Three-phase load reactor: stabilizer at the output end of power electronic equipment

In modern power systems, power electronic equipment such as frequency converters and rectifiers are increasingly widely used, and they provide strong technical support for industrial automation, energy conversion and other fields. However, these nonlinear loads will generate a large amount of harmonic currents during operation, posing a serious threat to the stability of the power system and the safe operation of equipment. In order to meet this challenge, three-phase load reactors, as an important power harmonic suppression device, are widely used at the output end of power electronic equipment to reduce voltage fluctuations and current distortion caused by harmonic currents and improve the stability of the power system.

Harmonic current refers to the current component in the power system whose frequency is not equal to the fundamental frequency (usually 50Hz or 60Hz). In power electronic equipment, a large amount of high-frequency harmonic currents will be generated due to the rapid switching of switching devices. These harmonic currents will not only increase the loss of the power system, but also cause problems such as voltage fluctuations and current distortion. In severe cases, they may even cause equipment damage and system collapse.

The hazards of harmonic currents are mainly reflected in the following aspects:
Voltage fluctuations: Harmonic currents will cause voltage fluctuations in the power system, resulting in voltage instability and affecting the normal operation of power equipment.
Current distortion: Harmonic current will distort the current waveform, increase the loss of the power system, and reduce the quality of power.
Equipment overheating: When harmonic current flows in the equipment, it will generate additional heat, causing the equipment to overheat and shorten its service life.
System collapse: In extreme cases, harmonic current may cause system resonance, causing the entire power system to collapse.
The three-phase load reactor is an inductive component whose working principle is based on the law of electromagnetic induction. When current passes through the reactor, a magnetic field is generated in its iron core, which in turn induces a back electromotive force, thereby hindering the change of current. Therefore, the reactor has an impedance effect on alternating current and can limit the magnitude and speed of change of current.

Adding a three-phase load reactor to the output end of power electronic equipment can play the following functions:
Reduce harmonic current: The reactor has a large impedance to high-frequency harmonic current, which can significantly reduce the amplitude of harmonic current, thereby reducing the interference of harmonics on the power system.
Suppress voltage fluctuations: By limiting the speed of change of current, the reactor can reduce the voltage fluctuations caused by harmonic current and keep the voltage stable.
Improve current waveform: The reactor can smooth the current waveform, reduce the degree of current distortion, and improve the quality of electric energy.
Protect power equipment: By reducing harmonic current and voltage fluctuations, the reactor can reduce the impact and damage to power equipment and extend the service life of the equipment.
The application of three-phase load reactors at the output end of power electronic equipment is extensive and important. It is not only suitable for the output end of nonlinear loads such as inverters and rectifiers, but also can be used in other occasions where harmonic currents need to be suppressed, such as UPS power supplies, wind power generation systems, etc.

The advantages of three-phase load reactors are mainly reflected in the following aspects:
Efficient harmonic suppression: The reactor has a significant effect on suppressing high-frequency harmonic currents, and can significantly reduce the amplitude and distortion of harmonic currents.
Improve system stability: By reducing harmonic current and voltage fluctuations, the reactor can significantly improve the stability of the power system and ensure the normal operation of power equipment.
Strong adaptability: The reactor can be customized according to different power system requirements and equipment characteristics to meet the needs of various application scenarios.
Economical and practical: Although the initial investment of the reactor is high, it can reduce the loss and maintenance cost of the power system and has high economic efficiency in the long run.
Easy to maintain: The reactor has a simple structure, easy maintenance, and can operate stably in harsh working environments.

When selecting a three-phase load reactor, the following factors need to be considered:
Rated current and voltage: Ensure that the rated current and voltage of the reactor are greater than or equal to the rated current and voltage of the power electronic equipment.
Harmonic frequency: Understand the harmonic frequency range generated by the power electronic equipment and select a reactor with better harmonic suppression effect on the corresponding frequency.
Impedance characteristics: Select a suitable reactor impedance value based on the impedance characteristics of the power system and equipment requirements.
Heat dissipation performance: Ensure that the reactor has good heat dissipation performance to prevent damage due to overheating.

When installing a three-phase load reactor, the following matters need to be noted:
Installation location: The reactor should be installed at the output end of the power electronic equipment, close to the load side, to reduce the propagation distance of the harmonic current.
Grounding treatment: Ensure that the reactor is well grounded to prevent safety problems caused by poor grounding.
Connection method: According to the wiring method of the reactor, correctly connect the power line, load line and ground line.
Protective measures: Set up protective measures around the reactor to prevent accidental touch or equipment damage.

As a stabilizer at the output end of power electronic equipment, the three-phase load reactor plays an important role in reducing harmonic current, suppressing voltage fluctuations, improving current waveforms and improving the stability of power systems. With the continuous development of power electronics technology and the increasing complexity of power systems, the application of three-phase reactors will be more extensive.

In the eyes of power engineers, three-phase load reactors are not only the guardian of the power system, but also the innovative force that promotes the development of the power industry. By continuously optimizing the design and improving the performance, the three-phase reactor will continue to contribute to the stability and safety of the power system and inject new vitality into the sustainable development of the power industry.