Investigate and analyze power quality issues

Steady, high-quality power supply is not only about availability, but also about power quality. However, identifying the root causes of power quality issues&#;ranging from harmonic distortions and voltage fluctuations to the effects of lightning strikes and equipment failures&#;can be a complex challenge. These disturbances, often invisible to the naked eye, can lead to equipment malfunctions, operational downtime, and even safety hazards. Conducting a thorough power quality survey is the first step towards analyzing and mitigating these issues, thereby enhancing the overall performance of electrical systems.

If you want to learn more, please visit our website SUIN.

This article provides useful tips and gists for conducting power quality surveys and analysis and identifying power quality problems. Whether you are a facility manager, an electrical engineer, or simply interested in electrical system optimization, these guidelines will serve as an essential tool in your efforts to ensure a stable and high-quality power supply.

Before Getting Started

Preparation is Key

Before diving into the measurements for a power quality survey, gathering detailed information about the site is essential. This foundational knowledge allows for a more accurate assessment and identification of potential improvement areas.

The following information must be collected.

Circuit wiring

Determine if the site operates on 3-phase or single-phase power.

Check for the presence of a neutral line.

Identify any mixed circuit wiring, such as 3-phase circuits divided into single phases.

Nominal supply voltage

Confirm the nominal supply voltage(s) &#; 110 V, 220 V, 440 V, etc.

Note if there are multiple power lines with different voltages, for instance, a higher voltage dedicated to the other A/C system.

Frequency

While most power supplies operate at 50 Hz or 60 Hz, exceptions exist. Specialized systems, like those in airplanes or ships, may operate at frequencies up to 400 Hz. It is crucial to verify the frequency of your power lines.

Current capacity

Grasping the current capacity within the system you're measuring is crucial. It aids in selecting the appropriate current sensors for the measurement, ultimately enhancing the accuracy and efficiency of your surveys.

Additional site information

Other information about the building, such as hours of operating key electronic equipment and what equipment has been added or removed, etc.

This comprehensive approach to pre-survey preparation ensures a thorough and effective power quality analysis, setting the stage for actionable insights and improvements.

Steps to Analyzing Power Quality Issues

Finding the root cause of power quality problems can be difficult. The following few tips can help with power quality measurements. Here are 4 tips to help you measure power quality.

1. What?

Understanding is the key to resolving troubleshooting caused by power quality problems. First, we need to know what type of trouble is occurring. A tip is to look for heat or unusual noises coming from the equipment.

2. When?

Next, it is necessary to know when the trouble occurred. Is it cyclical or intermittent? It is better if specific dates and times are known. If an event is recorded, the trouble could be caused by equipment that is running or restarting at that time of day. Knowing exactly what time the event occurred and when the trouble subsided will make it easier to determine which equipment or location caused the trouble.

3. Where?

The next step is to identify the measurement location. For example, if measurements are taken at a receptacle point, the trends in voltage and current may provide useful information. If both voltage and current are falling, the cause can be traced to outside the building. If the voltage is falling, it can be assumed that a short circuit or inrush current caused the problem inside the building. Simultaneous measurements at a number of locations can help identify the cause of the problem.

4. What may be the cause?

Finally, once the measurements have been completed, the root cause of the problem can be deduced. Sort power quality events by specific dates and times, and cross-reference them with site information such as equipment schedules and any recent changes in equipment (additions or removals). This approach can offer valuable clues to pinpoint the cause of issues.

Measurement Tools for Power Quality Analysis

For Measurement

To measure power quality, a specialized power quality analyzer is used. Hioki offers two types of analyzers: the advanced type PQ and the standard type PQ. Table 1 gives an overview of the two types.

