The Configuration screen can be found by clicking the gear icon in the top-right of the Transformer page. The values which can be configured here are critical to ensuring that data is measured and processed accurately.
There are two categories for configuration: Basic and Advanced. The values can be changed at any time and saving changes in the configuration will trigger all the data to be reprocessed using the new parameters.
In this article:
- Configuration Wizard
- Basic Configuration
- Advanced Configuration
The Configuration Wizard takes you step-by-step through the basic setup of the system for your transformer. They are only the Basic Configuration parameters that are required to get the analysis of the data working.
You can exit the wizard at any point by clicking Cancel in the bottom left and you can go back in again at any time by going into the Configuration screen and clicking Configuration Wizard at the top.
The Basic Configuration has all the critical attributes required to do analysis on the transformer. If these values are left blank, the graphs will not be able to be displayed and no analysis can be done. For help on filling out this section, you can go into the Configuration Wizard. This will run you through each of the attributes giving you a bit more detail on each.
There are three sections in the Basic Configuration:
This section provides information on where and how the sensor is installed.
Set the local time zone of the sensor. All measured and processed data on the EcoStruxure Transformer Expert App will be time stamped based on this setting.
Set the position on the transformer where the probe was inserted. This could be either at the Top or the Bottom. Please see Installation: Temperature Sensors for more information.
Secondary Temperature Sensor
Set the position of the external temperature sensor. Typically, this will be the opposite of the probe's position so that an accurate temperature model can be developed using the temperature gradient of the transformer from top to bottom. Please see Installation: Temperature Sensors for more information.
The specifications are some basic settings from the transformer's nameplate which are used for developing some of the data including the life left, load profile, and insights.
Name Plate Date
The date the transformer was manufactured. This is used to produce the aging profile of the paper insulation and for the calculations of the overall condition of the transformer.
Transformer's maximum power or rated power in MVA. This is used for estimating the load, load variability, hotspot temperature, and aging profile.
Primary and Secondary Voltage
The voltage of the primary (high voltage) and secondary (low voltage) windings in kiloVolts (kV). These are used for the analysis of the dielectric strength in relation to temperature, moisture, contamination, and age of the insulation.
The EcoStruxure Transformer Expert algorithms use the measured data to build up three models to describe the state of the transformer:
The Temperature Model
Tracking the temperatures at the top, bottom, and hotspot in the transformer.
The Water Model
Tracking the water content of oil, water activity. These are used with the Temperature Model to develop water content of paper at the top, bottom, and hotspot.
The Aging Model
Using the Temperature and Water Models to develop a historic aging profile and forecasting the aging of the paper over the transformer's life.
Using these models, as well as the other measured and derived data, the EcoStruxure Transformer Expert system provides the Insights and Overall Condition of the transformer. The following settings are critical to developing these models.
Historic DP Estimation
The EcoStruxure Transformer Expert algorithm creates an aging profile for the solid insulation from the transformer's nameplate date to today. It also calculates the average aging rate of the insulation over that time. These results are then used to forecast the aging of the paper, the degree of polymerization (DP), and the life left of the transformer.
The historical aging profile is shown in the DP History graph and the forecasted aging profile is displayed in the DP Forecast graph.
There are three methods for developing the Aging Model of the transformer:
System Estimated Historical Load + Furan Data:
The algorithm uses all the measured data that it has collected to estimate the average daily load % over the history of the transformer's service. The system combines this data with the furan data from oil tests to give the best estimate of the current DP and historical aging rate.
User Estimated Historical Load + Furan Data:
You can enter in an average historical daily load % instead of the system estimating it from the measured data. The system still combines this data with the furan data from oil tests to give the best estimate of the current DP and historical aging rate.
User Estimated DP:
You can enter a DP value if known from tests, estimations, or tracking. The algorithm will use this value to create an aging profile and calculate the aging rate based on this DP value. You can also select the date when this DP value was last tested.
Furan Data Only:
The option only use furan data from oil tests to give the best estimate of the current DP and historical aging rate. This option is best suited when load may have changed over the life of transformer i.e. current load is not representative of past load. Please note in case of no oil test data system will use the default option (using measured data) to calculate DP.
Set the cooling system method used by the transformer. This information is used to develop the transformer's Temperature and Water Model which are used to do the load estimation and develop the aging profile.
The most important value for this is the Temperature Rise: the temperature difference between top oil temperature and ambient temperature.
Several further settings become available depending on the selection of the cooling type.
- Fan On Temperature: The oil temperature when the Fan is turned On. Typical value is 60°C.
- Fan On Thermal Gradient: Temperature rise at 100% load when the Fan is On. Typical value is 20°C.
- Fan Off Thermal Gradient: Temperature rise at 100% load when the Fan is Off. Typical value is 40°C.
- Pump On Temperature: The oil temperature when the Oil Pump is turned On. Typical value is 70°C.
- Pump On Thermal Gradient: Temperature rise at 100% load when the Oil Pump is On. Typical value is 20°C.
