Identification of static load characteristics based on measurements in medium-voltage distribution network

The authors deal with static load (SL) characteristics (P-V and Q-V characteristics) of a medium-voltage distribution network derived from field measurements. The experiments have been performed by changing the tap position of an on-load tap-changing transformer in different seasons, different week days and day periods. P-V and Q-V load characteristics are divided into two classes, transient and steady-state characteristics. The differences between them are discussed and quantified. Both classes are mathematically described by polynomial, linear and exponential SL models. Model parameters are obtained by curve fitting using a least square method. The adequacy of developed load models is critically assessed and discussed. All the static characteristics are grouped according to seasons and day periods and are mutually compared. Finally, the parameters of the SL models for residential load without electrical heating are suggested for different seasons.