The study of distribution voltage drop and neutral-to-ground voltage of a healthcare facility / Nazihah Musa

The proliferation of modem medical devices has raised the issue of power quality related problems in healthcare industries. These devices represent non-linear loads which will inject harmonics into the system The concern lies on how fur the existing power system of a building can tolerate the increasing magnitude of current harmonic. This study presents prediction of how fur electrical system cable can operate before violating the permissible voltage drop and neutral-to-ground voltage during harmonic loading condition in the system It is based on case study at Clinical Training Centre (CTC) building, UiTM Sungai Buloh. The cost of equipment malfunction recorded (March 2013-April 2015) in this building shows a fatal loss of RM 298.389 and the list of equipment is included in this paper. Following the claim, Fluke 1750 power monitor device was logged at several affected feeders. The work is presented in this paper. The analysis of power log data found that there were several voltage dropout occurrences and current harmonic level was considerably high. Based on the facility 's single line diagram and measurement data, a selected feeder was simulated using MATLAB-Simul ink, where the original recorded ham10nic current percentage were increased percentage by percentages to predict the limit before violating the standard voltage drop and neutral-to ground (NGV) outlined by the utility provider. The results showed that the magnitude of harmonic current that can be borne by each A, B, and C phase cables and neutral cable are different. Phase cable C possesses the highest spare capacity. The finding of this study may help the facility in planning future load installation by phases such as prioritizing the installation of highly potential harmonic source load to phase C followed by B and A. It was also found that the neutral cable was fur underrated compared to the phase cables hence, in order to make the neutral cable to perform at equal level, neutral cable needs to be redesigned. 111is study also served as a preliminary study that is hoped to have influence to the facility in making decision before adopting mitigation equipment following the severity of equipment malfunction reported. Instead, the facility should inspect the grounding bonding of the facility in finding the source of the problem