Connection diagram for a three-phase meter Mercury 230 am. Connection diagram for test box with current transformers

When installing metering devices for three-phase consumers, they are often connected via current transformers (CTs). This scheme makes it possible to reduce the cost and increase the reliability of power supply. The fact is that direct connection metering devices do not produce more than 100 Amperes. This is due to the physical dimensions of the conductors - what more current, the larger the cross-section required for its passage. These restrictions are removed by the use of TT. Next we will tell you how to connect the test box with current transformers.

Purpose

When connecting the meter to the CT, a special instrumentation device is used - a test adapter terminal box or, as it is also called, IKK (pictured below).

The appearance of the terminal block, the contacts are specially grouped and jumpers are installed. Using the block allows you to safely disconnect and remove the electric meter for inspection or replacement. In addition, using IKK you can connect instruments for taking measurements without disturbing the circuit.

Installation diagram

The figure below shows electrical diagram connecting the meter through the test terminal box:

Let's take a closer look. A wire connected to the 380 volt power buses comes to the terminals in the block marked A, B, C, and then goes through jumpers to the meter.

From the transformers the wire comes to terminals 1-7. Then it goes to the counter via jumpers. If necessary, the jumpers unwind and move, breaking the chain. This allows you to remove the mains voltage and ensure safe operation of the device connected to the test box.

The IKK is equipped with a protective transparent cover and a device for sealing, a screw with a through hole. Removal and installation of the seal on it occurs simultaneously with the meter. The photo below shows an assembled panel with a Mercury electric meter and current transformers. This electrical panel is prepared for installation in a box.

The "Mercury-230" meter is equipment that is designed to meter power and energy (reactive, active) in one/two directions in three-phase 3- or 4-wire systems AC(50 Hz) via instrument transformers. It has the ability to take into account tariffs by day zones, losses, as well as transmit readings and information on energy consumption via digital interface channels.

Specifications

The Mercury-230 meter has the following technical characteristics:

• Overall dimensions - 258x170x74 mm.
• The weight of the device is 1.5 kg.
• The time interval between verifications is 120 months.
• Average time between failures is 150,000 hours.
• Average service life- 30 years old.
• Warranty period - 36 months.

Functionality

The three-phase meter "Mercury-230" performs storage, measurement, accounting, output to the LCD and subsequent transmission via interfaces electrical energy(reactive, active) for each tariff separately and in total for periods of time for all tariffs:

• From the moment the readings were reset.
• At the beginning and for the current day.
• At the beginning and for the previous day.
• At the beginning and for the current month.
• At the beginning and for each of the previous 11 months.
• At the beginning and for the current year.
• At the beginning and for the previous year.

Accounting parameters

The Mercury-230 meter is capable of monitoring 4 tariffs for 4 types of days in 16 time zones of the day. This equipment is programmed monthly in accordance with an individual tariff schedule. Within a day, the minimum period of validity of the tariff is one minute.

Also in power transformers and power lines, technical losses can be taken into account.

Parameter measurement

Additionally, the Mercury-230 meter can measure the following parameters in the network:

Logs

The following information remains in the logs:

• The time when Mercury-230 was turned on/off.
• Time to increase the set power and energy limits.
• Time of correction of the tariff schedule.
• Closing/opening time of the device.
• Time of appearance/disappearance of phases 1,2,3.

Interface

You can connect the Mercury-230 AM meter in this way using various schemes, in each of which current transformers will be used as a unique source of information.

The ten-wire connection diagram is considered the most common. Its main advantage is the availability of measuring and power circuits. The disadvantage of this connection option is the large number of wires used.

The sequence of connecting the meter and transformers looks like this:

• Terminal No. 1 - input “A”.
• Terminal No. 2 is the input of the end of the measuring winding “A”.
• Terminal No. 3 - output “A”.
• Terminal No. 4 - input “B”.
• Terminal No. 5 is the input of the end of the measuring winding “B”.
• Terminal No. 6 - output “B”.
• Terminal No. 7 - input “C”.
• Terminal No. 8 is the input of the end of the measuring winding “C”.
• Terminal No. 9 - output “C”.
• Terminal No. 10 - phase zero input.
• Terminal No. 11 - phase “zero” on the load side.

When installing a metering device for connecting to an open circuit of transformers, special terminals are used, designated L1 and L2.

Another option for connecting a meter using a semi-indirect circuit is to combine the current transformers into a star-like configuration. In this case, the installation of the meter is simplified, since installation requires fewer wires; this is achieved by complicating the internal circuit. Such changes do not in any way affect the accuracy or quality of the readings.

There is another connection option using current transformers - seven-wire. Today it is completely outdated, despite the fact that it can be found in real conditions. The main disadvantage is the lack of galvanic isolation of measuring and process circuits. This feature makes this circuit dangerous to maintain.

For metering devices operating using transformers, a special requirement is formulated in the regulatory documentation: between the meter and electric wire it is necessary to install a contact block or panel through which all necessary connections are made.

If necessary secondary winding is bypassed and the reference meter is connected to the measurement system. The presence of the block greatly simplifies installation. Equipment can be removed and replaced without interrupting the main power supply.

