The electrical system generates total energy, which is divided into useful or active and residual energy called reactive energy. The article will tell you what it is and how it is accounted for.
Residual energy: what is it?
All electrical machines are represented by reactive and active elements. They are the ones that consume electricity. These include reactive cable connections, capacitor and transformer windings.
In the process of flowing alternating current, reactive electromotive forces are indexed on these resistances, which create a reactive current.
Installations and devices that create alternating current use reactive energy in the mains, which creates a magnetic field of the electric field.
Influence of inductive reactance on the creation of a magnetic field
All devices that are powered by the mains have inductive resistance. It is thanks to him that the signs of current and voltage are opposite. For example, the voltage isnegative sign and the current is positive, or vice versa.
At this time, the electricity generated in the inductive element in reserve, oscillates through the network due to the load from the generator and vice versa. This process is called reactive power, which creates a magnetic field of the electric field.
What is reactive power for?
It can be said that it is aimed at regulating the changes that electric current causes in the network. These include:
- maintaining the magnetic field during inductance in the circuit;
- if there are capacitors and wires, support for their charge.
Problems in generating reactive power
If there is a large share of reactive power generation in the network, then you have to:
- increase the power of power devices that are designed to convert electrical energy of one voltage value into electrical energy of another voltage value;
- increase cable section;
- combat rising power loss in power devices and transmission lines;
- increase electricity consumption fees;
- combat power loss.
What is the difference between active and reactive energy?
People are used to paying for the electricity they consume. They pay for the energy used for space heating, cooking, heating water in the bathroom (who uses individual water heaters) and other usefulelectrical energy. It is she who is called active.
Active and reactive energy are different in that the latter is the remaining energy that is not used in useful work. In other words, they both form full power. Accordingly, it is unprofitable for consumers to pay, in addition to active energy, also reactive energy in the power grid, and it is beneficial for suppliers that they pay for full capacity. Is it possible to somehow resolve this issue? Let's take a look at this.
How is energy consumption measured?
To measure the consumed energy, an active and reactive energy meter is used. All of them are divided into meters with one phase and three phases. What is their difference?
Single-phase meters are used to account for electrical energy from consumers who use it for domestic needs. Power is supplied by single-phase current.
Three-phase meters are used for gross energy metering. They are classified based on the power supply scheme into three- and four-wire.
Distinguishing counters by the way they are turned on
The way they turn on, they are divided into three groups:
- Do not use transformers and directly connected to the network counters of direct connection.
- With the use of power devices, semi-indirect switching counters are switched on.
- Counters of indirect connection. They are connected to the network not only using current power devices, but also using voltage transformers.
Differentiatingcounters by payment method
According to the method of charging for electricity, it is customary to divide meters into the following groups:
- Meters based on the use of two tariffs - their effect is that the tariff for energy consumed changes during the day. That is, in the morning and during the day it is less than in the evening.
- Pre-paid meters - their operation is based on the fact that the consumer pays for electricity in advance, as he is in remote places of residence.
- Meters with indication of the maximum load - the consumer pays separately for the consumed energy and for the maximum load.
Full power metering
Accounting for useful energy aims to determine:
- Electric energy generated by voltage generating machines in a power plant.
- The amount of energy that is spent on own needs of the substation and power plant.
- Electricity to be used by consumers.
- Energy transferred to other power systems.
- Electric energy, which is launched through the tires of power plants to consumers.
It is necessary to take into account reactive electrical energy when transmitting to consumers from a power plant only if these data are calculated and control the operation mode of devices compensating this energy.
Where is the remaining energy monitored?
Reactive energy meter install:
- Same place asuseful energy meters. They are installed for consumers who pay for the full power they use.
- On sources of connection of reactive power for consumers. This is done if you have to control the work process.
If the consumer is allowed to let the remaining energy into the network, then they put 2 counters in the elements of the system where the useful energy is accounted for. In other cases, a separate meter is installed to account for reactive energy.
How to save on electricity consumption?
A device for saving electricity is very popular in this direction. Its operation is based on the suppression of residual electricity.
On today's market you can find many similar devices, which are based on a transformer that directs electricity in the right direction.
Electricity saving device directs this energy to a variety of home appliances.
Energy Efficiency
For the rational use of electricity, reactive energy compensation is used. For this, capacitor units, electric motors and compensators are used.
They help reduce active energy losses caused by reactive power flows. This significantly affects the level of transport technological losses of distribution electric networks.
What is the benefit of power compensation?
The use of power compensation settings can bring great benefits ineconomic plan.
According to statistics, their use brings up to 50% savings in electricity costs in all parts of the Russian Federation.
Money investments spent on their installation pay off within the first year of their use.
In addition, where these installations are designed, the cable is purchased with a smaller cross section, which is also very beneficial.
Advantages of capacitor units
The use of capacitor units has the following positive aspects:
- Slight loss of active energy.
- There are no rotating parts in capacitor units.
- They are easy to work with and operate.
- Investment costs are low.
- Work silently.
- They can be installed anywhere in the electrical network.
- You can choose any required power.
The difference between capacitor units and compensators and synchronous motors is that filter-compensating units synchronously perform power compensation and partially restrain the harmonics present in the compensated network. The cost of electricity will depend on how much power is compensated, and, accordingly, on the current tariff.
What types of compensation are there?
In the process of using capacitor units, the following types of suppressed power are distinguished:
- Individual.
- Group.
- Centralized.
Let's take a closer look at each of them.
Individual power
Condenser units are located right next to electrical receivers and are switched at the same time as they are.
The disadvantages of this type of compensation is the dependence of the time of switching on the capacitor unit from the start time of the operation of electrical receivers. In addition, before carrying out work, it is necessary to coordinate the capacity of the installation and the inductance of the electrical receiver. This is necessary to prevent resonant overvoltages.
Group power
The name says it all. This power is used to compensate the power of several inductive loads that are simultaneously connected to the same switchgear with a common capacitor bank.
In the process of simultaneously turning on the load, the coefficient increases, which leads to a decrease in power. This contributes to better operation of the capacitor unit. Residual energy is suppressed more effectively than with individual power.
The negative side of this process is the partial unloading of reactive energy in the power grid.
Centralized power
Unlike individual and group power, this power is adjustable. It applies to a wide range of residual energy consumption.
The reactive load current function plays a big role in regulating the power of a capacitor bank. In this case, the installation must be equipped with an automatic regulator, and its full compensation power is divided into separately switched steps.
What problems do capacitor units solve
Of course, they are primarily aimed at suppressing reactive power, but in production they help to solve the following tasks:
- In the process of suppressing reactive power, the apparent power is correspondingly reduced, which leads to a decrease in the load of power transformers.
- The load is powered by a cable with a smaller cross section, while the insulation does not overheat.
- It is possible to connect additional active power.
- Allows you to avoid a deep voltage drop on the power lines of remote consumers.
- The use of the power of autonomous diesel generators is going to the maximum (ship electrical installations, power supply for geological parties, construction sites, exploration drilling rigs, etc.).
- Individual compensation simplifies the operation of induction motors.
- In the event of an emergency, the condensing unit will shut down immediately.
- The heating or ventilation of the unit automatically turns on.
There are two options for capacitor units. These are modular, used in large enterprises, and monoblock - for small enterprises.
Summing up
Reactive energy in the power grid negatively affects the operation of the entire electrical system. This leads to such consequences as a loss of voltage in the network and an increase in fuel costs.
In connectionwith this, compensators of this power are actively used. Their benefit is not only good money savings, but also the following:
- The service life of power devices is increasing.
- Improving the quality of electricity.
- Save money on small gauge cables.
- Reduces electricity consumption.
