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Greenbyte Documentation

System Availability

This section contains information about the following:

Time-Based System Availability

The system availability in the Greenbyte Platform considers all the possible stops of the turbine as non-available. The platform uses the status codes of the turbine that imply a stop to identify these periods. In addition, warning events are categorized as unavailable if the turbine is stopped (power <= 0). System availability can be calculated based on time or energy. The time-based system availability counts the time the turbine was stopped compared to the total observed time. For example, if we monitor a turbine for one hour and the turbine has a stop status code for 30 min, the time-based system availability for that period will be 50%. On the other hand, if we want to quantify the effect of lost production during this unavailable time, we will have to use production-based availability.

Technology

Wind

Remarks

The calculation has 3 concepts of blocks of time: AvailableUnavailable, and Excluded.

The output is a percentage indicating the ratio of available to unavailable time.

Excluded time is not considered. This availability almost always follows the pattern of 0% if there is a stop status, 100% otherwise.

Allocation of available time and unavailable time is based on Stop statuses, Overriding Curtailment statuses* and partly on Warning statuses.

Note

*An Overriding Curtailment status means that:

  • There exists an active curtailment scheme for the wind farm.

  • If several Curtailment statuses of a different kind exist, the type with the highest priority overrides the other.

  • If a Stop status exists, the overriding curtailment type has the Override stops setting activated.

  • The overriding curtailment type has the Time-based system availability setting set to Available or Unavailable (that is, not to Default).

Time-Based_System_Availability_-_Remarks.png
Equation

For each period, the turbine will be seen as Available if there is no status and

w < cut-inPC + 1 m/s or w > cut-outPC

(As the turbine will never start producing at exactly the cut-in wind speed, a buffer of 1 m/s is added to account for this)

If this is not true, it will still be seen as Available, unless:

  • There is no status or the status is not a Stop or Curtailment, and w doesn’t exist, it means that the period will be seen as Excluded

  • Or else if the status is not a Stop or Curtailment and P <=0, it means that the period will be seen as Unavailable.

Where:

P

is the Power

w

is the Wind speed

cut-inPC

is the Power Curve Cut-in

cut-outPC

is the Power Curve Cut-out

The Time-based system availability, ATS, is then calculated as the sum of periods, according to the resolution:

Time-Based_System_Availability_-_Equation.png

Where:

Ta

is the amount of time where data is Available

Tu

is the amount of time where data is Unavailable

Inputs
Time-Based_System_Availability_-_Inputs.png
Usage Example

Here is an example of the Curtailment scheme setting Time-based system availability. Observe that even Override stops setting will influence if there is also a simultaneous Stop status:

Time-Based_System_Availability_-_Usage_Example.png
Time-based System Availability (Planned) (Turbine)

This calculation determines the availability (in %) of a device (turbine) based only on the planned downtimes that customers manage in the Plan → Downtime section of the Greenbyte platform.

Given a certain time interval, there are 3 possible cases:

  1. If there is no planned downtime in the given interval, the device is considered to be fully available.

  2. If there is one (or several) downtime(s) partially overlapping within the given interval, the device is partially available.

  3. If the given time interval is fully covered by downtime, the device is considered to be unavailable.

Technology

Wind

Remarks

The fact that downtimes can be planned in the future makes this calculated signal available for future time intervals.

Equation

For each bin (according to the Time resolution, default is 10-minute), the Time-based System Availability (Planned) ATS,Planned is calculated as:

Time-based System Availability (Planned) - Equation.png

Where:

Tdown

is the amount of downtime within the bin

Tbin

is the total amount of time in the bin

Inputs
Time-based System Availability (Planned) (Turbine) - Inputs.png
Example
Time-based System Availability (Planned) - Usage Example 1.png
Time-based System Availability (Planned) - Usage Example 2.png
Production-Based System Availability (Turbine)

The production-based system availability corresponds to the percentage of potential production that was lost during the time the turbine was stopped or in curtailment status. The calculation of this metric is based on the potential energy that the turbine could have produced during a period. Let's suppose that the turbine was stopped for 30 min in one hour. Let's imagine that during that 30 min of stop, the wind speed was under the cut-in wind speed. This means, that the potential energy that could have been produced is 0 kWh. This will lead to a potential energy loss of zero and therefore the production-based system availability will be 100%.

Technology

Wind

Remarks

Both the energy export and the potential production are clipped at 0 so that no negative values are allowed. If this results in both the energy export and the potential power being 0, then the Production-based system availability is set to 1.

Equation
Production-Based_System_Availability__Turbine__-_Equation.png

Where:

APS

is the Production-based system availability.

E+

is the Energy export, clamped to the positive part.

ELPD+

is the Lost Production to Downtime (Turbine), using the curtailment settings for Production-based availability and clamped to the positive part.

Inputs
Production-Based_System_Availability__Turbine__-_Inputs.png
Usage Example

Here plotted in data studio together with a status overview showing the stop status that causes the downtime.

Production-Based_System_Availability__Turbine__-_Usage_Example.png

Here is an example of the Curtailment scheme setting Production-based system avail. , note that even Override stops setting will influence if there is also a simultaneous Stop status:

Production-Based_System_Availability__Turbine__-_Usage_Example_2.png
Production-Based System Availability (Virtual) (Turbine)
Description

This signal calculates the production-based system availability for turbines by taking into account the compensated lost production. This means that the signal is using Virtual production instead of, Energy export as the produced energy for the device. Essentially this corresponds to the percentage of potential production that was lost to downtime and would not have been subjected to compensated curtailment. The curtailment availability settings are taken into account when determining what counts as “downtime” and if a curtailment status is compensated or not.

Compared to the signal Production-based system availability (Turbine), the Virtual Production-based system availability will always be equal or higher.

Technology

Wind

Remarks

N/A

Equation
Production-Based_System_Availability__Virtual___Turbine__-_Equation.png

Where:

APS, virtual

is the Virtual Production-based system availability.

E+

is the Virtual production of the turbine, clamped to the positive part. This corresponds to Energy export + Compensated Lost production.

ELPD+

is the Lost Production to Downtime (Turbine), using the curtailment settings for Production-based availability and clamped to the positive part.

Inputs
Production-Based_System_Availability__Virtual___Turbine__-_Inputs.png
Usage Example

To be added later.