The device and principle of operation of a digital electricity meter

An electronic electricity meter is used to control electricity costs in high-rise apartments. The digital device is connected through a common transformer. During operation, the meter constantly measures the power of a given network section and displays its value in a readable form.

Design and principle of operation

The measuring device is compatible with single-phase and three-phase AC circuits. Its design is presented:

• housing made of heat-resistant plastic or metal with terminal block;
• display - LCD indicator, where data and time are displayed, or mechanical;
• a power source for the electronic circuit;
• current transformer - serves as a meter;
• a microcontroller that converts the input signal into electrical quantities;
• telemetric output for integration with ASKUE;
• clock - allow you to track real time and dates;

  

• supervisor - monitors voltage fluctuations at the input and issues a reset command to the microcontroller when the voltage is turned off or on;
• control system;
• an optical port that allows you to take readings from the device.

A digital counter can be programmed via the optical port.

The principle of operation of a digital electricity meter is to directly measure voltage and current. He digitizes information, transferring it to the indicator and storing it in memory. The pulses of the input electronic solid-state elements are generated under the influence of a voltage current. The number of pulses depends on the activity of the energy.

Main characteristics of digital meters

On the territory of the Russian Federation, devices began to be used from the moment of the privatization of the energy industry and the rise in the price of electricity. Electronic devices have a number of positive characteristics:

• accuracy of readings with a rapid change in voltage or its decrease;
• electricity metering at several tariffs;
• counting different types of energy using one device;
• power, quantity and quality of energy resources are measured at the same time;
• storing data in memory and having user access to them;
• prevention of unauthorized access and theft of electricity;
• remote reading and preliminary calculation of losses;
• compatibility with automatic services for commercial metering of electricity.

The device cannot be hacked by intruders and connected to it to steal electricity. The product inspection interval is 16 years.

Differences between electronic and induction meters

Induction models work on the principle of creating an electromagnetic field in a coil and its interaction with a conductive disk. A single-phase apparatus is connected to the AC coil in parallel. Magnetic fluxes and eddy currents interact with each other only in the disk. The induction meter will function normally with a 90 degree phase shift. Energy consumption depends on the intensity of rotation of the disk, which corresponds to the power consumption.

The principle of operation of an electric meter is based on calculating the power of the active and reactive type.This allows you to accurately calculate energy costs if the room has a three-phase connection type.

Induction models calculate consumption at a single rate, digital devices track parameters depending on the time of day. The measurement accuracy of the new meter is of the 1st category, the traditional ones are produced with an accuracy class of 2.5.

Compared to an induction digital meter, it consumes a minimum of energy for its own needs. Traditional devices cannot be placed outside, and electronic devices can operate in frosty conditions, protected from moisture and dust.

Reliability of indications and the need for repair

A high-quality digital electricity meter is highly accurate. You can check the parameters without violating the integrity of the case and seals as follows:

1. When the power supply is cut off, the indicator stops. If accounting continues, the device is faulty.
2. The counter always buzzes during operation, a self-propelled gun indicates malfunctions.
3. The readings are distorted when all household appliances are turned off. The presence of a self-propelled vehicle is checked.

Testing is best done at night, with minimal load on the power grid. If there is no self-propelled gun, there are no indicator pulses for 15 minutes. An impulse that occurs when the connection is not made means a breakdown.

Only employees of the energy saving company should repair the digital meter. The user applies to the authority to obtain permission to check and replace the device.

Designation of indicators of a digital counter

Based on the data of the electronic meter, several readings are determined:

• Energy consumption for a specific time period. You will need to subtract the initial readings from the final readings. If necessary, the calculated data is multiplied by the transformation ratio;
• Connecting household appliances and lighting at a certain point. It is set by turning on / off the indicator light.
• Power parameters, values ​​of passing current, network and meter overload processes.

Digital devices can be programmed for day and night billing. For this, it is enough to choose the counting time.

Selection criteria

Before buying a device, you should pay attention to a number of parameters:

• Allowable current value. Digital models are designed for a current of 5-60A, which is suitable for apartments and private houses.
• Check date. The three-phase meter must have a seal no older than 1 year.
• Number of fillings. The first sealing is done by state authorities - a mark is put on the casing. The second seal on the clamping lid is from the utility company.
• Optional. The more functions, the more expensive the counter. But the internal tariffifier creates a load graph, and the event log records the increase and decrease in voltage in each phase.
• Service and guarantees. Quality models have a long warranty period. The brand's service center is located in the buyer's city.
• Check interval. Optimally - from 10 to 16 years.
  
• Integration with ASKUE. The readings are automatically transmitted to the provider.
• Phase. Information is indicated on the scoreboard. A single-phase device is marked 220 or 230 V, three-phase - 220/380 V or 230/400 V.
• Number of tariffs. The two-tariff scheme eliminates overpayments for electricity at night.
• Installation method. The digital apparatus is mounted on screws (S or W housing) or DIN rails (R or P housing).

The seller is obliged to put a seal on the device and record its starting readings.

List of the best accounting devices

Several devices are recommended by consumers and professional electricians.

Mercury 201.8

A durable budget device with a 7-digit LCD resolution and accuracy class 1. Designed for a network with a voltage of 220-230 V and a current of 5-80 A. It works well in hot and cold conditions with humidity up to 90%. Equipped with:

• modular body;
• measuring current converter;
• screw terminals;
• LED illumination of the indication zone.

The operational period of the model is 30 years, the revision period is 16 years.

Neva M.T. 123

A device with an operating voltage of 230 V and a rated current of 5 A. Manufacturer's warranty - 30 years. Designed to measure:

• mains voltage frequency;
• active power of the power line;
• indicators of current voltage and strength.

The model has 1 class of accuracy, can be installed in offices, houses, sales areas and apartments.

Energomera CE102M S7 145-JV

The accuracy class of the model is 1. It is not subject to climatic, electromagnetic and mechanical damage. The device is designed for a current of 5-60 A, an operating voltage of 220-230 V. It can work without interruptions at temperatures from -45 to +70 degrees and a humidity of 98%. Additional features:

• tongue;
• non-volatile memory;
• communication interfaces;
• custom reprogramming;
• output of data for the required period of time;
• removal of information without tension.

It is impossible to make corrections in the memory of the counter.

Electronic meters are modern accounting devices with wide functionality. They guarantee accurate measurements, are reliable and resistant to external influences.