PV Inverter PID Detection Using Existing Sensors
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Solution Overview
Problem
Existing methods for detecting potential-induced degradation (PID) in photovoltaic (PV) modules are often ineffective due to their subtle and progressive nature, leading to irreversible damage and reduced efficiency in PV installations.
Innovation Solution
A method that operates the PV generator at specific voltage ratios relative to the maximum power point, using existing current and voltage sensors to determine a characteristic quantity Y, which indicates the progress of PID, without requiring additional sensors for ambient conditions, allowing for early detection and minimal impact on power generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional sensors for ambient conditions are used to detect PID, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The PV inverter uses its existing current and voltage sensors to measure operating points and calculate the characteristic quantity Y, making the system self-sufficient for PID detection without requiring external sensors for ambient conditions
Solution Approach 2:
The existing current and voltage sensors in the PV inverter are made multi-functional by using them not only for power conversion control but also for PID detection through characteristic quantity calculation
2Measurement precision
If the PV generator is operated at reduced power for measurement, then measurement precision is improved, but productivity decreases
Solution Approach 1:
The method uses partial action by operating the PV generator at reduced power only temporarily during measurement passes to determine the characteristic quantity Y, while maintaining normal operation at maximum power point for the majority of time, thus achieving sufficient measurement precision with minimal impact on overall productivity
3Reliability
If early detection of PID is implemented, then reliability is improved, but loss of time for system operation increases
Solution Approach 1:
The PV inverter performs periodic measurement passes at intervals (e.g., daily, weekly, or monthly) to monitor the characteristic quantity Y, enabling early detection of PID progression while minimizing the time lost to measurements by conducting them only at scheduled intervals rather than continuously
Data Source
AI summary
A method for detecting a potential-induced degradation (PID) of PV modules of a PV installation includes operating a PV generator at a maximum power point (MPP), at a first generator voltage (U1) and first generator current (I1), and at a second generator voltage (U2) and second generator current (I2), where a first power (P1) at the first generator voltage (U1) is in a predefined first ratio V1=P1/PMPP and V1≤1, with the power (PMPP) at the maximum power point (MPP) of the PV generator, and where a second power (P2) at the second generator voltage (U2) is in a predefined second ratio V2=P2/P1 and V2<1, with the first power (P1) of the PV generator, and where a quantity Y that characterizes a progress of the potential-induced degradation (PID) is determined from the values of the voltages (U1, U2) and/or the currents (I1, I2).