Overview of harmonic protector functions and principle

What are harmonics?

Harmonics refer to the components in the voltage and current whose frequency is an integer multiple of the fundamental wave. Generally, it refers to the Fourier series decomposition of the periodic sinusoidal voltage and current, and the voltage and current components with an integer multiple of the fundamental frequency.

Harmonics are a steady-state power quality index parameter, and must be distinguished from transient phenomena. It is generally believed that the waveform of harmonics is periodically repeated, and transient phenomena such as high-frequency noise, pulse spikes, surges, etc., change or decay in the waveform within each cycle. They are not considered as harmonics, but only as a a transient phenomenon.

Harmonic reduction device basic principles

   The harmonic protector is a new type of protection device used to filter out high-order harmonics and protect precision instruments and equipment. It adopts ultra-microcrystalline alloy materials and innovative special circuits. It is mainly composed of voltage clamps, low-pass filters and absorbers, which can not only suppress and absorb random high-order harmonics and high-frequency noise, pulse peaks, surges and other interference generated by user electrical equipment, but also can track voltage at any time. Waveform, instantaneously filter out peaks, surges, and clutter in the power supply, correct high-order harmonics caused by harmonics, eliminate harmonic pollution from the source, and provide protection for electrical equipment.

   The basic principle of the harmonic protector (take three-phase as an example): use the voltage clamp to monitor the voltage change in real time, use the low-pass filter to filter out the higher harmonics, and then use the absorber to absorb the filter equipment of the higher harmonics.

Dynamic harmonic device functions

1. Automatic protection of electrical equipment

Paralleling harmonic protectors in the circuit can achieve destructive spike transients, surges, high-frequency noise, and high-order harmonics. Its effective elimination, thereby promoting the safe and stable operation of electrical equipment and improving the service life of electrical equipment.

2. Purify the power

The harmonic protector's ability to suppress and eliminate harmonics is remarkable. In the circuit of the parallel harmonic protector, 99% of the voltage and current distortion caused by various harmonics can be eliminated. At the same time, the computer screen stroboscopic caused by harmonics can be eliminated. , load change, short circuit, lamp flicker caused by switching can be avoided.

3. Protect power factor compensation equipment

In practice, the parallel resonance circuit will be generated under the interaction of high-order harmonic frequency and stray grid inductance and harmonic frequency of power factor compensation equipment, and the voltage and current waveforms will be aggravated by the harmonic amplification caused by the resonance circuit. Distortion, and thus just the service life of the equipment. In addition, the harmonic protector can purify the harmonic pollution and provide guarantee for the service life of the power factor compensation equipment.

4. Prevention of non-tripping of protective devices

The circuit breaker will cause the circuit breaker to trip incorrectly or refuse to trip due to the sound of harmonic current, and the parallel harmonic protector in the circuit can effectively eliminate the harmonic current, thereby effectively preventing the circuit breaker from tripping or refusing to trip.

Harmonic protection appliances have the function of eliminating harmonic pollution from the source, thereby providing protection for the normal operation of electrical equipment. The parallel harmonic protector in the power equipment circuit can not only continuously monitor the current state in the power system, but also absorb and block high-order harmonics in the circuit, thereby preventing other equipment from being affected by the harmonics generated by the equipment itself. interference.

The main function of high reduce harmonics

1. Eliminate high-order and ultra-high-order harmonics, surges, spikes, etc.

2. Suppress series and parallel resonance between inductance and distributed capacitance at harmonic frequencies.

3. Prevent the protection device from malfunctioning or refusing to operate.

4. Protect the safe operation of sensitive electrical equipment.

With the rapid development of power electronics technology and the increase of nonlinear loads, the distortion rate of voltage and current in the center of the distribution network is becoming more and more serious. Under normal circumstances, harmonic control can be performed on high-power equipment on the user side.

The actual situation is that many devices with low power consumption, such as precision instruments in hospitals, measuring instruments in laboratories, instruments in laboratories, control currents in control systems, PLCs, DCSs, sensors, etc., have high requirements for power quality. Especially the "high-order harmonics" in the power distribution network, among which the harmonics with a frequency above 2KHZ, will cause great interference to the normal use of the equipment.

In this case, installing the XC-HPF harmonic protector on the input side of these devices can protect the electronic equipment of the control system from the harm of high-order harmonics.

The XC-HPF harmonic protector can eliminate the high-frequency pulse spikes in the power grid, the interference of high-frequency (frequency above 2KHZ) harmonics to electrical equipment, remove high-frequency noise, and purify the power network.