| Summary: | The majority of energy conservation measures (ECM) implemented by South African Energy Service Companies (ESCOs), are funded by the Eskom Demand Side Management (DSM) initiative. In 2013 Eskom reported a total DSM savings of 595 MW. To measure this effect power usage data needs to be recorded. A slight variance with the accuracy of measurement will however have a significant impact on the reported savings. It is therefore of critical importance to ensure consistent energy measurements throughout the life cycle of the ECM.
A literature study was conducted in order to investigate the individual effects each step of the measurement process contributes toward the overall accuracy. Components investigated include instrumentation transformers, the ADC process and the different signal processing techniques available. The study also investigated different power loggers and their impact on the overall accuracy.
The study found that each component has the potential to affect the accuracy of the measurement. However, the most significant risk to accuracy was not any specific component, but rather the process of installation and setup of the equipment. This prompted the development of a new procedure to address the verification of measurements. The verification procedure consists of three main parts namely, Verify measurements of temporary power logger (1), Evaluation of data recorded (2) and Verification of permanent power logger (3).
The first part verifies the accuracy of the temporary power logger and assists with initial installation on site. Part two focuses on verifying the measurements of the temporary power logger with independent data. It then uses the temporary power logger to verify the measurements of the newly installed permanent power logger. The third part verifies the measurements of a permanent power logger post-implementation of the energy conservation measure.
The new verification procedure was tested on several industrial projects. The procedure identified an omitted load of 1 MW with a potential annual cost impact of R 4.8 million. The procedure also identified several examples of incorrect CT ratios amounting to a combined daily error of 3.4 MW were also identified. This relates to a direct impact of R 16.3 million for the project stakeholders per annum.
There is currently no procedure in place which mentions the need to compare the pre- and post-implementation data. This highlighted the importance for a new verification procedure. Case studies were used to verify the new procedure which was then validated by comparing theoretical calculations and installed capacity ratings. The verification procedure had a significant impact on the overall accuracy ratings of the projects. === MIng (Electrical and Electronic Engineering), North-West University, Potchefstroom Campus, 2015
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