Impact of harmonics on the petrochemical industry
The petrochemical industry has long production lines, a wide range of areas, and a high degree of automation. Due to production needs, there are many rapidly changing impact loads, and the composition of power loads has also undergone qualitative changes. The access of many nonlinear loads inevitably produces many power problems. Among them, frequency conversion equipment is the most obvious device that produces harmonic problems. When the frequency converter is working, it will generate many harmonics to interfere with the load and its adjacent equipment. Harmonics will also affect the public power grid through the input power line. While weakening and interfering with the economic operation of the power grid, abnormal start and stop of equipment often occurs, which reduces the safety of the equipment itself and increases the error of power metering instruments. Xixing Technology provides professional harmonic control products that can efficiently solve the power quality problems in the petrochemical industry and create a green, healthy, safe and stable power environment.
Where do harmonics in the petrochemical industry come from?
The inverter generally adopts an AC-DC-AC structure, which converts the industrial frequency (50HZ) into AC power of various frequencies to achieve variable speed operation of the motor. The input part of the inverter is a rectifier circuit, and the output part is an inverter circuit. These are composed of nonlinear components. During the disconnection process, high-order harmonics will be generated at both the input and output ends. The harmonics generated are mainly 5th, 7th, and 11th harmonics. The harmonic current distortion rate of petrochemical harmonics generally reaches about 30~40%.
Pain points of harmonics in the petrochemical industry
Harmonic current increases the temperature and loss of the transformer. When the load contains harmonic current, harmonic voltage is formed through impedance. The harmonic voltage will generate eddy current in the core laminations, causing it to generate heat and loss, and produce obvious noise.
Harmonic current increases the temperature and loss of the motor. The increase in iron loss and copper loss at harmonic frequency leads to a decrease in motor efficiency, increased vibration and noise. For some transmission equipment with multiple motors, the speed and torque of these motors must be consistent. Different operating speeds and torques will lead to a decrease in production quality.
Harmonic current will cause the copper bar to heat up. When AC current passes through a conductor, a physical effect called "skin effect" will occur. When the current flows through a conductor, the heat generated by the current is proportional to the square of its frequency. Therefore, when harmonic current flows through a conductor, it will cause the conductor to heat up severely and even cause a fire.
Therefore, in the petrochemical industry to avoid the above situation, special equipment must be used to control harmonic current.
Solutions for the petrochemical industry
The EasyPQ-APF series active filters of Xixing Technology can control 2-50 harmonics, and the harmonic filtering rate of low-order harmonics (harmonics within 13th order) can reach more than 95%. The harmonics generated by the petrochemical industry are mainly 5th, 7th, 11th, and 13th. The EasyPQ-APF series active filters can effectively control the harmonic problem, comprehensively improve the system power quality, and ensure the safety of electricity usage.
