Flight Leader Concept for Wind Farm Load Counting and Performance Assessment

Tom Obdam

2

Contents

• Introduction

• O&M Cost Estimator

• Flight Leader concept

• Flight Leader software

• Evaluation

• Conclusions

• Questions

3

Introduction

• O&M costs 25-30% kWh price

• O&M optimisation required!

• Analyse and use operational data• Maintenance sheets• Vessel usage• Condition monitoring systems• Oil inspections• Mechanical load measurements• …

4

O&M Cost Estimator

• Building Blocks for analysing the various data sources

• BB ‘Loads & Lifetime’ processes mechanical load measurements

OMCE Calculator

Condition Based

Maintenance

Unplanned Corrective

Maintenance

Calendar Based

Maintenance

BB Operation & Maintenance

INFORMATION

INFORMATION

DATA RESULTS

BB Logistics

BB Health Monitoring

BB Loads & Lifetime

5

Flight Leader concept (1)

Keep track of the (relative) accumulated loading at all turbines in an (offshore) wind farm

Possibilities:

• Equip all turbines with mechanical load measurements• Expensive, time consuming and labour expensive

• Flight Leader concept• Less expensive, less time consuming and less labour

intensive!• BUT: Concept needs to be proven

6

Flight Leader concept (2)

• Only few turbines at strategic locations equipped with mechanical load measurements

• Relations between load indicators and SCADA parameters

• Combining relations with SCADA data collected at all turbines

7

Flight Leader concept (3)

What needs to be proven?

• It is possible to establish accurate relations between SCADA parameters and load indicator

• It is possible to transpose the relations established at the Flight Leader turbines on the other turbines in the wind farm

8

Flight Leader model

Software model has been developed

• Includes all aspects of the Flight Leader concept

• Intended for offshore wind farm owners/operators

• Demo version applied at ECN’s wind farm EWTW

Categorisation module

Characteristic load module

Accumulated load & output module

Empirical DBmodule

SCADA data

Mechanical load

measurementsPre-processing

Data input

Generation of output

Simulated DB

9

Evaluation (1)

• Proving the Flight Leader concept• It is possible to establish accurate relations between SCADA

parameters and load indicators• It is possible to transpose the relations determined at the Flight

Leader turbines on the other turbines in the farm

• Preliminary results using data from ECN’s wind farm EWTW• 5 multi-MW pitch-controlled variable speed turbines• 24 months of data

10

Evaluation (2)

• Load indicator: • 1 Hz equivalent load

– Tower bottom for-aft bending– Blade root flapwise bending– Main shaft bending– High speed shaft torque

• SCADA parameters: • 10-minute statistics (avg, std, skew, kurt)

– Power output– Generator speed– Pitch angle (only avg & std)

Target

11

Evaluation (3)

• Relation:• Load indicator: Tower for-aft• Method: Artificial neural network• Target: measured value• Output: model prediction

• Data:• Training: T6 (blue)• Validation: T8 (red)

• Results:• Accurate & Generalisable

12

Evaluation (4)

• Next:1. Estimate load indicators all

five turbines

2. Calculate and compare load accumulation

• Results:• Turbine 3 has accumulated

most loading• No large (>> 10%)

differences observed

13

Evaluation (5)

• Breakdown of load accumulation• Large contribution from

emergency shutdowns• Partial wake operation leads to

significantly higher load accumulation

• During winter significantly more load accumulation occurs

14

Evaluation (6)

• For power production accuracy encouraging

• Largest prediction error for parked/idling

• Most larger prediction errors only marginally contribute to total load accumulation

Load cases:

1. Power production & free-stream

2. Power production & partial wake

3. Power production & full wake

4. Parked/idling

5. Start-up

6. Normal shutdown

7. Emergency shutdown

15

Conclusions

• O&M optimisation is necessary for lowering the kWh price of offshore wind energy

• Load monitoring could contribute to optimisation BUT: expensive, time consuming and labour intensive

• Flight Leader concept could prove a low-cost solution for monitoring the load accumulation at all turbines BUT: concept needs to be proven…

• Prove of concept using EWTW data Initial results look promising!

• Still some work to do… Include aero-elastic simulations Data analysis offshore wind farm OWEZ