can be performed, but the cost increases and operation becomes difficult in urban areas
Solution Approach 1:
The patent applies universality by using existing power transmission lines for multiple purposes: both their original function of power transmission and the new function of serving as electromagnetic signal sources for subsurface imaging. This eliminates the need for specialized airborne equipment and makes the survey method applicable in urban areas where power lines already exist.
Solution Approach 2:
The power transmission lines serve themselves by generating the electromagnetic signals needed for imaging through their normal operational transients (switching, load changes, lightning strikes). No separate transmitter system is needed - the power line infrastructure provides both the energy source and the signal generation mechanism.
2Productivity
If conventional TEM surveys use airborne platforms, then subsurface imaging is possible, but the equipment cost increases and repeated surveys become difficult
Solution Approach 1:
The power transmission lines are pre-installed throughout the survey area, with sensors already in place at multiple locations. This preliminary setup allows repeated surveys to be conducted without requiring repeated deployment of complex airborne equipment, enabling frequent monitoring of the same area.
Solution Approach 2:
The patent replaces the mechanical airborne platform system with an electrical field-based system using power lines. Instead of physically moving equipment through the air, the system uses electromagnetic fields generated by power lines to achieve the same imaging goal, enabling easier repeated surveys.
3Measurement precision
If conventional TEM surveys are conducted, then subsurface imaging is achieved, but the ability to detect deep features is limited
Solution Approach 1:
The patent changes the key parameter of signal source characteristics by using high-power transient events from power lines (lightning strikes, breaker operations, load switching) instead of conventional low-power airborne transmitters. These high-energy transients generate stronger electromagnetic fields that penetrate deeper into the subsurface, improving detection capability for deep features like basalts.
4Productivity
If power line transients are used for subsurface imaging, then cost-effective repeated surveys are enabled, but the signal detection becomes more challenging
Solution Approach 1:
The patent segments the signal detection process by using multiple sensor locations along the power line to detect transients at different positions. This segmentation allows the system to capture the electromagnetic signal at optimal points and process data from multiple locations to improve detection capability while maintaining cost-effectiveness.
Solution Approach 2:
The patent introduces sensors as intermediary devices that detect the electromagnetic signals induced in the power lines during transient events. These sensors act as mediators between the power line transients and the data processing system, enabling detection of the weak induced signals while filtering out noise from the original transient events.
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 cost-effective, repeated subsurface imaging over broad areas, including detection of deep features like deep basalts, without the limitations of traditional TEM surveys, and provides high signal-to-noise ratio through coordinated transient events.
Implementation Method 1
detecting an electrical signal induced in the power line at the two or more predetermined locations by a return electromagnetic signal generated by eddy currents induced in the subsurface by the transient event
Implementation Method 2
eddy currents induced in the subsurface by the transient event
Data Source
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AI summary
This disclosure describes a system and method for generating images by performing TEM surveys using pre-existing infrastructure such as transmission lines, or power lines, and naturally occurring transients such as lightning strikes or load switching. A relatively inexpensive sensor array can be installed on overhead power lines (e.g., electrical transmission or sub-transmission lines) which can detect transients in the overhead power lines. Transients in the overhead power lines can cause the power lines to emit pulses of electromagnetic (EM) radiation, which propagate into the earth's subsurface. This sudden change in electromagnetic field in the subsurface can induce eddy currents, which in turn emit return EM radiation that can propagate back to the overhead power line and induce secondary voltage and current transients. The magnitude of these secondary transients, and their time delay from the original transient are influenced by the properties of the subsurface in which the eddy currents formed.