Scheduled and corrective maintenance inputs

The maintenance tasks you define here form a critical part of your O&M cases. The main characteristics of scheduled and corrective maintenance tasks are as follows:

• Scheduled maintenance
  • Downtime only occurs during repair time.
  • Work orders are released with a fixed recurrence.
  • The minimum recurrence of the tasks is once a year.
  • Specify detailed yearly distributions:
    • On all instances of an asset.
    • On a fixed percentage of instances.
• Corrective (unscheduled) maintenance
  • Downtime can occur from moment of failure, which triggers the creation of a work order.
    • Specify curtailment percentages to reduce the downtime of the turbine due to failure.
  • Failures follow a specific pattern according to a time-to-failure distribution. You can model failures by defining lifetime-distribution and failure-intensity parameters:
    • Exponential
    • Weibull or exponential time series
  • Configure corrective maintenance with an HLV or towing vessel to simulate a major component replacement (MCR)

The resolution of maintenance work orders depends on the availability of vessels and personnel with the required skills. Each task within the work order is defined by the repair time and associated costs.

You can define the required vessel types, limitations, personnel, repair times, and associated costs within the maintenance tabs.

For corrective maintenance, the vessel you select for the task will provide additional parameters.

It is possible to import maintenance tasks using a CSV file if you already have them defined outside the Shoreline platform.

Corrective maintenance for major component replacements

Major component replacements (MCRs) are a specialized type of maintenance work that requires additional parameters to configure within Shoreline.

Create a corrective maintenance task, select an HLV or towing vessel in the Vessel input of the task, and configure the HLV- or towing vessel-specific parameters to model an MCR. If you use a towing vessel, the maintenance task will also require a crane to complete the work.

Scheduled maintenance

Parameter	Required	Description
Campaign start date	x	When the scheduled maintenance work orders are released. The simulation counts from this date to the end of the calendar year to resolve the tasks. Any tasks not resolved contribute to an Average scheduled maintenance completion per year rate of under 100 percent in your output page.
Scheduling		Whether the maintenance is conducted across all instances of the asset at regular intervals or on a fixed percentage of instances per year.
Recurrence	x	Maintenance frequency. The number represents the time between tasks. 0 results in the task only occurring the first year; 1, every year; 2, every second year, etc.
Asset percentage		The percentage of assets to which the maintenance task is assigned per year.
Production impact during work		Curtailment of energy output on the affected asset from the time the first personnel enter the asset until the last personnel fix and restart the asset.
Vessel	x	Vessels required for the maintenance task. This includes personnel transportation (COV, SOV or helicopter) and vessels for conducting the maintenance. By default, Any member is checked, meaning any available vessel of this type that you have added to your case will be used for the task. Uncheck Any member to select individual vessels you have added to your case specifically for this task. Choose Remote only to simulate failures that can be reset from the control room.
Lead time	x	Note: Only applicable to remote-only tasks. The time the maintenance task remains open.
Limitations		Apply a weather limitation to the maintenance task. Weather limitations defined in the Weather criteria tab appear here.
Personnel	x	The skill and number of personnel required to conduct the maintenance task. Select the skills defined here when adding personnel groups in the personnel tab of your case.
Person hours time series		Caution: This is an advanced feature and recommended only for users with training on its use. Check this box to apply per-year person hours for the maintenance task, e.g., year 1 requires 4 hours, year 2 requires 8 hours, etc.
Total person hours	x	Total hours of work across all personnel involved.
Repair time		The total person hours divided by the number of personnel. This equates to the downtime reported due to repairs if no further weather limitations are defined.
Spare part cost		Any costs associated with replacement parts for the maintenance work.
Consumables		Any additional costs associated with the maintenance work.

Corrective maintenance

The table below details the inputs relevant to all scheduled maintenance tasks. There are additional parameters depending on the vessel used. You can find the additional parameters in the relevant section:

• CTV, SOV, and helicopter
• HLV
• Towing vessel
• Remote-only

General corrective maintenance inputs

Parameter	Required	Description
Severity		See the critical vs. non-critical failures section for full details.
Lifetime distribution		Statistical distribution (Weibull or exponential) of the failure.
Failure rate time series		Applies to exponential distributions. Define the failure rate per year. Leave unchecked if the failure rate is the same every year.
Annual failure rate	x	Constant annual rate of failure. Select Failure rate time series to set different values per year. This is an advanced feature. We recommend modelling this with a Weibull.
Production curtailment from failure	x	Note: Only applicable to critical failures. Percent of energy production lost during failure downtime.
Production curtailment during work		Percent of energy production lost during maintenance.
PBA loss calculations for other WTGs		Whether a turbine being disconnected for maintenance causes turbines downstream in the cable string to stop producing power. Requires WTGs with cables configured.
Vessel	x	Vessels required to conduct the maintenance.
Limitations		Apply a weather limitation to the maintenance task. Weather limitations defined in the Weather criteria tab appear here.
Personnel	x	The skill and number of personnel required to conduct the maintenance task. Select the skills defined here when adding personnel groups in the personnel tab of your case.
Person hours time series		Caution: This is an advanced feature and recommended only for users with training on its use. Check this box to apply per-year person hours for the maintenance task, e.g., year 1 requires 4 hours, year 2 requires 8 hours, etc.
Total person hours	x	Total hours of work across all personnel involved.
Repair time		The total person hours divided by the number of personnel. This equates to the downtime reported due to repairs if no further weather limitations are defined.
Spare part cost		Any costs associated with replacement parts for the maintenance work.
Consumables		Any additional costs associated with the maintenance work.

