For grade selection, the electric energy metering devices in operation can be divided into five categories according to the amount of electric energy they measure and the importance of the measured objects
Class I electric energy metering device
Electric energy metering devices for high-voltage billing users with monthly average power consumption of 5 million kwh or above or transformer capacity of 10000kva or above, 200MW and above generators, power generation enterprises' on-line electricity consumption, electricity exchange points between power grid operation enterprises, and power supply gateway metering points of provincial power grid operation enterprises and their power supply enterprises.
Class II electric energy metering device
Electric energy metering device for high-voltage billing users with monthly average power consumption of 1 million kwh or above or transformer capacity of 2000kVA or above, generators of 100MW and above, and electric energy metering devices at power exchange points between power supply enterprises.
Class III electric energy metering device
The monthly average power consumption is 100000 kwh or above or the transformer capacity is 315KVA or above, the power consumption of generators below 100MW, the power consumption of power plants (stations) of power generation enterprises, the metering points used for contract assessment in power supply enterprises, and the electric energy metering devices for 110KVA and above transmission line lines to check the balance of active power.
Class IV electric energy metering device
It is a kind of electric energy metering device for billing users with load capacity less than 315KVA, internal economic and technical index analysis and assessment of power generation and power supply enterprises.
Class V electric energy metering device
The single-phase power supply electricity user charges the electric energy metering device.
Class I electric energy metering device shall be equipped with at least 0.2S or 0.5s class active power meter, 2.0 class reactive power meter and 0.2 class transformer.
Class II electric energy metering device shall be equipped with at least 0.5s or 0.5 class active power meter, 2.0 class reactive power meter and 0.2 class transformer.
Class III electric energy metering device shall be equipped with at least 1.0 class active power meter, 2.0 class reactive power meter and 0.5 class transformer.