The phenomenon of anti-symmetrical bifurcation of periodic solutionsoccurring near an integral manifold is the intrinsic cause resulting in harmonic resonanceover-voltage in power systems. Due to this discovery, the p...The phenomenon of anti-symmetrical bifurcation of periodic solutionsoccurring near an integral manifold is the intrinsic cause resulting in harmonic resonanceover-voltage in power systems. Due to this discovery, the principle of eliminating resonance byusing anti-bifurcation technique is presented, which makes that the theoretical bases of verymeasure to eliminate resonance are unified firstly from a point of view of basic theory. Ourdiscussion models depend on a class of nonlinear control model. Using the direct Lyapunov method, acomplete theoretical proof is given in accordance with the measure of eliminating resonance byconnecting nonlinear resistor in series to the neutral point of P. T., and the feedback control lawbeing applied. It comprises the action of parameters of resistor to eliminate resonance and theactual process of eliminating resonance, i.e., to go against bifurcation process which forces thebig harmonic solutions to retreat to the integral manifold gradually and disappear eventually, whichby using the nonlinear controllers. This makes it sure that the intrinsic cause of resonance iseliminated thoroughly. The obtained theory results and computing results are better than thepresented results.展开更多
Ferroresonance in distribution networks is usually hard to be identified and predicted because it is nonlinear and dependent on multiple factors and conditions.This study discusses different common antiferroresonance...Ferroresonance in distribution networks is usually hard to be identified and predicted because it is nonlinear and dependent on multiple factors and conditions.This study discusses different common antiferroresonance methods by numerical simulations and experimental tests.In order to study the reliability of the anti-ferroresonance measures,a 10 kV ferroresonance testing system was setup.Then a number of simulations and experiments were carried out to show the ferroresonance phenomena initiated by single-phase grounding faults and/or single-phase disconnection faults.In addition,potential transformer models with the characteristic of non-linear magnetic excitation were developed and used in PSCAD-based simulation studies.These studies investigated the performance of primary resonance eliminators and arc suppression coils on restraining the ferroresonance under multiple power system parameters and initialisations.In addition,a joint anti-ferroresonance method is proposed and verified.The simulation and experimental studies can provide guidelines for evaluating the anti-ferroresonance methods in distribution networks.展开更多
Several results on optical-axis perturbation and elimination of the mismatching error C of a monolithic triaxial ring resonator （MTRR） are reported. Based on the augmented 5×5 ray matrix method, by simultaneous...Several results on optical-axis perturbation and elimination of the mismatching error C of a monolithic triaxial ring resonator （MTRR） are reported. Based on the augmented 5×5 ray matrix method, by simultaneously considering axial displacement of a mirror and the misalignments in three planar square ring resonators of a MTRR, the rules of optical-axis perturbation are obtained. The mismatching error C of the MTRR is eliminated. The results obtained are important for cavity design, as well as in the improvement and alignment of MTRR.展开更多
文摘The phenomenon of anti-symmetrical bifurcation of periodic solutionsoccurring near an integral manifold is the intrinsic cause resulting in harmonic resonanceover-voltage in power systems. Due to this discovery, the principle of eliminating resonance byusing anti-bifurcation technique is presented, which makes that the theoretical bases of verymeasure to eliminate resonance are unified firstly from a point of view of basic theory. Ourdiscussion models depend on a class of nonlinear control model. Using the direct Lyapunov method, acomplete theoretical proof is given in accordance with the measure of eliminating resonance byconnecting nonlinear resistor in series to the neutral point of P. T., and the feedback control lawbeing applied. It comprises the action of parameters of resistor to eliminate resonance and theactual process of eliminating resonance, i.e., to go against bifurcation process which forces thebig harmonic solutions to retreat to the integral manifold gradually and disappear eventually, whichby using the nonlinear controllers. This makes it sure that the intrinsic cause of resonance iseliminated thoroughly. The obtained theory results and computing results are better than thepresented results.
文摘Ferroresonance in distribution networks is usually hard to be identified and predicted because it is nonlinear and dependent on multiple factors and conditions.This study discusses different common antiferroresonance methods by numerical simulations and experimental tests.In order to study the reliability of the anti-ferroresonance measures,a 10 kV ferroresonance testing system was setup.Then a number of simulations and experiments were carried out to show the ferroresonance phenomena initiated by single-phase grounding faults and/or single-phase disconnection faults.In addition,potential transformer models with the characteristic of non-linear magnetic excitation were developed and used in PSCAD-based simulation studies.These studies investigated the performance of primary resonance eliminators and arc suppression coils on restraining the ferroresonance under multiple power system parameters and initialisations.In addition,a joint anti-ferroresonance method is proposed and verified.The simulation and experimental studies can provide guidelines for evaluating the anti-ferroresonance methods in distribution networks.
基金supported by the National Natural Science Foundation of China under Grant Nos.60608002and 60608002
文摘Several results on optical-axis perturbation and elimination of the mismatching error C of a monolithic triaxial ring resonator （MTRR） are reported. Based on the augmented 5×5 ray matrix method, by simultaneously considering axial displacement of a mirror and the misalignments in three planar square ring resonators of a MTRR, the rules of optical-axis perturbation are obtained. The mismatching error C of the MTRR is eliminated. The results obtained are important for cavity design, as well as in the improvement and alignment of MTRR.
