Spread Spectrum Power Line Communication Reflectometry for Fault Detection
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Solution Overview
Problem
The existing methods for fault detection and positioning in aerospace power systems, such as SSTDR, increase device volume, weight, and cost, and suffer from signal interference due to coexisting carrier and fault detection signals, making it difficult to recover carrier signals and maintain system reliability.
Innovation Solution
The method employs spread spectrum power line communication reflectometry (SSPLCR), which segments and transforms the source signal, uses a pseudo-random code for modulation, and integrates fault detection and information transmission, reducing hardware requirements and minimizing signal crosstalk, enabling real-time online fault detection and positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If SSTDR fault detection method is used, then fault positioning accuracy is improved, but device volume and weight increase
Solution Approach 1:
The patent combines fault detection function with the existing power carrier communication system by integrating the detection module into the modem. The same power carrier signal is used for both communication and fault detection, merging two functions into one system without adding separate detection hardware, thus improving fault positioning accuracy while avoiding weight increase from additional devices
Solution Approach 2:
The power carrier signal serves multiple functions simultaneously: it transmits communication data and performs fault detection and positioning. The detection module utilizes the existing power carrier infrastructure to achieve SSTDR functionality, making the system multi-functional without requiring separate dedicated fault detection equipment, thereby avoiding weight penalties
2Reliability
If separate fault detection signals are injected, then fault detection capability is improved, but signal interference increases
Solution Approach 1:
Instead of injecting separate fault detection signals, the patent merges fault detection with the existing power carrier communication signal. The detection function is embedded within the communication signal itself, eliminating the need for additional separate signals and thus avoiding the signal interference and crosstalk problems that would arise from having multiple coexisting signals in the same channel
Solution Approach 2:
The power carrier signal performs dual functions as both communication carrier and fault detection probe. By making the signal multi-functional, the system achieves reliable fault detection capability without introducing separate detection signals that would cause interference, as the same signal pathway and frequency are used for both purposes
3Productivity
If additional communication lines are added, then information transmission capacity is improved, but cable number and weight increase
Solution Approach 1:
The power line serves multiple functions: it delivers electrical power and simultaneously transmits communication data. By making the power infrastructure multi-functional, the system achieves high information transmission capacity without adding separate communication cables, thus increasing productivity while keeping the quantity of cables unchanged
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 reduces hardware costs and volume, improves system reliability, and accurately detects and positions faults with reduced synchronization errors, enhancing the maintainability and efficiency of power transmission systems.
Implementation Method 1
uses a pseudo-random code for modulation, and integrates fault detection and information transmission
Implementation Method 2
Spread spectrum communication is applied to a power carrier, so as to obtain the ability to resist man-made interference, narrow-band interference and multipath interference
Data Source
AI summary
A method for implementing fault diagnosis by means of a spread spectrum carrier includes the following steps: designing incident signal parameters, selecting a spread spectrum sequence for fault detection, determining a center frequency and a sequence length of a spread spectrum code, and segmenting and transforming a power carrier source signal; using the fault detection spread spectrum sequence as a carrier spread spectrum code, and performing spread spectrum modulation on the transformed power carrier source signal to generate an SSPLCR sequence; coupling the SSPLCR sequence to a cable to be tested, and when the cable works normally without failure, transmitting the SSPLCR signal to the receiving terminal via the cable; when the cable fails, reflecting the SSPLCR signal back to the transmitting terminal.