Design system detecting and monitoring current harmonics using online S transformation based on LabVIEW

Nowadays, the civil, business, and industrial electrical power loads in Indonesia are growth rapidly. The main growth is in non-linear load as source of current harmonic which causes serious problem in power quality and safety of electric power system. To solve the problem, power quality monitoring system which is integrated with more effective measurement, control, communication, and supervision ability are needed. To realize those, in this research paper, an online real-time current harmonic detecting and monitoring system using S transform based on LabVIEW software is designed and created. S-transform is chosen to give the support for operation in dynamic condition. Resulting prototype is a harmonic analyzer that works in single or three-phase line through the addition of two identical CT with CT-235. When this prototype is operated in linear or non-linear load, it can monitor the current harmonic in real time mode with continuous data update every 1 second and around 1% measurement error. The testing result also pointed out that prototype still gets to work when the load is changed dynamically. It is different with another harmonic analyzer based on Fourier transform (with analysis update every 10 cycles at frequency 50 Hz) which stops operating when dynamic frequency happened less than 10 cycles (0.2 second).