The step load response of reciprocating engines is one of the key characteristics when considering its application in medium to large scale stationary power generation especially with islanded generation. This paper d...The step load response of reciprocating engines is one of the key characteristics when considering its application in medium to large scale stationary power generation especially with islanded generation. This paper discusses the impacts of power frequency deviation on the generators and electrical equipment in the network and presents the relationship between step load capabilities and generator operating parameters. For a power plant consisting of a number of generators both step load and power output requirements must be satisfied. An analysis method is proposed to facilitate the development of an operation strategy which can meet both step load and power demand requirements in the full load range.? Typical reciprocating engine step load curves are used to demonstrate the analysis method and the results are further optimised for lower operational cost. This analysis method provides a general approach to operation strategy of large reciprocating engines used in islanded power generation.展开更多
Power swing evoked by sudden changes like faults or switching operations will become more and more important for protective relaying, due to the growing load flow in electrical power networks. Unwanted trips of the di...Power swing evoked by sudden changes like faults or switching operations will become more and more important for protective relaying, due to the growing load flow in electrical power networks. Unwanted trips of the distance protection function must be avoided to prevent cascading effects and blackouts in the network. Selective out-of-step-tripping is required to stop unstable power swing and to prevent damage to affected generators. Therefore a reliable method for detection of power swing is presented, which requires no settings for operation. Power swing can be detected from 0.1 Hz up to 10 Hz swing frequency, also during open pole condition and during asymmetrical operation. A blocking logic prevents unselective trips by the distance protection. However, faults that occur during a power swing must be detected and cleared with a high degree of selectivity and dependability. For unstable power swing a flexible out of step tripping function will be proposed. The coordination of power swing detection, distance protection and out of step protection provides a reliable system protection.展开更多
The Francis turbine governing system models in PSD-BPA can’t precisely reflect the actual characteristics. Endeavor was done in this paper to solve the problem. An improved model of actuating mechanism was developed,...The Francis turbine governing system models in PSD-BPA can’t precisely reflect the actual characteristics. Endeavor was done in this paper to solve the problem. An improved model of actuating mechanism was developed, which could reflect the step closing characteristic of hydro guide vanes. The effect of the inflection point value of actuating mechanism on load rejection was analyzed based on simulation. The non-linear Francis turbine model with power versus gate position module was researched in this paper. Based on field test, comparisons of simulation results with measured data were presented. The analysis demonstrates that the improved models of Francis turbine and governor proposed in this paper are more realistic than the models of BPA, and can be applied in power system simulation analysis better.展开更多
为兼顾“双碳”目标与能源保供底线,提升能源系统源荷侧降碳能力,在有效挖掘系统降碳潜能的同时,缓解火电装机总量增长与风电消纳之间的矛盾,文章将绿氨生产、氨煤混燃以及多种灵活性资源结合构成绿氨耦合发电单元,同时考虑碳捕集等低...为兼顾“双碳”目标与能源保供底线,提升能源系统源荷侧降碳能力,在有效挖掘系统降碳潜能的同时,缓解火电装机总量增长与风电消纳之间的矛盾,文章将绿氨生产、氨煤混燃以及多种灵活性资源结合构成绿氨耦合发电单元,同时考虑碳捕集等低碳技术,并应用碳排放流理论,提出了考虑绿氨替代与多元阶梯碳势需求响应的综合能源虚拟电厂(integrated energy virtual power plant,IEVPP)低碳经济调度模型,以降低系统碳排放并提升系统经济性。首先,将绿氨替代作为解决风电供用能不匹配问题的手段,并将其与燃煤机组掺氨技术结合,分析其能量流动与低碳特性;其次,将电-碳-氢-氨多元耦合过程引入IEVPP,从而促进了风电消纳,提升了系统调节能力;最后,依托碳排放流理论,通过动态碳排放因子提出了多元阶梯碳势需求响应模型,从源荷两侧充分挖掘系统降碳潜能。算例仿真分析结果表明,所构建的考虑绿氨替代IEVPP联合多元阶梯碳势需求响应可有效降低系统碳排放量,提升系统经济性。展开更多
Theory has it that increasing the step length improves the accuracy of a method. In order to affirm this we increased the step length of the concept in [1] by one to get k = 5. The technique of collocation and interpo...Theory has it that increasing the step length improves the accuracy of a method. In order to affirm this we increased the step length of the concept in [1] by one to get k = 5. The technique of collocation and interpolation of the power series approximate solution at some selected grid points is considered so as to generate continuous linear multistep methods with constant step sizes. Two, three and four interpolation points are considered to generate the continuous predictor-corrector methods which are implemented in block method respectively. The proposed methods when tested on some numerical examples performed more efficiently than those of [1]. Interestingly the concept of self starting [2] and that of constant order are reaffirmed in our new methods.展开更多
文摘The step load response of reciprocating engines is one of the key characteristics when considering its application in medium to large scale stationary power generation especially with islanded generation. This paper discusses the impacts of power frequency deviation on the generators and electrical equipment in the network and presents the relationship between step load capabilities and generator operating parameters. For a power plant consisting of a number of generators both step load and power output requirements must be satisfied. An analysis method is proposed to facilitate the development of an operation strategy which can meet both step load and power demand requirements in the full load range.? Typical reciprocating engine step load curves are used to demonstrate the analysis method and the results are further optimised for lower operational cost. This analysis method provides a general approach to operation strategy of large reciprocating engines used in islanded power generation.