Instrument transformers used in metering devices do not always have the specified parameters. After a certain time they should be checked.

It is important to consider these details when taking readings. Semi-indirect connection schemes require additional attention. Sales organizations prefer to work with direct-connection devices.

Meter "Mercury-230": indirect connection

This option for connecting a metering device is not used in the domestic sphere. The indirect scheme is designed to account for electrical energy on the buses of generating enterprises. These include nuclear, hydraulic and thermal power plants.

Current transformers are installed on the busbars that extend from the generator. Data from the transformer terminals is sent to a metering device that records the amount of generated electrical energy. The latter, through distribution devices, along transmission lines, arrives at consumers connected to the network.

The three-phase electricity meter "Mercury 230" is considered a new generation electricity meter - it has telemetry outputs and an interface for data exchange. The meter is equipped with an electronic seal and can diagnose itself automatically.

The specialists of the 10 kilovolt company have been trained by LLC NPK Incotex, a manufacturer of Mercury electricity meters, and have the necessary certificates. Installing the most modern electricity meters is not a problem if professionals get down to business. Call - our employees will advise on issues of connecting electricity meters , conducting electricity to the site, electrical testing and electrical installation work.

Electric meter "Mercury 230"

The Mercury-230 series of electricity meters is used to account for active, active and reactive energy forward and reverse direction of alternating current, at a frequency of 50 Hz, in 3 and 4 wire electrical networks. The meter is connected both directly and using a transformer method: connecting current transformers to the Mercury 230 meter allows you to account for electricity at facilities where the current load is high.

The LCD display gives readings in kilowatt-hours (or kilovar-hours when measuring reactive energy). The display is 8-digit: 6 digits correspond to integer values, the last 2 show two decimal places, which corresponds to hundredths of kWh.

The meter corresponds to error class 1.0 according to GOST R 52322-2005. According to operating conditions, the Mercury-230 meter must be installed indoors: this is group 4 of GOST 22261-94, where the operating temperature range is from minus 40 to plus 55 degrees Celsius.

Connecting the Mercury 230 electric meter through current transformers allows you to measure a current that is obviously greater than what the electric meter is designed for. Connection three-phase meter Mercury through current transformers is carried out according to the following scheme:

Connecting "Mercury 230" via current transformers

The Mercury-230 meter has the ability to tariff electricity metering by zone of the day, takes into account losses and transmits measurements and accumulated information on energy consumption via digital interface channels.

According to many experts, "Mercury-230" is one of the most common electric meters for commercial accounting - without a doubt, this is one of best models Russian company-manufacturer of metering devices LLC NPK Incotex.

The spread of the model is facilitated by a large number of modifications, which are intended both for ordinary users and for electricity metering as part of the ASKUE.

Reliability characteristics of the electricity meter "Mercury-230"

The following can speak about the quality of products of LLC NPK Incotex: technical specifications reliability:

• Minimum time between failures up to 150,000 hours;
• Interval between verifications: 10 years;
• The average service life of the device is 30 years;
• The warranty period for "Mercury-230" is 3 years from the date of manufacture.

Call! Specialists of the 10 kilovolt company will help you turn on the meter and program it to the required tariff schedule.

The main assistant in saving electrical energy is a correctly selected meter. When purchasing, you will need to decide what type of meter is needed: single-phase or three-phase.

Meters of this type are characterized by increased reliability and technical characteristics. Previously, they were used to control electricity in production and enterprises. But on at the moment they are used to construct an electrical system in country houses. Why is this necessary? Increasing the number of electrical household appliances, which require more power from the network. It was decided to electrify houses. Read how to connect a grounded outlet.

If we consider the differences between three-phase and single-phase meter, then initially they stumble upon a parameter such as voltage. In the case of a single-phase device, it is equal to 220 V, but three-phase meters can operate with a voltage of 380 V. The design and principle of operation of the electric motor are described.

As for the advantages of a three-phase meter over a single-phase one, then:

• The three-phase device allows you to save significantly at night. This parameter is equal to 50%.
• It is fashionable to choose an option that will have the appropriate technical characteristics. The device corresponds to a certain accuracy class. The error in this case varies from 2 to 2.5%.
• Mono notate changes when analyzing the event log.
• There is a built-in electric power modem. He is responsible for exporting indicators over the network.

As for the minuses, this is overall dimensions and the need to have the experience and skills to install this type of equipment.

Types and device

Today there are only three types of three-phase meters:

When it becomes necessary to install a meter of this type, difficulties may arise that are directly related to their connection. If when installing a single-phase device you can use one schematic diagram, then in the case of three-phase meters, different schematic designs can be used. Read the guide on how to choose a detector hidden wiring and how to use it.

Connection diagram

It goes without saying that the connection diagram for a three-phase meter will have many similarities with connecting a single-phase device. However, there is a fundamental difference in this matter. This circuit will be depicted on the device body, or rather with reverse side its covers.

It is very important to remember that when connecting, you should follow the color sequence. In this case, even numbers of wires are the load, and odd numbers are the input.

There are the following options for connecting a three-phase meter circuit: