Borough Council introduces Power Quality Measurement to nurture Energy Savings Initiative
Measurement of power quality at several council buildings, schools and leisure facilities.
The council will use a Fluke 435-II power quality analyser at council buildings to re-balance loads
- Highest phase load current determines tariff paid
- Load re-balancing aims to reduce energy costs
- First user to be council leisure centre
A borough council has invested in power quality mitigation to recover council-wide energy costs at facilities like council offices, schools and leisure centres, and to investigate power disturbances, writes David Atkins, senior account manager at PASS Ltd.
Payback for investment in power quality measurement equipment can be effectively rationalised in terms of energy savings, but one key additional benefit among many is the ability to analyse circuit trips, the likes of which can bring parts of a facility or entire facilities to a standstill.
Now the council has armed itself with a power quality analyser to investigate the sources of electrical disturbances. The tool the council has chosen for this task is a Fluke 435-II.
The borough council’s electrical maintenance officer explains: “The aim is to measure power quality over a period of time at various council buildings to look at how loads are balanced currently and hopefully then re-balance them in order to reduce energy cost.
Payment on highest phase current
“We pay on the highest phase current, so if the three phases are drawing say 80, 60 and 40 amps, we get charged at 80 amps. It therefore makes sense for us to remove such load power anomalies.
“We are planning to use the Fluke 435-II power quality analyser at a leisure centre and library once it has been refurbished. We are going to hook up the power analyser there for a week and monitor power quality, harmonics, and other load disturbances.”
The leisure centre’s amenities include a six-court multi-purpose sports hall. Facilities also include a swimming pool, active gym, squash courts and a purpose-built dance studio.
Load balancing can be achieved in various ways, from switching cable routes within power distribution boards to physically shifting equipment around, possibly between floors in a building where different supply phases feed different floors. In this instance, he envisages most of the work being carried out within distribution boards.
He adds: “It will mostly mean a few cable swaps on a 400V three-phase supply. The reason we are staring at the leisure centre is that we had an overload issue there not too long ago when one of the fuses popped on our side of the supply, so it will be nice to hook up the analyser to see what loads are being drawn over the three phases and hopefully try to rectify the problem.
“We are also looking at energy assessment and management on lighting design schemes. We can monitor how much power we were using before and after the refurbishment and other such projects by attaching current transformer (CT) clamps around particular cables like the main incoming supply.
“We attach the clamps to the three phases to monitor voltage, what phase is pulling what power in kilowatts and current in amps. The Fluke 435-II power quality analyser is an excellent piece of kit and there are many functions we are hoping to get to grips with. A lot of the equipment we use is from Fluke and we have never really has any problems with them.”
He and a colleague attended a road show organised by the NICEIC in early 2014, where Fluke demonstrated its 435-II. They concluded it would be a useful piece of equipment and set about obtaining funding for it.
Recouped investment
“The kit is not cheap but we are looking to quickly recoup the investment by saving energy not only in council offices and leisure facilities but also at our schools,” he continues.
“When we visited the NICEIC road show, the Fluke representative showed us what it could do. We had already identified the need for power quality analysis on another project some three months before then and so we concluded it would be a good piece of kit to invest in.
“When we attended the demo we were looking at the Power Wave data capture and could see how the voltage, current and frequency values were interacting with one another, which is very useful to us all, and especially the apprentices for training purposes.”
The Fluke 435-II can also be used for troubleshooting things like voltage dips on individual phases of electrical supplies. This will allow the council to determine if there are problems at the incoming supply side of the power distribution panel and if necessary, to negotiate with the power utility if the supply is not in the right quality band.
He concludes: “The reason for the purchase is that we can measure power quality over a period of time in many council buildings. During this time we can check for things like peak operation times, spikes and harmonics.
“I expect the power quality analyser to also calculate energy waste due to poor supply power quality, which is great for our energy management team. Along with this it will be used to help us balance three phase loads more effectively.
“If we do have an imbalance, we could then swap circuits around to balance the phases better. This should hopefully save us money as some buildings will pay on the highest phase. We are also looking for energy efficiency savings when we execute certain types of projects like lighting schemes and so on.
Faults and intermittent issues
“We are going to measure the power load before and after the project to justify energy savings, which again will be useful to our energy monitoring staff. For our maintenance and repairs team, the unit can help us detect faults and intermittent issues that some of our other test equipment cannot detect.
“If we have any major power issues at any of our buildings like swimming pools, theatre and offices, we need to repair the system and get it back up and running as soon as we can. I believe this equipment will help us do that.
“It is also useful from a maintenance point of view if it is monitoring a specific building where there are possible problems which we can repair before we get any downtime.”
For further information on power quality measurement, please visit the power quality page at tester.co.uk.
Power quality measurement equipment from basic to advanced
Power disturbances can affect supply voltage, current and frequency so it is important to improve machinery and equipment efficiency. Power quality analysis provides an early diagnostic tool for repairing machinery to prevent power losses, while using a power quality analyser after equipment or machinery breaks down allows an engineer to quickly assess where the problem is coming from and take appropriate steps to counter it.
Key players in the power quality measurement market include Fluke, Chauvin Arnoux, Amprobe, Extech, FLIR, Hioki, Kewtech and Metrel. Power quality measurement equipment starts from just over a couple of hundred pounds for a basic power clamp meter like the FLIR CM83, to just under £30,000 for a top-end power quality analyser kit like the Fluke N5K with specialised printer.
At the lower end of the market, the FLIR CM83 clamp meter offers key power measurement functions for common electrical parameters and power factor by attaching its 37mm jaws to cables supplying AC or DC current to 600A and voltage to 1000V.
It offers harmonic analysis to 25th order to measure total harmonic distortion, inrush current, active power, diode test, capacitance, resistance, continuity threshold and frequency functions.
Weighing in at just under £5000 for a full kit, the Fluke 435-II described in the adjoining case study offers real-time troubleshooting, allowing the engineer to analyse trends while recording takes place in the background, and automatic transient mode to capture waveform data to 200kHz simultaneously on all phases up to 6kV.
It adheres to the latest IEC standards for flicker, harmonics, and power quality. Applications include energy assessment, quality of service compliance, long-term analysis, load studies, predictive maintenance and front-line troubleshooting.
For the most comprehensive power quality analysis equipment available today, the Fluke N5K sports a 5.7” colour screen for vector diagrams and data display, galvanically isolated inputs, Fast Fourier Transform (FFT) analysis and digital oscilloscope modes as standard.
Weighing around 7kg, the Fluke N5K analyser can also measure speed and torque by using appropriate external sensors. Simultaneous parallel acquisition of phase data allows simultaneous viewing of numerous dynamic events.
Fluke’s NormaView software provides data transfer to a PC to rapidly create power quality reports. With 4MB of on-board memory expandable to 128MB, information may be recalled on the screen at up to 1MHz sample rates and frequency from DC to 10MHz.
