Sensitive consumers such as semiconductor factories and chemical firms that have continuous process get substantial economical damages due to power quality phenomenon including an instantaneous voltage drop of less than 0.1 second that cannot be recognized by naked eyes or a power failure. Higher harmonics that are generated at electric power transformers which are used in invertors, UPS, converters and office equipments are the element newly introduced to deteriorate the power quality. In addition, an instantaneous voltage drop is generated due to the peak current during large-capacity load starting and it causes equipment faults, burns, overheating, generation of abnormal noise, malfunction of relay, instrumental error and so on. VITZROTECH VIMAC-3000 has the functions to analyze the causes of problems accurately and to take effective measures by constantly monitoring the electric power quality of this system.