Retrofitment of String Monitoring Boards (SMBs): Ensuring Reliability in Solar Operations
Introduction
In the lifecycle of a solar power plant, accurate monitoring at the string level is critical for ensuring maximum energy yield and operational reliability. String Monitoring Boards (SMBs) play a vital role in detecting underperforming strings, identifying faults, and enabling timely corrective action.
However, in many projects across India, SMBs are either not considered during the initial engineering stage due to stringent budgets, or their importance is overlooked in favor of minimizing upfront capital expenditure. As a result, the need for retrofitment of SMBs often arises later, once the plant is operational and real-world challenges begin to surface.
Why SMBs Are Skipped Initially
EPCs and developers frequently face tight project budgets and competitive bidding pressures. In such cases, string monitoring is sometimes treated as a “non-critical” feature and excluded to reduce initial costs. While this decision may appear cost-effective at the project stage, the long-term impact becomes evident during the Operations and Maintenance (O&M) phase, where detecting faults at the string level without SMBs is highly inefficient.
The Human Limitation in String-Level Detection
Without SMBs, fault detection relies heavily on manual inspection. Identifying an issue at the string level can take several hours to days, depending on the size of the plant. For instance, in a 50 MW solar plant with more than 1,500 strings, it may take a team 2–3 days to physically check all connections and isolate the underperforming string.
During this delay, the plant continues to operate sub-optimally. A single string failure in a 50 MW plant can result in generation losses of 20–30 kWh per day. Multiplied across multiple strings and days of delay, the cumulative loss can run into thousands of kilowatt-hours, directly affecting revenues.
By contrast, a digitally enabled SMB can identify the fault in real-time, minimizing both downtime and financial loss.
Other Scenarios Requiring Retrofitment
Retrofitment is not only relevant for projects that initially skipped SMBs. It is also required in cases where SMBs were installed during the project stage but later became ineffective due to external reasons, such as:
- OEMs discontinuing support due to company closure or product line changes.
- Obsolescence of components, making replacements unavailable.
- Design inefficiencies, leading to heat rise or unreliable performance over time.
In these situations, replacing or upgrading SMBs with retrofit solutions ensures that the plant continues to benefit from string-level monitoring.
What Is Retrofitment of SMBs?
Retrofitment refers to upgrading or replacing existing components within the String Combiner Boxes (SCBs) by installing new or modified string monitoring cards. The process leverages the existing infrastructure while introducing advanced monitoring capabilities.
SuryaLogix specializes in providing retrofitment solutions for multiple makes and types of SMBs. The process begins with a detailed study of the existing SCB structure to determine the most efficient mounting positions for the SMBs while ensuring that heat rise does not occur. If required, SuryaLogix also redesigns the printed circuit boards (PCBs) to suit available space, delivering a customized, efficient, and reliable retrofitment solution.
Linking Digital Analysis with Retrofitment
Once SMBs are retrofitted, they integrate seamlessly with digital monitoring platforms. This allows O&M teams to:
- Detect string faults instantly.
- Analyze performance trends across strings.
- Accurate Performance Analytics: Minimizes errors in PR calculation, generation forecasting, and benchmarking.
- Minimize generation loss by enabling proactive maintenance.
For example, in a 25 MW plant retrofitted with SMBs, SuryaLogix’s digital monitoring revealed string-level mismatches that had previously gone undetected for weeks. After retrofitting, corrective action reduced the annual energy loss by nearly 1.5%, a significant improvement in overall PR.
Conclusion
Skipping SMBs during the initial project stage may save costs upfront, but it often leads to greater losses during plant operation. Retrofitment offers a cost-effective and technically sound pathway to upgrade existing plants, ensuring real-time string-level monitoring, reduced downtime, and improved generation reliability.
With expertise in customized design, PCB adaptation, and multi-make compatibility, SuryaLogix delivers retrofitment solutions that extend the life and efficiency of solar assets. By combining field expertise with digital analysis, SuryaLogix helps EPCs, developers, and O&M teams unlock the full potential of their solar investments.
