Are there any differences and connections among reactors, inductors and capacitors?

Inductor is an element that can convert electric energy into magnetic energy and store it. The structure of inductor is similar to that of transformer, but there is only one winding. Reactors are also called inductors. When a conductor is charged, it will produce a magnetic field in a certain space it occupies, so all electrical conductors that can carry current have general inductance.

Two conductors close to each other, with a layer of non-conductive insulating medium between them, form a capacitor.

2. Different functions

Reactors are inductive loads, which can be divided into series and parallel. Series connection is mainly used to limit short-circuit current, and parallel connection is mainly used to compensate the capacitance of the line when ultra-high voltage long-distance transmission is carried out. The reactors commonly used in power system are series reactors and parallel reactors. Series reactors are mainly used to limit short-circuit current, and some are connected in series or parallel with capacitors in the filter to limit higher harmonics in the power grid.

Capacitors are capacitive loads, which are mainly used to compensate reactive power and store energy. In a DC circuit, capacitance is equivalent to an open circuit. Capacitor is a kind of component that can store charge, and it is also one of the most commonly used electronic components.

Inductor has the characteristics of preventing alternating current from passing and allowing direct current to pass smoothly. The higher the frequency, the greater the coil impedance. Therefore, the main function of inductance is to isolate and filter AC signals or form a resonant circuit with capacitors and resistors.

3. Different characteristics

The most common function of inductance in circuit is to form LC filter circuit with capacitance. Capacitors have the characteristics of "DC resistance and AC resistance", while inductors have the functions of "DC resistance and AC resistance". If DC with more interference signals passes through LC filter circuit, AC interference signals will be converted into heat energy by inductance and consumed; When pure DC current passes through the inductor;

Among them, AC interference signals are also converted into magnetic induction and heat energy, and higher frequencies are most easily impedance by inductance, which can suppress the interference signals with higher frequencies.

4. Usually in industry and people's daily life, reactors are used in many occasions. There are many kinds of reactors: filter reactors, series reactors, parallel reactors and starting reactors. Each reactor has its corresponding scope of application, and different reactors can be used in different occasions to achieve the best results.

Series reactor? Series reactor is an important supporting equipment of reactive power compensation device in power system. After the power capacitor is connected in series with the series reactor, it can effectively suppress the higher harmonics in the power grid, limit the operating inrush current and overvoltage, improve the voltage waveform of the system, and improve the power factor of the power grid, which plays a great role in the safe operation of power capacitors and other power equipment.

The filter reactor is used in series with the parallel capacitor bank to form a series resonant circuit to filter out the specified higher harmonics. Start the reactor? When AC asynchronous motor starts at rated voltage, the initial starting current is very large, often exceeding many times the rated current;

In order to reduce the starting current and not affect the power grid, AC asynchronous motors usually start by step-down, and the common step-down method is to use reactors or autotransformers.

Shunt reactor? In order to improve the transmission capacity of long-distance transmission lines, improve the operation status of lines, and weaken the rise of power frequency voltage caused by the capacitance effect of long-time no-load or light-load lines;

Improve the voltage distribution and reactive power distribution along the light load line, reduce the line loss, reduce the secondary power supply current, accelerate the extinguishing of the secondary power supply arc, and improve the success rate of automatic reclosing of the line. Shunt reactors are widely used in long-distance power transmission and distribution projects.

Inverter reactor? Proper selection of reactor and frequency converter can effectively prevent the impact of overvoltage and surge current caused by operating AC incoming switch, reduce the pollution of harmonics generated by frequency converter to power grid and improve the power factor of frequency converter.

Split reactor? Split reactor is a special hollow current-limiting reactor with middle tap, which is used to limit the short-circuit current of power lines. When the line is short-circuited, the split reactor uses its reactance characteristics to limit the short-circuit current of the line to a certain limit, which is beneficial to the smooth and effective removal of the fault of the switching equipment. Widely used in power supply and distribution systems of various power plants and large industrial and mining enterprises.

Extended data:

Relationship and difference between inductance and magnetic beads

1, inductor is an energy storage element, and magnetic beads are energy conversion (consumption) devices;

2. Inductors are mostly used in power filter circuits, and magnetic beads are mostly used in signal circuits and EMC countermeasures;

3. Magnetic beads are mainly used to suppress electromagnetic radiation interference, and inductors are used to suppress conducted interference, both of which can be used to deal with EMC and EMI problems; EMI has two ways: radiation and conduction, and different ways adopt different suppression methods, the former uses magnetic beads and the latter uses inductance;

4. Magnetic beads are used to absorb UHF signals, such as some RF circuits, phase locked loops, oscillation circuits and circuits containing UHF memories (DDRSDRAM, RAMBUS, etc.). Inductor is a kind of energy storage element, which is used in LC oscillation circuit, medium and low frequency filter circuit, etc. , its application frequency range rarely exceeds 50MHZ；;

5. Inductors are generally used for circuit matching and signal quality control, and are generally connected to the power supply. Use magnetic beads where analog and digital are combined. Magnetic beads are also used for signal lines.

The size of magnetic beads (accurately, it should be the characteristic curve of magnetic beads) depends on the frequency of interference waves that magnetic beads need to absorb. Magnetic beads have high frequency resistance, low DC resistance and high frequency resistance.

Because the unit of magnetic bead is nominal according to the impedance it produces at a certain frequency, the unit of impedance is also ohm. Frequency and impedance characteristic curves are usually attached to the data sheet of magnetic beads. The general standard is 100MHz, such as 20 12B60 1, that is to say, the impedance of magnetic beads at 100MHz is 600 ohms.

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