FEATURE MONITORING & METERING Monitoring electricity meter accuracy Innovation for utility companies is going beyond the hardware that is used to
monitor energy consumption on the grid, bringing forth analytics to understand meter accuracy, which previously could not be tracked in the field. By Mika Nousiainen,
metering manager, Helen Electricity Network; Juha Lohvansuu, technology manager, Aidon; and David Lath, applications engineer, Analog Devices
M
eters deployed in industrial, municipal and residential environments are subject to
varying conditions over time, including harsh weather, unpredictable loading, lightning strikes, and more. As such, measurement accuracy may drift or change, resulting in overbilling or underbilling, which can lead to the customer losing trust in the utility company. Today, most utility companies initiate periodic sample testing and replace meters at regular intervals – methods that are both costly and intrusive. In collaboration with Helen Electricity Network
(a distribution system operator in Helsinki) and Aidon (a supplier of smart grid and smart metering technology and services in the Nordics), a field trial was performed utilising Energy Analytics Studio, Analog Devices’ edge-to-cloud meter analytics solution using mSure technology. This monitors the accuracy of an electricity meter through its life and detects a wide range of tamper types. Meter accuracy monitoring is particularly pertinent to the Finnish market.
TAKE A LOOK AT THE SOLUTION The solution consists of mSure, which can be integrated in every new meter in the field, and a cloud-based analytics service that continually monitors and reports measurement accuracy of each meter in situ. The analytics service provides a utility company with visibility into the accuracy of all meters in its meter population to get ahead of issues, quickly replace meters that are outside of their allowed accuracy limits and, if allowed by regulation, reduce and eliminate sample testing. A utility company can therefore take better advantage of the AMI network. As energy consumption becomes more dynamic
due to renewables, EV charging, etc., consumers’ electricity costs become more erratic. This new solution allows a utility company to quickly assess meter accuracy, avoiding a field visit.
FIELD TRIAL DEPLOYMENT
VTT/MIKES – shows that, for these 19 devices, the analytics service was able to track the accuracy drift to better than 0.1%. All 19 devices were grouped tightly and near 0%, showing minimal drift. In phase 2, the meters were allowed to age
for eight months in an accelerated environment that simulated about 10 years in the field at 30˚C average ambient temperature. Phase 2 was performed in a controlled laboratory environment. Similar to phase 1, the accuracy drift of the 19 devices was tracked to better than 0.1%, (as shown below), but now both the accuracy testing and the analytics service show an average negative drift of about -0.05%. As part of the laboratory experiments, one
Spread of drift of phase 2 devices With the cloud-based analytics service, Helen
Electricity Network has visibility to meter accuracy information for 40 evaluation devices using mSure technology deployed in the field since August 2018. Validation of the accuracy of these devices has been conducted by VTT/MIKES, an independent testing house in Finland. Phase 1, where 19 working devices were removed from the field for accuracy testing, concluded in October 2018. Phase 2, where the same 19 devices were subjected to accelerated lifetime testing by VTT/MIKES, was concluded in November 2019. Testing with high accuracy test equipment was performed to find a baseline accuracy for all the devices prior to the trial and to validate accuracy drift in the devices (see image, above). The cloud-based analytics service is used with
purpose-built evaluation devices, in series with a primary meter. The evaluation devices feature Analog Devices’ ADE9153B energy measurement IC, which includes mSure technology to enable advanced diagnostics. This way, the meter can pass raw diagnostic information to the analytics service, which performs analysis to provide alerts, observe trends, and give reports on the health of the meter. In a real deployment, utility companies can deploy meters based on the ADE9153B energy measurement IC and use the analytics service to gain the benefits of mSure.
View of meter accuracy in cloud-based analytics service 28 AUTUMN 2020 | ENERGY MANAGEMENT
TRIAL RESULTS In phase 1, the data from the cloud-based analytics service – when compared to the reference measurements performed by
meter was artificially aged to show the capability of the analytics to accurately track larger drifts. The artificial ageing was performed by placing a resistor in parallel with the shunt to modify the shunt value. The shift caused by this ageing was measured by VTT/MIKES to be -1.91%, while the analytics determined the accuracy shift of this meter to be -1.96%, or only a 0.05% difference.
IN CONCLUSION Phase 1 of the field trial showed that the analytics service is able to track the accuracy of mSure enabled devices deployed in the field very closely, within 0.1% but little meter drift was seen. For phase 2, in a simulated 10 years in the field, the accuracy drift continued to be tracked at 0.1% as the accuracy testing and analytics showed the meters drifting in the negative direction. The field trial demonstrated the ability for mSure technology coupled with an analytics service to monitor meter drift with enough accuracy to be used in place of meter sample testing.
Analog Devices
www.analog.com
Accuracy drift of the 19 devices was tracked
/ ENERGYMANAGEMENT
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