Want to know how does energy meter work? This article will introduce it from different aspects.
Digital Energy Meter Working Principle
A Digital Energy Meter operates by continuously sampling instantaneous voltage (V) and current (I) signals through high-precision transducers. The analog signals are converted into digital values via high-resolution ADCs. An embedded microprocessor or DSP multiplies these instantaneous values to compute instantaneous active power (P = V × I).
The meter integrates power over time to calculate cumulative active energy (kWh), storing it in non-volatile memory. Measured values are presented on an LCD and optionally transmitted via digital communication protocols such as RS485/Modbus RTU, DL/T645, LoRa, or NB-IoT.
Single Phase Energy Meter Working Principle
Designed for single-phase, two-wire systems (L+N), this meter multiplies real-time voltage and current, integrates active power over time, and displays or transmits the accumulated kWh.
Three Phase Energy Meter Working Principle
In a three-phase meter, voltage and current of each phase are independently sampled and digitized. Instantaneous power for each phase is computed:
P₁ = V₁ × I₁
P₂ = V₂ × I₂
P₃ = V₃ × I₃
The total active power is the sum:
P_total = P₁ + P₂ + P₃
Energy is accumulated by integrating this value over time.
Dual Source Energy Meter Working Principle
A dual-source meter has two separate input circuits for voltage and current — typically one for the utility and one for backup power, such as a generator. It independently measures both sources for consumption tracking and source switching.
DC Energy Meter Working Principle
DC meters sample voltage and current from a DC power system, compute instantaneous power (P = V × I), and integrate it to calculate energy (Wh / kWh).
Smart Energy Meter Working Principle
A smart energy meter enhances digital meter functionality by integrating two-way communication (RS485, NB-IoT, GPRS, LoRa, or Ethernet). It supports remote data reading, load control, real-time alarms, tariff switching, and grid monitoring.
Prepaid Energy Meter Working Principle
This meter allows customers to purchase energy credits in advance. Energy consumption deducts from the prepaid balance. When the balance reaches zero, the meter can automatically disconnect the load. Supports remote recharge and credit alerts.
Bi-Directional Energy Meter Working Principle
Used in renewable systems, it measures both energy consumed from the grid and energy exported back to the grid (like from solar or wind systems). It records both import and export energy flows separately and calculates net consumption.
kWh Energy Meter Working Principle
Measures accumulated active energy in kilowatt-hours (kWh) by continuously calculating real-time power (P=U×I) and integrating over time.
| Meter Type | Voltage Range | Application Scope |
| Single-Phase | 220V | Residential, lighting |
| Three-Phase | 3×230/400V | Industrial, commercial |
| Dual Source | 220V / 400V | Backup power systems |
| DC Energy | 10-1000V DC | Solar, telecom, EV charging |
| Smart Energy | 220/400V | Smart grid, intelligent buildings |
| Prepaid | 220V / 400V | Prepaid apartments, dormitories |
| Bi-Directional | 220V / 400V | Distributed generation |
| kWh Meter | 220V / 400V | General-purpose |
To sum up, different types of electricity meters have their own characteristics and applicable scenarios, from single-phase meters that meet household electricity metering to three-phase meters suitable for complex industrial environments. Together, they build a complete electricity metering system to provide accurate measurement and effective support for electricity management and use in different fields.
