Solar Panel Watchdog Shutdown for Safe String Isolation
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Solution Overview
Problem
Photovoltaic systems pose safety risks due to lethal voltage potentials during installation and maintenance, and existing solutions like covering panels with opaque materials or working at night introduce additional hazards, while the practice of connecting solar modules in series limits energy production and increases equipment damage risks.
Innovation Solution
A system and method that includes a normally closed safety switch integrated into solar panel junction boxes or modules, which can be opened during installation or maintenance to isolate the panel from output connectors, and a watchdog system to monitor communication and electrical signals, allowing for shutdown or modification of system operation if anomalies are detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If solar modules are connected in series to reduce equipment cost, then equipment cost is reduced, but voltage rises to dangerous levels and energy production is limited
Solution Approach 1:
The patent divides the solar module system into independently controllable segments. Each module or group of modules is equipped with its own switchable disconnect mechanism, allowing individual modules to be isolated from the series string. This segmentation enables safe maintenance of individual modules without exposing personnel to high voltage from the entire array, while still allowing the remaining modules to operate and contribute to energy production.
Solution Approach 2:
The patent implements pre-installed disconnect switches and isolation mechanisms within each solar module or junction box before the system becomes operational. These preliminary safety features are integrated into the module design, allowing installers to quickly disconnect individual modules or strings by simply operating local switches rather than having to physically disconnect cables or use complex isolation procedures.
2Object-affected harmful factors
If panels are covered with opaque materials to prevent energization, then safety risk is reduced, but wind can catch the material and pull personnel off the roof
Solution Approach 1:
The patent replaces the mechanical approach of physically covering panels with opaque materials with an electrical control system. Automated switches and disconnect mechanisms are integrated into the module design, allowing electrical isolation to be achieved through controlled switching rather than physical barriers. This eliminates the need for personnel to handle unstable covering materials on the roof.
Solution Approach 2:
The patent implements self-isolating features where the solar modules or junction boxes automatically disconnect or can be quickly isolated through locally controlled switches without requiring external covering materials. The system serves its own safety needs through integrated disconnect mechanisms that are activated locally at each module or string level.
3Object-affected harmful factors
If work is performed at night to minimize energization risk, then electrical shock risk is reduced, but safety risks from poor lighting increase
Solution Approach 1:
The patent implements pre-installed disconnect switches and isolation mechanisms that can be activated during daytime before maintenance work begins. This preliminary disconnection ensures that when maintenance personnel work on the system during the day, the modules are already isolated and de-energized, eliminating the need to wait for nighttime when lighting is poor.
4Reliability
If a watchdog system monitors communication signals to detect anomalies, then system safety is improved, but device complexity increases
Solution Approach 1:
The patent combines the watchdog monitoring function with the existing module communication and control circuitry. The same communication bus and microcontroller units used for normal system operation are also employed to monitor for anomalies such as unexpected disconnects, communication failures, or abnormal voltage levels. This merging of monitoring functions with existing system components achieves enhanced safety without adding separate complex watchdog hardware.
Solution Approach 2:
The patent implements multi-functional communication protocols where the data communication channels serve dual purposes: normal system control/monitoring and anomaly detection for safety. The same communication infrastructure used for routine operations is leveraged to detect watchdog conditions, eliminating the need for dedicated separate monitoring channels or additional complex safety infrastructure.
Data Source
AI summary
A system and method for automated shutdown, disconnect, or power reduction of solar panels. A system of solar panels includes one or more master management units (MMUs) and one or more local management units (LMUs). The MMUs are in communication with the LMUs with the MMUs and LMUs “handshaking” when the system is in operation. The MMUs are connected to one or more controllers which in turn are connected to emergency detection sensors. Upon a sensor detection of an emergency, the associated MMU is notified which in turn instructs associated LMUs to take appropriate action. In the event that communication with the MMUs has been cut off, the LMUs take the initiative to shut down, disconnect, or reduce the output of associated string(s) of solar panels.