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Model

A thermal model to calculate transformer temperatures under specified load and ambient temperature profiles.

Initialising a transformer model with a temperature simulation profile 
>>> from datetime import datetime
>>> from transformer_thermal_model.cooler import CoolerType
>>> from transformer_thermal_model.schemas import InputProfile, UserTransformerSpecifications
>>> from transformer_thermal_model.transformer import PowerTransformer
>>> from transformer_thermal_model.model import Model

>>> # First, we necreate the input profile
>>> datetime_index = [
...     datetime(2023, 1, 1, 0, 0),
...     datetime(2023, 1, 1, 1, 0),
...     datetime(2023, 1, 1, 2, 0),
... ]
>>> load_profile = [0.8, 0.9, 1.0]
>>> ambient_temperature_profile = [25.0, 24.5, 24.0]
>>> input_profile = InputProfile.create(
...     datetime_index=datetime_index,
...     load_profile=load_profile,
...     ambient_temperature_profile=ambient_temperature_profile,
... )
>>> # Then, we create the transformer with some basic specifications
>>> tr_specs = UserTransformerSpecifications(
...     load_loss=1000,  # Transformer load loss [W]
...     nom_load_sec_side=1500,  # Transformer nominal current secondary side [A]
...     no_load_loss=200,  # Transformer no-load loss [W]
...     amb_temp_surcharge=20,  # Ambient temperature surcharge [K]
... )
>>> tr = PowerTransformer(
...     user_specs=tr_specs,
...     cooling_type=CoolerType.ONAN
... )
>>> # Finally, we can use the input profile in the transformer model
>>> model = Model(temperature_profile=input_profile, transformer=tr)

Attributes:

Name Type Description
transformer Transformer

The transformer that the model will use to calculate the temperatures.
data DataFrame

The data that the model will use to calculate the top-oil and hot-spottemperatures.
init_top_oil_temp float | None

The initial top-oil temperature. Defaults to None. If this is provided, will start the calculation with this temperature. If not provided, will start the calculation with the first value of the ambient temperature profile.
init_hot_spot_temp float | None

The initial hot-spot temperature. Defaults to None. If this is provided, will start the calculation with this temperature. If not provided, will start the calculation with the first value of the ambient temperature profile.
hot_spot_temp_profile Series

The modeled hot-spot temperature profile.
top_oil_temp_profile Series

The modeled top-oil temperature profile.

Parameters:

Name Type Description Default
temperature_profile InputProfile

The temperature profile for the model.

 required
transformer Transformer

The transformer object.

 required
init_top_oil_temp float | None

The initial top-oil temperature. Defaults to None. If this is provided, will start the calculation with this temperature. If not provided, will start the calculation with the first value of the ambient temperature profile.

 None
init_hot_spot_temp float | None

The initial hot-spot temperature. Defaults to None. If this is provided, will start the calculation with this temperature. If not provided, will start the calculation with the first value of the ambient temperature profile.

 None
Source code in transformer_thermal_model/model/thermal_model.py 
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def __init__(
    self,
    temperature_profile: InputProfile,
    transformer: Transformer,
    init_top_oil_temp: float | None = None,
    init_hot_spot_temp: float | None = None,
) -> None:
    """Initialize the thermal model.

    Args:
        temperature_profile (InputProfile): The temperature profile for the model.
        transformer (Transformer): The transformer object.
        init_top_oil_temp (float | None): The initial top-oil temperature. Defaults to None. If this is provided,
            will start the calculation with this temperature. If not provided, will start the calculation
            with the first value of the ambient temperature profile.
        init_hot_spot_temp (float | None): The initial hot-spot temperature. Defaults to None. If this is provided,
            will start the calculation with this temperature. If not provided, will start the calculation
            with the first value of the ambient temperature profile.

    """
    logger.info("Initializing the thermal model.")
    logger.info(f"First timestamp: {temperature_profile.datetime_index[0]}")
    logger.info(f"Last timestamp: {temperature_profile.datetime_index[-1]}")
    logger.info(f"Amount of data points: {len(temperature_profile)}")
    logger.info(f"Max load: {np.max(temperature_profile.load_profile)}")
    if transformer.specs.hot_spot_fac is None:
        raise AttributeError(
            "The given Transformer has no hot-spot factor specified. Please specify the hot-spot "
            "factor or calibrate it using the calibrate_hotspot_factor function."
        )
    self.transformer = transformer
    self.data = temperature_profile
    self.init_top_oil_temp = init_top_oil_temp
    self.init_hot_spot_temp = init_hot_spot_temp

run 

run() -> OutputProfile

Calculate the top-oil and hot-spot temperatures for the provided Transformer object.

This method prepares the calculation inputs, calculates intermediate factors, and computes the top-oil and hot-spot temperature profiles for the transformer based on the provided load and internal parameters.

Returns:

Name Type Description
OutputProfile OutputProfile

Object containing the top-oil and hot-spot temperature profiles.
Source code in transformer_thermal_model/model/thermal_model.py 
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def run(self) -> OutputProfile:
    """Calculate the top-oil and hot-spot temperatures for the provided Transformer object.

    This method prepares the calculation inputs, calculates intermediate factors, and computes
    the top-oil and hot-spot temperature profiles for the transformer based on the provided
    load and internal parameters.

    Returns:
        OutputProfile: Object containing the top-oil and hot-spot temperature profiles.

    """
    logger.info("Running the thermal model.")
    dt = self._get_time_step()
    load = self.data.load_profile
    t_internal = self._get_internal_temp()

    f1 = self._calculate_f1(dt)
    f2 = self._calculate_f2(dt)
    top_k = self.transformer._end_temperature_top_oil(load)
    static_hot_spot_incr = self._calculate_static_hot_spot_increase(load)

    top_oil_temp_profile, hot_spot_temp_profile = self._calculate_temperature_profiles(
        load, t_internal, f1, f2, top_k, static_hot_spot_incr
    )
    logger.info("The calculation with the Thermal model is completed.")
    logger.info(f"Max top-oil temperature: {max(top_oil_temp_profile)}")
    logger.info(f"Max hot-spot temperature: {max(hot_spot_temp_profile)}")

    return OutputProfile(
        top_oil_temp_profile=pd.Series(top_oil_temp_profile, index=self.data.datetime_index),
        hot_spot_temp_profile=pd.Series(hot_spot_temp_profile, index=self.data.datetime_index),
    )