SYSTEM METERING Station metering systems will enhance easy viewing, assessing and vetting of bulk supply point metering and bills by generation companies. Electronic data on the periodic interval profile of voltages, currents, demands and energy will enrich load studies, power outages studies and energy audit studies. In Ghana about 200. out of the 1000. of feeders have AMR compliant meters. An example of its impact on loss reduction and monitoring system was the detection of over 3 mil kWh energy leakage from only one 11 kV customer when a trend of meter bypasses was investigated against the feeder serving it. Many more meter bypasses have been detected with that approach. Boundary metering and area management Boundary metering is the installation of AMR compliant meters for the measurement of import and export energy at remote locations of identified area boundaries where electricity flows across operational areas. Its terminal objective is to technically measure and commercially segregate electricity consumption at various management areas of the distribution processes for the appropriate apportioning of sales, revenue and system losses. With this method, different management teams can apply strategic approaches and their effort measured to achieve an overall impact. loss canker. Though the project is at its preliminary stage with ECG, strategic moves are being developed at various areas of the company to own the losses and work at reducing them. AMR for Distribution Transformers Automatic Remote Meter Reading technology for DTs is the ultimate system to enhance AMR technology to be deployed for other high consuming customers who share public transformers. This defines the scope for sizeable and effective loss reduction programmes to specifically address identified leakage sources. It is also used to ensure a healthy life span for transformers. Additional benefits include easy access to an electronic soft copy of metering data like voltage variation trends, power outage occurrences, loading of transformers and many more technical data points for performance indicators. It is simply the installation of AMR In conclusion it is important to emphasise that system metering is a tried and tested system. If utilities wish to really improve upon their system reliability as well as reduce system losses as they strive to become more viable and be amongst the best in Africa, they need to first measure – and continuously measure – electricity at various stages of their operations. System metering is the long awaited measuring instrument. It is very effective with a remote meter reading system and complete meter data management software. This metering system tool is a strategy to co-opt the commitment of area managements in the drive to reduce loss reduction. compliant meters at the low voltage side of DTs for the measurement and logging of voltages, currents, power, energy and harmonics and notifications of power outages. This definitely has been a missing link in the overall drive to reduce losses for most institutions as the overall losses of a company are summarised as one with no appropriate indication of areas contributing heavily to the overall figure. In this case, the performance indicators of management teams in different operational areas are now being extended to cover system loss figures. This has generated constructive competition amongst operational areas to address the system 26 • Limited scientific segregation of technical and commercial losses at any given time except on one-time study basis every 5 years. • Regional loss figure calculated with some assumptions, i.e. that no electricity flows across boundaries. • Very limited means of identifying sources of commercial losses in the distribution network. • Inability to tell which transformers/ operational areas are responsible for the worst commercial losses – assumption or speculative calculations. • Limited means of checking whether loss figures have reduced after an intervention in some areas. • Limited scientific ways of studying the trend of voltage, currents and energy usage per public transformers. • Limited means of power outage notifications except through customer calls. • Limited means of checking the unbalanced loading of transformers and assigning new customers to specific phases for acceptable load balancing. • Limited feedback on causes of unplanned power outages, transformer burning etc. Used for effective load balancing and management of public transformers, these meters are read remotely through a Web Application database, providing easy viewing, assessing and analysis of data. Ways to determine if a utility could benefit from system metering: • Calculation of losses is derived from total BSP purchases as against total sales (bills) figure for all consumers. No loss figures for primary station, operational areas or per distribution transformer. If utilities, particularly in developing countries, develop their business plan with the big picture in mind, they will see how meters can better serve the achievement of the terminal objective of reducing losses. MI ABOUT THE AUTHOR: Eng. Sariel Etwire has worked for the Electricity Company of Ghana (ECG) since 1995, and has 18 years’ working experience in metrology and implementation of various LV, MV and HV metering systems in Ghana. She has supervised several metering projects that have advanced the integrity of the metering systems of the company and reduced the company’s commercial losses. She currently manages the company’s Meter Laboratory, the AMR Metering Project and the System Metering Project of her company. About the company: The Electricity Company of Ghana (ECG) is a limited liability company wholly owned by the Government of Ghana and operating under the Ministry of Energy (ME). ECG is responsible for the distribution of electricity in the southern part of Ghana namely, Ashanti, Central, Eastern, Greater Accra, Volta and Western Region. Its system loss figure for December 2013 was 23.37%. METERING INTERNATIONAL ISSUE - 2 | 2014