Energy Metering System Validation – Case Study

Powerpoint Engineering Limited recently installed an Energy Metering System (monitoring Gas and Electricity usage on site) at a metal fabrication factory in Cork. The electrical energy meters were retrofitted on existing switchgear, using any existing infrastructure available (Measure-Voltage fused signals and current transformers). The factory is Ireland’s only independently owned manufacturer of extruded aluminium profiles. They specialise in aluminium extrusion, powder coated aluminium and sheet metal fabrication as well as providing many other services from their vast 250,000 sq. ft. facility.

The installed system consists of:

  • 30 Electrical energy meters and 10 gas meters, capturing total site consumption and significant energy users (SEU’s);
  • Modbus data communication over ethernet for all meters;
  • Energy metering software (Powerstudio Scada) with real-time meter reading, historical data trending and automated periodic reporting;

After the system installation was complete, the installed meters were accuracy tested and validated. For electrical energy meters, this is generally achieved by using a calibrated portable power analyser and comparing the installed panel mounted energy meter reading against the reading on the portable analyser. This process ensures that each sub meter reading can be deemed to be valid.

Once the meters had been validated for electrical accuracy, then the communications between the meters and the software system were configured.

In the Energy Metering software, all electrical and gas meters were set up in a hierarchical grouped fashion.

The metering system was now started recording and allowed to log for a time period. After this time period the site was re-visited for final validation.

On this system, there were 3 electrical switch-rooms and one main ESB supply. The were 10 gas meters, including the main incoming gas supply.

As part of system validation, the total energy consumption at the main electrical meters at each switch-room was summed and compared to the total main supply energy consumption (ESB meter). This validation was also performed for all gas sub-meters against the total incoming gas supply meter.

This validation proved successful, where the total of the sub-meters equalled the total main meter for both electricity and gas.

The next level of validation was performed at each individual switch-room. The main meter reading was compared to the sum of the sub-meters at that location. For two out of three of these areas this validation was successful. At one switch-room, it was found that the main meter reading was less than the total of the sub-metered total. On investigation, it was found that the main meter was measuring correctly. This pointed to an issue with one or more of the sub-meters. All sub-meters were found to be reading correctly, with the exception of one meter.

This meter of concern was found to have been configured incorrectly. This was a retrofit project, where some existing wiring was utilised and old meters were replaced with new meters. The assumption was made that the original wiring was correct. It was found that the phase sequence of the meter voltage signal wiring did not match that of the meter current signals. It was also found that the connected load being metered was unusually, highly inductive (75kW, 150kVAr lag, 170kVA, 0.43 power factor). This actual load was validated using a portable power analyser. The panel meter was incorrectly reading 163kW, 170kVA @ 0.96 power factor. This reading would appear to be ‘normal’. It was also noted that the Power Factor Correction equipment was connected to the same busbar with 4 x 50kVAr stages connected (200kVAr total). The meter wiring was corrected and the meter was re-configured. The following table shows the before and after, meter readings:

Meter readings – Before remedial works
Meter Name kW kVA kVAr power factor
Sub meter 163 170 48 0.96
Main Breaker 167 174 49 0.96
Power Factor Correction 200
Meter readings – After remedial works
Meter Name kW kVA kVAr power factor
Sub meter 73 170 153 0.43
Main Breaker 167 174 49 0.96
Power Factor Correction 200

The remedial works now showed that all sub-metered loads were now summing to approximately 98% of the total supply at this switch-room. It was also found that the sum of the switch-rooms main meters summed to the main ESB meter reading (Total site supply).

This validation process in summary should consist of a number of stages:

  • individual meter validation against a calibrated portable power analyser;
  • logging data for a period of time and then compared to utility bills;
  • with reconciliation of sub-metered loads versus main meters;

For further information, email or call us on 057 866 2162, we’d be happy to answer any queries you might have.

Energy Metering Systems

At Powerpoint Engineering we offer energy monitoring equipment and the best solution to all of your energy monitoring and power quality requirements. We have over 24 years’ experience in all aspects of the electrical industry and 20 years’ experience in energy monitoring and power quality.

We supply leading energy monitoring hardware with technical support on all energy meters and sensors. We also supply monitoring equipment to monitor gas and water consumption.

Our sales team can offer a site survey to discuss any technical requirements you may have, to deliver the best metering solutions. 

We offer a full turn key energy monitoring solution for new builds and existing systems, with our online energy monitoring platform or a software that can be housed at your premises, fully designed to meet your requirements with communication installation and configuration.

We can install a non-intrusive energy monitoring system with design, communication installation and configuration, where the client may have critical loads that a power shutdown is not possible or vies able. 

