Types of electric energy meters

Electric energy meters are instruments used to measure electric energy and play a vital role in modern power systems and energy management. The following are some common types of electric energy meters:

I. Classification by measurement principle
1. Induction electric energy meter
- The induction electric energy meter is a traditional electric energy meter. It works based on the principle of electromagnetic induction and is mainly composed of voltage coil, current coil, aluminum disk, brake magnet and other components. When current passes through the current coil and voltage coil, induced eddy currents are generated in the aluminum disk, which in turn causes the aluminum disk to rotate under the action of electromagnetic force. The rotation speed of the aluminum disk is proportional to the electric energy consumption. By counting the number of revolutions of the aluminum disk, the electric energy consumption can be measured. For example, in some old residential and small commercial buildings, induction electric energy meters were once widely used. This type of electric energy meter has a relatively simple structure and high reliability, but relatively low accuracy and is easily interfered by external magnetic fields and other factors. Quoted from the knowledge content of the working principle of relevant electric energy meters in 
2. Electronic energy meter
- Electronic energy meter is the mainstream product of modern energy metering. It uses electronic circuits to measure energy. Its working principle is to sample voltage and current, convert them into analog-to-digital data, and then use a microprocessor to process data and calculate energy. Electronic energy meter has the advantages of high accuracy, multiple functions and low power consumption. For example, it can realize time-sharing energy metering and separate statistics for electricity prices in different time periods, which is very beneficial for demand-side management of power departments and electricity fee control of users. At the same time, electronic energy meter can also be easily connected to the communication network to realize functions such as remote meter reading and remote control, which improves the intelligent level of power management. Quoted from [2] on the reliability research of electronic energy meter and other related content.

II. Classification by function
1. Single-phase energy meter
- Single-phase energy meter is mainly used to measure energy in single-phase AC circuit. It is widely used in household users. For example, ordinary residential buildings generally only use single-phase electricity, so single-phase energy meter is sufficient to meet the needs of energy metering. It only needs to connect a live wire and a neutral wire to work properly, and can accurately measure the power consumed by household electrical appliances (such as lights, TVs, refrigerators, etc.).
2. Three-phase energy meter
- Three-phase energy meter is used to measure the power in three-phase AC circuits. Three-phase circuits are more common in industrial production, commercial buildings and large-scale electrical equipment. Three-phase energy meters can be divided into three-phase three-wire energy meters and three-phase four-wire energy meters. Three-phase three-wire energy meters are suitable for three-phase three-wire circuits, and are generally used in high-voltage power supply systems or symmetrical three-phase load measurement; three-phase four-wire energy meters are suitable for three-phase four-wire circuits, and can accurately measure three-phase unbalanced loads. They are widely used in various industrial and commercial places, such as various motors in factories, lighting and air conditioning equipment in large shopping malls.

3. Classification by payment method
1. Ordinary energy meter (post-paid energy meter)
- This energy meter is a traditional metering method. Users use electricity first, and then pay the electricity bill regularly (such as monthly) according to the reading of the energy meter. The staff of the power department will regularly read the meter at the user's place, calculate the electricity bill amount based on the meter reading data, and then the user will pay the bill. This method has been widely used for a long time in the past, but there are problems such as low efficiency of manual meter reading and easy errors.
2. Prepaid energy meter
- Prepaid energy meter requires users to purchase electricity first and recharge the electricity value into the energy meter. During use, the energy meter will automatically deduct the consumed electricity. When the remaining value of electricity is close to zero, the energy meter will send a prompt signal to remind the user to recharge in time. Prepaid energy meters can effectively avoid the problem of user arrears, improve the efficiency of electricity bill recovery of the power department, and for users, they can also better control their own electricity costs.