The automobile workshop (stamping workshop, welding workshop, assembly workshop, etc.) uses a large number of nonlinear loads such as electric welding machines, laser welding machines and large-capacity inductive loads (mainly motors), resulting in serious harmonic currents in all transformer load currents in the workshop, mainly 3, 5, 7, 9 and 11 times, the total distortion rate of the 400V low-voltage bus reaches more than 5%, and the total distortion rate (THDi) of the current reaches about 40%. The total harmonic distortion rate of the voltage of the 400V low-voltage power supply and distribution system seriously exceeds the standard, and leads to serious harmonic power loss in the electrical equipment and transformers. At the same time, all transformer load currents in the production workshop have serious reactive power demand, and the average power factor of some transformers is only about 0.6, which has serious power loss problems, and leads to a serious shortage of transformer output active capacity, and harmonic interference makes the automotive fieldbus automated production system unable to work normally.

Automotive load analysis

The workshop uses a large number of nonlinear loads such as electric welding machines, laser welding machines and large-capacity inductive loads (mainly motors), resulting in serious harmonic currents in the transformer load currents in the workshop, and the harmonic currents are mainly 3, 5, 7, 9 and 11.

The automobile manufacturing industry uses a large number of impactful, nonlinear loads in the main production processes, such as electric welding machines and laser welding machines in body shops; Stamping machines in the stamping workshop; frequency conversion device in paint shop; The automatic production line of the final assembly workshop, etc., these impact and nonlinear loads have a common feature, large load fluctuations and large harmonic generation. Most of the spot welding equipment in the automotive industry uses 380V power supply, powered by two phases (L1-L2, L2-L3 or L3-L1), which will cause zero sequence current due to three-phase imbalance, and it is necessary to consider the choice of imbalance compensation.

Welding machine is an indispensable equipment in the automobile manufacturing industry, because the welding machine has the characteristics of randomness, speed and impact, so that a large number of welding machine caused by serious power quality problems, resulting in unstable welding quality, high degree of automation of robots due to voltage instability and can not work, reactive power compensation system can not be used normally.

Solution

The existence of power quality problems has brought serious harm to the automobile manufacturing industry, for this reason, Bowo provides a complete set of solutions, as follows:

User value of reactive power compensation and harmonic governance

• Reduce the influence of harmonics, avoid various faults such as voltage amplification caused by harmonics damaging electrical equipment, and improve power supply security;
• Control harmonics, reduce the harmonic current injected into the system, and meet the requirements of national standards;
• Dynamic compensation of reactive power, power factor up to standard, avoid fines from power supply companies;
• After reactive power compensation, the system power supply current is reduced, and the capacity utilization rate of transformers and cables is improved;
• Energy saving and consumption reduction.

Application Case

1.BW-APF application in Guangzhou Honda Automobile Plant