Table 1: Overview of power quality analyzers

Product modelPQPQ

• PQ

• PQ

Standard compliance

• Power quality: IEC -4-30 Class A, EN , IEEE
• Harmonics: IEC -4-7, IEC -2-4 Class 3
• Flicker: IEC -4-15

• Power quality: IEC -4-30 Class S, EN , IEEE
• Harmonics: IEC -4-7, IEC -2-4 Class 3
• Flicker: IEC -4-15

Fundamental frequencyDC/50 Hz/60 Hz/400 HzDC/50 Hz/60 HzEvent parametersTransient, swell, dip, interruption, frequency fluctuation, inrush current, THDAdvance event capture features for troubleshooting:

• RMS values
• Voltage/current waveform peak
• Voltage waveform comparison
• Harmonics
• Unbalance factor
• Power
• Mains signaling voltage

N/AAdvance transient measurement: 2MS/s, 6 kVStandard transient measurement: 200kS/s, 2.2 kVBasic harmonics measurement

Harmonics 0 to 50 for V & I

Detect the DC element on the AC circuit (0th order).

Advanced harmonics measurementHigh order harmonics (Supraharmonics) : 2 kHz to 80 kHzN/ABest forWhen it is necessary to investigate, diagnose and countermeasure power supply conditions that cause equipment malfunctions.Where a power survey needs to be conducted to determine the load size of the system or to determine the power quality of the system.

For Analyzing

Measuring instruments are only for recording data, while software is needed for analysis. Let me remind you that both are important. The data acquired by Hioki's power quality analyzer can be analysed using software called PQ ONE.

Here are some useful features of PQ ONE in this area:

• 1.

  Event statistics

• 2.

  Event list

• 3.

  Trend graphs and event details

• 4.

  EN determination function

1. Event statistics

Displays event statistics by date or time. This function makes it easy to discover anomalies that occur at specific times of the day or on specific days of the week. Alternatively, anomalies occurring on specific days of the week can be easily detected

2. Event list

This feature allows you to view all captured events or filter them by specific occurrences, making it simpler to identify power anomalies based on duration and severity.

3. Trend graphs and Event details

Trend graphs give an overall picture of the measurement. Trend graphs make it easy to spot anomalies. Event details provide detailed information on the power quality events that occurred during the measurement. It provides details such as event magnitude, time, length and waveform shape. By analysing these data, clues to power quality problems can be found

4. EN judgment function

This function analyses the measurement data and judges whether or not it complies with the EN standard based on the voltage fluctuations in the trend section. Basically, it judges whether the power quality is good or not.

PQ One software also offers a convenient way to generate reports automatically with just a few clicks.

Finally

By clearly understanding what the true problem is, when and where it occurs, and the causes of those problems, you can take action to mitigate them and improve the power quality on your site. With Hioki&#;s power quality analyzer, you can diagnose even difficult-to-detect problems in power quality.Contact one of our experts today to find out more about how we can help you improve your production process.

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Power quality analyzers

Power quality analyzers

MrJam

(Electrical)

(OP)

28 Jun 05 23:15

      I&#;m looking for the Power quality analyzer that I can get the most out of We&#;ve looked at the Fluke, the Ideal, the AEMC, and the Hioki and have narrowed it down to the Hioki and the AEMC because of the flexibility of these to meters. The hioki is a great deal more then the AEMC. I&#;d like to know why it&#;s so much better. The Hioke has a neutral voltage clamp for each phase that it reads. The AEMC is incapable of giving a neutral ampacity on a single phase 240 system if any one knows of an even better PQA then these to. We have to make a purchase soon and any intelligent input on the matter would be very helpful                   Thank you

Replies continue below

Recommended for you

RE: Power quality analyzers

dpc

(Electrical)

29 Jun 05 00:54

I'm not familiar with these particular devices but some basic issues are the number of channels that can be monitored simultaneously, frequency range (highest order harmonic that can be measured), data storage and playback capability, and input voltage range and isolation rating.  

It probably comes down to what types of systems you will be dealing with and the type of troubleshooting that you do.  

