为研究半波长交流输电的点对网并网特性,通过PSCAD (power system computer-aided design)仿真,分析了并网点两侧电压存在幅值偏差、相角偏差或频率偏差时的并网特性。等值系统能将半波长线路另一端的发电机拉入同步,但并网后的功率振...为研究半波长交流输电的点对网并网特性,通过PSCAD (power system computer-aided design)仿真,分析了并网点两侧电压存在幅值偏差、相角偏差或频率偏差时的并网特性。等值系统能将半波长线路另一端的发电机拉入同步,但并网后的功率振荡持续时间相对较长。通常,串联调谐器要比并联调谐器更适合于阻尼这些功率振荡,因此,仅对串联调谐器的控制策略进行修改。PSCAD仿真结果表明串联调谐器能有效地阻尼这些功率振荡,显著改善半波长交流输电线路的并网性能。展开更多
This paper describes the design and implementation of an intelligent computer-aided design (ICAD) system for hydraulic circuits of pressing machines. The CAD system is developed based on the object-oriented approach. ...This paper describes the design and implementation of an intelligent computer-aided design (ICAD) system for hydraulic circuits of pressing machines. The CAD system is developed based on the object-oriented approach. The application domain of hydraulic presses has been studied thoroughly. The engineering data and the design knowledge are organized in an object-oriented database. A case study has been selected to illustrate the usefulness of the object-oriented CAD system in real applications.展开更多
岸基供电系统设备参数的确定,需要依托其系统短路电流大小.以低压上船为例,根据船舶行业标准与国家标准,确定系统设备初始参数,分别用标幺值法和等效电压源法计算系统短路电流并进行对比.利用电磁暂态仿真软件(Power System Computer Ai...岸基供电系统设备参数的确定,需要依托其系统短路电流大小.以低压上船为例,根据船舶行业标准与国家标准,确定系统设备初始参数,分别用标幺值法和等效电压源法计算系统短路电流并进行对比.利用电磁暂态仿真软件(Power System Computer Aided Design;PSCAD)搭建系统模型,进行仿真分析,验证了计算结果的正确性.最后依据计算结果,为电缆、开关柜、断路器、互感器等一次设备选择参数.展开更多
以糯扎渡—鹤山±800 kV特高压直流输电系统为研究对象,利用电力系统计算机辅助设计和电磁暂态模拟程序软件(power system computer aided design and electric magnetic transient in DC system,PSCAD/EMTDC),建立交流系统、换流...以糯扎渡—鹤山±800 kV特高压直流输电系统为研究对象,利用电力系统计算机辅助设计和电磁暂态模拟程序软件(power system computer aided design and electric magnetic transient in DC system,PSCAD/EMTDC),建立交流系统、换流器、换流变压器、交直流滤波器、直流平波电抗器、直流输电线路的仿真模型,并在这个仿真平台上进行单极、双极全压仿真模拟分析,仿真结果表明所建模型较准确地模拟糯扎渡—鹤山特高压直流输电系统,可以作为研究特高压直流输电系统的有效工具。展开更多
More and more high voltage direct current(HVDC) converters are being located in a load area in the Yangtze River Delta Region in China. It's large transmission capacity and intensive placement are hardly seen in o...More and more high voltage direct current(HVDC) converters are being located in a load area in the Yangtze River Delta Region in China. It's large transmission capacity and intensive placement are hardly seen in other countries. Accurate and reliable study tools and methods are extremely needed for power system engineers and researchers to deal with such problems which were never met before and otherwhere. A novel approach on electromagnetic modeling of alternating current / direct current(AC/DC) system is proposed and simulation is carried out to replay a real AC 3-phase to ground fault on a multi-infeed high voltage direct current(MIHVDC) system. AC system is specially simplified. Dynamic models and real parameters are adopted in main AC/DC equipments concerned and retained. Modeling and simulation are based on the power system computer aided design/electro-magnetic transient in direct current(PSCAD/EMTDC) system software package.Comparisons between simulation results and the records from the fault recorders are studied including both AC and DC quantities.展开更多
文摘为研究半波长交流输电的点对网并网特性,通过PSCAD (power system computer-aided design)仿真,分析了并网点两侧电压存在幅值偏差、相角偏差或频率偏差时的并网特性。等值系统能将半波长线路另一端的发电机拉入同步,但并网后的功率振荡持续时间相对较长。通常,串联调谐器要比并联调谐器更适合于阻尼这些功率振荡,因此,仅对串联调谐器的控制策略进行修改。PSCAD仿真结果表明串联调谐器能有效地阻尼这些功率振荡,显著改善半波长交流输电线路的并网性能。
文摘This paper describes the design and implementation of an intelligent computer-aided design (ICAD) system for hydraulic circuits of pressing machines. The CAD system is developed based on the object-oriented approach. The application domain of hydraulic presses has been studied thoroughly. The engineering data and the design knowledge are organized in an object-oriented database. A case study has been selected to illustrate the usefulness of the object-oriented CAD system in real applications.
文摘岸基供电系统设备参数的确定,需要依托其系统短路电流大小.以低压上船为例,根据船舶行业标准与国家标准,确定系统设备初始参数,分别用标幺值法和等效电压源法计算系统短路电流并进行对比.利用电磁暂态仿真软件(Power System Computer Aided Design;PSCAD)搭建系统模型,进行仿真分析,验证了计算结果的正确性.最后依据计算结果,为电缆、开关柜、断路器、互感器等一次设备选择参数.
文摘以糯扎渡—鹤山±800 kV特高压直流输电系统为研究对象,利用电力系统计算机辅助设计和电磁暂态模拟程序软件(power system computer aided design and electric magnetic transient in DC system,PSCAD/EMTDC),建立交流系统、换流器、换流变压器、交直流滤波器、直流平波电抗器、直流输电线路的仿真模型,并在这个仿真平台上进行单极、双极全压仿真模拟分析,仿真结果表明所建模型较准确地模拟糯扎渡—鹤山特高压直流输电系统,可以作为研究特高压直流输电系统的有效工具。
文摘More and more high voltage direct current(HVDC) converters are being located in a load area in the Yangtze River Delta Region in China. It's large transmission capacity and intensive placement are hardly seen in other countries. Accurate and reliable study tools and methods are extremely needed for power system engineers and researchers to deal with such problems which were never met before and otherwhere. A novel approach on electromagnetic modeling of alternating current / direct current(AC/DC) system is proposed and simulation is carried out to replay a real AC 3-phase to ground fault on a multi-infeed high voltage direct current(MIHVDC) system. AC system is specially simplified. Dynamic models and real parameters are adopted in main AC/DC equipments concerned and retained. Modeling and simulation are based on the power system computer aided design/electro-magnetic transient in direct current(PSCAD/EMTDC) system software package.Comparisons between simulation results and the records from the fault recorders are studied including both AC and DC quantities.
