Estimation of Voltage Dependent Load Models Through Power and Frequency Measurements

This letter proposes an optimization-free technique to estimate the parameters of voltage dependent loads through the measurements of only the load active and reactive power consumption and frequency deviations at the load bus. The technique is shown to be a relevant consequence of the dependency of power flow equations on the bus voltage phase angles. The WSCC 9-bus and the IEEE 14-bus systems serve to illustrate the proposed technique.

I. Introduction

Measurement-Based approaches to estimate the behavior of loads have flourished in recent years due to the advances and ubiquity of Phasor Measurement Unit (PMU) technology. Relevant techniques have been proposed to estimate the parameters of different load models commonly used in dynamic and stability analyses of power systems such as the exponential Voltage Dependent Load (VDL), both with and without exponential recovery [1], voltage and frequency dependent loads [2], and ZIP loads [3], [4]. The main features that the approaches proposed in the references above have in common is that measurements are taken either at the load bus, only, or at every bus of the system to ensure system observability, and they are generally based on often intricate optimization techniques.