The maximum power of electricity and methods for its determination. Electrical connection: what is "maximum power"? How is it calculated? Official clarifications of power engineers

After buying a home on the secondary real estate market, first of all, the new owners, as a rule, change the wiring. In the process of this, it turns out that with the replacement of the introductory circuit breaker, not everything is so simple. If for the installation of the same type of model it is enough to call the electricians of the company providing services, then for the connection of AB with a large rated current, it is required to submit an application so that the allocated power of electricity is increased. Detailed information on this issue is provided below.

What is "allocated power capacity"?

To explain the meaning of this term plain language, then the allocated (or allowed) power is the maximum allowable load on the consumer's network. It is established in accordance with current regulations and is indicated in the power supply contract.

Those who want to understand this issue in detail should have an idea of ​​the connected, installed, one-time and permitted power. Let's give short definition each of them:

• Attached, this term means the total installed capacity of all electrical receivers powered from the consumer's network.
• Installed- specified in technical documentation to electrical equipment, that is, one in which consumer devices will operate in normal mode.
• One-time – calculated value power consumption of electrical installation equipment for a certain time.
• Dedicated (allowed)- the maximum one-time power that the consumer can connect to the grid of the power supply company. This parameter is indicated in the technical specifications for the connection of energy receiving facilities and in the contract between the consumer and the organization supplying electricity.

What is the danger of exceeding the permitted power?

At the moment, when an excess is detected maximum load the power company introduces a mode of consumption limitation. The reason for this is a violation of the obligations prescribed in the energy supply contract. As a rule, consumption limitation is a shutdown electric current. The algorithm for sending such a notification is shown in the figure.

After 10 days, after sending the notice, the company performs a power outage. To avoid this, the consumer must eliminate the violation within ten days, and then contact the service provider to draw up an appropriate act. Electricity supply will be resumed after the electric company has paid a penalty in accordance with the contract.

More serious consequences may arise if, in addition to violating the amount of allocated energy, an accusation of uncontrolled consumption of electricity is brought. The basis for this will be the removal of seals from the introductory machine. You can get more detailed information about the consequences of uncontrolled electricity consumption, electricity metering rules, etc. on our website.

Rules and Regulations

The electrification of any facility is carried out in accordance with the specifications developed by the company providing electricity services. In one of the paragraphs of this document, the parameters of the allocated power for the consumer's network are indicated. The power supply company forms the specifications on the basis of the declared capacity, justified by calculations.

During the electrification of residential and public buildings are guided by SP 31 110 2003 and temporary instructions PM 2696 01. According to these documents, residential buildings belonging to the 1st category are not standardized in terms of power output. That is, if there is technical possibility, then such objects are formed on the basis of the submitted application.

For residential buildings of the 2nd category, two electrification standards are provided:

1. 5 - 7 kW, for private house or an apartment with gas stoves.
2. 8 - 11 kW - with electric stoves.

In this case, the lower threshold for power release is provided for small apartments in houses under construction under the social housing program. Note that these standards were established relatively recently; for electrical installations of residential facilities built before 2006, they were lower.

How to find out how much power is allocated?

Those who do not know the amount of permitted power for a house or apartment can use the following methods to obtain information:

1. Get a certificate from the power supply company. It should be borne in mind that such a service is considered paid, for example, in Mosenergosbyt, you will have to pay from 1.3 to 3.1 thousand rubles for it, depending on the category of a residential facility.
2. Search for the required parameter in the power supply contract or technical specifications.
3. Obtain information empirically by looking at input parameters protective device. The fact is that in most cases, in addition to its direct functions, it plays the role of a power limiter. To set its maximum value, it is enough to know the operating current of the machine.

The figure shows a diffuser with a working current of 32 A (I nom). Therefore, the maximum allowable load power can be calculated by the formula: P max \u003d U x I nom x 0.8; where U is the rated voltage of the network. Therefore, 230 x 32 x 0.8 ≈ 5.5 kW.

Of all the options presented, the first one is the most reliable, especially since a certificate will still be needed if it is planned to increase the allocated power (it is included in the package). required documents).

A calculation based on the operating current of the introductory machine should not be trusted too much. Some models of modern electronic counters have a built-in load relay. In such cases, the rated current of the machine may be overestimated.

Calculation of the required power

This calculation will be needed to understand whether the amount of allocated electrical power for an apartment or house will be sufficient. To do this, you will need to calculate the maximum load by summing up the relevant parameters of all consumer electrical installations. Moreover, it is necessary to take into account all household electrical appliances that can be turned on at the same time.

