In recent years Power and Energy Loggers (PELs) have become more prominent in the facility manager or site electrician’s arsenal as their many different use cases increase, particularly those concerning energy efficiency and maintaining the economic and reliable performance of the electrical installation.
Whether it be for identifying inefficient equipment, which is responsible for 20% of the electrical energy used by the average UK SME, or reporting out of hours electricity use, which accounts for 46% of UK SME electricity consumption, many businesses are already benefitting financially from investing in a PEL.
Add to that the PELs ability to identify poor phase loading and balance, which would otherwise result in one or more phases carrying a higher current than the others. This increases losses due to heating and reduces the available supply capacity, and at its worst, could lead to a voltage imbalance that negatively affects some of the 3-phase equipment in the same installation. Fortunately, the measurement of voltage and load (current) balance, and therefore the identification of imbalance, is easily achieved using a PEL.
A Power and Energy Logger will also monitor and record power factor, with poor (low) power factor reportedly affecting almost 50% of UK businesses resulting in higher energy bills. Poor power factor also impacts on the reliability of the installation itself and can cause a variety of electrical issues that may result in the early failure of capital equipment. This equipment often gets replaced at great expense without the root cause ever being observed or identified. Poor power factor can also impact heavily on the capacity to add new loads when a business expands.
Logging with a PEL to determine maximum demand is rapidly growing due to the complexity of the diversity calculations required, the fact that the figures in the IET On-site guide are out of date, and the large margins for error built into the calculations. In many recent cases logging has revealed an actual maximum current demand significantly lower than that arrived at using the prescribed diversity calculations, and generally with significant implications on cost savings pertaining to expansion work or determining supply suitability.
PV / Battery installation surveys are being performed using PELs prior to embarking on a solar PV project, enabling businesses to gain a comprehensive understanding of their electricity usage patterns by measuring consumption throughout the day and night, assessing variations on a daily, weekly, and monthly basis, and identifying seasonal fluctuations due to factors such as lighting, heating and air-conditioning. The data captured by the PEL provides valuable insights into the actual energy consumption patterns, identifying peak demand periods and usage trends. Information that is imperative when sizing battery systems.
In addition to these existing uses for Power and Energy Loggers there are a few “modern day” issues that are now being reported, one of which is the increasing numbers of businesses that are having problems with their EV chargers unexpectedly shutting down. This mostly concerns light industrial, commercial and other similar sized facilities that take a 230V single-phase or 400V 3-phase supply from their energy supplier, rather than those on higher voltage supplies with their own substations.
Aside from the EV charger being faulty or poorly installed, one of the main reasons for them shutting down is being found to be due to a high mains supply voltage, with every EV charger having a manufacturer-set threshold over which they will not operate.
The permitted voltage tolerance in the UK is –6% +10% which for a single-phase supply gives an upper limit of 253V, and 440V between phases for a 3-phase supply. It is the responsibility of the Distribution Network Operator (DNO) to maintain the supply voltage to within these limits and accordingly, many EV charger manufacturers set a maximum supply voltage threshold based on that. However, there are a growing number of businesses with EV chargers experiencing problems, with single-phase mains voltages as high as 259V, and phase to phase voltages of 450V being reported.
The same issue is also starting to rear its head in the PV world with grid tied inverters that should be exporting energy failing to do so and reporting high grid voltage alerts instead, and installations with combined PV / battery systems having batteries set to charge during the night on low-cost tariffs, that simply haven’t. This is again caused by a manufacturer-set threshold designed to protect against over voltage.
While it is the DNO’s responsibility to maintain the voltage within limits, customers with EV and PV shutdown issues are finding the best way to get them to investigate and resolve the problem is to prove to them that it exists. To do that they need to somehow measure and record the mains voltage over time with something appropriately accurate, and for this they are best served by using a PEL.
To summarise, the logging of electrical parameters in an installation is becoming increasingly common for a variety of reasons, and these new EV and PV issues provide further justification for facility managers and site electrician’s considering benefitting from investing in a PEL.
Whatever the electrical installation logging requirements the best solution is to use a 3-phase portable power and energy logger like the PEL104 from Chauvin Arnoux. The PEL104 is a powerful tool that measures and records key parameters such as voltage, current, frequency, power factor, as well as power and energy usage. It even measures and records individual current and voltage harmonics, a feature generally reserved for power quality analysers.
It can log from a few seconds to a few months, with all measurements being recorded to a standard SD card which can be read directly with a PC. Alternatively, measurements can be retrieved via Wi-Fi or the integrated web server. The PEL104 is complemented by Chauvin Arnoux’s PEL Transfer and Dataview PC software packages which makes it easy to analyse the results and to generate preformatted reports.
With all of this in mind, there has never been a greater need or a better time to buy a PEL, but when you are choosing a power and energy logger it pays to think carefully about the instrument you’re buying. PELs are not all the same and are not hard to use, but there may be times when a little advice and guidance will be welcome. Chauvin Arnoux UK not only have a reputation for delivering quality products, but also for providing expert support should it ever be needed. Why not put us to the test. www.chauvin-arnoux.co.uk