Power System Load Modelling

Exhibitor: Adeline Chan

Supervisor: Zhao Dong

Research Group: Complex and Intelligent Systems

Industry Sector: Energy and Utilities

Power System Load Modelling is a technique used to model the power system and essential for stability assessments. Accurate modelling of loads continues to be a difficult task due to several factors like, lack of precise information on the composition of the load, changing of load composition with time delay and week, seasons, weather, through time and more. Electric utility analysts and their management require evidence of the benefits of improved load representation in order to justify the effort and expense of collecting and processing load data, as well as to modify computer program load models.

The purpose of this thesis is to study different types of load models and their impact on system security. Based on a two-bus system, different types of load models are modelled using the Static approach. The finding from this approach is that when the load power reached a certain limit, the two-bus system becomes unstable. It also indicates that transmission line impedance does contribute to system stability.

A probabilistic load model is investigated using a two-bus system to allow quantitative assessment of reliability and security on the existing system to give the probability of any line being overloaded. Based on power consumption of the Queensland Electricity Market in year 2002, the probability density function (PDF) is calculated. The PDF, helps to calculate the probabilities of the stability. It is observed that at higher power demand, even with lower PDF, the system has a higher probability of being unstable.

With the theoretical analysis and case studies, an objective decision can be made with regard to contingency plans and security reinforcement.

Thesis Document (PDF)