KPI Calculation Service – KPI State Calculation¶
In order to use the KPI calculation functionality of the KPI Calculation Service for a unit, its states have to be known for the time interval of interest. Sometimes various sources, such as sensor readings, control unit data and calendar entries, have to be taken into account to determine the unit's state. The KPI State Calculation can automatically calculate a unit's states from this data.
The following conditions must be fulfilled for this service:
- Available sensor readings clearly indicate Service states.
- Available control unit data clearly indicates Forced Outage and Reserve Shutdown states.
- Available calendar entries define Planned Outage states.
- When neither sensor nor control unit or calendar provide sufficient information, a default state can be assumed.
This section lists some input parameters, which have to be provided to the KPI State Calculation.
- Sensor readings, provided as time series data
- Calendar entries (planned outage intervals defined by
- Control system events (can be
The state which is assumed at the start of the time interval, can be
The state to be assumed when there is not enough input data available for state calculation, can be
Service Indication Threshold (SIT)¶
The service indication threshold
SIT is required when using sensor data. It defines the minimum value for sensor data, below which the unit is assumed to be stopped.
Shutdown Correlation Threshold (SCT)¶
The shutdown correlation threshold
SCT is required when using control unit data. It is defined as
[Timestamp[i] - SCT, Timestamp[i] + SCT].
Decision process at T=0¶
Set the state to initial state. If this contradicts a calendar entry, emit an error.
Decision process at T≠0¶
At each timestamp t≠0, the algorithm evaluates the unit's state using the following decision process:
- If a calendar entry is indicates a planned outage at this timestamp, set the state to
POH. Otherwise proceed.
- If the sensor reading is NULL and all previous sensor readings are NULL, set the state to default state. Otherwise proceed.
- If the sensor reading is NULL, use the value of the nearest previous sensor reading ≠0 and proceed.
- If the sensor reading is above the Service Indication Threshold (
SIT), set the state to
SH. Otherwise proceed.
- If there is no control system event within the Shutdown Correlation Threshold (
SCT), set the state to default state. Otherwise proceed.
- If the first control system event within the Shutdown Correlation Threshold (
SHUTDOWN, set the state to
FOH. Otherwise, set it to
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