摘  要:随着经济的发展，电网存在冲击性负荷和非线性负荷大量增加，造成电网电压波动，闪变，功率因数低下，因此需要对电网电能质量进行治理成为人们关注的问题，其中对电网无功补偿显得越来越重要。静止无功发生器（SVG）能够很好的补偿电网中的无功分量成为改善电能质量的一种手段。

　　　本设计采用静止的无功补偿装置（SVG），对380V低压侧电网进行动态无功补偿。本文首先对当前国内外的无功补偿技术进行了介绍和补偿的原理分析，在此基础上，采用基于PLC的低压动态无功补偿控制系统(SVG) 。系统在硬件方面，采用与直接控制交流电容方案不同的功率单元投切控制，使系统控制更准确，避免出现失误。在软件上，由于PLC抗干扰能力更强，反应速度更快而采用PLC控制。该系统遵循模块化设计，提高了通用性并易于以后的维护与升级，同时本文对无功补偿技术进行了总结和未来发展方向的思考。

关键词：无功补偿；PLC；SVG；功率单元

ABSTRACT:With the development of economy, increase the number of impact load and nonlinear load in power grid, cause the voltage fluctuation, flicker, low power factor, it is an urgent need for the power quality management, and to the power grid without power compensation becomes more and more important. As a means of improving power quality, without static var generator (SVG) can compensate the power grid's wattless component.

　　　No reactive power compensation device design using the static (SVG), low voltage side of 380V grid dynamic wattless power compensation. First introduced the domestic and foreign current wattless power compensation technology, principle of wattless power compensation is analyzed, on this basis, designed the control system of compensation of low-voltage dynamic wattless power based on PLC (SVG). In the aspect of hardware, the power unit switching control, compared with the direct exchange of capacitor switching control scheme is common, more accurate, avoid mistakes. In the software, control the use of PLC programming, anti-interference ability is stronger, faster. Follow the principles of modular design, improve the system's versatility and maintenance and upgrade easily later, thinking the wattless compensation techniques are summarized and the future development direction

Key words :reactive compensation; PLC; SVG;Power unit