PV Sub-generator Junction Box Power Line Modem Data Transmission
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Solution Overview
Problem
The complexity and cost of laying cables for data transmission in large PV systems are increased due to the need for multiple signal or data lines from central PV inverters to numerous sub-array junction boxes, which is time-consuming and expensive, and existing radio data links are insecure due to shielding effects from PV modules.
Innovation Solution
Implementing a power line modem that modulates data on the existing PV sub-array cables, allowing data transmission between the central PV inverter and sub-array junction boxes without the need for separate data lines, using carrier frequency systems like TFA, which can couple and decouple data capacitively, inductively, or resistively, enabling bidirectional communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate data lines are laid from central PV inverters to sub-array junction boxes, then data transmission reliability is improved, but cable laying complexity and cost increase
Solution Approach 1:
The patent combines data transmission function with existing power transmission cables by implementing power line communication. The data signal is superimposed on the power cable, eliminating the need for separate data transmission cables. This merging approach maintains data transmission reliability while significantly reducing cable laying complexity and cost.
Solution Approach 2:
The existing PV power cables are made to serve dual functions: power transmission and data transmission. By equipping sub-array junction boxes with communication modules that can modulate and demodulate signals on the power line, the system achieves multi-functionality without additional dedicated data cables.
2Reliability
If separate data lines are installed for each sub-array junction box, then data communication security is improved, but installation time and cost increase
Solution Approach 1:
The invention merges data communication functionality into the existing power cable infrastructure. By using power line communication technology, the system eliminates the need to lay separate data cables to each sub-array junction box, thereby reducing installation time while maintaining communication security through the use of communication protocols on the powered lines.
3Ease of operation
If radio data links are used for communication, then cable laying effort is reduced, but data transmission security deteriorates due to shielding effects
Solution Approach 1:
The patent uses the existing power cable as an intermediary medium for data transmission. Instead of using radio waves that can be blocked by PV module shielding, the system modulates data signals onto the power cable, which already provides a conductive path. This intermediary approach eliminates cable laying effort while maintaining data transmission security through the shielded nature of the power cable infrastructure.
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 solution reduces the effort and cost of cable laying by eliminating the need for separate data lines, ensuring secure and efficient data transmission over existing power lines, and allows for improved monitoring and control of PV systems with reduced cable duct cross-sections and assembly costs.
Implementation Method 1
Implementing a power line modem that modulates data on the existing PV sub-array cables, allowing data transmission between the central PV inverter and sub-array junction boxes using carrier frequency systems like TFA
Implementation Method 2
which can couple and decouple data capacitively, inductively, or resistively
Implementation Method 3
which can couple and decouple data capacitively, inductively, or resistively
Data Source
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AI summary
A photovoltaic (PV) sub-generator junction box (1) for a PV system (100) comprises a plurality of electric terminals (11) for optionally connecting one respective PV string (2) of one or more serially connected PV modules (3). Said PV sub-generator junction box (1) further comprises a sub-generator line terminal (12) for connecting a PV sub-generator line (4) of a remote central PV inverter (5) or connecting a PV sub-generator line (4) of an inserted PV generator junction box (6). The PV sub-generator junction box (1) also comprises an electronic control unit (10) that is connected to a central control unit (7) of the PV inverter (5) in order to exchange data (DAT). According to the invention, the PV sub-generator junction box (1) comprises a power line modem (8) for feeding and retrieving the data (DAT) via the PV sub-generator line (4).