As a rule, all the necessary information indicated on a sticker affixed to the equipment case or provided in the documentation. In the event that the sticker has become illegible, and the technical passport has been lost, you can use the table that shows the typical active power of household equipment.

After calculating the total consumption, do not rush to consider the work completed, you need to add a reserve, taking into account the possible increase in load over time. As a rule, the size of the reserve is set at 20-30% of the calculated parameters.

By adding these two values, we get a result that can be compared with the allowed power. If it turns out to be less than the calculated loads, it makes sense to think about applying for an additional 1 kW or 3 kW. Details on the connection of additional kilowatts will be discussed below.

How to increase the allocated power?

Unfortunately, consumption electrical energy do not keep up with the increase in active load. In residential premises, more and more household power receiving devices appear, the simultaneous operation of which causes the thermal protection of the input AB to operate. There are only two ways out of this situation:

1. Reduce household consumption by refusing the one-time operation of a piece of equipment, which may cause some discomfort.
2. Contact your electricity supplier for additional capacity.

Since consuming less electricity is not an option, the latter option is the most rational. Consider how to increase the amount of electricity to individuals and legal entities. Let's start with the first.

For a private person

The algorithm of actions can be conditionally divided into the following stages:

1. Preparation of necessary documents.
2. Drawing up a project for the electrification of a residential facility.
3. The process of coordinating the developed project with the company providing services for the possibility technological connection or increase electrical power.
4. Project approval in local authority Energy Supervision.
5. Inspection of the electrical installation with the subsequent preparation of an appropriate report and an admission certificate confirming the readiness of the facility for operation under the new conditions of power supply to power receiving installations. The report is compiled by an employee of the electric company, the act of admission - by a representative of Energonadzor.
6. The completed documents are sent to the electric company, after which it increases the amount permissible load(released power).

Now we list the package of necessary documents, they are almost identical to those needed when connecting electricity:

As a rule, the company involved in the development of the project simultaneously offers services for its implementation. In some cases, it makes sense to use their help so as not to waste time.

For legal entities and enterprises

Technically, the procedure for allocating additional capacity for legal entities and private traders is practically the same. The difference lies in the package of necessary documents. For example, instead of identity documents, it is necessary to prepare constituent documents.

Each certificate, contract, photocopy of a document, etc. must be certified by the round seal of the consumer enterprise and the signature of the responsible person.

Important to know:

Electricity consumption is constantly increasing. According to the latest data, only the kitchen in a standard apartment began to spend twice as much. But besides this, computers, air conditioners, microwaves… Power grids that have been operating for decades often cannot cope with today's demands. In this situation, it is important to have an idea of ​​​​what the calculated power is and what load the network in your apartment can withstand.

How much electricity does your apartment use?

Residents of new old houses today connect all necessary equipment: computer, oven, microwave, air conditioning, stove and extractor. To avoid a power outage, you need to find out in advance how powerful the cable is to the apartment. That is, to what extent it can be loaded.

These data are contained in two documents. First - « The act of delimitation of balance responsibility » . It indicates which trails the tenant owns and what the terms of that ownership are. You can get this paper in the HOA or in another service of operation. Second document - « Information about permitted capacities » . Here, specific figures for the estimated and installed capacity are already indicated.

Estimated power (or one-time switching power) is the power that makes it possible to connect a certain amount of technology in the apartment. If something else is connected in addition, the protective automation will fail. If you add together the power of all electrical equipment in the apartment, you get the installed power. But we cannot connect all at once, as the network will be overloaded, and protective automation will again work. It includes RCDs, differential automata. Thanks to protective automation, we ourselves determine how much we can load the network in the apartment. In older houses, these numbers, of course, will be less.

There is such a concept as input". Let's explain clearly. On the landing there is an electrical panel, an introductory machine, from which the cable goes to the apartment. If the whole system is located inside the apartment itself, then the cable starts desired section. After that, an automatic machine is installed that protects the wiring, then a meter, then an additional machine and a shield that distributes the load along the lines.

In most old houses, the power supply single-phase- classic 220 volt. Just it does not allow to load the line too much and connect everything modern devices that you would like to have at home. For this you need three-phase input, that is 380 V. It consists of three lines that redistribute the total load. As a result, with intensive consumption of three-phase power, the load is distributed equally to each of the phases. Therefore, if you want to electrify your home to the maximum, you must first figure out whether your current is single-phase or three-phase. If this is the last option, then there is no problem. Such input is available in almost all new houses. It is approximately 14-20 kW on input, that is, it is permissible enough a large number of household appliances. However, with regard to old buildings, as a rule, there is only an aluminum cable with a load capacity of only 4 kW.

