Electricity meters, also called energy meters or utility meters, are gadgets installed by energy companies to measure how much electricity you use. They're usually found near your main electrical panel or in a special meter box located near the front of your home or business.
Each meter has a unique meter number and identification number. This is referred to as an NMI (National Meter Identifier). Your meter number/identification number is usually listed on the second or third page of your electricity bill.
How do electricity meters work?
Electricity meters work by measuring the flow of electrical current and voltage. Regardless of the meter type you have, they measure the amount of electricity you use in watts, which is then converted to kilowatt-hours. A watt is the result of multiplying voltage (volts) by current (amperes), representing the electrical potential.
However, to measure actual energy usage, you need to consider the element of time. All electricity usage is measured in kilowatt-hours (kWh). This accounts for the watts used over a specific time period. For instance, if you have a 100-watt light bulb turned on for 10 hours, the energy usage would be calculated as 100 watts x 10 hours = 1,000 watt-hours, or 1 kilowatt-hour (1 kWh).
Here's a more detailed explanation of the process:
●Current measurement: The meter measures the electric current flowing through your property's electrical system. It uses current transformers to convert the current into a proportional voltage.
●Voltage measurement: The meter also measures the voltage of the electricity supply. This is typically done using voltage transformers or directly from the mains electricity supply.
●Calculating energy consumption: By multiplying the measured current and voltage, the meter calculates the instantaneous power consumption. It then integrates this power consumption over time to determine the total energy consumed in kilowatt-hours (kWh).
●Data recording: The meter records this energy consumption data, which can then be accessed either by a meter reader, or sent directly to your energy provider without the need for a physical meter reading.
Products and reference designs of Basic electricity meter
AC/DC flyback (option one)
Electricity meters derive DC power supplies from the main AC lines. Depending on the power requirements of the electronic circuitry, we offer solutions for flyback controllers that support wide input voltage ranges, various output power levels and high efficiency. AC/DC flyback (option one) includes Flyback controllers、PWM controllers、Shunt voltage references、Isolated DC/DC converters & modules, the corresponding products are UCC28742、UCC28C50-Q1、TL431LI、UCC12040
DC/DC power supply
To generate multiple rails for various sub-systems, we have DC/DC converters, LDOs and OR-ing diodes that can help improve efficiency and reduce solution size. DC/DC power supply includes Buck converters (integrated switch)、Boost converters (integrated switch)、Linear & low-dropout (LDO) regulators、Ideal diode/ORing controllers, the corresponding products are TPS560430、TPS61046、TLV755P、LM66100
AC/DC capacitive drop (option two)
For basic electricity meters with low power requirements, an AC/DC capacitive drop power supply can be used. We have fully integrated AC/DC LDOs or DC/DC converters as well as high efficiency LDOs that can be used with discrete cap-drop power supplies. AC/DC capacitive drop (option two) includes Linear & low-dropout (LDO) regulators、Buck converters (integrated switch)、Buck controllers (external switch), the corresponding products are TLV709、LMR51440、TPS40303
Metrology
The metrology subsystem contains minimal components to measure line current and voltage as well as compute energy parameters. We offer highly integrated metrology SoC microcontrollers with internal ADCs to perform accurate measurement. Metrology includes MSP430 microcontrollers、Noninverting buffers & drivers、Inverting buffers & drivers, the corresponding products are MSP430F47177、SN74LVC1G07、SN74LVC14A
Wired interface
Wired signal interfacing includes transmission of power consumption data through RS-232 or RS-485. We offer various solutions that support the RS-232 or RS-485 interfaces with and without isolation. Wired interface includes RS-485 & RS-422 transceivers、RS-232 transceivers、ESD protection diodes、TVS diodes, the corresponding products are SN65HVD07、MAX3232E、ESDS552、TVS0500
Wireless interface
To comply with advanced metering infrastructure (AMI) networks, meters support various RF protocols. We have solutions for sub-1 Ghz (WMBus, 6LowPAN, WiSUN) and 2.4 GHz (ZigBee, BLE, Thread) low power wireless standards including support for antenna layout and protocol stacks. Wireless interface includes Wi-Fi products、Low-power 2.4-GHz products、Sub-1 GHz wireless MCUs、Sub-1 GHz transceivers、ESD protection diodes、TVS diodes, the corresponding products are CC3301、CC2340R5、CC1312R7、CC1190、ESDS552、TVS0500
Anti-tamper
The tamper protection subsystem detects attempts to compromise the smart meter function via magnetic or mechanical tampering. We offer ambient light sensors, hall effect sensors , and supporting logic to prevent successful tampering. Anti-tamper includes Hall-effect latches & switches、Multi-axis linear & angle position sensors, the corresponding products are DRV5032、TMAG5273
How do I read my electricity meter?
To give your electricity provider a meter reading, you will need to provide five numbers. To read an analog electricity meter, start with the number on the far left dial inside the meter, and read each face in turn towards the far right face. Write down each number in order from left to right to give you the five required numbers.
It’s important to remember that if the dial is in between two numbers, the reading should be recorded as the smaller of the two numbers. For instance, if the dial is between three and four, the reading would be recorded as a three.
When you look at the five dials on an analog electricity meter, the first, third, and fifth dial numbers run in a clockwise direction, while the second and fourth dials run counterclockwise.
Reading a digital meter or a smart meter is easier, as the required numbers are displayed in one panel. If you are not sure that you are reading the correct numbers, contact your electricity retailer for assistance.
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