涟钢电网安全稳定性研究

【作者】 李学军；

【导师】 王击；

【作者基本信息】 中南大学 ， 电力系统及其自动化， 2008， 硕士

【摘要】 为了节约资源、提高效益,目前各大中型钢铁企业都在充分利用高炉煤气、焦炉煤气及生产过程中产生的余热蒸汽进行发电。企业自备发电机组点多面广,分布在厂区各个角落。由于受到企业原有电网及经济效益的局限性,几乎所有的企业自备发电机组都选择在企业内部电网的中压侧(10KV或35KV)并网。大量小机组的并网使企业电网的规模越来越大,网络结构日趋复杂。本文介绍了涟钢电网主接线方式,利用PSASP仿真软件验证了自备发电机组的并网带来短路容量增大的事实,并提出在相关回路中应用带快速开关的故障限流电抗器,一方面降低了回路短路电流,另一方面解决了加装电抗器后所带来的电能损耗增大的问题。分析了自备发电机组并网后对原有电网继电保护的影响,在此基础上提出修改保护定值和优化电网结构的思想,详细讨论了电网结构改变后,系统进线电源发生故障情况下自动重合闸和备自投的动作情况。建立了涟钢电网各元件的数学模型,应用BPA仿真软件对大量自备发电机组因故障带来的孤网运行情况下的机电暂态稳定性进行了研究,研究结果为电网运行方式的制定给出了理论依据,为涟钢电网的稳定运行提供了参考方案,可为钢铁、水泥等行业有新建小型自备发电机组电网的稳定运行提供参考。本文的创新之处在于将大区电网的励磁系统建模方法应用于企业电网的自备发电机组中,得到了励磁系统数学模型的准确参数,保证了仿真结果的有效性。更多还原

【Abstract】 At present,many of the lardge or medium iron and steel enterprises put up a lot of generators by use of blast frunace gas,coke oven gas and redunt steam for saving resource and gaining more benefits.The generators distribute everywhere in factory.Restricted by former distributed network and economic profits,almost every generator synchronizes at the medium voltage level(10KV or 35KV).It enlarges the scale of distribution network and complicates the electric power network composition when building so many generator sets.This paper introduces the power system drawing of Lianyuan Iron and Steel group company,validates the enlargement of the short circuit current capabilit after distributed generators synchronizing by use of Power System Analysis Synthetical Programe.It suggests adding reactor accompanied with quick switch.In the one hand,the reactor reduces the short circuit current,on the other hand,it does not increase energy loss on the reactor.It analyzes the influence of distribution network protection system by distributed generation.In this foundation,this paper points out that it must modify the definite value of relay protection and optimize distribution network.Meanwhile it discusses detailedly the operation of ZCH and BZT when new grid facing system failure.This paper erects the mathematical model of Lianyuan Iron and Steel group company power grid,studies the transient stability when enterprise power grid isolated the main power grid by using BPA.The work of studying provides theory foundation for power grid safety and stability operation and put forward reference for other homologous enterprise.The creativity in this thesis lies in applying excitation system modeling method used in area grid into enterprise grid’s generators,obtaining precise parameters of excitation system,assuring correctness of the simulation.更多还原