Power quality is of major concern to all types of industries, especially those operating with critical machinery and equipments. Poor quality of power leads to major problems like break-downs, production interruptions, excess energy consumption etc. Modern industries require automation of their operation enabling them to produce quality products and also for mass production. The conventional systems are being replaced by modern Power Electronic systems, bringing a variety of advantages to the users. Classic examples are DC & AC Drives, UPS, soft starters, etc. Since the Thyristor converter technology is rapidly gaining ground in the modern industrial plants, the power supply systems are contaminated as the ideal sinusoidal current and voltage waveforms are getting distorted. This in turn is affecting the performance of the equipment in the electrical network.

The myth that the UPS system is the ultimate power protection method is only true to certain extend and depends for a great deal on the technology deployed. Beside this, most power disturbances within a data centre or telecom room are caused by the equipment itself. New power supplies often used in today’s equipments is based on switch mode instead of the traditional linear mode used years ago.

Switch Mode power supplies draw high peak currents at high frequencies causing current and voltage disturbances to its upstream supply. When using multiple equipments on a single power layout, which is very common in data centers, the problem is compounded. This can result in issues which are often blamed on hardware and software such as random reboots and system hangs spurious characters and slow network performance, higher than normal failure rates on particularly network equipment, network/system cards and hard disks.

Other issues such as imbalance, high harmonics and other factors often lead to unacceptable levels of Normal Mode and Common Mode Noise which are considered to be the most damaging factors for today's equipment. The Power Quality Audit (PQA) is providing an in-depth analysis of the power quality. The measurements and evaluation will be based on international norms for computer equipments.