A New Single-Phase Power Component Theory for Instantaneous Powers in an Electric Power System

Abstract

Many authors have identified the need to improve the definitions of non-active power under non-sinusoidal conditions. It has also been stated the need for a generalised power theory to provide a simultaneous common base for measurement, compensation, power quality and identification of sources of distortion. A solution is to decompose, as accurately as possible, the total instantaneous power into active and non-active components based on the power system properties. To enable this, the load model must closely represent the actual. This paper presents a new instantaneous power theory that achieves this for the single-phase system. This theory is based on both voltage and current harmonic components. With good knowledge of the time profile of active/non-active power components, an accurate time-domain measurement of the non-active power is achieved. This non-active component can be utilised to achieve optimal compensation, as well as gauge power quality. The theory is evaluated for linear and non-linear loads in the presence of harmonics using case studies. The case studies use single-phase resistive and inductive loads with diodes to create non-linear load as necessary. Evaluations of the results demonstrate good performance of the proposed theory.

Key Words:

• Active
• Compensation
• Definitions
• electrical power
• instantaneous
• measurement
• non-active;
• non-linear
• non-sinusoidal

Additional information

Notes on contributors

H. Khalsa

Harnaak Khalsa received his BEng degree from the University of Malaya in 1976. Subsequently he worked in the National Electricity Board (Malaysia) and General Electric (USA). In 1981 he started his career in ABB (then ASEA). At present he is working with the Power Systems Division of ABB Pty Ltd in Melbourne, Australia. His working experience in mainly in the area of protection and control in power systems. He completed his MEngSc at Monash University in Melbourne in 1998 where, at present, he is pursuing his PhD. He is a member of the IEEE. His current research interests are measurements and protection of electrical power systems.

J. Zhang

Jingxin Zhang received his MEng and PhD degrees in Electrical Engineering from Northeastern University, China. Between 1988 and 1992, he was with Northeastern University, China, as associate professor. Since 1989, he has held research positions in the University of Florence, Italy, the University of Melbourne, and Cooperative Research Centre for Sensor Signal and Information Processing, Australia; and senior lecturer positions in the University of South Australia and Deakin University, Australia. He is currently with the Department of Electrical and Computer Systems Engineering, Monash University, Australia. He is the author and coauthor of over 130 research papers in diverse areas such as adaptive and predictive control, time varying systems, robust filtering, multi-rate signal processing, and medical imaging; many of these papers are published in the prestigious international journals such as IEEE Transactions and Automatica. He is the first inventor of an Australian provisional patent on parallel magnetic resonance image reconstruction. He has led numerous research projects funded by Australian Research Council, Australian Industry and Natural Science Foundation of China. He has been a reviewer for many international journals and a regular referee of research grants for Australian Research Council, as well as the Italian Ministry of Education, University and Scientific Research. He has been a member of international program committees of many international conferences. He is recipient of 1989 Fok Ying Tong Educational Foundation (Hong Kong) for the outstanding Young Faculty Members in China and 1992 China National Education Committee Award for the Advancement of Science and Technology. His current research interests are in control and signal processing, and their applications to biomedical and industrial systems.