GB/T 39857-2021 in English
VALIDSpecification of photovoltaic power generation efficiency
- Issued on:2021-03-09
- Implemented on:2021-10-01
- File Format:PDF
- Delivery:Via email within 1~3 business days
$243.00
《GB/T 39857-2021光伏发电效率技术规范》由524（中国电力企业联合会）归口，主管部门为中国电力企业联合会。
Introduction
Interpretation of the core content of the standard
GB/T39857-2021 systematically stipulates the full-link efficiency evaluation system of photovoltaic power generation for the first time, focusing on the efficiency indicators of key equipment such as photovoltaic modules and inverters, as well as system-level parameters such as system energy efficiency (PR) and mismatch rate.
Comparison of key technical requirements
| Indicators | Crystalline silicon modules | Thin film modules | Test conditions |
|---|---|---|---|
| Initial efficiency | ≥17.8%(single crystal)/17%(polycrystalline) | ≥12% | STC conditions(1000W/m²,25℃) |
| Annual attenuation rate | ≤3% in the first year, ≤0.7% in the subsequent years | ≤5% in the first year, ≤0.4% in the subsequent years |
Innovation in test methods
Mismatch rate test technology
The standard innovatively proposes a synchronous online test method:
- The series mismatch rate test requires a sampling frequency ≥10kHz
- The parallel mismatch rate test needs to cover all input branches of the combiner box
- The current/voltage deviation rate dual indicators are introduced to evaluate the consistency of the string
Efficiency test case
The measured data of a 100MW power station shows:
- Component dust loss rate: 3.2%-5.8% (Northwest region)
- String parallel mismatch rate: 1.7% (after optimized layout)
- Inverter weighted efficiency: 98.5% (1500V system)
Standard implementation recommendations
- Equipment selection phase: give priority to components with an efficiency degradation rate lower than 20% of the standard limit
- System design phase: control the parallel mismatch rate to ≤1.5% through string current grading
- Operation and maintenance phase: establish an efficiency degradation early warning mechanism, and start special testing when the annual degradation of the component exceeds 0.5%
Technology evolution analysis
The main improvements of this standard compared with the previous version:
- Added a thin-film component efficiency evaluation system
- Clarified the test requirements for the 1500V system
- Introduction of Intelligent IV Diagnosis Technical Specifications
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