Case Introduction
Two 185kW air compressors were installed at a gas station in Zhejiang. The load current of each compressor during actual operation fluctuates from 0-350A with the gas filling situation, and the power factor is 0.84. The distance between the distribution room and the on-site control cabinet is about 300 meters. Before the renovation, there were the following problems: after the load increased, the air compressor occasionally issued overcurrent alarms, the terminal voltage dropped from 227.5vac to 215vac, and the line loss increased. The on-site measurement data is as follows (measuring instrument: FLUKE43B):
Reactive power compensation scheme
Based on the load and actual on-site conditions, reactive power compensation is carried out at the control cabinet, with the following configuration:
Product Introduction
The SFR-L series low-voltage power capacitor modules are mainly composed of two (△ type) or one (Y type) compensating capacitor, highly integrated with composite switch modules, microprocessors, and various functional modules. The product adopts a modular structure, with a small volume and easy maintenance. Mainly used for reactive power compensation in situations where harmonics are not very severe, it is suitable for on-site compensation, decentralized compensation, and centralized compensation. This series of products adopts double zero crossing switching technology to ensure that overvoltage and high surge current are not generated when switching capacitors, thereby extending the service life of capacitors and the switching life of switches for millions of times. The product has complete protection functions and special protections such as internal temperature of capacitors, harmonic content of the power grid, overcurrent, overvoltage, undervoltage, three-phase imbalance, etc., making the product safer and more reliable. The product can be used in a modular manner with multiple units. When multiple units are used, a main unit is automatically generated, while the rest are secondary units, forming a reactive power automatic control system. In case of individual faults, the secondary unit automatically exits without affecting the operation of other units. In case of a main unit failure, it automatically exits and generates a new main unit, forming a new system for operation. The level of intelligence is extremely high. At the same time, this series of products also integrates the functions of power instruments, which can measure the conventional electrical parameters of the system.
Application Effect
After the completion of reactive power compensation using this scheme, the expected goals were achieved. The power factor of the air compressor branch was increased to 0.98, and the line voltage loss was reduced to 6vac. The air compressor operated stably (the previous overcurrent alarm was cleared), purified the electricity environment, ensured the safe and stable operation of the equipment, and greatly improved the effective utilization rate of electricity; Reduced power distribution line losses, increased terminal voltage of air compressors, and extended service life of cables and equipment.
