Load Estimation (LE) is a function used to estimate individual loads on a feeder based on load classes, load type, load curve, and load measurements.
- The Load Class specifies the nature of a load, such as residential, commercial, or industry load. It is used to divide the feeder load into several components, each of them having the same nature or class.
- The Load Type specifies the characteristics of a load in terms of its relationship between its real and reactive power. There are two different load types: conforming and non–conforming. A conforming load uses power factor as a fixed ratio between its real and reactive power; while a non–conforming load defines its real and reactive power by its “load versus time” curves respectively.
- Load measurements are telemetered load values through the SCADA system. They can be either an individual load measurement or a branch load flow measurement.
In the Load Estimation function, individual loads on each node are calculated by two methods:
- Static Load Estimation (SLE): individual loads are identified through the ownership between loads and the feeders carrying those loads.
- Dynamic Load Estimation (DLE): the real–time branch flow measurements are used to adjust load values obtained by static load estimation to produce dynamic load estimation.
In addition to the network connectivity information and switch statuses required to perform topology analysis, the inputs used specifically in the LE function include:
- System date, time, and associated normalized load curve for each load class
- Feeder peak load and the percentage of each load class among the feeder load
- Nominal load values
- Normalized load curves for real and reactive power of each non–conforming load
- Power factor of each conforming load
Outputs from the LE function consists of estimated real and reactive power of each individual load.