Compared with conventional transformers, the rectiformer is special in connection mode, which is multi-tap and not equipped with the differential protection. In this paper, the differential protection algorithm for Mu...Compared with conventional transformers, the rectiformer is special in connection mode, which is multi-tap and not equipped with the differential protection. In this paper, the differential protection algorithm for Multi-tap special transformer was derived. The regulating methods for the rectiformer were studied first, and then the rectiformer model of one electrolytic aluminium plant was built by PSCAD/EMTDC, characteristics of the rectiformer bank were also analyzed. The algorithm was derived on the basis of the per-unit system, and the processing methods of the regulating transformer’s tap position information were proposed. Finally, a contrast of differential protection algorithm between the multi-tap special transformer and the conventional transformer was made.展开更多
A transform method was used to model a discrete time multi-tap direct sampling mixer. The method transforms the mixed filtering and down-sampling stages to separate cascade filtering and sampling stages to determine t...A transform method was used to model a discrete time multi-tap direct sampling mixer. The method transforms the mixed filtering and down-sampling stages to separate cascade filtering and sampling stages to determine the unfolded frequency response which shows the anti-aliasing ability of the mixer. The trans-formation can also be applied to other mixed signal and multi-rate receiver systems to analyze their unfolded frequency responses. The transformed system architecture was used to calculate the unfolded frequency response of the multi-tap direct sampling mixer and compared with the mixer model without noise in the advanced design system 2005A environment to further evaluate the frequency response. The simulations show that the -3 dB bandwidth is 3.0 MHz and the voltage gain is attenuated by 1.5 dB within a 1-MHz baseband bandwidth.展开更多
光伏(photovoltaic,PV)的接入改变了配电网的结构,给传统的调压方式带来了很大影响。为此提出PV高渗透配电网分层调压控制策略,该策略利用有载调压变压器(on-load tap changer,OLTC)与逆变器对网络电压进行分层调节,实现了时间和空间上...光伏(photovoltaic,PV)的接入改变了配电网的结构,给传统的调压方式带来了很大影响。为此提出PV高渗透配电网分层调压控制策略,该策略利用有载调压变压器(on-load tap changer,OLTC)与逆变器对网络电压进行分层调节,实现了时间和空间上的解耦。在日前进行集中控制,采用基于OLTC的最优分接头控制(optimal tap control,OTC)方法,在控制周期内进行时段划分,降低分接头动作频率;在实时进行本地控制,利用逆变器剩余的无功调节能力来修正日前预测造成的误差。以IEEE33节点系统为例进行了仿真,结果表明,所提策略可保证电压不越限的同时有效地提升PV的渗透率。展开更多
文摘Compared with conventional transformers, the rectiformer is special in connection mode, which is multi-tap and not equipped with the differential protection. In this paper, the differential protection algorithm for Multi-tap special transformer was derived. The regulating methods for the rectiformer were studied first, and then the rectiformer model of one electrolytic aluminium plant was built by PSCAD/EMTDC, characteristics of the rectiformer bank were also analyzed. The algorithm was derived on the basis of the per-unit system, and the processing methods of the regulating transformer’s tap position information were proposed. Finally, a contrast of differential protection algorithm between the multi-tap special transformer and the conventional transformer was made.
基金Supported by the National Natural Science Foundation of China (No. 90407011)the National High-Tech Research and Development (863) Program of China (No. 2007AA01Z2b3)
文摘A transform method was used to model a discrete time multi-tap direct sampling mixer. The method transforms the mixed filtering and down-sampling stages to separate cascade filtering and sampling stages to determine the unfolded frequency response which shows the anti-aliasing ability of the mixer. The trans-formation can also be applied to other mixed signal and multi-rate receiver systems to analyze their unfolded frequency responses. The transformed system architecture was used to calculate the unfolded frequency response of the multi-tap direct sampling mixer and compared with the mixer model without noise in the advanced design system 2005A environment to further evaluate the frequency response. The simulations show that the -3 dB bandwidth is 3.0 MHz and the voltage gain is attenuated by 1.5 dB within a 1-MHz baseband bandwidth.
文摘光伏(photovoltaic,PV)的接入改变了配电网的结构,给传统的调压方式带来了很大影响。为此提出PV高渗透配电网分层调压控制策略,该策略利用有载调压变压器(on-load tap changer,OLTC)与逆变器对网络电压进行分层调节,实现了时间和空间上的解耦。在日前进行集中控制,采用基于OLTC的最优分接头控制(optimal tap control,OTC)方法,在控制周期内进行时段划分,降低分接头动作频率;在实时进行本地控制,利用逆变器剩余的无功调节能力来修正日前预测造成的误差。以IEEE33节点系统为例进行了仿真,结果表明,所提策略可保证电压不越限的同时有效地提升PV的渗透率。
