What load terminals are low-voltage capacitors typically installed on?

In low-voltage power distribution systems, the rational configuration of low-voltage capacitors is a key aspect for enhancing the efficiency of energy utilization. The selection of the position where capacitors are installed directly affects the compensation effect and the stability of system operation. This requires scientific planning based on load characteristics and the structure of the distribution network. Different types of electrical equipment have significantly different demands for reactive power. Accurately identifying the load ends that require compensation and rationally configuring capacitors can not only effectively improve the power factor but also avoid problems such as over-compensation or resonance.

1. Sensory load concentration area

Electromagnetic devices such as motors and transformers require a large amount of inductive reactive power to establish the magnetic field during operation, resulting in a significant decrease in the system's power factor. By concentrating the investment of capacitors in the workshop distribution cabinets or motor control centers, the reactive power demand of these devices can be compensated locally, reducing the flow of reactive current in the distribution lines. This compensation method is particularly suitable for industrial sites where electric motors are the main load, such as textile machinery and injection molding machines, and can effectively reduce line losses and voltage drops.

2. Power supply end of high-power frequency conversion equipment

Although the inverter itself generates capacitive reactive power, the rectifier circuit on its input side still causes a decrease in the power factor on the grid side. By installing an appropriate capacity of capacitors at the power supply inlet of the inverter, the overall power factor can be improved. However, special attention should be paid to the influence of harmonics. It is advisable to use anti-harmonic capacitors or add filter reactors to avoid forming a resonant circuit between the capacitor and the system impedance, which would amplify the harmonic current and cause equipment damage.

3. Work area for welding equipment

Intermittent working equipment such as electric welders and spot welders generate significant fluctuating reactive power demands during operation, and fixed compensation is difficult to effectively track. For such load terminals, automatic switching of capacitor banks or dynamic reactive power compensation devices should be adopted. The compensation capacity should be adjusted in real time according to the welding cycle. At the same time, the potential impact of high-order harmonics generated by the welding equipment on the capacitors should be considered, and necessary harmonic suppression measures should be taken. 

The reasonable configuration of low-voltage capacitors at the load end requires comprehensive consideration of multiple factors such as load type, operating characteristics, and distribution structure. The ideal compensation scheme should follow the principle of "graded compensation and local balance", forming a scientific compensation network in each level of the distribution system.