What is the main role of AC input reactor in power system?

In power system, AC input reactor, as a key power electronic device, plays a pivotal role. It can not only protect power equipment from the impact of short-circuit current, but also improve the power factor of the system, filter harmonic current, and smooth the power supply voltage. So, how does it affect the current and voltage in the circuit?
The core of AC input reactor lies in its inductance characteristics. When current passes through the reactor, due to the existence of inductance, an electromotive force proportional to the rate of change of current will be generated. This electromotive force will react on the circuit, thereby affecting the distribution of current and voltage.
Specifically, the influence of AC input reactor on the current in the circuit is mainly manifested in the current limiting effect. When a short circuit or load mutation occurs in the power system, the current will increase rapidly. The inductance characteristics of the reactor will hinder the growth of current, thereby limiting the peak value of the short-circuit current and protecting power equipment from the impact of large current. This current limiting effect not only helps to protect the equipment, but also improves the stability of the system.
At the same time, the influence of AC input reactor on the voltage in the circuit cannot be ignored. In the power system, voltage fluctuations and spike pulses are common phenomena. These voltage changes may cause instantaneous impact and damage to the equipment. The existence of the reactor is like a voltage ""buffer"". It can absorb these voltage mutations, making the voltage changes smoother, thereby protecting the power equipment from voltage shock damage.
In addition to the above-mentioned current limiting and voltage smoothing functions, the AC input reactor can also improve the power factor of the system. The power factor is an important indicator for measuring the efficiency of the electrical system. By adjusting the phase difference between current and voltage, the reactor can improve the power factor of the system, reduce the ineffective loss of energy, and achieve efficient use of energy.
In addition, the AC input reactor also has the function of filtering harmonic currents. With the increasing popularity of power electronic equipment, the problem of harmonic currents has become increasingly prominent. Harmonic currents not only cause equipment overheating, performance degradation, or even damage, but may also cause pollution to the power grid. The reactor, through its inductance effect, can effectively reduce the impact of harmonic currents on the system and improve the reliability and service life of electrical equipment.