两种灵活性改造技术的热电特性对比研究

Comparative Study of Thermoelectric Characteristics of Two Flexibility Transformation Technologies

高低旁联合供热和低压缸零出力技术作为2种重要的灵活性改造技术,能够有效提升火电机组供热工况的调峰能力与供热能力。本文基于华北电网内2台同型号350 MW超临界机组,采用热力系统建模仿真软件Ebsilon搭建了机组高低旁联合供热和低压缸零出力模式下的热电性能计算模型,通过对比实际现场性能试验结果论证了模型的可靠性。模型的全运行区间性能计算结果分析表明:高低旁联合供热的最大热负荷可以比低压缸零出力大57.27 MW,最小电负荷比低压缸零出力小141.04 MW,其热电解耦能力更优秀;在主蒸汽流量和热网抽汽流量相等时,低压缸零出力比高低旁联合供热的电负荷高61.01 MW,其能量利用率更高;在现有华北电网调峰收益机制下,在主蒸汽流量小于505 t/h时,低压缸零出力供热可以获得更高的综合收益;在主蒸汽流量为505 t/h时,2种技术可以获得相同的最大综合收益;在主蒸汽流量大于505 t/h时,高低旁联合供热可以获得更高的综合收益。

High and low pressure bypass combined heating supply and low-pressure cylinder zero output technology are two important flexibility transformation technologies,which can effectively improve thermal power units’peak regulation capacity and heating capacity.In this paper,for the two same model 350 MW supercritical units of North China power grid,a therma lsystem simulating software named Ebsilon is used to build the high and low pressure bypass combined heating supply and low-pressure cylinder zero output model,whose reliability are demonstrated by actual field performance tests.The models’full operation interval calculation results show that:the high and low pressure bypass combined heating supply model has better thermoelectric decoupling capacity because of it's maximum heating load capacity is 57.27 MW more and minimum electrical load capacity is 141.04 MW less than the low-pressure cylinder zero output model;The low-pressure cylinder zero-output model has a higher energy utilization rate because of its’electrical load is 61.012 MW higher than high and low pressure bypass combined heating supply model when they have the same main steam and heating steam.Under the existing peak regulation revenue mechanism of North China Power Grid,the low-pressure cylinder zero-output heating can obtain a higher maximum comprehensive income when the main steam flow is less than 505 t/h;the two technologies can obtain the same max comprehensive benefit when the main steam flow is 505 t/h;the high and low pressure bypass combined heating supply model can obtain higher maximum comprehensive revenue when the main steam flow rate is greater than 505 t/h.