PV Inverter Linkage Control for Anti-PID and Insulation Monitoring
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Solution Overview
Problem
Photovoltaic power stations face challenges with potential-induced degradation (PID) and insulation faults, where existing systems often cannot simultaneously address both issues due to interference between anti-PID and insulation-monitoring modules.
Innovation Solution
A linkage protection system that integrates both anti-PID and insulation-monitoring modules, allowing them to alternate operations to prevent interference, using communication protocols like Modbus or dry contacts to coordinate their actions and avoid false alarms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If both anti-PID module and insulation-monitoring module are configured in the photovoltaic power station, then both PID problem and insulation fault problem can be addressed, but the two modules interfere with each other when operating simultaneously
Solution Approach 1:
The patent implements periodic action by dividing operation into alternating time periods: during first time periods the anti-PID module operates while the insulation-monitoring module is disabled, and during second time periods the insulation-monitoring module operates while the anti-PID module is disabled. This periodic switching eliminates mutual interference between the two modules while ensuring both functions are periodically performed, thereby maintaining system reliability without generating harmful interference effects.
2Reliability
If the anti-PID module operates continuously, then PID protection is maintained, but the insulation-monitoring module cannot detect insulation faults due to interference
Solution Approach 1:
The system employs periodic action by scheduling the anti-PID module to operate during first time periods and the insulation-monitoring module to operate during second time periods. This ensures that PID protection is continuously maintained through periodic anti-PID operations, while insulation fault detection accuracy is preserved by performing insulation measurements during dedicated time periods when the anti-PID module is not injecting interfering signals.
3Measurement precision
If the insulation-monitoring module operates continuously, then insulation faults are detected, but false alarms occur due to interference from the anti-PID module
Solution Approach 1:
The patent applies periodic action by enabling the insulation-monitoring module to operate during second time periods when the anti-PID module is disabled, and disabling the insulation-monitoring module during first time periods when the anti-PID module operates. This periodic scheduling ensures insulation monitoring accuracy by performing measurements when no interference is present, while simultaneously eliminating false alarms caused by anti-PID module interference.
4Reliability
If both modules operate simultaneously, then complete protection and monitoring coverage is achieved, but the voltage injected by anti-PID module is detected by insulation-monitoring module causing false alarms
Solution Approach 1:
The system implements periodic action by alternating the operation of the anti-PID module and insulation-monitoring module in different time periods. During first time periods, the anti-PID module operates to provide PID protection while the insulation-monitoring module remains disabled. During second time periods, the insulation-monitoring module operates to detect insulation faults while the anti-PID module is disabled. This ensures complete protection and monitoring coverage through periodic execution of both functions, while eliminating false alarms by preventing simultaneous operation that would cause measurement interference.
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 effectively mitigates PID and insulation faults, enhancing power generation efficiency and ensuring safety by allowing both modules to operate independently while coordinating their activities.
Implementation Method 1
The anti-PID module is configured to inject a voltage into an input end or an output end of an inverter, to increase or decrease a voltage-to-earth of a photovoltaic system
Implementation Method 2
The insulation-monitoring module is configured to inject an insulation-monitoring voltage into a direct current (DC) side or an alternating current (AC) side of the inverter, to monitor an insulation fault of the system
Data Source
AI summary
A linkage protection system includes an inverter, an anti-potential-induced degradation (PID) apparatus, and an insulation-monitoring apparatus. The anti-PID apparatus is configured to inject a voltage into an input end or an output end of the inverter, to increase or decrease a voltage-to-earth of a photovoltaic system. The insulation-monitoring apparatus is configured to inject an insulation-monitoring voltage into a direct current (DC) side or an alternating current (AC) side of the inverter. The anti-PID apparatus and the insulation-monitoring apparatus directly or indirectly communicate with each other, to learn of information about whether a peer apparatus is operating, and perform linkage control. The anti-PID apparatus and the insulation-monitoring apparatus operate in different time periods.