IEC 62053-21:2020 applies only to static watt-hour meters of accuracy classes 0,5, 1 and 2 for the measurement of alternating current electrical active energy in 50 Hz or 60 Hz networks and it applies to their type tests only.
This document applies to electricity metering equipment designed to:
• measure and control electrical energy on electrical networks (mains) with voltage up to 1 000 V AC;
• have all functional elements, including add-on modules, enclosed in, or forming a single meter case with exception of indicating displays;
• operate with integrated or detached indicating displays, or without an indicating display;
• be installed in a specified matching socket or rack;
• optionally, provide additional functions other than those for measurement of electrical energy.

Link

https://webstore.iec.ch/publication/28660

Technology

Forecasting (RES)

Smart metering infrastructure

Integrated Grid