A Wind Turbine includes a number of sensors, input electronic cards and cabling that feed its Controller; they are used to decide what to do next. The values of some of them are stored inside the Controller, but they are not available externally. Typically the Controller admits requests (from the SCADA) to provide information that are related to these data, normally as aggregated data. For example, the data about wind speed, wind direction, generated active and reactive power, temperatures, etc., are available from the Controller as aggregated 10 minutes data.
This is an important drawback in order to know the history of the Wind Turbine, required to have an adequate level on characterization for Due Diligence reports.
Our line of DL1300 dataloggers are designed to log all the signals arriving to the Controller (inputs) as well as its output signals (that control subsystems in the Wind Turbine), each one at a rate that makes sense for that signal.
These dataloggers are sold as part of a project, specific for each installation, as they must consider:
- The types of connections for the sensors.
- The location of necessary additional cabling and electronics, so that the existing cabinets are respected and the plant may continue undisturbed operation.
- The access method to the logged data.
In this way, the knowledge about the detailed history of the Wind Turbine does not depends (do not take resources from) the Controller. The collected data can be exported without disturbing its behavior.
The actual structure of the datalogger depends on:
- The types and number of sensors.
- The type of connection between the sensors and the Controller. analog (4-20 mA, 0 to +5V, -10V to +10V), frequency, specific protocol (RS485, RS232, CANBUS, etc.)
- Availability of space for the additional Electronics inside the cabinets
- Accesibility to the central computer.
A typical layout with remote Electronics cards near the sensor, with the additional Electronics for the sensor interface, and communications through serial lines (copper, or fiber optic) is shown in the next figure.
Main advantages and characteristics
- Easy to deploy:
Thanks to the associated engineering work, this dataloggers can be installed by the Wind Turbine maintenance technician.
- No programming required
Only a XML configuration file is required to set all details about connections, communications lines, mapping physical channels to signal names (tags), setting sampling period, etc.
- Specific treatment of every signal (tag) to comply with the following requirements:
- Minimizing the size of the resulting files.
- Collecting enough number of samples for analog signals.
- Collect all changes of digital signals.
- Timestamps with better than 1 millisecond resolution, keeping full date description.
- Tolerance to crashes in the connections:
The logger detects when any of the communication lines are broken, or the associated input device is no working, so no data are store till the line or device become operative again.
- Protection for data losses due to storage malfunction:
Rather than storing the logged data in a single database file, they are splitted (on-line) in several files so that eventually only some of these files may actually be lost.
The datalogger works as an standalone application in a real time Linux computer. The bootstrapping of this Linux machine executes all the programs required by the DL1300 applications, as well as the own application. In this way, turning the Linux machine ‘On’ proceeds to start the datalogging process.
One of the threads of the DL1300 ‘listens’ the commands issued to a particular IP address. The DL1300 is supplied with a Windows application that uses TCP/IP communications to know about and to control the DL1300 application running in the Linux machine. See next figure.
Logged data files can be transferred using standard FTP protocol.
Data visualization and analysis
The DL1300 uses compressed XML files to store the collected data. It comes with an application that allows:
- Transformation of the internal data to any SLQ based data base manager. By default, MS Access / MS SQL SERVER
- Visualization of the recorded data using the ‘Oscilloscope‘ application.
- Tools to edit the raw data (to eliminate noise, missing data, etc.)