Through an example of a main transformer switch-in with load during the reverse transmission of a 750 kV power plan,the paper introduces the basic principle of transformer switch-in with load.EMTPE program that is use...Through an example of a main transformer switch-in with load during the reverse transmission of a 750 kV power plan,the paper introduces the basic principle of transformer switch-in with load.EMTPE program that is used to establish a calculation model,at the same time mainly considers the excitation characteristics of the transformer,the transient model of the circuit breaker,and the model of high voltage transformer,and calculated the inrush current with transformer switch-in with load in this plan.During system debugging in the plan,the two sets of main transformers passed the closing and opening test,and the data of inrush current in the test are recorded and analyzed.The simulation calculation and measured data show that the results are consistent.The simulation calculation also shows that it is not recommended to perform on-load closing of the transformer except for special circumstances,because of the influence of hysteresis characteristic when the transformer was switched in with load or the terminal voltage of the transformer resumed normal level from a low one after an external near-end fault was cleared,which various transformer differential protection using the characteristics of inrush to implement block scheme may mal-operate.展开更多
某核电厂主变压器采用中性点经过气体绝缘封闭母线(GIB)直接接地的方式,由于GIB外壳接地方式不明确,存在GIB外壳和接地体环流过大的现象,严重威胁着变压器的安全可靠运行。为研究接地体数量和接地位置对GIB外壳环流大小及分布的影响,使...某核电厂主变压器采用中性点经过气体绝缘封闭母线(GIB)直接接地的方式,由于GIB外壳接地方式不明确,存在GIB外壳和接地体环流过大的现象,严重威胁着变压器的安全可靠运行。为研究接地体数量和接地位置对GIB外壳环流大小及分布的影响,使用电磁暂态仿真软件EMTP搭建500k V GIB环流仿真模型,分析了稳态运行时GIB外壳不同接地组合对感应环流大小及分布的影响。研究表明,GIB外壳一点接地时,流过GIB外壳和接地线上的感应环流最小,此研究对同类型设备的接地方式选择有一定的指导作用。展开更多
为探讨变电站设备实际耐受的雷电冲击电压波形与标准雷电冲击电压波形的差异,对变电站雷电侵入过电压的波形特征及其影响因素进行了仿真研究。通过在电磁暂态计算程序(EMTP)中建立500 k V交流变电站–输电线路模型,并结合过电压形成的...为探讨变电站设备实际耐受的雷电冲击电压波形与标准雷电冲击电压波形的差异,对变电站雷电侵入过电压的波形特征及其影响因素进行了仿真研究。通过在电磁暂态计算程序(EMTP)中建立500 k V交流变电站–输电线路模型,并结合过电压形成的物理过程,分析了雷击类型、输电线路传输过程以及避雷器对雷电侵入过电压波形的影响。研究结果表明:受雷击工况、输电线路传输过程及避雷器等非线性设备的影响,变电站设备实际耐受的雷电侵入波形近似为平顶波,波前时间可达8μs,波尾时间最短仅为10μs,最长可达数百μs。严苛情况下,变电站设备在实际雷电侵入电压波形下的绝缘耐受水平低于标准雷电冲击试验值。该研究为进一步探讨雷电冲击试验标准的合理性奠定了基础。展开更多
文摘Through an example of a main transformer switch-in with load during the reverse transmission of a 750 kV power plan,the paper introduces the basic principle of transformer switch-in with load.EMTPE program that is used to establish a calculation model,at the same time mainly considers the excitation characteristics of the transformer,the transient model of the circuit breaker,and the model of high voltage transformer,and calculated the inrush current with transformer switch-in with load in this plan.During system debugging in the plan,the two sets of main transformers passed the closing and opening test,and the data of inrush current in the test are recorded and analyzed.The simulation calculation and measured data show that the results are consistent.The simulation calculation also shows that it is not recommended to perform on-load closing of the transformer except for special circumstances,because of the influence of hysteresis characteristic when the transformer was switched in with load or the terminal voltage of the transformer resumed normal level from a low one after an external near-end fault was cleared,which various transformer differential protection using the characteristics of inrush to implement block scheme may mal-operate.
文摘某核电厂主变压器采用中性点经过气体绝缘封闭母线(GIB)直接接地的方式,由于GIB外壳接地方式不明确,存在GIB外壳和接地体环流过大的现象,严重威胁着变压器的安全可靠运行。为研究接地体数量和接地位置对GIB外壳环流大小及分布的影响,使用电磁暂态仿真软件EMTP搭建500k V GIB环流仿真模型,分析了稳态运行时GIB外壳不同接地组合对感应环流大小及分布的影响。研究表明,GIB外壳一点接地时,流过GIB外壳和接地线上的感应环流最小,此研究对同类型设备的接地方式选择有一定的指导作用。
文摘为探讨变电站设备实际耐受的雷电冲击电压波形与标准雷电冲击电压波形的差异,对变电站雷电侵入过电压的波形特征及其影响因素进行了仿真研究。通过在电磁暂态计算程序(EMTP)中建立500 k V交流变电站–输电线路模型,并结合过电压形成的物理过程,分析了雷击类型、输电线路传输过程以及避雷器对雷电侵入过电压波形的影响。研究结果表明:受雷击工况、输电线路传输过程及避雷器等非线性设备的影响,变电站设备实际耐受的雷电侵入波形近似为平顶波,波前时间可达8μs,波尾时间最短仅为10μs,最长可达数百μs。严苛情况下,变电站设备在实际雷电侵入电压波形下的绝缘耐受水平低于标准雷电冲击试验值。该研究为进一步探讨雷电冲击试验标准的合理性奠定了基础。
