An apparatus for prediction of the residual lifetime of an electrical system, comprising: - an input unit; - a processing unit; and - an output unit; wherein, the input unit is configured to provide at least one sensor data from at least one sensor to the processing unit; wherein the at least one sensor data comprises the measurement of at least one physical parameter of at least one component of an electrical system; wherein each of the at least one sensor data is associated with a corresponding sensor from which the sensor data is provided and relates to the measurement of the at least one physical parameter of a corresponding component of the electrical system which is comprised in the sensor data; wherein each sensor data extends over a plurality of time windows and that sensor data at each time window is assigned to a certain data class of a plurality of data classes, such that sensor data at each time window has a value that falls into one of the data classes and wherein the plurality of data classes encompasses a data range within which the respective sensor data can vary; wherein, for each sensor data the processing unit is configured to assign the sensor data at each time window into a corresponding data class on the basis that sensor data at a particular time window has a value that falls into that corresponding data class; wherein for each of the at least one physical parameter of each of the at least one component the processing unit is configured to determine a load spectrum, wherein the load spectrum is the sum of all data classes including the data values and duration in each data class for the corresponding physical parameter of the component, wherein the processing unit is configured to determine the total duration of the sensor data within each data class by summing up the plurality of time windows of the sensor data within each data class; wherein for each of the at least one physical parameter of each of the at least one component the processing unit is configured to determine plurality of rates of change of sensor data, wherein each time window of the plurality of time windows has an associated rate of change of sensor data assigned to it; wherein the processing unit is configured to determine a predicted lifetime for each of the at least one the component comprising application of an aging model from at least one aging model to the corresponding load spectrum for each of the at least one physical parameter of each of the at least one component and utilization of the plurality of rates of change of sensor data for each of the at least one physical parameter of each of the at least one component of the electrical system. - an input unit; - a processing unit; and - an output unit; wherein, the input unit is configured to provide at least one sensor data from at least one sensor to the processing unit; wherein the at least one sensor data comprises the measurement of at least one physical parameter of at least one component of an electrical system; wherein each of the at least one sensor data is associated with a corresponding sensor from which the sensor data is provided and relates to the measurement of the at least one physical parameter of a corresponding component of the electrical system which is comprised in the sensor data; wherein each sensor data extends over a plurality of time windows and that sensor data at each time window is assigned to a certain data class of a plurality of data classes, such that sensor data at each time window has a value that falls into one of the data classes and wherein the plurality of data classes encompasses a data range within which the respective sensor data can vary; wherein, for each sensor data the processing unit is configured to assign the sensor data at each time window into a corresponding data class on the basis that sensor data at a particular time window has a value that falls into that corresponding data class; wherein for each of the at least one physical parameter of each of the at least one component the processing unit is configured to determine a load spectrum, wherein the load spectrum is the sum of all data classes including the data values and duration in each data class for the corresponding physical parameter of the component, wherein the processing unit is configured to determine the total duration of the sensor data within each data class by summing up the plurality of time windows of the sensor data within each data class; wherein for each of the at least one physical parameter of each of the at least one component the processing unit is configured to determine plurality of rates of change of sensor data, wherein each time window of the plurality of time windows has an associated rate of change of sensor data assigned to it; wherein the processing unit is configured to determine a predicted lifetime for each of the at least one the component comprising application of an aging model from at least one aging model to the corresponding load spectrum for each of the at least one physical parameter of each of the at least one component and utilization of the plurality of rates of change of sensor data for each of the at least one physical parameter of each of the at least one component of the electrical system.