Power Quality Monitoring Power quality monitoring is the process of gathering, analyzing and interpreting raw measurement data into useful information. The process of gathering data is usually carried out by continuous measurement voltage and current over and extended period. Why needed? What are the objectives/consideration? The monitori ng objectives often determines the choice monitoring equipment, triggering threshold, methods of data acquisition and s torage, analysis and interpre tation requirements. There are several common objectives of power quality monitoring such as i) Monitoring to characterize system performance ii) Monitoring to characterize specific problems iii) Monitoring as a part of an enhanced power quality service iv) Monitoring as a part of predictive or just-in-time maintenance
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
8/2/2019 Dr. Hannan Week9 Power Quality Monitoring
Site survey are performed to evaluate concerns for power quality and equipment performance
throughout a facility. The survey will includes inspection of wiring and grounding concerns,equipment connections, and voltage and current characteristic etc. This information is specially
important when monitoring objective intended to address specific PQ problems. This information
are as follow;
i) nature of problems
ii) Characteristics of sensitive equipment experiencing problems
iii) time at which problems occur
iv) Coincident problems or known operationv) possible source of power quality variations
vi) existing power conditioning equipment being used
vii) Electrical system data
8/2/2019 Dr. Hannan Week9 Power Quality Monitoring
Digital oscilloscope: data storage available for analysis i. e. energy calculation and spectrum analysis
Communication to pc for additional analysis using software.Over
Hand-held oscilloscope: Display waveform, performing signal processing, portable and permits
connection with PC for further data analysis.
Disturbance Analyzer: Disturbance analyzer and monitor measure a wide variety of systemdisturbances from short duration transients to long duration outage or undervoltage. Basically,
there are two types;
Conventional analyzers: Over voltage/under voltage magnitudes, sag and surge magnitude and
duration, transient magnitude and duration
Graphics-based analyzers:Display, save and print the actual waveform of the disturbances
8/2/2019 Dr. Hannan Week9 Power Quality Monitoring
►Flicker meter measures the level of flicker. The flicker evaluation level can be divided into two
Categories such as follows;
i) Short term Pst: Evaluation of flicker severity based on an observation period of 10 minute
Where the percentages P0.1, P1.0s, P3.0s, P10.0s and P50.0s are the flicker level that are exceeded0.1, 1.0, 3.0, 10,0 1nd 50.0 percent of time, respectively.
ii) Long term PLT: The long term variation flicker assessment of flicker severity is determined by
using PST equation
Where N is the number of PST reading and is determined by the duty cycle of flicker producing load
SSSSST PPPPPP5010311.0
08.028.00657.00525.00314.0 ++++=
N
P
P
N
i
ST
LT
∑== 1
3.
8/2/2019 Dr. Hannan Week9 Power Quality Monitoring
►There are many advance PQ monitoring system are equipped with off-line and on-line
intelligent systems to evaluate disturbances and system conditions so as make conclusionabout the cause of the problems before they occur. Out of many, the three types are
as follows.
i)Industrial PQ monitoring application
ii)Power system performance assessment and benchmarking
iii)System maintenance, operations and reliability applications
8/2/2019 Dr. Hannan Week9 Power Quality Monitoring