Wind Turbine Drivetrain Vibration Analysis

Evaluates drivetrain vibration health across three subsystems: main bearing, gearbox, and generator.

When to Use

Load this skill when the user wants to:

Assess drivetrain vibration health from CMS or SCADA data
Interpret RMS, peak-to-peak, or spectral findings for main bearing, gearbox, or generator
Correlate vibration alarms with operational events
Decide whether to continue operating, increase monitoring, or shut down

Drivetrain Components

| Component | Sensor Location | Key Frequencies | |-----------|----------------|-----------------| | Main Bearing | Non-drive end, drive end | BPFO, BPFI, BSF, FTF | | Gearbox LSS | Low speed shaft | Gear mesh (LSS x teeth), bearing defect freqs | | Gearbox IMS | Intermediate shaft | IMS gear mesh harmonics | | Gearbox HSS | High speed shaft | HSS gear mesh, bearing defect freqs | | Generator NDE | Non-drive end bearing | Electrical harmonics, bearing defect freqs | | Generator DE | Drive end bearing | Bearing defect freqs, rotor unbalance |

Vibration Thresholds (ISO 10816 / CMS Reference)

| Location | Normal | Warning | Critical | |----------|--------|---------|----------| | Main Bearing RMS (g) | < 0.3 | 0.3 - 0.8 | > 0.8 | | Gearbox HSS RMS (g) | < 0.5 | 0.5 - 1.5 | > 1.5 | | Gearbox LSS/IMS RMS (g) | < 0.3 | 0.3 - 1.0 | > 1.0 | | Generator RMS (g) | < 0.5 | 0.5 - 1.2 | > 1.2 | | Peak-to-peak step change | < 10% | 10-30% | > 30% |

Note: Always evaluate against site-specific baseline. A 20% rise from stable baseline is more significant than an absolute value alone.

Frequency Fault Signatures

| Fault | Frequency Signature | |-------|-------------------| | Bearing outer race (BPFO) | (N/2) x (1 - d/D x cos a) x RPM | | Bearing inner race (BPFI) | (N/2) x (1 + d/D x cos a) x RPM | | Gear mesh | number of teeth x shaft RPM | | Gear mesh sidebands | GMF +/- shaft frequency | | Rotor unbalance | 1x RPM dominant | | Misalignment | 2x RPM dominant, axial component | | Looseness | Sub-harmonics (0.5x, 1.5x) or high harmonic content |

Severity Scale

| Severity | Label | Description | Action | |----------|-------|-------------|--------| | 1 | Healthy | All values normal, stable trend | Continue normal operation | | 2 | Early warning | 1-2 parameters in warning zone, stable | Increase CMS polling frequency | | 3 | Moderate | Multiple warning flags or single critical | Inspect within 2 weeks | | 4 | Significant | Critical zone or rapid trend growth | Plan shutdown within 48-72 hours | | 5 | Critical | Multiple critical flags, step-change | Immediate shutdown required |

Procedure

Collect inputs: CMS trend (last 30-90 days), current RMS and peak-to-peak per component, frequency spectrum findings, SCADA alarms, operational context.
Evaluate RMS values against thresholds. Flag Warning or Critical zones.
Analyze trend:
- Stable: value in warning zone but flat for >30 days = lower urgency
- Gradual rise: value increasing steadily = schedule inspection
- Step change: sudden jump >30% = treat as Critical regardless of absolute value
Interpret frequency spectrum if available:
- Match dominant peaks to fault signatures table
- Note sidebands around gear mesh frequencies
- Note sub-harmonics or 1x/2x dominance
Correlate with SCADA alarms and operational events.
Assign severity per component, then determine drivetrain-level severity as highest.
Generate output report using the format below.

Output Format

=== DRIVETRAIN VIBRATION REPORT ===

ASSET : [Turbine ID] SITE : [Site name] DATA PERIOD : [Date range of CMS/SCADA data] MISSING DATA : [List any unavailable inputs]

MAIN BEARING: RMS : [value] g - [Normal / Warning / Critical] Trend : [Stable / Gradual rise / Step change] Spectrum : [Key findings or not available] SCADA Alarms : [Count and type] Severity : [1-5] - [Label]

GEARBOX (LSS / IMS / HSS): RMS : LSS [value] g / IMS [value] g / HSS [value] g Trend : [per shaft] Spectrum : [Key findings] SCADA Alarms : [Count and type] Severity : [1-5] - [Label]

GENERATOR (DE / NDE): RMS : DE [value] g / NDE [value] g Trend : [per bearing] Spectrum : [Key findings] SCADA Alarms : [Count and type] Severity : [1-5] - [Label]

DRIVETRAIN SEVERITY : [1-5] - [Label] SHUTDOWN : [Yes / No / Conditional]

FAULT HYPOTHESIS:

[e.g., HSS bearing outer race defect - BPFO peak confirmed at X Hz]
[e.g., Gear mesh sideband modulation - possible gear wear or load variation]

RECOMMENDED ACTIONS:

[e.g., Increase CMS polling to daily for HSS channel]
[e.g., Oil sample with ferrography within 72 hours]
[e.g., Plan HSS bearing replacement at next scheduled outage]

ESCALATION TRIGGERS:

[e.g., RMS exceeds 1.5 g on HSS - immediate shutdown]
[e.g., Step change >30% on any channel - treat as critical]
[e.g., New BPFO or BPFI peak confirmed in spectrum - escalate to Severity 4]

Cross-Skill Correlation

If gearbox visual data is available, load wind-turbine-gearbox skill and cross-correlate:

High Fe ppm + rising HSS vibration = active wear confirmation
Spalling in borescope + BPFO peak in spectrum = bearing failure progression
Normal oil + rising vibration = early fault not yet generating debris (higher urgency)

If blade inspection data is available, check for rotor imbalance:

1x RPM dominant in main bearing spectrum + blade damage = aerodynamic imbalance
Asymmetric blade damage across A/B/C = mass or aerodynamic imbalance source

Pitfalls

Do not evaluate vibration in isolation. Cross-reference with oil analysis and visual inspection.
A single high RMS reading during a storm or grid fault is not a fault indicator. Check operational context.
Spectrum analysis requires RPM-normalized data. Raw frequency peaks are meaningless without shaft RPM.
Generator electrical faults can appear as vibration. Check electrical data before attributing to mechanical cause.
Stable high RMS is less urgent than rapidly rising moderate RMS. Trend rate matters more than absolute value.

Verification

After generating the report, confirm with the user:

Does the severity match CMS system alerts or OEM recommendations?
Is shaft RPM data available to normalize spectrum frequencies?
Are there recent maintenance events that could explain vibration changes?
Is SCADA power curve deviation consistent with vibration findings?