Megamic’s Wireless String Monitoring Solution

Problem statement:

Megamic was challenged with a requirement to Implement a Wireless Monitoring System for individual String currents of close to 3500 strings spread across an area of about 70 acres. This was for one of India’s oldest Solar Power Projects built without any String Monitoring Infrastructure.

There were close to 320 String Combiner boxes without any shunt or hall effect sensors for monitoring currents. Another big challenge was the lack of RS485 cabling for communication of the combiner boxes with Control room.

Megamic’s Solution:

: Replaced all the legacy String Combiner Boxes with Megamic’s Wireless String Monitoring Boxes. Due to operational constraints all the replacement activities were carried out during non-generation hours (after sunset)

: Established Wireless communication across the 70 acre area with 100% coverage of all SMBs

: Installed Megamic’s proprietory SolarNxt software for String Monitoring in the Main Control Room

Hardware Solution Highlights:

: Solution retrofits into existing mounting structure 

: Individual String Current reading accuracy of better than 0.7%

: Includes inside ambient temperature readings of the SMB

: Supports Two additional PT-100 sensors for taking temperature inputs from nearby Solar PV modules

: No need of external Antennas

: 27 dBm Wireless Signal strength operating in License free band of Indian spectrum

: Directly communicates with SCADA via Modbus-TCP

: Redundant Power supply and Controller in the central Gateway

Megamic’s String Monitoring Box

Megamic’s Wireless RS485 Transceiver

SolarNxt String Monitoring Solution Highlights:

: Single Software for Monitoring, Performance analysis and Diagnostics

: Intuitive plots to monitor underlying trends

: Detection of shadows and soiling

: Heatmaps for comparison of SMBs as well as individual strings

: Fuse blown and Temperature alerts for abnormal SMBs identification

: End of Day Daily performance reports auto-email feature to configurable email IDs

SolarNxt : HeatMap view of SMB performance across the plant

SolarNxt : HeatMap view of String Currents along with actual figures and colour coded deviation

SolarNxt : Time series view of a particular SMB’s String current for a day

SolarNxt : Alerts Screen showing “Isolator”, “FuseLink”, “SPD Blown”  along with other status

Value Add to Customer

Individual String performance monitoring is essential to ensure at grass root level the Solar PV Plant is performing as expected. For Solar PV Plants without such a monitoring infrastructure, Megamic’s solution brings significant value with its hardware retrofit as well as software solution with  String performance analysis, real time Alerts and advanced reporting Feature.

Any string underperformance is instantly reported, any abnormal heat generation within a SMB due to a loose bus bar connection or a faulty Isolator switch or any other reason is instantly flagged. Clubbed with Irradiance data, the losses can also be quantified in kW-h. All of this without a need for RS485 wiring is an additional advantage. 

About Megamic

Megamic provides Monitoring, Analytics, Diagnostics And Asset Management Capabilities to O&M Teams and asset owners to Improve their ROI on large scale distributed solar PV Plants through its innovative portfolio of field proven products and solutions ranging from Dataloggers, String Monitoring Units, smart SCADA panels, Plant Power Controllers, Zero Export Controllers and SolarNxt – Cloud based solution.