文摘Power swing evoked by sudden changes like faults or switching operations will become more and more important for protective relaying, due to the growing load flow in electrical power networks. Unwanted trips of the distance protection function must be avoided to prevent cascading effects and blackouts in the network. Selective out-of-step-tripping is required to stop unstable power swing and to prevent damage to affected generators. Therefore a reliable method for detection of power swing is presented, which requires no settings for operation. Power swing can be detected from 0.1 Hz up to 10 Hz swing frequency, also during open pole condition and during asymmetrical operation. A blocking logic prevents unselective trips by the distance protection. However, faults that occur during a power swing must be detected and cleared with a high degree of selectivity and dependability. For unstable power swing a flexible out of step tripping function will be proposed. The coordination of power swing detection, distance protection and out of step protection provides a reliable system protection.
文摘The Francis turbine governing system models in PSD-BPA can’t precisely reflect the actual characteristics. Endeavor was done in this paper to solve the problem. An improved model of actuating mechanism was developed, which could reflect the step closing characteristic of hydro guide vanes. The effect of the inflection point value of actuating mechanism on load rejection was analyzed based on simulation. The non-linear Francis turbine model with power versus gate position module was researched in this paper. Based on field test, comparisons of simulation results with measured data were presented. The analysis demonstrates that the improved models of Francis turbine and governor proposed in this paper are more realistic than the models of BPA, and can be applied in power system simulation analysis better.
文摘为兼顾“双碳”目标与能源保供底线,提升能源系统源荷侧降碳能力,在有效挖掘系统降碳潜能的同时,缓解火电装机总量增长与风电消纳之间的矛盾,文章将绿氨生产、氨煤混燃以及多种灵活性资源结合构成绿氨耦合发电单元,同时考虑碳捕集等低碳技术,并应用碳排放流理论,提出了考虑绿氨替代与多元阶梯碳势需求响应的综合能源虚拟电厂(integrated energy virtual power plant,IEVPP)低碳经济调度模型,以降低系统碳排放并提升系统经济性。首先,将绿氨替代作为解决风电供用能不匹配问题的手段,并将其与燃煤机组掺氨技术结合,分析其能量流动与低碳特性;其次,将电-碳-氢-氨多元耦合过程引入IEVPP,从而促进了风电消纳,提升了系统调节能力;最后,依托碳排放流理论,通过动态碳排放因子提出了多元阶梯碳势需求响应模型,从源荷两侧充分挖掘系统降碳潜能。算例仿真分析结果表明,所构建的考虑绿氨替代IEVPP联合多元阶梯碳势需求响应可有效降低系统碳排放量,提升系统经济性。
文摘Theory has it that increasing the step length improves the accuracy of a method. In order to affirm this we increased the step length of the concept in [1] by one to get k = 5. The technique of collocation and interpolation of the power series approximate solution at some selected grid points is considered so as to generate continuous linear multistep methods with constant step sizes. Two, three and four interpolation points are considered to generate the continuous predictor-corrector methods which are implemented in block method respectively. The proposed methods when tested on some numerical examples performed more efficiently than those of [1]. Interestingly the concept of self starting [2] and that of constant order are reaffirmed in our new methods.
