Using Inverter Logs for Legal and Insurance Claims

Use SUN2000 inverter logs as tamper-proof evidence for grid overvoltage claims, power curtailment compensation, warranty disputes, and access audits.

Inverter logs function as a flight recorder for your solar installation. The Huawei SUN2000 writes timestamped records of every grid abnormality, every forced curtailment command, every protection event, and every user login to non-volatile memory that cannot be altered after the fact. When a dispute arises — whether with the grid operator, an insurer, or a maintenance contractor — these logs provide the kind of precise, time-stamped evidence that verbal accounts and manual site inspection reports cannot match.

Grid overvoltage claims

When the grid voltage rises above the inverter’s configured protection threshold (typically 253 V on a 230 V nominal grid), the inverter disconnects automatically to protect itself and complies with grid code requirements. Each such event is recorded in alarmg_history with the exact timestamp of the onset and the time of recovery.

If your plant experiences frequent “Grid Overvoltage” alarms, export alarmg_history and count the events over a representative period — a few months is usually sufficient to demonstrate a pattern. Present this report to your grid operator as evidence that the local distribution transformer or line is consistently operating out of specification. A documented history of hundreds of such events is difficult to dispute and provides the factual basis to demand infrastructure upgrades: transformer tap adjustment, line reinforcement, or reactive power compensation equipment.

Power curtailment compensation

When a grid dispatcher issues a forced generation limit through a SmartLogger, the command and its effect are recorded in grid_adj_log. This log captures the exact time the curtailment started, the level to which generation was reduced, and when the limit was lifted. Using the generation data from perfmg_data alongside grid_adj_log, you can calculate the precise kWh you were prevented from generating and apply your feed-in tariff or PPA rate to arrive at the lost revenue figure for a compensation claim.

grid_adj_log is only available on sites equipped with a SmartLogger. On sites connected exclusively via SDongle, this log is not generated. As an alternative, use register 32080 (Active Power) from the his_inv_rd archive: compare the recorded power output during the curtailment window against the expected output based on irradiance data from the same period.

Export your logs within 30 to 90 days of any incident. The SUN2000 uses a circular buffer (FIFO) in its internal flash memory. Once the buffer fills, the oldest records are overwritten by new data. Logs older than 30 to 90 days — depending on the inverter model and logging frequency — may no longer be recoverable.

Warranty claims

When an inverter component fails, the key question for a warranty claim is whether the failure was caused by an internal defect or by an external event such as a lightning surge. The dsp_wave_data log records the oscillographic waveform of voltage and current at millisecond resolution in the moments immediately before a protection event triggers.

An internal defect typically produces a clean fault signature with no preceding voltage spike. An external lightning surge or switching transient leaves a clearly visible impulse on the waveform before the failure. Present dsp_wave_data to the Huawei service team or your insurer alongside the fault record from alarmg_history: together, they establish the cause of failure with a level of precision that no post-event inspection can provide.

Unauthorized access disputes

The usrmg_usrlog_2 log records every login to the inverter’s management interface: the username, the timestamp, and the interface used (for example, Bluetooth via the FusionSolar app). This log resolves a common dispute in O&M: did the inverter shut down due to an internal fault, or did a service technician issue a manual shutdown command?

If a contractor denies having issued a command, or if a plant owner suspects that settings were changed without authorization during a site visit, usrmg_usrlog_2 provides a verifiable record. Combined with alarmg_history and cfg_file_ctrl (which records configuration changes), you can establish exactly who accessed the inverter, when, and whether any settings were modified.