Power Line Pulse Detection for Overhead Disconnection Faults
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Solution Overview
Problem
Conventional methods fail to detect disconnection faults in overhead power lines due to low or nonexistent fault currents, leading to potential fires and forest fires, especially in areas with low ground fault currents, and existing technologies are costly or inefficient for underground installations.
Innovation Solution
A device and method using a transmitter and receiver system that transmits and receives current pulse signals through a balanced/unbalanced three-phase voltage source, employing a DC_link unit with an accumulator to prevent ferroresonance and transient voltages, and magnetic field sensors to detect disconnection faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fault detection methods are used, then the system operates with standard protection mechanisms, but disconnection faults in overhead power lines cannot be detected due to low or nonexistent fault currents
Solution Approach 1:
The patent introduces a current pulse signal as an intermediary diagnostic tool. Instead of relying on fault currents that don't exist in disconnection scenarios, the system injects a test current pulse through the transformer and detects its presence or absence at the receiving end. This intermediary signal enables indirect detection of disconnection faults without requiring actual fault conditions.
Solution Approach 2:
The power line itself serves as the transmission medium for the diagnostic signal. The system uses the existing power infrastructure (transformers, power lines) to carry the test current pulse, eliminating the need for separate dedicated testing equipment or infrastructure. The power line network performs both its primary function of power transmission and the secondary function of fault detection.
2Device complexity
If backup protection systems are relied upon, then the system maintains standard protection architecture, but the systems may not function properly when ground fault currents are low
Solution Approach 1:
The system performs preliminary diagnostic testing by continuously or periodically injecting current pulse signals through transformers. This proactive approach detects disconnection faults before they lead to hazardous conditions, rather than waiting for backup protection systems to activate after a fault occurs. The preliminary detection enables preventive maintenance and early warning.
Solution Approach 2:
The system establishes a feedback loop where the injection of current pulse signals and the detection of their presence or absence provides continuous information about the operational status of power lines. This feedback mechanism enables real-time monitoring and automatic warning when disconnection faults are detected, allowing the system to respond to actual conditions rather than relying on predetermined protection thresholds.
3Reliability
If existing detection technologies are used, then conventional methods are applied, but they are costly or inefficient for underground installations
Solution Approach 1:
The current pulse injection method is universally applicable to both overhead and underground power line installations. The same basic principle of injecting a test signal through a transformer and detecting its presence works regardless of whether the power line is exposed overhead or buried underground. This eliminates the need for different detection systems for different installation types, reducing overall system complexity and cost.
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
Effectively detects disconnection faults in both overhead and underground power lines, reducing the risk of fires by coordinating with backup protection systems and ensuring reliable power line monitoring without system instability.
Implementation Method 1
a converter unit configured to convert an input AC voltage into a DC voltage (V+), an inverter unit configured to switch a DC voltage (V+) of a converter at a set phase angle time and transmit a current pulse signal to a power source of the public distribution network through a pure resistive load (LR)
Implementation Method 2
magnetic field sensors to detect disconnection faults
Data Source
AI summary
The present application relates to a device and method for surveying a power line-buried path, wherein the device includes a transmitter which selects a balanced/unbalanced voltage to output input and rectified output power as a current pulse in the form of an unmodulated pulse or a frequency-modulated signal when a current pulse signal is transmitted to a conductor (power line) of a public distribution network, and a receiver in which a plurality of magnetic field sensors inductively couple the pulse or the frequency-modulated signal within a near magnetic field distance to obtain a difference value in each direction to obtain a depth.