- Pump Off Thermal Gradient: Temperature rise at 100% load when the Oil Pump is Off. Typical value is 40°C.
Load Estimation Method
The EcoStruxure Transformer Expert algorithm estimates the load that the transformer is supplying. The load estimated is a percentage of the rated load and is used to calculate the hotspot temperature and aging profile of the transformer.
The Load Estimation graph shows the load estimated by the system over time based on the method of estimation selected. There are three methods for estimating the load:
IEC Load Estimation:
The IEC Load Model uses the measured Top Oil and Ambient temperatures to calculate the transformer's instantaneous load. This method is described in the IEC Loading Guide  and provides a load estimation that best aligns with the operating conditions of a standard transformer supplying typical loads.
The IEC load estimation method may require some calibration. The Configuration screen offers a calibration tool to do this. It is recommended to collect a couple of weeks of data and to get some overlapping load data from the transformer. This can then be used to calibrate the load model.
After more than 2 weeks of data has been measured and uploaded to the EcoStruxure Transformer Expert Dashboard, Schneider Electric would be able to perform load calibration to match the Estimated Load with the actual load measured on the transformer.
This can be done by providing email@example.com with load data from the transformer in a CSV or Excel format, as long as the load data overlaps with data collected by the EcoStruxure Transformer Expert since the installation.
With our load calibration tool, we will adjust all the configuration parameters until your load data and the Estimated Load match.
These parameters can then be used in the Transformer Configuration screen to provide a more accurate assessment.
 BS IEC 60076-7:2018. Power Transformers. Part 7: Loading Guide for Mineral-Oil-Immersed Power Transformers. 2018.
Average Diurnal Load Model:
The load estimation can be set to an average value with typical daily variations. This can be set as a single Annual average or with four Seasonal averages for loads that vary from season to season.
Constant Load Model:
The load is set to a constant percentage of the rated load. It is just a straight line that is constant over time which is used for all the temperature, water, and aging profile calculations. This option is good for very specific applications where the load is non-linear and does not vary over the day. For example, in some industrial applications, the transformer will be supplying power to machinery that draws constant load or in a server farm where the load is constant 24/7.
The Advanced Configuration only becomes available once all the Basic Configuration has been completed. This section provides some general information and allows for more refinement of the parameters and characteristics of the transformer to get more accurate results.
This section provides some general information about the transformer which can be found on the nameplate or from the manufacturer.
Manufacturer of the transformer.
The transformer’s model or serial number.
Full replacement cost of the transformer including equipment, plant, transport, and labor.
Set the transformer tank’s oil volume in liters.
On-load Tap Changer
Is the transformer fitted with an on-load tap changer (OLTC)?
Input and Output Connection Type
Set the connection types for the transformer’s input-output. This can be set as:
More advanced settings relating to the Basic Configuration and the operational characteristics of the transformer. Most of the attributes are prefilled with reasonably typical default values that can provide sufficient accuracy. But these can be adjusted if you are able to get more exact values.
Thermally Upgraded Paper Installed
Is the insulation paper thermally upgraded? Thermally Upgraded Kraft (TUK) paper can operate at a higher temperature without degradation, giving it a lower rate of aging. This is taken into account during data processing.
Top to Hotspot Thermal Gradient at Rated Load
The temperature difference between the hot spot and the top oil temperature at 100% of the rated power. This value is typically provided by the manufacturer and is found by measurements during a heat run test. The default is 15°C, however, typical values can be anything between 12°C and 18°C.
DP at Start of Life
The degree of depolymerization of new paper insulation at the time of manufacture and installation of the transformer on-site. The default is set to 900 DP but this value can be adjusted in line with your own standards or known values.
DP at End of Life
The degree of depolymerization of aged paper insulation that is considered end of life for the transformer. This is used to determine the life left of the transformer in the calculations. The default is set to 200 DP but this value can be adjusted in line with your own standards or known values.
Air Breathing Type
Set the transformer’s breather type:
- Free Breather
- Tank-sealed Conservator
- Tank-inert Gas Pressure System.
Each breather type is affected differently by the ingress of air. By default, this is set to Free Breather.
Oxygen Content of Oil
The level of oxygen in the oil will have an impact on the rate of aging of the insulation due to the effects of oxidation and this is taken into account when calculating the rate of aging of the insulation.
This can be determined from oil test data uploaded to the EcoStruxure Transformer Expert or it can be manually set.
Top Temperature Offset
An offset can be applied to the measured top temperatures to adjust the measurements closer to the actual value.
This can be done in cases when the probe is not installed directly in the top oil, such as in a pipe from the top of the tank to the radiator. Or if the external temperature sensor is unable to be installed directly on a top pipe to the radiator.
Set the type of oil insulation; either Mineral or Ester oil.
Last Oil Dryout
Set the date of the most recent time the oil was dried out.
Last Oil Reclamation
Set the date of the most recent oil replacement, filtration, or reclamation. The algorithms will take into account this date when analyzing oil quality, DGA, and 2FAL to calculate the DP of the paper.