Tarık Ateş  
Smart Meter Solution Manager  
Aktif Mühendislik

WHAT IS ENERGY METER?

The hardware which can measure produced/consumed electrical energy is Electric Energy Meter or shortly Meter.

Briefly, Energy meter measures to electrical power and application time of this power. Therefore, unit of this calculation is Wh (Watt/hour). There are a lot of unit definitions created form here. 1.000 times of Wh is kWh (kilowatt/hour), 1.000.000 times of Wh is MWh (megawatt/hour), etc…

WHAT İS THE DIFFERENCE BETWEEN ENERGY METER AND ENERGY ANALYZER?

The biggest superior features of Energy Meters from Energy Analyzers are; sealable structure, inerasable memory/display and it don’t need any auxiliary power supply. To be able to talk more about these capabilities of energy meter, we first need to mention the types of energy meters. There are a lot of energy meter types. We can group to these energy types according to current values of measurement points, structure of energy meters and connection of measurement points.

ENERGY METER TYPES

• According to measurement points current types;
  • AC Energy Meter
  • DC Energy Meter
• According to structure of energy meter;
  • Mechanical Energy Meter: The Energy meter operates according to the torque created by the magnetic field generated by the current passing through the current coil and the voltage falling to the voltage coil on the aluminum disk. Numbers on the numerator value increase while the disk turns.

Electronic Energy Meter: As it can be understood from the name, it is the type of meter that allows measurement with electronic circuit, much more precise than mechanical meters, advanced system and communication options to be explained in the further. Although the meter is designed as a standard product when it is described in this way, the equipment used or not used (rogowski bobbin etc.) can change both the measurement accuracy and the internal consumption which cannot be expected from a meter. Especially, at last times when the energy efficiency is very important. Energy distribution firms must take into account to this fact because of their huge energy meter system investments.

• According to Physical Connection;
  • Direct Connected Energy Meter: It is a type of meter which can connect directly to the circuit with 100 ampere and 120 ampere in some special meters without needing any current or voltage transformer.
  • CT Connected Energy Meter: These energy meters work up to 5 ampere measurement current level, and they are regroup according to voltage transformer usage on voltage measurement point.
    • LV (Low Voltage): These energy meters use only current transformers for measurement. They don’t need any voltage transformers. They can be connected to Low voltage directly.
    • HV (High Voltage): These energy meters use current transformers and voltage transformers.

Note: Electricity meters used in transmission (TEİAŞ) or any other places where sensitive measurement is required have to be high accuracy class, especially in solar (GES), wind (RES) and hydroelectric (HES) plants where production, transportation or consumption are made at very high rates.

At this point, accuracy classes of used current and voltage transformers used as reference are very important. Therefore, if you use high precision energy meter, it will be proper that to use high accuracy class measurement transformers too.

You can take help from linked page for proper transformer selection subject.

• According to Phase Connection
  • Monophase (Single phase/two wired Measurement): Generally, This type energy meters are used for small residential and lighting areas consumption.
  • Polyphase (Three phase Measurement):

• • • Three Phase/Three Wired (ARON) Connection: Generally, It is used at balanced loads. At this connection type, Provide gains from current and voltage coils.
    • Three Phase/Four Wired Connection: It is connection type that every phase energy are measured separately and total energy consumption is calculated.

ENERGY METERS NAMED ACCORDING TO MEASUREMENT PARAMETERS:

• Active Energy Meter: This type energy meters can measure only active energy as energy parameter. These energy meters can be used at residential and small workplaces.
• Active/Reactive (Combi) Energy Meter: Combi energy meters measure active and reactive energy together. These type energy meters are used at high energy consumption points like factories, big shopping malls, etc… There are two type reactive energy as inductive and capacitive. Especially, because of needed high reactive energy, system require a reactive compensation. If specific limits are passed, there can be happen very serious sanctions. For that reason, Reactive energy must be measured in these point.

TARIFF ENERGY METER:

There are three type tariff.

• According to Demand Power: When subscribing with the distribution company, contracts can be made in two forms, single term and double term.
  • Single Term Subscription: It is only the charge of electricity consumed at a certain price.
  • Double Term Subscription: At this subscription type, customer pays extra additional price according to their demand power with his consumed energy price. There must be a demand measurement featured energy meter for this type usage.

Disadvantages: At Double term subscription, The energy unit price is lower than single term subscription because of agreement according to demand power. But, Unit price will be increased as a punishment if the demand power limit is passed over.

When the distribution company considers that the infrastructure is designed, designs are made to meet the existing demand forces and unnecessary investments are avoided.

• According to Time Lines:
  • Single Tariff (Single Time Line) Subscription It is subscription type that only single unit price is used for all 7/24 time line.
  • Multi Tariff (Multi Time Line) Subscription: This tariff type can be divided like day, night and puant (maximum price time line) time lines to 24 hour. The main target; is to pull subscriber consumption from the peak rate of high consumption time line (puant) and direct it to the overnight rate, which is less general consumption.

In some countries, additionally holiday tariff can be used too.

• According to Used Supply (Network/Generator): This tariff type energy meter systems generally used in Shopping Malls and Residential structures. Goal in this tariff system to separate normal price of network energy and expensive cost of generator energy in energy meter.

REFERENCES