09-10-2010, 01:57 PM
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Presented by:
Uma Rao
S.N.Singh
Abstract
This paper describes power quality audits conducted at hospitals in India. Voltage , current and power measured at various points were used to assess the quality of the power. The main power quality problems found in hospitals were voltage flicker, neutral currents , and harmonic distortion (THD)value. Measurement, analysis and cond-itioning of power quality has been studied in different hospitals as a case study. Recommendations have been made to mitigate the issue.
Introduction
Power quality is the term used for overall voltage quality, current quality and nature of output waveform which directly or indirectly affect the loads as well as source. Power quality has been a major issue in today’s industrial, commercial, residential and military and medical environments. Poor power quality may lead to disastrous consequences like break-downs, production interruptions, excess energy consumptions etc. In this paper power quality issues have been discussed in the hospitals where these issues are becoming more important due to greater impact on sensitive medical equipment which utilizes microprocessor controls and switched DC power supplies. Medical devices driven by electric power have come to be commonly used in hospitals and rapid changes of voltage or current can easily cause them to fail or does not respond as per the desired control action. Externally and internally induced power surges and harmonics can have a dramatic effect on equipment performance. A stable and high quality power supply is indispensable in order to maintain safety in the modern clinical setting. The widespread use of sensitive, microprocessor /microcontroller based equipment at hospitals requires that the power delivered to such sensitive facilities be of a higher quality . Power quality problems may be caused by generation of harmonics by equipment itself, external sources like lightning or internal sources like interaction of loads.
