Currently,a grid-connected inverter is required to inject a dual-sequence current during asymmetric grid sags,which means both positive and negative sequence phases should be tracked.This paper proposes an open-loop p...Currently,a grid-connected inverter is required to inject a dual-sequence current during asymmetric grid sags,which means both positive and negative sequence phases should be tracked.This paper proposes an open-loop phase synchronization(OLS)method of positive and negative sequences for an asymmetric grid based on the moving average filter(MAF),which does not need to separate the positive and negative sequence fundamental components of grid voltage.As a benefit,there is no double-frequency oscillation in the estimated phases at offnominal frequencies since the positive and negative sequence phases are obtained simultaneously.The proposed method not only has the inherent advantages of OLS,but also further improves the dynamic response since the window length of MAF is only 1/6 of the fundamental period.The effectiveness of the proposed OLS is verified by experimental results.展开更多
The paper describes the application of a static var compensator to improve the electrical system of the ACN （Cravo Norte Association） oil field in Colombia. The paper summarizes the application, including system asp...The paper describes the application of a static var compensator to improve the electrical system of the ACN （Cravo Norte Association） oil field in Colombia. The paper summarizes the application, including system aspects that require special control functions in the SVC （static var compensator） regulator. Several important benefits for the system operation are demonstrated, such as increased power transmission import over an existing 230 kV network, dynamic bus voltage stabilization for various load conditions, including system outages and load rejection, and reduction of variable speed drive shutdowns by up to 95%. Some relevant design features of the SVC are treated, as well.展开更多
文摘Currently,a grid-connected inverter is required to inject a dual-sequence current during asymmetric grid sags,which means both positive and negative sequence phases should be tracked.This paper proposes an open-loop phase synchronization(OLS)method of positive and negative sequences for an asymmetric grid based on the moving average filter(MAF),which does not need to separate the positive and negative sequence fundamental components of grid voltage.As a benefit,there is no double-frequency oscillation in the estimated phases at offnominal frequencies since the positive and negative sequence phases are obtained simultaneously.The proposed method not only has the inherent advantages of OLS,but also further improves the dynamic response since the window length of MAF is only 1/6 of the fundamental period.The effectiveness of the proposed OLS is verified by experimental results.
文摘The paper describes the application of a static var compensator to improve the electrical system of the ACN （Cravo Norte Association） oil field in Colombia. The paper summarizes the application, including system aspects that require special control functions in the SVC （static var compensator） regulator. Several important benefits for the system operation are demonstrated, such as increased power transmission import over an existing 230 kV network, dynamic bus voltage stabilization for various load conditions, including system outages and load rejection, and reduction of variable speed drive shutdowns by up to 95%. Some relevant design features of the SVC are treated, as well.
