Power Quality in Healthcare Facilities

Power quality can have a significant impact on a building’s electrical distribution system and the associated loads. The results of poor power quality can range from operational issues and premature failure of equipment to additional charges on your utility bill that can negatively affect an organization’s bottom line. One of the load types proven to be most sensitive to poor power quality is the diagnostic medical imaging equipment found in healthcare facilities including ultrasound, x-ray, computed tomography (CT), magnetic resonance imaging (MRI) machines, and other similar imaging equipment.

The quality of power can be characterized in many ways but is essentially the overall stability and adequacy of an electric supply to a load. This can be measured in deviations of voltage from acceptable ranges, frequency from nominal or rated values, the presence of harmonic currents or distortion, low power factor, to complete power outages. Even the slightest deviations from nominal system values can create noticeable imbalances and instability depending on the load type.

It is often difficult to pinpoint the origin of poor power quality, as diagnosis may require detailed investigation and symptoms can occur at any point within an electrical power distribution system. It can be found at the utility level as well as within the facilities infrastructure. The quality of utility power distributed to a facility can be impacted by other customers on the same circuit, the switching of utility-owned loads such as capacitor banks, reactions to stress on the grid due to increased demand, lightning strikes, or inclement weather. Downstream of the electric service connection, building electrical distribution systems can also see many power quality issues caused by internal components and equipment. Damaging harmonics can be injected onto the system by connected nonlinear loads. Voltage sags, swells, spikes, or imbalances can be caused by the on/off cycling of different load types or even lightning strikes.

Most medical diagnostic imaging equipment will have specific operating tolerance ranges for frequency, voltage, voltage phase-to-phase imbalance, voltage transient magnitude at certain duration and frequencies. When the provided power to the equipment is outside of the acceptable ranges it may cause failure of numerous components and significantly reduce scanning image quality. Poor power quality can also force premature system shutdowns resulting in lost scanning data, or prolonged duration of downtime requiring repairs or system restart.

Resolution to these issues can often be found by implementing one or more of the following: an in-line partial or full uninterruptible power supply system, a centralized uninterruptable power supply system with dedicated distribution, an in-line power conditioner, or emergency generator backup. Increasing the power quality to any medical imaging equipment can greatly improve image quality, reduce system downtime, increase staff productivity, increase patient throughput, and prolong equipment lifetime. If your facility is having medical imaging equipment or any other equipment performance issues, Barton Associates can assist in evaluating your system’s power quality as well as developing strategic plans for integrating the right solution into your infrastructure. For more information, please do not hesitate to contact Michael H. Ginder, PE, LEED AP at 717-845-7654 or mhg@ba-inc.com.