Root cause (asset downtime)

The root cause measurement logic

1. When an alarm is registered the downtime counter starts by setting a timestamp on the alarm. 

2.   Planning and diagnosing → A new timestamp is set when diagnosing and planning is done and a work order has been created. The time from when the alarm is registered until that timestamp counted as   Planning and diagnosing. 

3.   Waiting to be handled   → The time registered,   from   diagnosing      and     planning , is counted as   Waiting to be handled. This ends with a new timestamp which is set when the maintenance manager handles work orders (Point 5). If this is not possible due to one of the below-listed reasons, the state change into one of the following defined states (Point 4).  

4. The main purpose of the maintenance manager agent in the model is to assign work orders to vessels and teams of technicians. However, if for some reason this action isn't possible, it generates additional downtime, which is tracked in one of the following root causes (checked in this order):

Input label	Description
No available vessel	The maintenance manager cannot assign a work order due to lack of available vessels or those available lack capacity for additional technicians.
Emergency response limit	The maintenance manager cannot assign a work order because said work order is not within the emergency response radius of the already assigned work orders to that vessel, then the root cause is set to.
No available technicians	The maintenance manager cannot assign a work order due to lack of technicians with required skills, that is on duty and allowed to travel with the vessel in question. Tip ? If adding technicians doesn't reduce the amount of downtime due to lack of technicians, it could be because there is not a night shift.
Not enough time	The maintenance manager cannot assign a work order due to lack of time left for the current shift.
Waiting on weather	The maintenance manager cannot assign a work order because the weather does not permit access to or work on the respective asset.

5.   Mobilising  → When a work order has been assigned to a vessel and a technician team, the shift starts, and the vessel begins mobilization. A new time stamp is set for all work orders assigned to the said vessel.

6.   Vessel transit  → After mobilising is done the vessel starts its transit to the wind farm and a new time stamp is set for all work orders assigned to this vessel.

7.   Time on asset  → When a vessel arrives at an asset, a new time stamp is set for the respective work order only and the time an asset is shut down for maintenance is tracked as  Time on the asset. All other work orders assigned to the vessel still has  Vessel transit as the root cause. Point 6 repeats until all work orders have been started.

8.   Waiting to be handled  → If there are work orders that have not been completed during the current shift a new time stamp is set for said work orders. 

9.   Scheduled maintenance  → Scheduled maintenance is treated separately from other downtime causes and is counted in the  Scheduled maintenance root cause. 

Waiting for weather time tracking for vessels with process criteria
When setting the inputs for installation vessels, weather limitations can be specified in the  Process criteria menu. Waiting on weather (WoW) time tracking starts when an installation vessel cannot transition to a new process because of weather restrictions (no weather window of sufficient length with required weather criteria, as specified in the process). Once the required weather is found, time tracking is stopped and its result is recorded in the database.

O&M Design allows tracking the total WoW value for all vessels, while Construction Design allows tracking the monthly WoW-time for each vessel. 

For example, the commissioning of a turbine done. This operation had the following steps:

• 08:00 Team arrives on the turbine and start working
• 16:00 Team finished work and request the vessel for pick-up
• 16:30 Pick-up of the team

To make it easy, it's calculated that the turbine was shut down for the time between 08:00 - 16:30.
Due to this, the values can be calculated like:

16:30 - 08:00 = 8.5 h Downtime
16:00 - 08:00 = 8 h Downtime due to an operation (Time on asset)
16:30 - 16:00 = 0.5 h Downtime due to waiting on vessel

8 h / 8.5 h = 0.9412 = 94.12 % Time on asset
0.5 h / 8.5 h = 0.0588 = 5.88 % Waiting on vessel

In this case, the whole downtime for one turbine on one day spilt up in 94.12 % time on asset and 5.88 % waiting on vessel.
These would be calculated for all turbines during the whole time period to get the root cause (downtime).