Let's see what is 4 kW at home. According to the standard in a residential apartment on square meter usable area needs lighting 15 to 25 W. Let's say the area of ​​the apartment 100 m2, take the average 20 W: 100X20=2000 W. It's already 2 kW. And it's just light. For example, if you wished to have heated floors in the bathroom and kitchen, then this is a plus 100 W per 1 m2. So what else 20 m such floors - here's more 2kW. As a result we have 4 kW, and, it turns out, nothing more can be connected. But it's simply impossible. Now everyone has a computer that consumes about 500 W, a washing machine that takes about 2 kW! The dryer will take its 2.5 kW, dishwasher 2 kW, oven - 4-6 kW, hob - 6 kW. How about without a kettle? The kettle will "eat" its 2.2 kW, so that, in general, one can type and 15 kW and more. So, first of all, when you are going to install another electrical appliance, find out what input cable you have. If it is single-phase, then count on normal work nothing. We will have to contact the housing and communal services with a request to allocate additional capacity.

What if you want more?

If possible, then you will receive a permit in your hands, and pay for the corresponding work. This means that an additional cable with the required cross section will be connected to your apartment. Professionals themselves will determine the diameter of the section, that is, it will be clear what load the cable will withstand. All these actions will need to be coordinated with city structures. And this, of course, is not so easy. Not only will you have to run through various authorities and spend a certain amount of money to obtain a permit, but it may turn out that the city will simply have nowhere to find additional capacity. Most power grids have existed for a long time, they are already operating at full capacity, and no one has calculated the additional load before. True, the power can be found in the region. In this case, a cable is pulled to your house, and inside there is a new trunk power cable. Through it, additional power enters the apartment. No matter how serious it may sound, the work is quite simple. You may not even need to scrape anything. After all, you can always use existing embedded channels. By the way, you should not contact public utilities bypassing official authorities, hoping to save time and money. In case of occurrence emergency you will have to bear the responsibility. In addition, all changes will still have to be recorded in the documentation when selling an apartment. You can contact the relevant organizations with questions about the work and coordination, but you will have to pay for it.

By the way, there is another important point. In rooms with high humidity(in the bathroom or in the kitchen) you need to install the so-called fifth wire. This is a potential equalization system that eliminates unnecessary potential on all current-carrying metal elements: bath, sink, case washing machine. These wires must also be brought to the metal risers for supplying hot and cold water. This is required condition security. The fifth wire repeats the earth wire, it has a larger cross section.

In older houses, everything is more complicated. If there is a single-phase wire, then there is no grounding in principle. As for the three-phase wires, the current flows through the first wire to the consumption sources, through the second - the current flows back, the third is the ground wire, which needs to be grounded. If there is no grounding in the house, then the third wire will not be useful. Without grounding, there is a direct threat to human life and health. If there is damage in the case, and a person touches it, then the current will pass through the person.

There is a common misconception that you just need to replace the wiring in the apartment with a newer one - and you can safely connect any devices. Actually throughput 4kW will remain the same. So there is a risk that if you turn on all your amenities at once, the automation will immediately turn off the voltage. More than allowed 4 kW you still won't get it.

By the way, if in the whole house there is no separate protection for each cable extending from individual apartments, then the neighbors begin to depend on each other. There is a main cable at the entrance. A branch is drawn from it, and a circuit breaker is mounted, which controls the amount of electricity for each consumer. An electric meter and an introductory circuit breaker are installed for each apartment. If it does not work, and the network is overloaded, the entire trunk cable will fail, so it is very important that the individual circuit breakers are in order. Although most of them have been working for a very long time, so the risk increases every year.

Note to owners of apartments in old houses

There is a limit on the power of equipment in houses with old wiring. For example, in houses where electric stoves are installed, they can only be about three burners, because the wires will not withstand a heavy load. In houses to which gas is supplied, only gas stoves and cooktops.

Connecting devices in ordinary apartment must be carried out according to the instructions for use, by service specialists. For each device, a water supply tap or a separate outlet of installed power is mounted, an individual power line and a safety switch are made. The diameter of the wires and the data of the safety switches correspond to the power consumption of the equipment (it can be found in the data sheet). If we connect a device of greater power than usual (a stove, for example), then we need to check whether the electric meter can withstand it. If not, then you will have to deal with the utilities to install a new electricity meter. After that, an individual power line is made that is not related to the old network.

