Parameter Estimation of Dynamic Load Model Using Field Measurement Data Performed by OLTC Operation

An accurate representation of the dynamic behavior of an electrical load is very important for the analysis of power system operation regarding its stability characteristics, especially for voltage stability analysis. This paper presents the practical experience of dynamic load modeling using the real system measurement data. In order to capture the dynamic behavior of the power system on a load bus, a perturbation was introduced into the system by adjusting the transformer OLTC (on-load tap changer). That caused voltage changes in the network, and the resultant dynamic system response could be recorded by the power system monitoring devices. Before starting the load modeling process, the measurement data were preprocessed by a proposed DWT-based algorithm (Discrete Wavelet Transformation) to suppress the signal noises of the measurement data and, moreover, to make it more feasible to estimate the load model parameters. By performing the parameter optimization process, the parameters were then identified with the measurement data by NONLSQ technique (non-linear least square).