RE: Power quality analyzers

MrJam

(Electrical)

(OP)

29 Jun 05 01:26

That&#;s just it I'm not sure what type of situation I'll need the meter for I don't want to buy it for the current application and then regret that I can&#;t use it for anything else I want to buy a well rounded unit

I'm not familiar with the isolation rating what exactly does that refer to

RE: Power quality analyzers

ScottyUK

(Electrical)

29 Jun 05 07:40

Have a look at the range from Voltech Instruments. Yokogawa also make power analysers which may be worth a look. Get a unit on demo if you can. These are expensive items of equipment - you have the right to try them out before you buy, and the better manufacturers will assist you in this.

----------------------------------

If we learn from our mistakes,
I'm getting a great education!

RE: Power quality analyzers

jschwei314

(Electrical)

29 Jun 05 10:21

Mr. Jam,

A good question and I have the same question also, What Power Quality Meter to buy?

1st.  I am cheap.

2nd.  Fast data logging is what 90% I need.  I need 4 voltage, 4 currents.  The data time stamped and put into a spead sheet.  I would like data every cycle,60hz, RMS value.

The best my HOMEMADE logger can do is 1.5 sec but I have no confidence in my readings, homemade equipment.

Is there a meter out there that can do this for me.

RE: Power quality analyzers

dpc

(Electrical)

29 Jun 05 12:42

The voltage isolation relates to the maximum voltage you can apply to the inputs without causing damage or safety problems.

If you're only connecting to 120V voltage transformer secondaries, this isn't a big concern, but we often do direct 480V or 600V connections and these can see transients exceeding V or probably higher.  

RE: Power quality analyzers

sksimonsen

(Specifier/Regulator)

29 Jun 05 19:56

We purchased a PowerSight Meter several years ago from Summit Technology (

Mr. JamWe purchased a PowerSight Meter several years ago from Summit Technology ( www.summittechnology.com ). I beleive it offers everything you are looking for, and I thought at a reasonable price. They now have a model that has even more capabilities. Check them out.

RE: Power quality analyzers

Skogsgurra

(Electrical)

30 Jun 05 04:15

The LeCroy is extremely good at transients. It has a very flexible trigger with lots of specialised functions. But it has no battery back-up and cannot record what is happening when power returns after a black-out. Also, it has only four channels. It has date and time of day. It can save to hard disk on trigger and communicate over internet.

The Yokogawa (I use a small OR 300) has 12 bit resolution and gives me very accurate recordings. It is fast enough for normal "power transients". It has very good harmonic analysis. The triggering is complete with window out/in, mask triggering (using either an ideal wave or an acquired one as mask). Four channels plus eight logic chanels. AND/OR triggering using results from several channels and lots of other functionality. It has an internal battery that is good for a couple of hours recording during an outage. It can save to PC card on trigger, or fax via an analog modem. It has date and time of day. It is light and very portable.

LabView is VERY FLEXIBLE, but you need some time to set it up and test the functions you have implemented. It can be quite fast and being graphically programmable, you can make it do just about anything you want. Usually eight channels. But more are available. Ties up a computer.

The Dranetz/BMI PP is a dedicated power analyzer. It has four isolated voltage channels and four isolated current channels. It does voltage levels, harmonics, transients, frequency, phase difference, flicker and still some measurements. It can take lots of overvoltage without being damaged and it has a battery for black-out recordings. Data are saved to a PC card (the formatting of which takes a long time - it is called "building data base"). The PP is a typical "disturbance recorder" and is not good if you want to record other things like looking at an automation variable like a changing speed or a valve operation. The PP is also the more expensive of these instruments.

Sometimes, you really need a "recognised" instrument. If you connect an instrument that you know will do the job. And even if you get better results with the LeCroy than with the PP - you will still have a discussion with those people that "are used to" the PP. That's why I have many different instruments.

I also use a FLUKE 41, which is a single phase analyzer. Voltage and current. Handheld. Rather old now, but very useful for a quick look.

There are also some PicoTechnology data acquisitions units on my shelves. I use them for long-term measurements where only a few channels are needed. Can be left for months and save data to disk when something happens. The do tie up a computer, though.