We bring to your attention the concepts collected in one place "Power" :

Transformer power - this is the total power of transformers of power receiving devices of the consumer of electrical energy, calculated in(MBA)

Declared power - the limit value of the power consumed in the current period of power regulation, determined by the agreement between the grid organization and the consumer of services for the transmission of electric energy, calculated inmegawatts (10 6 )

Max power - the value of power, due to the composition of the power-receiving equipment and technological process consumer, calculated inmegawatts (10 6 )

Connected power - the total value of the rated power connected to electrical network(including indirectly) transformers and power receivers of the consumer of electrical energy, calculated in(MBA)

Power of the electrical installation (groups of electrical installations) — The total active power delivered to this moment time by a generating electrical installation (a group of electrical installations) to receivers of electrical energy, including losses in electrical networks [ ]

Installed power of the electrical installation - The highest active electrical power with which the electrical installation can operate for a long time without overload in accordance with the technical specifications or the passport for the equipment [ ]

Connected power of the electrical installation - The sum of the rated powers of transformers and receivers of electrical energy of the consumer, directly connected to the electrical network [ ]

Instant Power - called the product of the instantaneous voltage applied to the circuit and the instantaneous value of the current in this circuit

Full power - a value equal to the product of the effective values ​​\u200b\u200bof periodic electric current I in circuit and voltage U on her clamps: S = U I;

The unit of total electrical power is volt-ampere ( VA, V A);
Full power has practical value, as a value that describes the loads actually imposed by the consumer on the elements of the supply network (wires, cables, switchboards, transformers, power lines), since these loads depend on the consumed current, and not on the energy actually used by the consumer. That is why the rated power of transformers and switchboards measured in(VA), not in

Estimated power - the value of the expected power at a given level of power supply. Given power is an the most important indicator, based on it, electrical equipment is selected. Estimated power shows the actual value of consumption by power receiving devices and depends on the specific consumer ( apartment buildings, various industries). Obtaining the value of the design power is a complex task, which must take into account various factors such as load seasonality, technology features. Based on statistical data, tables of utilization factors have been developed, according to which the value of the design capacity is found as the product of the installed capacity and the utilization factor

Reactive power - due to the ability of reactive elements to accumulate and give off electrical or magnetic energy. Capacitive load in the circuit alternating current during half a period, it accumulates a charge in the capacitor plates and gives it back to the source. An inductive load stores magnetic energy in the coils and returns it to the power supply as electrical energy. Reactive power in the network can be either excess or deficit, this is due to the nature of installed equipment. Excessive reactive power (the capacitive nature of the network prevails) leads to an increase in the voltage of the network, while scarce (the predominance of the inductive nature of the network) leads to a decrease in voltage. Because in distribution networks in most cases, inductance prevails over capacitance, i.e. there is a shortage of reactive power, then capacitive elements are artificially introduced into the network, designed to compensate for the inductive nature of the network, as a result, to reduce the phase shift between the mains voltage and current, which means to transfer to the consumer to a greater extent only active power, and reactive "generate" on the spot. This principle is widely used by network companies that oblige consumers to install compensating devices, however, the installation of these devices is needed to a greater extent by the network company, and not by each consumer individually. measured in Reactive Volt-Amps (VAr)

Whether you live in an apartment, cottage or have country house in a gardening partnership, one way or another you had to deal with the limitation of the power supply of your home .

Why are such restrictions imposed?

There may be several reasons.

1. Limited energy resources of the power supply organization in the area.

2. Insufficient "capacity" of trunk or distribution cable lines or overhead power lines.

3. Insufficient power transformer substation in rural or suburban areas.

Whatever the reason, the result is the same: you are given the maximum, or, in other words, permitted powerwhich you are not allowed to exceed.

Permitted power is established by the local power supply organization for each specific consumer in a document called specifications for power supply and is mandatory. Violations carry very severe sanctions. Power outage is one of them.

How can you ensure compliance specifications? After all, often installed capacity(calculated value of the power of the entire set of electrical appliances, equal to the sum capacity of each unit) of the electrical equipment of the object (cottage, apartment) exceeds permitted power?

6 principles of organization of power supply of the object allow finding a compromise solution between the needs and capabilities of the subscriber.

