Sunday, March 13, 2011

Power Quality Analyzers (PQA) are test equipment designed to monitor and measure electrical power parameters to avoid power quality disturbances (or sometimes to determine the problem as in post-analysis), track steady-state and transient variations, and ensure the reliability of power distribution systems. Simply put, power quality analyzers function to evaluate power quality of a certain electrical system for detection and mitigation purposes.

Power Quality Analyzers (PQA) are available in both three-phase and single-phase units. Most modern PQAs are multifunctional unlike their first-generation counterparts that are only capable of monitoring specific power quality parameters. This make installation and tracking power quality parameters and impending problems very arduous. Conventional power quality analyzers are classified in one of the following categories

Ø      Wiring and grounding test devices
Ø      Multimeters
Ø      Oscilloscopes
Ø      Disturbance analyzers
Ø      Harmonic analyzers and spectrum analyzers
Ø      Flicker meters
Ø      Energy monitors
Conventional Power Quality Analyzer

PQ analyzers nowadays have a combination of the several functions listed above. Usually, modern units are capable of functioning as a multimeter, oscilloscope, energy monitors, disturbance, harmonics and spectrum analyzers.

Modern Power Quality Analyzer
Subsequently, monitoring and the corresponding installation of such power quality analyzers have become easy with comprehensive data results saving valuable time for engineers to analyze the situation and determine whatever power quality problem that will occur or that have occurred. Furthermore, modern power quality analyzers are graphics-based and have a waveform capture capability for detailed analysis of a power quality problem.

Sample Result From Power Quality Analyzer

More About Modern Power Quality Analyzers

Power quality phenomena are measurable events that are triggered by irregularities in voltage or current. Steady-state variations compare changes to normal values and are measured by sampling voltage and/or current levels over time. Power quality analyzers deliver information as individual events, trends, or statistical summaries in monitoring power quality problems. Individual events include voltage sags, voltage spikes and interruptions. Power quality analyzers can also measure transients such as primary magnitude, time of occurrence, and rate of rise. Transients generated by fast-switching electronics, computer systems, aircraft components, and load transfer are immediately characterized as impulsive or oscillatory and detailed for further analysis. Power quality analyzers deliver a full profile, with events time stamped to the millisecond of the entire transient, to locate the exact source and know the cause of the event.

Power quality analyzers collect a range of power and electrical parameters that include voltage, current, and frequency. Also, load-related parameters include volt-amperes (VA), watts (W), and volt-ampere reactive (VAR), frequency instability, power factor and load excursions. Other power quality parameters include power factor, the ratio of actual power to apparent power. Another parameter, K-factor, is a numeric value that accounts for both the magnitude and frequency of the component of a current waveform. Typically, K-factor is used to indicate whether a full-rated transformer is designed to handle non-linear loads.

Power quality analyzer operators can select the length and mode of data recording, including data logging, power quality surveys, advance power troubleshooting, energy and load balancing. Moreover, in-depth analysis using PC-based software and reporting tools are part of the equipment capability. Data interfaces for power quality analyzers include general-purpose interface bus (GPIB), universal serial bus (USB), RS232, RS485, and Ethernet. PQAs that can convert digital to analog signals are also available.

Dugan, R., McGranaghan, M., Santoso, S. and Beaty, H.W. (2004). Electrical Power Systems Quality (2nd ed.). New York: McGraw-Hill.
Kusko, A. and Thompson, M. (2007). Power Quality in Electrical Systems. New York: McGraw-Hill.

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About Me

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I am a Professional Electrical Engineer with a Masters Degree in Business Administration. My interest is in Power Quality, Diagnostic Testing and Protective Relaying. I have been working in an electric distribution utility for more than a decade. I handle PQ studies, power system analysis, diagnostic testing, protective relaying and capital budgeting for company projects.