A solar plant without monitoring is a revenue leak you can't see. Performance ratio degradation, partial shading from soiling, string failures and grid curtailment events can reduce a plant's output by 5–20% before they show up in a monthly energy report. Real-time monitoring — with the right alerts, KPIs and fault detection — catches these issues in hours, not months. This guide covers what to monitor, how Sungrow's iSolarCloud platform works, and when to consider SCADA or third-party systems.
The key performance indicators to track
Every monitoring system should track these core metrics:
| KPI | Formula | Alert threshold |
|---|---|---|
| Performance Ratio (PR) | Actual yield / (Irradiance × Rated capacity) | PR < 75% over 7 days → investigate |
| Specific yield | kWh generated / kWp installed | Benchmark vs. P50 model |
| Inverter availability | % of time inverter is online and generating | < 98% → fault investigation |
| String current deviation | Actual string Isc vs. expected at measured irradiance | > 10% deviation → soiling or fault |
| PR vs. temperature-corrected PR | Adjusted for cell temperature | Separates weather effect from real degradation |
| Export limitation events | Hours curtailed × power curtailed | Track for grid operator compliance and lost revenue claim |
Sungrow iSolarCloud
iSolarCloud is Sungrow's native cloud monitoring platform, included free with all Sungrow inverters and BESS. It connects via 4G/LTE logger, Ethernet, or Wi-Fi dongle on the inverter or logger unit.
What iSolarCloud monitors
- Plant-level: Total generation, CO₂ offset, PR, specific yield, irradiance (if sensor connected)
- Inverter-level: AC/DC power, voltage, current, frequency, temperature, efficiency, fault codes
- String-level: Individual string current and voltage for each MPPT input (diagnostic view)
- BESS-level: State of charge (SoC), charge/discharge power, cell temperatures, cycle count
- Environment: Irradiance (W/m²), ambient temperature, wind speed if connected to sensors
Alert types in iSolarCloud
- Inverter fault (hardware failure, communication loss, grid fault)
- String current anomaly (one string significantly below others at same irradiance)
- Over-temperature alert (inverter or BESS cells above threshold)
- Grid voltage/frequency excursion
- Export limiting active (curtailment notification)
Alerts are delivered via SMS, email, or push notification to the iSolarCloud app. The platform stores 25 years of data and provides automated monthly/annual reporting templates — useful for investor reporting and O&M KPI tracking.
When to add a separate SCADA system
iSolarCloud handles most monitoring needs for projects up to ~10 MW. Above that — or when the plant needs to integrate with a broader site energy management system — a dedicated SCADA solution makes sense.
| Scenario | iSolarCloud sufficient? | SCADA needed? |
|---|---|---|
| Single-site C&I (< 5 MW) | Yes | No |
| Multi-site portfolio (same owner) | Yes — multi-site view | Only if cross-site automation needed |
| Utility > 10 MW with grid operator telemetry | Partial | Yes — grid operators require certified SCADA with dedicated communication |
| Hybrid microgrid (solar + BESS + diesel + load) | No | Yes — EMS/SCADA for dispatch optimisation |
| IPP with revenue metering and balancing group | No | Yes — balancing group management requires SCADA integration |
Sungrow iSolarCloud SCADA integration
Sungrow supports Modbus RTU/TCP, IEC 60870-5-104, and IEC 61850 communication protocols for integration with third-party SCADA systems. The SG320HX-20 also supports PLC (Power Line Communication) for plant-level communication without separate cabling. For utility projects, Sungrow provides a dedicated Plant Controller (PC) unit that aggregates data from all inverters and communicates to the grid operator's SCADA system in the required format.
Third-party monitoring platforms
Several third-party platforms (Solar-Log, SMA Sunny Portal, AlsoEnergy, Powerfactors) support Sungrow inverters via Modbus. These are relevant when you have a mixed-brand plant or when a portfolio owner wants one dashboard across inverters from multiple manufacturers. For single-brand Sungrow plants, iSolarCloud is typically superior — it has deeper data access to Sungrow hardware than any third-party integration can achieve.
Remote O&M: what good monitoring enables
- Predictive maintenance: Trend analysis on inverter temperatures and string currents can predict component failures 2–4 weeks before they cause downtime.
- Remote firmware update: iSolarCloud pushes firmware updates to all connected inverters simultaneously — no site visit required for most software patches.
- Soiling detection: Comparing PR across strings in the same row reveals differential soiling. A consistent PR drop in one section indicates cleaning is needed in that zone, not across the whole plant.
- Yield guarantee verification: For EPC contracts with yield guarantees, monitoring data provides an audit trail for P50/P90 performance verification and insurance claims.