To conclude. There are many possible ways of doing a power quality analysis. I would look for these features:

1  Can it withstand the voltage levels? European 690 V grids can be a problem.

2  Does it have enough channels? A PE-N channel is very good to have. That means at least four (not three) voltage channels. There shall also be at least three current channels - with calibrated current clamps.

3  Does it have battery operation. If it hasn't, you will not be able to see what happens when power returns after an outage.

4  Does it have the triggering possibilities needed? You should have at least voltage level (hi and lo), transients (settable to at least twice the nominal voltage level). There are many other trigger functions that may be useful, like harmonics level, current cunsumption, var consumption and so on. The more you have the better.

5  Can it save the results? A printer is good, but often a problem generator. Better to save to disk, PC card or USB stick. An internet connection can be good, but I do not trust it - nor the fax connection. Too many factors out of your control.

6  Is it accepted by your customer? This is an important point. If you do a measurement and if it is questioned by the utility company or the machine manufacturer, then using a calibrated and universally regognised instrument makes things a lot easier.

7  Can you afford it? If not - wait until you can. Or hire an instrument. In my opinion, owning is much better than hiring. It allows you to "make friends" with the instrument and become a real expert - not just a "Messknecht" (a German expression meaning "measurement infantry man" - or "measurement GI")

8  Do you feel happy with the instrument? Life is so much easier if you do.

I use anything from a LeCroy scope or a Yokogawa recorder or a LabView DacqCard with a logging VI up to a Dranetz/BMI PowerPlatform .The LeCroy is extremely good at transients. It has a very flexible trigger with lots of specialised functions. But it has no battery back-up and cannot record what is happening when power returns after a black-out. Also, it has only four channels. It has date and time of day. It can save to hard disk on trigger and communicate over internet.The Yokogawa (I use a small OR 300) has 12 bit resolution and gives me very accurate recordings. It is fast enough for normal "power transients". It has very good harmonic analysis. The triggering is complete with window out/in, mask triggering (using either an ideal wave or an acquired one as mask). Four channels plus eight logic chanels. AND/OR triggering using results from several channels and lots of other functionality. It has an internal battery that is good for a couple of hours recording during an outage. It can save to PC card on trigger, or fax via an analog modem. It has date and time of day. It is light and very portable.LabView is VERY FLEXIBLE, but you need some time to set it up and test the functions you have implemented. It can be quite fast and being graphically programmable, you can make it do just about anything you want. Usually eight channels. But more are available. Ties up a computer.The Dranetz/BMI PP is a dedicated power analyzer. It has four isolated voltage channels and four isolated current channels. It does voltage levels, harmonics, transients, frequency, phase difference, flicker and still some measurements. It can take lots of overvoltage without being damaged and it has a battery for black-out recordings. Data are saved to a PC card (the formatting of which takes a long time - it is called "building data base"). The PP is a typical "disturbance recorder" and is not good if you want to record other things like looking at an automation variable like a changing speed or a valve operation. The PP is also the more expensive of these instruments.Sometimes, you really need a "recognised" instrument. If you connect an instrument that you know will do the job. And even if you get better results with the LeCroy than with the PP - you will still have a discussion with those people that "are used to" the PP. That's why I have many different instruments.I also use a FLUKE 41, which is a single phase analyzer. Voltage and current. Handheld. Rather old now, but very useful for a quick look.There are also some PicoTechnology data acquisitions units on my shelves. I use them for long-term measurements where only a few channels are needed. Can be left for months and save data to disk when something happens. The do tie up a computer, though.To conclude. There are many possible ways of doing a power quality analysis. I would look for these features:1 Can it withstand the voltage levels? European 690 V grids can be a problem.2 Does it have enough channels? A PE-N channel is very good to have. That means at least four (not three) voltage channels. There shall also be at least three current channels - with calibrated current clamps.3 Does it have battery operation. If it hasn't, you will not be able to see what happens when power returns after an outage.4 Does it have the triggering possibilities needed? You should have at least voltage level (hi and lo), transients (settable to at least twice the nominal voltage level). There are many other trigger functions that may be useful, like harmonics level, current cunsumption, var consumption and so on. The more you have the better.5 Can it save the results? A printer is good, but often a problem generator. Better to save to disk, PC card or USB stick. An internet connection can be good, but I do not trust it - nor the fax connection. Too many factors out of your control.6 Is it accepted by your customer? This is an important point. If you do a measurement and if it is questioned by the utility company or the machine manufacturer, then using a calibrated and universally regognised instrument makes things a lot easier.7 Can you afford it? If not - wait until you can. Or hire an instrument. In my opinion, owning is much better than hiring. It allows you to "make friends" with the instrument and become a real expert - not just a "Messknecht" (a German expression meaning "measurement infantry man" - or "measurement GI")8 Do you feel happy with the instrument? Life is so much easier if you do.

