Innovations for power company applications are not limited to monitoring hardware devices that consume grid energy. They can now also provide analysis capabilities to understand the accuracy of meters that could not be tracked on-site before. We cooperate with Helen Electricity Network (a distribution system operator in Helsinki, Finland) and Aidon (a well-known smart grid, smart meter technology and service provider in the Nordic region), using ADI’s advanced terminal-cloud meter analysis solution (using mSure ®Technology) Energy Analytics Studio conducted field trials. This solution can monitor the accuracy of deployed meters over the lifetime and detect multiple types of electricity theft. The accuracy monitoring of electric meters is particularly closely related to the Finnish market, which is also the focus of this test.
Figure 1. Pilot equipment deployed in the field.
The value of precision monitoring
Over time, electric meters deployed in industrial, municipal, and residential environments are vulnerable to severe weather, unpredictable loads, lightning and other conditions. Therefore, the measurement accuracy of the electricity meter may shift or change, resulting in overcharge or undercharge. It takes a lot of time and money to solve the resulting problems, but it is impossible to find errors immediately after problems occur, or prevent errors in advance .
To make matters worse, the power company will lose the trust of its customers because of meter accuracy problems leading to incorrect billing. Nowadays, most power companies begin to conduct regular sampling tests and regularly replace electric meters, but this method is not only costly, but also causes interference to electricity users.
The solution uses a new technology called mSure, which can be integrated into each new meter on the spot, and continuously monitor and report on the measurement accuracy of each meter through cloud-based analysis services. Power companies can use this analysis service to understand the accuracy of all meters deployed, solve meter problems early, quickly replace meters that do not meet the accuracy requirements, and reduce and eliminate meter sampling testing when permitted by laws and regulations, so as to better play Existing advantages of AMI network.
Figure 2. View the accuracy of the electricity meter through a cloud-based analysis service.
In addition, due to the influence of factors such as renewable energy and electric vehicle charging, energy consumption has become more dynamic, and consumers’ electricity bills have fluctuated more, which will lead to consumer inquiries or complaints. This solution allows power companies to quickly evaluate the accuracy of specific meters, avoiding costly on-site inspections, and therefore improving customer satisfaction.
Field test deployment
Since August 2018, Helen Electricity Network has used cloud-based analysis services to view the meter accuracy information of more than 40 evaluation devices using mSure technology deployed on-site. VTT/MIKES, an independent testing company in Finland, verified the accuracy of these devices. The first stage: 19 normal equipments were removed from the site for accuracy testing, and the test results were obtained in October 2018. Phase 2: VTT/MIKES implemented accelerated life testing on these 19 devices, and the test results were obtained in November 2019. Use high-precision test equipment to test to find the reference accuracy of all equipment before the test, and verify the accuracy of the equipment deviation. Figure 3 shows the offset results obtained from the VTT/MIKES test and the implementation of the analysis service after the second phase.
Figure 3. Offset range of stage 2 equipment.
Use cloud-based analysis services with locally installed evaluation equipment connected in series with the main electricity meter. The evaluation device shown in Figure 1 uses ADI’s ADE9153B energy metering IC, integrated mSure technology to achieve advanced diagnostic functions. In this way, the electricity meter sends the original diagnostic information to the analysis service, after analysis, provides warning information, observes the development trend, and provides a health report of the electricity meter. In actual deployment, power companies can deploy meters based on ADE9153B energy measurement chips, and use analysis services to seamlessly utilize mSure’s technical advantages.
Field test results
In the first stage, the data from the cloud-based analysis service was compared with the reference measurement results performed by VTT/MIKES. The results showed that for these 19 devices, the analysis service can track an accuracy deviation better than 0.1%. All 19 devices are strictly grouped, and nearly 0% shows the minimum deviation.
In the second stage, these meters can be aged in an accelerated environment for 8 months to simulate the use of the meters at an average ambient temperature of 30°C for about 10 years. Phase 2 is carried out in a controlled laboratory environment, rather than on-site, in order to accurately assess the performance of analytical services and accelerate the aging process of these meters. Similar to the first stage, the accuracy deviation of the 19 devices tracked is better than 0.1% (as shown in Figure 4), and the accuracy test and analysis service both show that the average negative deviation is about -0.05%.
Figure 4. In the second stage, the equipment difference between the analysis service and the offset result of the VTT accelerated life test.
The laboratory also uses manual methods to age an electric meter to show the ability of the analysis service to accurately track large excursions. The experimenter connected the resistor in parallel with the manganin shunt to change the impedance to achieve artificial aging. VTT/MIKES measured the offset caused by this aging, and the measured value was -1.91%, while the analysis service determined that the accuracy offset of the meter was -1.96%, and there was only a 0.05% difference between the two.
In summary, the first phase of the field test shows that the analysis service can track the accuracy of the mSure technology-enabled meters deployed in the field very accurately. The accuracy error is within 0.1%, but the offset of the meters at this stage is very small. In the second stage, that is, when the analog meter is used in the field for 10 years, the accuracy test and analysis service show that the meter is offset in the negative direction, and the accuracy offset tracking is continuously performed with an error of 0.1%. Proof of field test. The combination of mSure technology and analysis services can monitor the error deviation of the electric meter with sufficient accuracy and replace the sample test of the electric meter.
Mika Nousiainen is the measurement manager of Helen Electricity Network, responsible for the management of measurement assets and measurement services. He has been engaged in the business case and project management of the smart meter project. Recently, he was mainly responsible for the life cycle and partnership management of the meter. Mika has been working at Helen Electricity Network since 2002. He has a master’s (engineering) degree in electrical engineering.