【作者】 高连强；

【导师】 梁秀霞；

【作者基本信息】 河北工业大学 ， 检测技术与自动化装置， 2007， 硕士

【摘要】 随着电力系统负荷的增加,对无功功率的需求也日益增加。无功功率在电网中传输会造成网络损耗以及受电端电压下降,使电能利用率大大降低且严重影响供电质量。因此,在电网中的适当位置装设无功补偿装置是满足电网无功需求的必要手段。本文介绍了无功补偿的目的和意义,阐述了国内外无功补偿的现状与发展趋势。针对低压电网,本文分析了无功补偿原理及补偿接线方式,讨论了几种不同负荷情况下电网最佳补偿点的位置及容量配置的问题。同时,在分析各种无功补偿控制策略的基础上,将模糊控制理论引入电容器的投切控制,兼顾了提高功率因数与改善电压质量,并且避免了无功补偿装置往复投切问题。本文设计了一种适用于低压电网进行集中无功补偿的晶闸管投切电容器装置。在装置设计中采用电压无功复合投切判据,以无功功率作为主判据、电压作为辅助判据,有效地克服了以功率因数作为投切判据的控制方式中的轻载时容易产生投切振荡而重载时容易出现补偿不充分的缺点,同时兼顾了降低功率损耗与改善电压质量;投切复合开关采用单独的脉冲触发装置触发,保证了晶闸管在两端电压过零时触发,从而在硬件电路上实现电容器组的无过渡过程投切,且简单可靠;控制系统采用价格比较便宜的AT89C51单片机作为控制系统主体。装置能够实现无功功率的快速、准确补偿且成本较低,具有较好的实用性以及广阔的应用前景。论文阐述了该控制系统的原理及软硬件设计过程。最后,本文通过软件MATLAB/Simulink对装置进行了仿真研究,仿真结果表明该装置可以有效的对系统无功进行补偿。更多还原

【Abstract】 Due to increasing loads of electric power system, demand on reactive power was also increasing. Because transmission of reactive power in electric network can lead to network loss and step-down voltage, resulted in reduction of using efficiency of power energy and severely effected voltage quality. It became necessary means that reactive power compensation devices were installed in proper position of electric network.This paper introduced the principle and objective of var compensation, and presented the developmental actuality and trend of reactive power compensation system. Based on compensation principle and connection way, this paper studied switches of capacitors and the model of reactive power optimization planning about low voltage system. Based on analysis of other criterion methods, the paper introduced fuzzy control into var compensation. This new method can manage the relationship between voltage quality and power factor properly and eliminate the repeatedly switching problem.A TSC reactive power compensation device which was fit for low-voltage distribution network was introduced in this paper. The compound criterion whose main criterion is reactive power and whose assistant criterion is voltage was applied in the device, which effectively overcame the defects of the power factor criterion in which switching oscillation was often resulted in under light load and compensation was insufficient under heavy load, and the compound criterion gave attention to decreasing power loss and improving voltage quality.The system adopted thyristor as switch that connect capacitors to main circuit, and the Thyristor was triggered by a special device in the zero-voltage condition and thus greatly reduced surge current. This sort of switch circuit achieved switching of capacitors without transition course and was simple and reliable. The device took the AT89C51 which is a sort of cheap single chip micro-controller as main control chip. This device could fleetly and truly compensate reactive power and was low-cost. It processed preferably practicability and wide application foreground in low voltage network.At last, the device was simulated through software MATLAB/Simlink, and simulation and experiment show that the basic principle and method was totally feasible and effectual.更多还原