【作者】 王建中；

【导师】 李铁鹰；

【作者基本信息】 太原理工大学 ， 控制理论与控制工程， 2007， 硕士

【摘要】 随着电网容量的不断扩大，短路电流的值不断提高，给系统的安全、稳定和可靠运行埋下了严重隐患，传统的限流技术已逐渐显现出局限性而越来越不能适应当今社会对电能质量上的高要求。短路电流限制技术已成为故障保护的一个研究热点。超导故障限流器以现今流行的超导技术为背景，被普遍认为是目前比较先进的短路故障电流限制装置。饱和铁芯型高温超导故障电流限制器就是其中一种。传统的饱和铁芯型高温超导故障限流器(high temperature superconducting fault current limiter，简称HTSFCL)在短路发生后采取不切断直流励磁的方式，限流效果较弱、超导励磁线圈要承受很高的感应电压和直流电源在较大的感应电压干扰时仍要保持恒流状态。为此，本文提出了一种新型主动式饱和铁芯型高温超导故障限流器，即在检测到短路故障时采用高压IGBT快速切断直流励磁系统的方式。并针对这种超导故障限流器的直流励磁控制系统进行研究，设计了这种高压IGBT的驱动和保护电路，并参与了380V／50A新型饱和铁芯型高温超导故障限流器的实验样机制作和短路故障限流实验。新型饱和铁芯型高温超导故障限流器样机的监控系统的作用就是电网正常运行时，闭合直流励磁系统，超导限流器工作在饱和段，呈现低阻抗；当电网故障发生时，切断直流励磁系统，此时限流器呈现高阻抗，超导限流器进行限流，当电网故障排除，需要重合闸时，限流器重新进入饱和段，使电网稳定运行。控制系统的设计要采用合理的故障检测和判断方法，对直流励磁系统采用合理控制策略，并能保证控制系统的可靠性。数据采集和检测由NI的16位PCI总线数据采集卡和电压电流传感器等组成，以LabVIEW为开放平台，实现故障信号高精度、高速率采样、显示和存储。短路故障限流实验系统主要包括短路实验平台、实时数据采集系统、监测控制系统三部分。同时，为了使系统中的短路冲击达到最大，以反并联晶闸管作为短路开关，对短路合闸角和短路时间进行控制。最后完成了新型主动式饱和铁芯型高温超导限流器的低压短路实验。短路实验结果表明，采用该控制系统的高温超导限流器能有效限制短路故障发生后的短路电流冲击峰值和稳态短路电流，从而验证了这种高温超导限流器原理的可行性，为下一步研发35kV／1.5kA的新型饱和铁芯型高温超导限流器并在云南电网公司普吉电站进行挂网实验运行提供了理论和实践支持。更多还原

【Abstract】 Along with the expanding power network, the fault current has increased greatly. It will bring hidden troubles to the security, stability, credibility of the power system. Conventional current limiters gradually show their limitation and can’t fit the request of high power quality. The fault current limiting technology has become a hotspot of fault protects research.On the background of developed superconductivity, superconducting fault current limiter (SFCL) is the most promising device in power grid. When the short current occurs, the traditional saturated iron core High Temperature Superconducting Fault Current Limiter (HTSFCL) doesn’t cut off the dc excitation, the effect is inconspicuous and superconducting excitation wedding must endure inductive high voltage, In this case, dc power supply is difficulty to maintain constant current. In this paper, we suggest a new type SFCL and emphases its control system, Active Saturated Iron Core HTSFCL, which is when detected the fault happened, cut off the dc circuit as quickly as possible in safety. When the grid is in normal operation, the dc current is adjusted to make the iron cores in deeply saturated so that the voltage drops on the ac windings are low. When a fault comes, break off the dc current, inductive voltages appear, limit the fault current. In our approach, the dc circuit brealdng strategy was adopted. High temperature superconductor silver sheathed Bi-2223 tape was used for the dc coil. Accurate fault detection and a reliable high speed dc circuit breaker are critically important. We used a High Voltage Insulated Gate Bipolar Transistor (HVIGBT) as the circuit breaking element.Based on this, a 380V/50A SFCL system and short current test platform are developed, on the platform of LabVIEW, which consist of voltage sensors, current sensors, a 16 precision data acquire card and back-to-back connected thyristors and so on.Different kinds of short circuits are conducted and the theoretical predictions and simulations are validated by the experiment results, which lay a sound foundation for the 35kV/1.5kA HTSFCL system that will be installed to a power grid in PUJI station of YUNNAN province.更多还原