Pollution control of harmonics, causes and treatment methods of harmonics

Harmonic generation: In an ideal clean power supply system, both current and voltage are sine waves. In a simple circuit with only linear components, the current flowing through is proportional to the applied voltage, and the current flowing through is a sinusoidal side-leakage wave.

In the actual power supply system, due to the existence of nonlinear loads, when the current flows through the load that is not linear to the applied voltage, a non-sinusoidal current is formed. Any periodic waveform can be broken down into a fundamental sine wave plus many harmonic frequencies. The harmonic frequency is an integer multiple of the fundamental frequency.

The solutions are: installing harmonic filters, isolating transformers and active harmonic regulators

1. Install harmonic filter: For the harmonics generated by the motor controller, the shape of the harmonics is very distinct, and the filter can be used to reduce the harmonic current.

2. Installation of isolation transformer: the problem of balanced third harmonic current flowing back to the power supply can be weakened by an isolation transformer with Dyn connection.

3. Equipped with an active harmonic regulator: the side bands and harmonics generated by the converter inverter cannot be filtered out well by ordinary filters, because the frequency searched on the side band changes with the speed of the transmission device, and is often very close to the fundamental frequency.

Harmonic refers to the amount of electricity contained in the current whose frequency is an integer multiple of the fundamental wave, and generally refers to the amount of electricity generated by the Fourier series decomposition of the periodic non-sinusoidal charge, and the rest of the current greater than the fundamental frequency.

At present, the electrical equipment is complex and complex, and the nonlinearity of the load is becoming more and more common, which has caused a great threat to the safe and normal operation of the power system and equipment. Among them, such as air conditioners, Zenshou pumps, fans, local elevators, computer room network equipment, office equipment, UPS, lighting control systems, fire protection systems, monitoring systems and other power electronic equipment.

Hazards of harmonics:

It is generally done in an active or passive manner.

Active is to use IGBT inverter to invert the harmonic of the original harmonic in opposite phase, so as to cancel out the original harmonic, which is more expensive.

Passive is to use capacitive reactance to tune to the harmonic frequency, absorb the harmonic current to the filtering loop, the traditional filtering method.

It is to limit harmonics to the range of certain standards, or within the tolerance of equipment, to minimize the harm of harmonics, and to solve the behavior of harmonics interfering with other equipment and harmonics harming other equipment.

Beijing Lingbu power quality service platform will answer for you:

The function of harmonic control is to improve the stability rate of system voltage, reduce the failure rate of equipment, reduce the heat generation of load, prolong the service life of equipment, reduce the error rate of the system, save electric energy, ensure the stability of production and improve the quality by filtering out the harmonics in the power grid, etc.

Chasing Sun Electric - harmonic control experts will give you professional answers!

1.Energy saving, production and efficiency improvement: After the installation of harmonic control device, the harmonic current is effectively reduced, the effective capacity of the transformer is increased, and the corresponding load capacity can be increased to reduce the investment required for capacity expansion.

2.Harmonic control to improve the quality of electricity consumption for customers; Meet the requirements of the electricity bureau.

3.Harmonic control device protects electrical equipment and components: it not only saves energy and reduces consumption, but also protects the safe operation of its own electrical equipment, and does not burn the fuse tube on the switch cabinet, breakdown capacitors, etc.

First of all, it can improve the power supply quality of enterprise equipment, improve the reliability of equipment operation, and reduce the economic loss caused by equipment malfunction.

Secondly, it can reduce the loss of harmonic current on the transmission and distribution line, reduce the heating of electrical equipment, reduce the aging of insulation, so as to improve the service life of the equipment and reduce the maintenance cost of the equipment;

Thirdly, harmonic control can reduce the resonance probability of compensation capacitors in the power grid, and at the same time, reduce the influence of harmonics on system signal transmission and increase the reliability of the system.

Fourth, harmonic pollution to the public power grid can be reduced.