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In an earlier article, I mentioned that typically buildings represent about 40% of the total energy consumption and costs, so it’s important to “control your energy costs with Fluke’s three-phase power and energy loggers”, but what we didn’t cover are the essential steps you need to consider and follow to ensure you successfully monitor and document energy usage, these are:
1 – Understand the problem or symptoms
Before taking any measurements, it’s best to understand exactly what is happening, especially if you are unfamiliar with the equipment or the environment - an operator may be able to provide insight into when the issue occurs (could happen at a certain time/part of a process / specific machinery is involved), having this insight can be very useful when comparing the data taken from the power quality measurements.
2 – Understand the environment
Reviewing circuit diagrams (if available) to understand how loads are fed, as sometimes it may be evident that a sensitive load is on a circuit that feeds equipment known to cause power quality anomalies, so also aids in knowing where to connect the power quality measuring device.
Take a look at the load, as knowing how they operate/cycle will help you understand the captured data.
Check the electrical connections for anything loose or any overheating – it could be useful to use a thermal camera to quickly spot overheating connections or circuit breakers – it's also useful to take a note of the breaker ratings, as when you review the data any marginal loading problems can be compared to the ratings and help identify the source of the issue.
3 – Connect the power quality measurement device
Connect the voltage leads to the instrument and circuit, paying careful attention to the connector labels and circuit phases.
Make sure the alligator clips are secure and the voltage leads supported, so they don't detach from the circuit.
If connecting via a terminal block with recessed screws, it is recommended to use magnetic tipped probes.
Connect the current probes and ensure the current flow matches the arrow on the probe with the matching phase
If powering the instrument from the circuit, make sure you use the jumper cables from the stackable plugs, or power via an AC power cord
4 – Verify connections
Verify the measurement connections before you start logging, the Fluke 1736 and 1738 power loggers can actually do this for you via the intelligent verification function, if it identifies a connection issue, you can simply make the physical change or hit the “AutoCorrect” button for the instrument to make the changes inside the instrument
5 – Begin with a dry run
It’s always good to do a dry run to verify the setups are what you expect and that the voltages and current readings in the meter mode are what you would expect, as if any of the setup is wrong, you will be repeating the measurements with incorrect or insufficient data.
6 – Secure the location
Make sure the instrument is powered by the mains and not the battery
Ensure all connections are secure and not exposed to any moving parts
Close the cabinet or secure the area so everything is safe
Tag the equipment so everyone knows that the equipment is being monitored (so it’s not disturbed) and who to contact.
7 – Spot checks
Considering you may need to make measurements over a longer period, for example, a week or a month, it’s advisable to do regular spot checks to ensure everything is working fine. At the same time, this may show whether an issue has already occurred or not. If so, you may need to extend the measurement period.
8 – What to look out for?
If you have access to an incident log from the operator, then look at the data just before, during and after the incident and see if any significant changes to the measurement data have happened.
Equipment trips or resets can often be caused by significant decreases in the voltage
With nuisance breaker tripping, look carefully at the breaker ratings and compare to the recorded current recordings as when a load is energized a large inrush current can occur for a short period that exceeds the breaker rating, but at the same time, this increase in current often causes a dip in voltage.
Check the harmonics as an increase in total harmonic distortion can cause overheating and tripping.
9 – Wrapping things up
Once all logging has been completed, carefully pack the instrument away and inspect the area to ensure no loose screws or panels
10 – Reporting
Document what you did and clearly detail the findings - dedicated power quality software makes this much easier.
If the measurements were for a baseline (to compare at a later date if an issue occurs), then a generic report is sufficient
Select the data from around the incident, not the complete data dump
Make sure your conclusions are clear and easily interpreted, especially to someone not use to power quality measurements
Include all data references like thermal cameras for identifying hot spots.
The following video shows how comprehensive power quality and energy studies can be conducted with the Fluke 1736 & 1738 Power Loggers
Fluke 173x Three-Phase Energy Monitor and Loggers:
This article looks at the procedure and considerations needed for successful energy monitoring, however, Fluke has its own in-depth electrical power training program(123-7974), to help you understand and identify energy savings and covers:
Basic DC power and single-phase AC power
Case study: Single phase measurements
3 phase AC power: Symbols and colours, balanced sine wave systems, WYE and delta systems
3 phase AC power: Unbalanced sine wave systems, symmetrical components, unbalanced sine wave examples
Case study: The costs of reactive power
3 phase AC power: Combined power, neutral currents and power summaries
Single phase and 3 phase power losses
An extract of this training course can be found at the bottom of this article.
Fluke Electrical Power Explained Training Course (123-7974)
Fluke 1738 Gold Edition Energy Monitor & Logger + Training Course (178-9015)
Note: Power and energy measurements should be performed by qualified engineers adhering to safe practices with recommended personal safety equipment
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