在深度调峰负荷50%THA、40%THA及30%THA条件下，对某超超临界660 MW燃煤机组常规回热系统和弹性回热系统内高压加热器抽汽节流调频方式的变负荷能力进行静态分析。结果表明：单台高压加热器抽汽节流调频方式只对最末级高压加热器有效，零号高压加热器在50%THA、40%THA及30%THA工况下的最大变负荷能力依次为1.2%Pe、0.9%Pe和0.5%Pe（Pe表示额定负荷）；常规回热系统给水旁路(1号+2号HP)流量比例为50%时，在50%THA、40%THA及30%THA工况下机组负荷增量依次为1.8%Pe、1.4%Pe和1.0%Pe；增设零号高压加热器后各负荷工况下机组负荷增量分别提高32%、37%和26%；在30%THA以上负荷凝结水节流调频方式的变负荷能力明显低于给水旁路调频方式，在30%THA及以下深度调峰负荷下凝结水节流技术将退出一次调频；通过给水旁路调频方式提供1%Pe负荷增量时，50%THA、40%THA及30%THA工况下最终给水温度分别降低9.8~13.4、15.4~16.8和20.8~22.1 ℃，1段抽汽温升分别为2.4~3.1、3.4~3.7和4.3~4.5 ℃，2段抽汽温升分别为2.9~3.9、4.0~4.6和5.1~5.7 ℃。

The static analysis of the load change capability of high pressure(HP) heater steam extraction throttling frequency modulation mode in conventional regenerative system and flexible regenerative system of an ultrasupercritical 660 MW coalfired unit under deep peak load regulation of 50% THA,40% THA and 30% THA was carried out. The results show that the steam extraction throttling frequency modulation mode of a single HP heater is only effective for HP heater at the last stage,the maximum load change capabilities of No.0 HP heater under 50% THA,40% THA and 30% THA conditions are 1.2% Pe,0.9% Pe and 0.5% Pe successively;when the flow ratio of feedwater bypass(No.1 and No.2 HP heaters) of conventional regenerative system is 50%,the unit load increments under 50% THA,40% THA and 30% THA conditions are 1.8% Pe,1.4% Pe and 1.0% Pe successively;after adding No.0 HP heater,the unit load increments under each load condition are increased by 32%,37% and 26% respectively;when the unit′s load is above 30% THA,the load change capability of condensate throttling frequency modulation mode is significantly lower than that of feedwater bypass frequency modulation mode,and at the deep peak load regulation of 30% THA and below,the condensate throttling technology will exit the primary frequency modulation;when 1% Pe load increment is provided through feedwater bypass frequency modulation mode,under 50% THA,40% THA and 30% THA conditions,the final feedwater temperatures decrease by 9.8 to 13.4 ℃,15.4 to 16.8 ℃ and 20.8 to 22.1 ℃ respectively,the temperature rises of the first stage extraction steam are 2.4 to 3.1 ℃,3.4 to 3.7 ℃ and 4.3 to 4.5 ℃ respectively,and the temperature rises of the second stage extraction steam are 2.9 to 3.9 ℃,4 to 4.6 ℃ and 5.1 to 5.7 ℃ respectively.

TK221