1. Set the PZR corresponding to the permitted power

If a permitted power is limited or the dwelling is oversaturated with electrical receivers - household electrical appliances, electronics, lighting fixtures- and there is a possibility of power consumption exceeding it in magnitude, then instead of the introductory circuit breaker, it is necessary to install PZR(protective relay device), consisting of an electronic unit, a current relay, a magnetic starter and an automatic switch.

When the load current of the internal network reaches the threshold value corresponding to permitted power, the current relay is activated and switches the internal network to the periodic power supply mode: the network is connected to voltage for 5 seconds, then there is a pause of 180 seconds, during which there is no voltage in the network.

This mode lasts until the subscriber takes measures to reduce the current consumption.

PZR multifunctional. In addition to limiting the load current, it protects the internal network from currents. short circuit, insulation leakage currents, overvoltages.

2. Install sectional circuit breakers that provide current selectivity of protection

In order not to bring the matter to the point of disconnecting the entire object from the power supply due to an overload of some separate section, for example, a section of sockets, while turning on several sufficiently powerful electrical receivers at the same time, they use sectional circuit breakers.

They are installed after PZR and protect the circuits of the section from short circuit currents and from overloads. Each sectional circuit breaker protects one particular section. The current settings of the thermal relays built into them are selected in such a way that when any section is overloaded, the sectional automat protecting it will turn off earlier, without leading to operation. PZR.

Protection sectional circuit breakers effective, but not very convenient.

Firstly, the load in several sections may not reach the maximum value at which the sectional machine would work, but in total it will be large enough to work PZR.

Secondly, in order to restore the protective functions of a triggered machine, you need to manually transfer it from a non-working to a working state - the lever from position "0" (or "off") to position "1" (or "on").

3. Apply priority relay

In the conditions when installed capacity home electrical receivers far outperforms permitted power and the probability of shutdown sectional circuit breakers increases, use priority relay.

This is an electric current relay, to the input terminals of which the supply voltage is connected, and to the output terminals - separate sections of the internal electrical network, which have different priorities. For example, a socket section and an electric floor heating section. The outlet section is given higher priority than the electric floor heating section.

Priority relay a mode is set in which the total load current in the connected sections reaches a certain value, it works and turns off one or more sections with a lower priority.

After some set time the relay loses power and sections with lower priority are automatically connected to the power supply. If the nature of the load has not changed, the relay operates again.

4. Use blocking relays

Latching relay(a current relay is used as a blocking relay) makes it impossible to simultaneously turn on two sections or separate electrical receivers high power depending on the connection point of the relay coil and its break contact.

That section or that receiver (No. 1) is switched on, in the circuit of which the relay coil is installed, and that section or that receiver (No. 2), in the circuit of which its opening contact is located, is turned off.

If a blocking relay has an adjustable setting, then the section or receiver No. 2 is switched off when the current in the section or receiver No. 1 reaches the specified value. Section or receiver No. 2 is connected to the voltage when the current in the section or receiver No. 1 drops to the setting value multiplied by the relay return factor, without time delay.

When using one relay, the effect is similar to that which occurs when using a priority relay: the section or electrical receiver in the circuit of which the relay coil is connected will have a higher priority.

If you install blocking relays in both sections or in the power circuit of two receivers in a cross circuit, then the one (that) that was turned on first will remain working.

5. Apply power controls

There are a number of electrical receivers, the power consumption of which can and should be regulated. These are light sources (chandeliers, sconces, etc.), heating devices (heated floors).

The power circuit of such receivers includes power regulators, containing thyristors.

By adjusting the moment of unlocking the thyristors, they change the magnitude of the current of electrical receivers, and, therefore, the power they consume.

As a rule, such regulation is carried out manually or using a remote control.

When by regulation it is impossible to achieve a condition that the maximum power consumption value did not exceed the value permitted power, use backup power .

Backup power supply - it's usually diesel generator or gas generator(For economic reasons, they are usually used as an emergency source).

Turning on the generator and switching part of the sections or the entire internal network to standby power usually occurs automatically, but manual mode is also possible. At the same time, it is important that, in order to avoid a short circuit, the internal network is first disconnected from the supply network, and only then connected to generator.

Backup power in the event of a power failure in the mains, it is used as an emergency.

It's very important to get it right choose a generator and know where install generator. And the quality of electricity and the reliability of the backup power supply system will depend on how it is done.

Conclusion

As you can see, all contain not prohibiting the use by the consumer of the totality of available electrical receivers, a make it impossible to use a certain part of them at the same time.

6 principles for organizing power supply in conditions of limited permitted power allow at rational use available energy resources to satisfy consumer demand in a longer time interval.