What tests are required for a qualified smart electricity meter?

In today's world, not wearing a watch is no longer unusual, but not having an electricity meter is a serious issue. As a measuring instrument vital to people's daily lives, the electricity meter is an essential tool for power consumption measurement and billing in every household. According to current national strategic requirements for smart grid development, smart electricity meters have been widely applied and promoted, bringing entirely new and extensive market opportunities to the metering industry.

In the early 1990s, households commonly used traditional mechanical meters. When connected to a circuit, these mechanical meters carried two alternating currents through coils, generating alternating magnetic fluxes in their iron cores. These alternating magnetic fluxes passed through an aluminum disc, inducing eddy currents within it. The interaction of these eddy currents with the magnetic field produced a torque, causing the aluminum disc to rotate. The greater the load power, the larger the current through the coil, resulting in stronger eddy currents and a larger rotational torque on the disc. The power consumed by the load was proportional to the number of rotations of the aluminum disc. In contrast, smart electricity meters are composed entirely of electronic components. They first sample the user's voltage and current, then use dedicated electronic integrated circuits to process the collected voltage and current data, converting them into pulses proportional to the electrical energy. Finally, a microcontroller processes these pulses and displays them as the measured electricity consumption.

The verification methods for these two types of meters also differ. Traditional mechanical meters measure power consumption by detecting mechanical work—meaning the meter only rotates and records usage when electrical appliances are operating. Outside of active usage, the mechanical meter does not accumulate readings. Compared to traditional mechanical meters, smart meters not only provide energy measurement but also offer intelligent management functions such as data recording, electricity usage monitoring, and information transmission.

However, it cannot be ignored that smart meters are ultimately electronic devices, susceptible to interference from weather, electromagnetic fields, and other external environmental factors. Their measurement accuracy is not only crucial to the economic benefits of power companies but also directly affects consumers' financial interests. Therefore, to better improve the quality of smart electricity meters, conducting necessary testing is indispensable.

Verification procedures generally include general mechanical and electrical requirements and test conditions, functional marking requirements, requirements and test conditions related to climatic and electromagnetic environments, tests for resistance to external influences, embedded software requirements, as well as auxiliary input and output circuits, operating indicators, and test outputs for energy measurement equipment.

Typically, the electromagnetic immunity capability of smart meters is evaluated by testing their performance under various electromagnetic disturbances. The standard GB/T 17215.211, "Electrical measuring equipment for AC—General requirements, tests and test conditions—Part 11: Measuring equipment," specifies various immunity tests for smart electricity meters.

Currently, this standard is undergoing further revision, with the updated version adding more interference factors. An important new test item has been introduced for electromagnetic compatibility (EMC) immunity testing of smart electricity meters: short-duration overcurrent testing. The standard specifies a peak impulse current of 6000 A as the maximum current, specifically designed to assess the damage and performance changes in smart electricity meters caused by instantaneous high-power current pulses.