An operation such as electricity metering has a specific purpose. It consists in the following: obtaining accurate information about how much was released and how much the consumer of this resource spent. This must be done in order to make financial payments for electric energy, as well as power consumption.
general information
To date, there are two types of electricity metering. Technical accounting is carried out in order to organize power consumption, as well as energy conservation at a specific facility. There is a second type of accounting - commercial. It is used in order to be able to calculate the financial costs of the electricity used. For this purpose, various enterprises and facilities have specially designated places where the means for registering consumed energy are installed.
As for the means for accounting for electricity, these are devices that perform only two functions. They consist in recording measurements and resource consumption. These devices also include several types. There are electricity meters that are designed to account for electricity of the active and reactive type. There are also whole transformers used to record data such as voltage and current. A separate group includes such devices as telemetric sensors, information-measuring systems, as well as their communication lines.
At industrial enterprises, the measuring complex is most often installed. By this we mean a certain number of measuring instruments, which are an integral system operating according to one electricity metering scheme. There is also a more sophisticated system for fixing electricity consumption. It is presented in the form of a combination of several measuring complexes.
Common devices for registration
To date, in order to successfully record data, it is most often electric meters that are used, which are divided into two types - active and reactive, depending on what type of resource they control. In addition, among them there are meters that connect directly to the network itself, and there are those that connect to transformers for measuring current and voltage. A significant difference is that if the electricity metering system includes a meter installed in the transformer circuit, in order to obtain accurate data, it is necessary to multiply the data that are available on it by the calculated coefficient .
For more convenient work with certain transformers there are special meters that are initially calibrated so that they fit a certain type of device. This is usually indicated in their documentation. Such devices are usually called transformer, and you do not need to recount their readings.
There is also a separate group of devices that relate to electricity meters. Single-phase or three-phase devices are used here. They are divided into two types and can be induction or static. It is important to add that both types are electronic equipment.
Metering device
As for induction models, then inside their box there is a movable type disk. A current flows through this element under the influence of an induced magnetic field of a conductive coil. In order to record electricity using such devices, the following principle is used.
The alternating current and voltage that flow in the circuit have a direct effect on the solid state type electronic elements. This effect creates a pulse, which is the output signal. The number of recorded output signals of this type is the expenditure of spent active electricity.
Such devices that are used to verify the metering of electricity must have a metering device. Most often, such a mechanism is made in the form of an electronic or electromechanical device, additionally containing a display for displaying readings, as well as a storage device. Such elements are usually used so that during an emergency power off, those readings that were already on the meter do not get lost. Despite this, in recent years, the industrial industry has been actively replacing all induction devices with electronic ones. The thing is that this type of device is able to provide a higher indicator of measurement accuracy, it is also able to register and store data, and the ability to transfer data has also become an additional function. In addition, electricity meters, acts for which are drawn up during installation, have a higher degree of protection against external interference. This means that interfering with the operation of the device in order to change its readings to false is more difficult.
Switching schemes
Another feature of the electronic meter that affects the connection scheme is the presence of multi-tariff types. Such equipment has a set of counting mechanisms. Each set will be included at a specific time of the day, which corresponds to a certain tariff. The use of such devices has led to the fact that the consumer can choose a tariff that will differentiate by time of day.
Further it is worth saying that there are certain features of connecting any electronic meter circuits. The electricity metering unit, which is supplied with such a device, must be switched on according to a standard scheme, which implies the proper connection of the polarities for data output. This is quite important, since this particular moment of connection will be responsible for the correct operation of the counting mechanism, and will also help to avoid theft. The meter has generator clamps. They must be connected to a power source. In addition to them, there are also load clamps that must be connected to the load current circuit.
When drawing up the act of electricity metering during the installation of equipment, it is necessary to ensure that the system is fully protected. Protection is necessary from such influences as external mechanical damage, exposure to external magnetic fields, as well as from unauthorized interference. In order to provide the necessary protection and to be sure that it was not violated, the installation companies for such devices install two types of seals. The first type of seals are factory seals that are mounted on the meter body and prevent external interference in order to disrupt the operation of the meter mechanism. The second type is organization seals. With their help, financial settlements are protected.
Types of Counters
Installations for metering electricity in the form of active energy meters are by far the most common. It should be noted that such devices have a different accuracy class. This coefficient indicates the largest quantitative error of the instrument readings in percent. If we talk about meters of active energy, then everything depends on belonging to the class. Induction devices have the following accuracy classes: 0.5; 1.0; 2.0; 2.5. As for electronic, there are only four classes: 1; 2; 0.2S; 0.5S. At enterprises and other facilities, there are rules according to which, depending on the purpose and place of installation, it is necessary to select the accuracy class correctly. In addition, the acts of electricity metering may indicate which devices should be installed in certain places. This is quite important, since in the electricity market the requirements for this indicator are quite stringent.
It is worth noting that the consumers of this resource can be not only large enterprises, but also private homes. For them, the installation rules, as well as the requirements for accuracy classes, are somewhat different. If the capacity of the connected consumers does not exceed 750 kW * A, then the accuracy class can be 2.0 and higher. If the power mark of 750 kW * A is exceeded, then the accuracy class must be changed to 1.0 or higher.
