Background introduction

In recent years, with the accelerating pace of urban modernization, intelligent buildings have gradually developed rapidly to intelligent buildings, intelligent blocks, and intelligent cities. In China, because the concept of intelligent building conforms to the concept of ecological and harmonious development of sustainable development, the intelligent building in China mainly highlights the characteristics of intelligent buildings, such as energy saving, environmental protection, practicability, advanced nature and sustainable development. 

Compared with intelligent buildings in other countries, China pays more attention to energy saving and emission reduction of intelligent buildings. What we pursue more is the high efficiency and low carbon of intelligent buildings. All this has a very positive role in promoting energy conservation and emission reduction and reducing energy consumption.

Existing problems

Computers, printers, photocopiers, elevators, energy-saving lamps, UPS, energy-saving air conditioners, LED displays, etc. are widely used in intelligent buildings. Most of these devices have small capacity, but a large number of them have a great impact on power quality as a whole. Non-linear loads are mainly used in intelligent buildings, and their load characteristics mainly include the following aspects:

① There are many single-phase electrical equipment, and its power consumption generally accounts for about 50% of the total. The use of single-phase power supply causes unbalanced three-phase distribution load, excessive neutral line current and neutral point offset;

② Because the electric equipment is non-linear, its harmonic content is high and its power factor is low. 3K times current harmonics will also be superimposed on the neutral line, resulting in the decline of power quality of intelligent buildings. The research shows that intelligent buildings are an important source of harmonics;

③ Most electric equipment have high requirements for power quality and are sensitive to harmonics.

Product introduction of reactive power compensation design

According to different intelligent building load types and transformer capacity, the reactive power compensation design capacity configuration between the incoming cabinet and the load. Among them, SFR-M series intelligent dynamic harmonic suppression low-voltage power capacitor module is specially aimed at the harmonic and power factor problems in the 0.4kV low-voltage distribution network where the harmonic pollution is serious, so as to improve the power factor, effectively suppress harmonics, reduce line loss Integrated reactive power compensation products to improve power quality.

The intelligent dynamic harmonic suppression reactive power compensation module includes: digital processing circuit, highly integrated detection, control, protection, display unit, zero crossing switching module, discharge and air cooling unit, filter reactor, low-voltage filter power capacitor and functional module operation state indication circuit. 

This series of modules is a new generation of dynamic filter compensation equipment for 0.4kV low-voltage distribution network. It is suitable for electric field switching with frequent load changes and high requirements for voltage qualification rate. The total time of judging switching and switching actions is ≤ 20ms, which is a typical dynamic tracking compensation integrated module.

Technical parameter

Product specifications

Typical design

The example uses the company's intelligent dynamic harmonic suppression reactive power compensation module, configures the WGK-31-203 controller, determines the compensation capacity and reactance coefficient according to the demand, improves the system power factor, and suppresses the harmonic component. When the compensation capacity needs to be increased, just increase the number of dynamic compensation modules and change the specifications of knife-fuse switch and fuse.

Matching controller

Technical parameter

Typical wiring diagram