Power quality monitoring ensures continuous, error-free operation of data centers. Without clean, stable power, racks of computer servers cannot be counted on to provide data in a moment’s notice. Power quality analyzers provide the measurements needed to check the status of the power flowing to those servers. The measurements must be accurate and precise because even minor power disturbances to data center servers can result in loss of data and expensive errors for all relying upon the data. 

Modern data centers serve constantly growing numbers of customers, including network operators and cloud operators with many of the customers relying on continuous service. Data centers guard against power failures and degradation of power quality via multiple backup energy sources, often combining diverse power sources, including sustainable renewable-energy and solar-power sources. As demand for data and the power to back it grows, data center power density grows along with it, often requiring application of new thermal management technologies to maintain the performance of compact network cabinets with increasing loads. 

Even so, data centers must carefully balance workloads in the cloud and those powered directly at the data center. The slightest disturbances in power quality can be damaging and costly to a data center and its users. Excess harmonic energy, for example, can not only lead to loss of data, but also loss of equipment not engineered to handle elevated levels of harmonic distortion.

Power quality monitoring is a proven means of assuring reliable, high-quality power for a data center. When orchestrated by suitable software tools, measurements for power quality monitoring can protect against and prevent costly downtime of data centers and servers of all sizes. 

Test instruments equipped for power quality monitoring should be capable of measuring voltage and current, total harmonic distortion (THD), high-order harmonics, and energy consumption under various conditions, such as before and after a modification to the power infrastructure is made. In addition, recording voltage and current events that can cause problems can provide a warning of conditions that might lead to a power failure. Also, the capability to measure conditions such as dips, swells, and inrush currents can warn of power conditions or events that might trip circuit breakers. A well-equipped test instrument for power quality monitoring features manual and automatic operation with suitable resolution and accuracy that can provide information technology (IT) professions with accessible measurement data to check on instabilities and other problems with a data center’s power. The test results can help achieve increased power efficiency at a data center and support extended operating lifetimes for its IT equipment under stable power conditions. 

 

Probing Power

The Fluke 1736 Three-Phase Power Logger is well equipped for power quality monitoring and contained in a compact portable package. It studies all three phases and neutral connections of a power line after a simple setup procedure. Supplied with four probes which it automatically detects and scales when connected, the Fluke 1736 can set measurement averaging intervals from 1 s to 30 min. It can measure voltage as high as 1000 V RMS with 0.1-V resolution and current to 600 A (6000 A peak). Test results are shown on a 4.3-in. color touch-screen display with 280 × 272 pixel resolution. They can also be saved directly to a USB flash drive or transferred from the 1736’s internal memory via USB, Wi-Fi, and Bluetooth wireless connectivity. Data are saved as PC-compatible file formats for ease of analysis with measurement software programs, including Fluke Connect® mobile connectivity software. 

With its detachable power supply, the Fluke 1736 can be powered by a standard AC outlet or from the circuit it is testing, across a range of 100 to 500 VDC. It performs all the measurements needed for power quality analysis, logging the results automatically at specified averaging intervals. It can measure RMS voltage, RMS current, voltage and current events, voltage and current THD, voltage and current harmonics as high as the 50th harmonic, and power factor (PF). Depending upon averaging interval, the 1736 integrates enough memory to log as much as a year’s worth of test data for a comprehensive analysis of a data center’s power quality. 

The Fluke 1777 Three-Phase Power Quality Analyzer also provides four input ports for logging three-phase power quality measurements and can also be used as a troubleshooter to find problems. Depending upon probe, it can measure voltages to 1000 V RMS (1700 V peak) and voltage transient events with 14-b synchronous sampling resolution to 8 kV. It can also measure current from 1 to 6000 A with its four probes. As with the Fluke 1736, the Fluke 1777 features simple setup, with operational power drawn from the circuit under test. Logging averaging times can be set from 1 s to 30 min. It tackles measurements of over 500 power quality variables, including dips and swells and harmonics to the 50th harmonic. The Fluke 1777 is supplied with Fluke Energy Analyze Plus software for ease of creating customized reports. 

The Megger MPQ1000 Power Quality Analyzer also measures voltages to 1000 VAC and 1000 VDC. The handheld unit is a flexible and compact instrument ideal for three-phase power quality monitoring and load balancing. It performs a wide range of measurements and can record data for voltage, current, power, energy, harmonics, total demand distortion (TDD), THD, and transients. Equipped with generous data processing power, it aggregates test data per the IEC61000-4-30 Class A standard. The MPQ1000 includes a clean front-panel display with simple controls and provides scope and DMM modes to ease measurements. It can capture events as brief as 1 µs and save data via SD card or USB port. 

The AEMC Instruments PEL 103 Power & Energy Logger measures voltage, current, power, and energy on three input channels, recording to SD cards as large as 32 GB. It logs single-phase and poly-phase test data at 50/60 Hz and 400 Hz, saving 128 samples per cycle at 50/60 Hz and 16 samples per cycle at 400 Hz. It measures, calculates, and displays harmonics to the 50th order for 50/60-Hz circuits and to the 7th order for 400-Hz circuits as well as the many measurements vital to power quality analysis, such as active power, reactive power, PF, and THD. Its measurement versatility is contained within an enclosure weighing only 8.8 lbs. (4 kg) with backlit liquid crystal display (LCD). 

In an even smaller portable package, the Dranetz HDPQ XPLORER-400-PLUS Power Quality Analyzer offers four differential AC/DC test channels rated to 1000 V. It measures AC/DC voltage with 16-b resolution, AC/DC current, and transient events and can operate with an AC power supply or for 2.5 h on its own rechargeable battery. It weighs just 4.2 lbs. (2 kg) with a bright 7-in. WVGA color graphics screen. For communications, the analyzer incorporates Ethernet and USB ports, with Wi-Fi available as a wireless communications option. The portable power quality monitor is compliant to IEC 61000-4-30 Class A Edition 3 and IEEE 1159: 2009. 

When measuring and monitoring time stamping matters, the Hioki PQ3198 Power Quality Analyzer offers GPS time synchronization. It provides four isolated measurement channels with the capability of analyzing power and efficiency on two circuits simultaneously. It performs 50/60-Hz voltage, current, power, and frequency measurement accuracy of ±0.1% and can monitor 400-Hz lines. The PQ3198 complies with the IEC 61000-4-30 Ed. 2 Class A standard. It can capture continuous voltage, current, power, and energy as well as transient events such as swells, dips, and interruptions.

Additional information on these and other power quality analyzers can be found on the Transcat | Axiom Rentals website (www.Transcat.com) or by contacting an advisor at 800-264-4059.