A separate topic is the connection of new consumers to an existing network. In this case, if the power again does not exceed 750 kW, then the registration device is changed to one whose accuracy class is 1.0 or higher. If for any reason the power consumption exceeds this indicator, then there is a need to install a device that will measure hourly volumes of electricity consumption. As for the accuracy class, it should be increased to a minimum of 0.5S and higher.
Adjusted energy metering
It so happens that electricity meters are not located on the border of the enterprise’s balance sheet. In this case, there is a need to adjust the electricity supplied to this consumer, taking into account such factors as regulatory electricity losses. Such losses occur in those parts of the network that are the border to the installation site of the metering device. In order to determine the magnitude of these regulatory losses, there is a certain methodology that must be agreed upon in advance between both parties. In order to avoid additional calculations, there are special devices that initially contain algorithms for calculating such losses. In this case, the readings of electricity meters can be immediately used for calculations.
Recently, many enterprises have begun to devote more time to such an issue as reducing production costs for energy resources. A feature of this was that industrial facilities implement such technical areas that can reduce the cost of the electric energy they consume. In addition, along with this, the issue of increasing the efficiency of using the same amount of this resource is also being decided.
Types of energy metering
There is a commercial, or estimated, consumption of electric energy, which is used to conduct financial settlement operations between the supplier of this resource and its consumer. The technical, or control, type of electricity consumed is the accounting process that is carried out within the enterprise when dividing the energy resource into internal facilities.
Commercial electricity metering has some features:
- Most often it is a conservative system. In other words, over time, it changes rather weakly and usually has an established pattern.
- The number of points for accounting for the resource is small, but counters with a high accuracy class indicator are required.
- In order to keep track of the lowest as well as the average level of ASCA, only those technical measuring devices that are on the list of the state register of measuring devices should be selected.
- In order to avoid such a violation as distortion of the recorded data, it is necessary to have seals on all blocks, individual parts, as well as on terminal connections.
Technical features also have their own characteristics:
- Unlike commercial, this accounting usually has constant dynamics of growth and development. This is associated with the development of an industrial facility and its structure.
- Accounting points in this case are also much larger.
- According to the rules, with such accounting it is allowed to use electricity meters with a lower accuracy class. In addition, there are no seals on the part of the energy supplying company.
How is energy consumption accounted for in an enterprise?
To date, there are three methods that are used in the case when it is necessary to record the consumption of electric energy. The first method is the instrument, the second is the calculation, the third is the experimental calculation.
The main way is precisely the first, instrument. This method assumes that the accounting for the consumption of this resource will be carried out using instrumentation. The second method, that is, the calculation, is used only if it is impossible to use the instrumental method from a technical point of view, or if its application is not justified from an economic point of view. The experimental design option implies that the flow rate will be measured using any portable devices, after which the received data will be calculated.
Also, accounting records are intended only for accounting for the electric energy that has been generated or supplied to consumers in order to further the process of monetary settlement. It is carried out by installing electricity meters. There is a slight caveat. In the event that the meter is mounted in the power supply system of the enterprise in such a way that it is below the interface with the power system, then all losses of energy resource that will occur in all elements of electricity supply to the meter are paid by the supplier.
Load graphs
It happens that an enterprise that consumes electricity does not fulfill the declared load schedule. In this case, penalties are provided, and payment is made in accordance with a different tariff. This is one of the features of accounting for electricity readings. For this reason, the company should always monitor the consumption of electricity and regulate it in different workshops, if possible. The following provisions are conditionally accepted:
- The technological process at the enterprise is the same in every cycle or shift, which means that the energy consumption is the same. However, it is possible to adjust the beginning and end of this cycle, if you move the time. This means that it is possible to transfer the maximum load to the electrical network at another time of the day.
- The process is continuous, however, the products that are produced may differ in such a parameter as electric capacity. In addition, the process can be adjusted according to its intensity. All this makes it possible to ensure that the company does not produce highly energy-intensive products during peak hours.
- An interruption of the cycle is allowed at the factory, however, only if the savings in electricity costs will completely cover other inconveniences caused by such a step.
Such enterprises, which have the ability to regulate their energy consumption, are classified as regulated load consumers. Most often, those objects that have autonomous energy sources are carefully considered as such regulators. Such industrial enterprises, in addition to fixing costs, can sell surplus resources, if any. This permission allows you to organize more economical modes of operation.
Home electricity metering
Unlike large industrial facilities, the energy consumption of a private home is much less. However, when compared, for example, with a multi-storey building, this value will be higher. For example, in an apartment of a multi-storey building, the load on the electric meter rarely exceeds 2-2.5 kW. For this reason, most often a conventional single-phase network is installed, and therefore a simple electric meter. In addition, the operation of electricity metering is also simplified. As for a private house, at peak times, the energy consumption parameter can reach 10 kW in power. Naturally, only a three-phase network can provide such a load, and therefore, the installation of a more sophisticated metering device, that is, a three-phase meter, will also be required.
Here you also need to know that there are certain rules that prohibit sharing the load by installing multiple counters. According to the rules, it is allowed to install only one fixing device, which should be located at the entrance to the house. There are also several rules for installing measuring instruments in private housing.
- The connection diagram of the electric meter should have the ability to disconnect the device from external voltage. Most often this requirement is achieved due to the fact that a contact coupling is used.
- Installation of the meter for energy metering in an electric panel is possible only on a vertical wall of a house or on a special rack. The installation height may not exceed 1.7 meters. In addition, the location should be such that nothing interferes with the reading of the meter by a person.