This paper discussed the experimental results of the performance of an organic Rankine cycle(ORC)system with an ultra-low temperature heat source.The low boiling point working medium R134a was adopted in the system.Th...This paper discussed the experimental results of the performance of an organic Rankine cycle(ORC)system with an ultra-low temperature heat source.The low boiling point working medium R134a was adopted in the system.The simulated heat source temperature(SHST)in this work was set from 39.51°C to 48.60°C by the simulated heat source module.The influence of load percentage of simulated heat source(LPSHS)between 50%and 70%,the rotary valve opening(RVO)between 20%and 100%,the resistive load between 36Ωand 180Ωor the no-load of the generator,as well as the autumn and winter ambient temperature on the system performance were studied.The results showed that the stability of the system was promoted when the generator had a resistive load.The power generation(PG)and generator speed(GS)of the system in autumn were better than in winter,but the expander pressure ratio(EPR)was lower than in winter.Keep RVO unchanged,the SHST,the mass flow rate(MFR)of the working medium,GS,and the PG of the system increased with the increasing of LPSHS for different generator resistance load values.When the RVO was 60%,LPSHS was 70%,the SHST was 44.15°C and the resistive load was 72Ω,the highest PG reached 15.11 W.Finally,a simulation formula was obtained for LPSHS,resistance load,and PG,and its correlation coefficient was between 0.9818 and 0.9901.The formula can accurately predict the PG.The experimental results showed that the standard deviation between the experimental and simulated values was below 0.0792,and the relative error was within±5%.展开更多
特高压变压器是特高压电网的重要设备,其短路电压百分比UK%的选择会影响到电网的多个指标。在1 000 k V变电站的模拟系统平台,采用理论计算方法分析了特高压变压器UK%的变化对1 000 k V系统注入500 k V母线的短路电流值的影响;兼顾变压...特高压变压器是特高压电网的重要设备,其短路电压百分比UK%的选择会影响到电网的多个指标。在1 000 k V变电站的模拟系统平台,采用理论计算方法分析了特高压变压器UK%的变化对1 000 k V系统注入500 k V母线的短路电流值的影响;兼顾变压器负载率的改变和是否通过第3绕组进行无功补偿两个方面,通过选取特定范围内的变压器不同的UK%值,运用PSCAD仿真软件,分析和讨论了500 k V母线电压变化情况,得出特高压变压器UK%为15%~23%时任何值均能通过无功补偿或有载调压将500 k V母线电压控制在515~530k V的范围内的结论。此工作可为特高压变压器UK%的选择提供一定的参考。展开更多
基金This work was supported by Tianjin Natural Science Foundation(No.21JCZDJC00750).
文摘This paper discussed the experimental results of the performance of an organic Rankine cycle(ORC)system with an ultra-low temperature heat source.The low boiling point working medium R134a was adopted in the system.The simulated heat source temperature(SHST)in this work was set from 39.51°C to 48.60°C by the simulated heat source module.The influence of load percentage of simulated heat source(LPSHS)between 50%and 70%,the rotary valve opening(RVO)between 20%and 100%,the resistive load between 36Ωand 180Ωor the no-load of the generator,as well as the autumn and winter ambient temperature on the system performance were studied.The results showed that the stability of the system was promoted when the generator had a resistive load.The power generation(PG)and generator speed(GS)of the system in autumn were better than in winter,but the expander pressure ratio(EPR)was lower than in winter.Keep RVO unchanged,the SHST,the mass flow rate(MFR)of the working medium,GS,and the PG of the system increased with the increasing of LPSHS for different generator resistance load values.When the RVO was 60%,LPSHS was 70%,the SHST was 44.15°C and the resistive load was 72Ω,the highest PG reached 15.11 W.Finally,a simulation formula was obtained for LPSHS,resistance load,and PG,and its correlation coefficient was between 0.9818 and 0.9901.The formula can accurately predict the PG.The experimental results showed that the standard deviation between the experimental and simulated values was below 0.0792,and the relative error was within±5%.
文摘特高压变压器是特高压电网的重要设备,其短路电压百分比UK%的选择会影响到电网的多个指标。在1 000 k V变电站的模拟系统平台,采用理论计算方法分析了特高压变压器UK%的变化对1 000 k V系统注入500 k V母线的短路电流值的影响;兼顾变压器负载率的改变和是否通过第3绕组进行无功补偿两个方面,通过选取特定范围内的变压器不同的UK%值,运用PSCAD仿真软件,分析和讨论了500 k V母线电压变化情况,得出特高压变压器UK%为15%~23%时任何值均能通过无功补偿或有载调压将500 k V母线电压控制在515~530k V的范围内的结论。此工作可为特高压变压器UK%的选择提供一定的参考。