All of our metering systems can be integrated into existing metering and BMS systems.

With the new design of current transformers and energy meters. They are now more compact and safer than ever before. 

Remote monitoring system with our online platform

With our online Energy Monitoring platform, it is now easier than ever to monitor consumption of energy remotely. Our online platform and energy metering system makes it easier for the user to generate reports and monitor the power quality of their plant or power generation station.

We have installed our systems throughout Ireland and Europe. Our Clients include universities, pharmaceutical & bio medical industry, the catering &hospitality sector, utilities sector, hospitals, schools, product production plants and data centres. Also, in some of the most remote parts such as broadcasting stations, Windfarms and Water treatment plants.

Benefits of monitoring energy usage:

  • Real time usage.
  • Energy usage in most cases can have a direct correspondence to production and turn over.
  • Energy Monitoring can produce a trend, overtime it could show early indication of machine failure in pumps and motors.
  • Identify areas with large energy consumption.
  • Identify area where cost savings can be achieved.
  • Monitoring generation of energy.
  • Optimise the use of equipment
  • Measure Efficiency

View a sample of our Clients and Case Studies.

Contact us today to find out more or book your Energy Metering System Survey.

Case Study – Power Factor Correction (PFC) Equipment Failure

Powerpoint Engineering were called to investigate electrical power quality issues in November 2019 at a meat factory in Cork.

It was found on site that the automatic Power Factor Correction (PFC) equipment was overheating and had a history of repeated failures of capacitors and switching contactors.

Some components were replaced and maintenance was performed on the equipment. It was found that the PFC bank was constantly running at full capacity, and under-dimensioned for the site electrical load. A report was issued to the client that the equipment was at end of life and should be replaced.

In February 2020, the equipment finally failed, beyond repair.

At this time it was decided by the factory to replace the equipment. New equipment was dimensioned (Electrically and physically) from the previous maintenance report. A turnkey offer was made to the client for supply, installation and commissioning of the new equipment. The factory ordered the equipment in late March. The equipment was supplied in mid-April, installed and commissioned the same week.

During the 8 week period while the PFC was inactive, the factory bore electrical utility bill penalties of almost €2,000 per month for ‘Bad Power Factor’ charges.

At commissioning, it was noted that there were Panel Mounted Energy meters installed on the incoming supplies. It could be seen that the connected load had > 440kVAr of Watt-less Power component. Once the PFC unit was commissioned and switched on, this Watt-less Power was reduced to 40kVAr and the site power factor was corrected to 0.99 lag. This now has the benefit of eliminating the utility bill of ‘Bad Power Factor’ charges and also the MIC/kVA demand is reduced.

Pay-back/Return on investment calculations were made very easy, with a utility bill reduction of €2,000 per month.

Electric Ireland have an explanation of Watt-less charges on their website at: https://www.electricireland.ie/business/help/efficiency/wattless-charges-for-business—explained.

‘If the number of wattless units you use in a single billing period exceeds a limit of one-third of all your general units (both day and night), then a charge will apply.’ (www.electricireland.ie April 2020)

Email us for further information or call us on 057 866 2162, we’d be happy to answer any queries you might have.

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Read more about the power quality issues faced, and learn what solutions were offered by Powerpoint Engineering Ltd.

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Read more about the power quality issues faced, and learn what solutions were offered by Powerpoint Engineering Ltd.

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TracePQM

TracePQM

The TracePQM “Traceability routes for electrical power quality measurements” research project has now concluded. The overall aim of this project was to develop and validate a modular metrology grade system for the measurement of power and PQ parameters using digital sampling techniques. Arising out of the project, the NSAI, National Metrology Laboratory, Glasnevin, Dublin 11 – www.nsai.ie) hope to develop a capability for the calibration of power & power quality meters and calibrators.

The Project stakeholders included: ESB Networks, UCD Energy Institute, Compliance Engineering Ireland, Fluke Calibration, various European Universities and Calibration Houses and Powerpoint Engineering Limited. Powerpoint Engineering Limited was represented on the Stakeholder’s committee by Garrett Kelly.

More information on this project can be found by contacting Garrett Kelly or at www.tracepqm.cmi.cz.

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This is a synopsis of power quality case study regarding the installation of electrical energy meters, gas meters and water meters at a third level education institution. An ongoing contract with a tertiary education institution has seen the installation of a large number of electrical energy meters, gas meters and water meters which are all connected over the site LAN back to a central PC.

Read more about the power quality issues faced, and learn what solutions were offered by Powerpoint Engineering Ltd.

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