一次调频中的锅炉建模与参数在线确定

Boiler Modeling and Online Parameters Identification for Primary Frequency Regulation

火电机组作为主要的一次调频能力提供者,其锅炉主蒸汽压力模型对系统的频率响应有较大影响,锅炉参数和机组一次调频能力随工况变化而变化,而现有的一次调频模型无法反映这种特性。通过串联的换热单元等效锅炉并引入流体热容带来的延迟效应,建立考虑流动与传热的锅炉模型,并提出基于分散控制系统(distributed control system,DCS)数据的参数在线确定方法。以某1000MW机组为例进行计算,0.2Hz频差扰动下加入锅炉模型与无锅炉模型的一次调频60s积分电量相差733.5kW×h。机组调频能力与锅炉热力动态密切相关,验证不同工况下机组一次调频能力的差异。该锅炉模型与参数确认方法可在扰动发生前为电网安全运行提供参考指导。

As the main provider of primary frequency regulation capability,the boiler main steam pressure model of steam unit has a great impact on the frequency response of power system.The parameters and primary frequency regulation(PFR)capability of steam unit change with varied working conditions,but the existing model cannot reflect this characteristic.A boiler model considering flow and heat transfer is established by using a series heat exchange unit to equivalent the boiler and by introducing the delay effect caused by fluid heat capacity.An on-line parameter determination method based on DCS(distributed control system)data is proposed.Taking a 1000MW unit as an example,the difference between the 60s integrated power of primary frequency regulation with and without boiler model under 0.2hz frequency difference disturbance is 733.5kw×h.The frequency regulation capability of the unit is closely related to the thermal dynamic of the boiler,and the difference of the primary frequency regulation capability of the unit under different working conditions is verified.The boiler model and parameter confirmation method can provide reference for dispatchers before disturbance.