超超临界1000 MW机组一次调频多变量优化策略

Multivariable optimization strategy of primary frequency modulation for an ultra-supercritical 1000 MW unit

针对凝结水节流变负荷技术在燃煤机组灵活性改造时存在响应滞后10～20 s的情况,本文在某超超临界1 000 MW机组上进行凝结水节流变负荷、抽汽调节变负荷及给水分配变负荷试验,重点分析了后两种变负荷技术的安全性及有效性;并在传统凝结水节流技术的基础上,结合该机组回热系统的布置情况,提出凝结水节流与抽汽调节、给水分配变负荷技术相结合的一次调频多变量优化控制策略,再利用改进的滑压优化系统进一步提高机组节能潜力。一次调频考核试验验证了该优化策略的有效性和可行性,同时证明投入多变量优化系统及滑压优化系统后,该机组年平均节约煤耗1.5 g/(kW·h),节能效果显著。

The condensate throttling varying load technology has a response lag of 10~20 s during the flexible retrofit of coal-fired units,to solve this problem,the condensate throttling test,high pressure heater extraction adjustment test and feedwater distribution tests on an ultra-supercritical 1000 MW unit were carried out.Especially,the security and effectiveness of the last two load-changing methods were analyzed in detail.Combining the conventional condensate throttling technology with the special layout of the regenerative system of this unit,a multivariable optimization strategy of primary frequency modulation including condensate throttling,extraction adjustment and feedwater distribution was proposed.Moreover,the improved sliding pressure optimization system was used to further improve the energy saving potential of the unit.Through the primary frequency modulation assessment test,the effectiveness and feasibility of the improved strategy was proved.The experiment proves that,after the multivariable optimization system and sliding pressure optimization system was put into service,the annual average coal consumption of the unit decreased by 1.5 g/(kW·h),indicating the energy saving effect is dramatic.