Gunnar Englund
www.gke.org

RE: Power quality analyzers

itsmoked

(Electrical)

30 Jun 05 13:21

Very nice synopsis skogs thanks.

RE: Power quality analyzers

NorthSlope

(Electrical)

30 Jun 05 21:58

It depends on what is most imprtant to you in a "power quality" analyzer.  I have used both an rpm (now made by Fluke)and an AstroMed.  If you want primarilly voltage triggered transients use the rpm. (It has 5 current channels and 4 voltage channels in "Y" configuration),and an AstroMed Dash 18 if you want cycle by cycle recording and are happy to do your own analysis of Megabytes of data.

The rpm does all the normal kW, kVA, kVAR, p.f. calculations and plots them over time.  Its' triggering is not selectable or adjustable by the end-user and is voltage change based - not current change.  On the other hand, the AstroMed is a great, multi-channel (up to 18) recorder with no "intelligence".  It will record to disk any input you can convert to a voltage, millivolts to 800 V pk-pk. at a selectable digitization rate. Great for raw data but you can spend weeks in analysis - depending on what you recorded and what you're looking for.

RE: Power quality analyzers

bacon4life

(Electrical)

1 Jul 05 22:41

I just went to a presentation on the PowerMonic by www.gridsense.net . It is more of a power quality monitor with the analysis part taking place once you download the data to a computer, but it may be worth a look.

RE: Power quality analyzers

cflatters

(Electrical)

12 Jul 05 13:29

I have seen and used the square D power logic range on several jobs (PM650+ > now PM810).  They are excellent instruments and measure all mannor of power quality parameters but do not do real-time waveform capture.

If you need a more powerful option look at the Power Logic CM power quality meter.  I have just specified a unit for a project where I am expecting to experience high levels of harmonics and regen power from container cranes.

I am sure there are some other similiar spec units (ABB ?)

RE: Power quality analyzers

MissMe

(Electrical)

13 Jul 05 08:41
If you need a good Power quality analyzer I would highly recommend LEM Topas (
It can be used as data logger, distrubance recorder, logs transients... all at the same time.
Has a hard disk of 1 GB and can be accessed over the LAN.
It easy to set up and has a powerful software.
Maybe the price is too high, but it's worth it.
MissMe

Hello, MrJam!If you need a good Power quality analyzer I would highly recommend LEM Topas ( www.lem.com ).It can be used as data logger, distrubance recorder, logs transients... all at the same time.Has a hard disk of 1 GB and can be accessed over the LAN.It easy to set up and has a powerful software.Maybe the price is too high, but it's worth it.MissMe

RE: Power quality analyzers

alehman

(Electrical)

13 Jul 05 21:49

I recently purcahsed an Amprobe DM-III. It is fairly inexpensive ($+-) and seems to do a good job with the basics - 3ph. volts, amps, power, VARs, pf, demands and energy usage. It also does harmonic analysis and waveform captures. It is very simple to use and amprobe has several CT options. It's not suitable for analyzing high speed transients.

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