On-line analysis of power quality problems in non-sinusoidal/non-linear distribution systems

Abstract

The paper presents the definitions of powers and currents associated with systems characterized by non-sinusoidal sources and/or non-linear loads in the time domain. An expression for the required static element for reactive power compensation is developed. The analysis is carried out for two cases: theoretical and experimental. The Excel spread sheet is used to analyze the theoretical case to demonstrate the validity of the method. Furthermore, a circuit is designed, for the experimental case, using a microcontroller board for online measurement and performing the time domain analysis. The microcontroller is programmed to sample voltage and current waveforms, analyze current into components, calculate the value of the required passive element and display it using a Liquid Crystal Display. The microcontroller can be used to control STATCOM devices to achieve maximum obtainable compensation. This presents a fast online method (3 to 5 cycles) to enhance the power quality of the system.

Keywords

• Power quality
• Distribution systems
• Time domain analysis
• Reactive power compensation
• Microcontroller