Site I.6

Health
COD
2016
Nominal Capacity
40 kWp
Yield since COD
600 kWh/kWp
Possible Gain
13% to 16%
CAPEX, OPEX
0.8 ₹/Wp, 1.5 ₹/Wp/a

Abstract

The PV plant shows design failures such as the disregard of the inter-row and near shadings, inverter tripping and a strong deviation towards SW that reduces significantly the amount of the solar resource. It is recommended to (i) shorten the strings to mitigate the tripping and shading effects (ii) change the module tilt to 15°, increase the cleaning frequency based on a previous study the adjust the needs to the dry and wet season, and (iii) increase the albedo using white gravel and sticking reflective materials to the walls and shading objects. The estimated production boost caused by the retrofitting actions lies between 13% and 16%.

Image gallery

Main Findings

The near shading effects were not considered during the design phase and are the main issue of this system. The modules were installed surrounded by walls, antennas and building structures that induce hotspots and inactivity of individual cell strings.
In the area of the system where two module rows are installed, the inter-row losses are significantly higher.
The modules have been installed with an azimuth deviation of 60° towards South West.
Moderate soiling was detected on site.
The inverter configuration generates constant tripping losses due to the high amount of modules connected in series.

Impact on Performance

Near Shading

The near shading lead to irradiation losses on the module surface of around 8%

Estimated Loss
≈ 8%
Soiling

Soiling measurements were conducted measuring both the short circuit current and nominal power before and after cleaning at irradiations higher than 900 W/m2. The estimated soiling factor is in the range 1 – 4%.

Estimated Loss
1%-4%
≈ 2.5%
Deviation from South

The strong azimuth deviation leads to an irradiation loss of around 7%.

Estimated Loss
≈ 7%
Total Estimated Energy Loss
≈ 17.5%

Proposed Solutions

The cleaning cycles shall be increased and defined based on a soiling study that adjusts the cleaning needs to each season.
It is recommended to shorten the strings in order to reduce the tripping and mitigate the impact of the near shading losses. A DC/DC converter at the inverter input may be needed. This could represent a 2-3% performance boost.
The walls close to the shaded areas shall be covered with reflective material and the ground re-painted in order to increase the albedo effect. A performance boost of at least 5% is expected.
A modification of the tilt angle to 15° would increase the irradiation on the module surface by at least 1.5%.