Critical vs. non-critical failures

Critical failure:

• Creates downtime from the moment of failure to the completion of maintenance work.
• Production doesn’t shut down: the turbine continues generating power. There are two additional inputs to define how much power is lost:
  • Production curtailment from failure
  • Production curtailment during work
• More failures cannot occur on the turbine until the maintenance work is complete.

Non-critical failure:

• Does not create downtime from the moment of failure, only during maintenance work.
• Production doesn’t shut down, except during maintenance. Power lost during maintenance is defined using the Production curtailment during work parameter.
• Further failures can occur on the turbine during the non-critical failure period.
• Additional maintenance work can still occur on a turbine during both critical and non-critical failures.

CTV-, SOV-, and helicopter-specific inputs

Parameter	Required	Description
Personnel		Role and number of personnel in each role required to conduct the maintenance.
Person-hours time series		Set personnel hours required by simulation year, i.e., year 1, year 2, etc. Note: This is an advanced feature that can result in simulation errors when used incorrectly.
Total person-hours		Total number of hours required to conduct the maintenance.
Repair time		Automatically calculated as Total person-hours / Total Personnel.
Lead time		Time required between the failure occurring and maintenance beginning, for, e.g., parts procurement, transit to wind farm, disconnecting the turbine, etc.
Spare part cost		Any costs associated with the parts for the maintenance work.
Consumables		Any additional costs associated with the maintenance work.

HLV-specific inputs

info

For all MCR-specific parameters (from Inspection person-hours down to Finalization time), a dedicated CTV is required in the Logistics section of your case, with the Dedicated tasks parameter checked. No additional personnel are required: the only limitation is the seat capacity on the dedicated CTV.

Parameter	Required	Description
Spare part cost		Any costs associated with the parts for the maintenance work.
Consumables		Any additional costs associated with the maintenance work.
Allow scheduled work while waiting		Whether other maintenance work can occur on the asset instance before the corrective maintenance is completed.
Used capacity	x	Amount of the HLV’s capacity required for the task. You can set the vessel capacity on the HLV’s Capacity tab in the Logistics section of your case.
Maximum delay at base	x	How long the vessel will wait at base in case new work orders are created and scheduled so they can be bundled.
Inspection person-hours		Time required to inspect asset instance condition before preparing replacement parts. Must be greater than 0.
Inspection crew size		Number of personnel required for the inspection. Must be greater than 0.
Inspection time		Automatically calculated as Inspection person-hours / Inspection crew size.
Preparation person-hours		Time required to prepare the replacement parts and conduct preliminary work, e.g., disassembling components, before the main maintenance task. Must be greater than 0.
Preparation crew size		Number of personnel required of the preparation work. Must be greater than 0.
Preparation time		Automatically calculated as Preparation person-hours / Preparation crew size.
Replacement person-hours		Time required to conduct the replacement. Must be greater than 0.
Replacement crew size		Number of personnel required to conduct the replacement. Must be greater than 0.
Replacement time		Automatically calculated as Replacement person-hours / Replacement crew size.
Finalization person-hours		Time required for finalization work, e.g., placing the housing. Must be greater than 0.
Finalization crew size		Number of personnel required to conduct the finalization work. Must be greater than 0.
Finalization time		Automatically calculated as Finalization person-hours / Finalization crew size.
Lead time		Time required between the failure occurring and maintenance beginning, for, e.g., parts procurement, transit to wind farm, disconnecting the turbine, etc. Must be greater than 0.

Towing vessel-specific inputs

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A towing vessel requires a crane as a supporting vessel for maintenance tasks. Add the necessary vessels in the Logistics tab of your case.

Parameter	Required	Description
Repair time		Time taken to complete the maintenance work.
Lead time		Time required between the failure occurring and maintenance beginning, for, e.g., parts procurement, transit to wind farm, disconnecting the turbine, etc.
Spare part cost		Any costs associated with the parts for the maintenance work.
Consumables		Any additional costs associated with the maintenance work.
Allow scheduled work while waiting		Whether other maintenance work can occur on the asset instance before the corrective maintenance is completed.

Remote only-specific inputs

Parameter	Required	Description
Lead time		Response time in the control room between initial alarm and the resetting of the asset.
Spare part cost		Any costs associated with the parts for the maintenance work.
Consumables		Any additional costs associated with the maintenance work.

Import maintenance tasks

You can import scheduled and corrective maintenance tasks in a single CSV file. Upload the file in either the Scheduled Maintenance or Corrective Maintenance tab.

1. Click Import CSV file on either the Scheduled Maintenance or Corrective Maintenance tab.
2. Select a Column delimiter and Decimal delimiter option according to how your CSV file is formatted.
3. Click Select file.
4. Navigate to the file on your computer and double click it.
5. Click the Data Mapping tab.
6. Map your CSV columns to the Shoreline naming schema by completing the relevant entries under File Column Name.
   • If your columns use the same naming conventions as Shoreline, click Reset to default to automatically fill the File Column Name entries.
7. Click Import tasks.

Your maintenance tasks will automatically appear in the relevant tabs for your asset.

See our How to create CSV files for import page for information on how to format your file.