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

1. 1. Collect inputs: CMS trend (last 30-90 days), current RMS and peak-to-peak per component, frequency spectrum findings, SCADA alarms, operational context.
2. Evaluate RMS values against thresholds. Flag Warning or Critical zones.
3. 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

1. 4. 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

1. 5. Correlate with SCADA alarms and operational events.
2. Assign severity per component, then determine drivetrain-level severity as highest.
3. 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?