This paper introduces a multi-model approach to design a robust supplementary damping controller. The designed fixed-order supplementary damping controller adjusts the voltage reference set point of SVC. There are two...This paper introduces a multi-model approach to design a robust supplementary damping controller. The designed fixed-order supplementary damping controller adjusts the voltage reference set point of SVC. There are two main objectives of the controller design, damping low frequencies oscillations and enhancing power system stability. This method relies on shaping the closed-loop sensitivity functions in the Nyquist plot under the constraints of these functions. These constraints can be linearized by choosing a desired open-loop transfer function. The robust controller is designed to minimize the error between the open-loop of the original plant model and the desired transfer functions. These outcomes can be achieved by using convex optimization methods. Convexity of the problem formulation ensures global optimality. One of the advantages of the proposed approach is that the approach accounts for multi-model uncertainty. In contrast to the methods available in the literature, the proposed approach deals with full-order model (i.e., model reduction is not required) with lower controller order. The issue of time delay of feedback signals has been addressed in this paper for different values of time delay by applying a multi-model optimization technique. The proposed approach is compared to other existing techniques to design a robust controller which is based on H2 under pole placement. Both techniques are applied to the 68-bus system to evaluate and validate the robust controller performance under different load scenarios and different wind generations.展开更多
In this paper, a data-driven stochastic subspace identification(SSI-DATA) technique is proposed as an advanced stochastic system identification(SSI) to extract the inter-area oscillation modes of a power system from w...In this paper, a data-driven stochastic subspace identification(SSI-DATA) technique is proposed as an advanced stochastic system identification(SSI) to extract the inter-area oscillation modes of a power system from wide-area measurements. For accurate and robust extraction of the modes’ parameters(frequency, damping and mode shape), SSI has already been verified as an effective identification algorithm for output-only modal analysis.The new feature of the proposed SSI-DATA applied to inter-area oscillation modal identification lies in its ability to select the eigenvalue automatically. The effectiveness of the proposed scheme has been fully studied and verified,first using transient stability data generated from the IEEE16-generator 5-area test system, and then using recorded data from an actual event using a Chinese wide-area measurement system(WAMS) in 2004. The results from the simulated and recorded measurements have validated the reliability and applicability of the SSI-DATA technique in power system low frequency oscillation analysis.展开更多
This paper presents a procedure for designing a supplementary damping stabilizer for a static synchronous series compensator(SSSC) in multi-machine power systems.The objective is to shift the lightly damped inter-area...This paper presents a procedure for designing a supplementary damping stabilizer for a static synchronous series compensator(SSSC) in multi-machine power systems.The objective is to shift the lightly damped inter-area modes toward the prescribed stability region.A lead-lag stabilizer is used to demonstrate this technique,in which a particular measure of stabilizer gain is considered as an objective function.Constraints of the problem for phase-lead and lag structures are derived.The objective function with the constraints is formed as a quadratic mathematical programming problem.For robust design,the parameters of the stabilizer are calculated under various operating conditions.Two types of SSSC-based stabilizer have been presented and designed.Numerical results including eigenvalue analysis and the nonlinear simulations on the 4-and 50-machine power systems are pre-sented to show the effectiveness of the proposed method.展开更多
为了提升光纤的传输性能,设计了一种空气孔-沟槽辅助六芯光纤结构。六芯光纤中每根纤芯被一层低折射率沟槽包围,纤芯与沟槽之间存在一层包层,同时光纤周围环绕着空气孔辅助结构。基于光纤的耦合模式理论,对光纤的串扰、模场面积以及弯...为了提升光纤的传输性能,设计了一种空气孔-沟槽辅助六芯光纤结构。六芯光纤中每根纤芯被一层低折射率沟槽包围,纤芯与沟槽之间存在一层包层,同时光纤周围环绕着空气孔辅助结构。基于光纤的耦合模式理论,对光纤的串扰、模场面积以及弯曲损耗3种传输特性进行了深入分析。研究结果表明:带有空气孔-沟槽辅助结构的光纤在芯间串扰方面表现最佳,串扰值达到最低约-55 d B;而单沟槽辅助结构则有效增大了光纤的模场面积,达到最大值约390μm^(2)。然而,不同结构下光纤的弯曲损耗变化并未呈现明显规律,但其对数取值集中在4~9 d B/m。展开更多
文摘This paper introduces a multi-model approach to design a robust supplementary damping controller. The designed fixed-order supplementary damping controller adjusts the voltage reference set point of SVC. There are two main objectives of the controller design, damping low frequencies oscillations and enhancing power system stability. This method relies on shaping the closed-loop sensitivity functions in the Nyquist plot under the constraints of these functions. These constraints can be linearized by choosing a desired open-loop transfer function. The robust controller is designed to minimize the error between the open-loop of the original plant model and the desired transfer functions. These outcomes can be achieved by using convex optimization methods. Convexity of the problem formulation ensures global optimality. One of the advantages of the proposed approach is that the approach accounts for multi-model uncertainty. In contrast to the methods available in the literature, the proposed approach deals with full-order model (i.e., model reduction is not required) with lower controller order. The issue of time delay of feedback signals has been addressed in this paper for different values of time delay by applying a multi-model optimization technique. The proposed approach is compared to other existing techniques to design a robust controller which is based on H2 under pole placement. Both techniques are applied to the 68-bus system to evaluate and validate the robust controller performance under different load scenarios and different wind generations.
基金supported by the National Natural Science Foundation of China(No.51507028)the Hong Kong Polytechnic University under Project G-UA3Z
文摘In this paper, a data-driven stochastic subspace identification(SSI-DATA) technique is proposed as an advanced stochastic system identification(SSI) to extract the inter-area oscillation modes of a power system from wide-area measurements. For accurate and robust extraction of the modes’ parameters(frequency, damping and mode shape), SSI has already been verified as an effective identification algorithm for output-only modal analysis.The new feature of the proposed SSI-DATA applied to inter-area oscillation modal identification lies in its ability to select the eigenvalue automatically. The effectiveness of the proposed scheme has been fully studied and verified,first using transient stability data generated from the IEEE16-generator 5-area test system, and then using recorded data from an actual event using a Chinese wide-area measurement system(WAMS) in 2004. The results from the simulated and recorded measurements have validated the reliability and applicability of the SSI-DATA technique in power system low frequency oscillation analysis.
文摘This paper presents a procedure for designing a supplementary damping stabilizer for a static synchronous series compensator(SSSC) in multi-machine power systems.The objective is to shift the lightly damped inter-area modes toward the prescribed stability region.A lead-lag stabilizer is used to demonstrate this technique,in which a particular measure of stabilizer gain is considered as an objective function.Constraints of the problem for phase-lead and lag structures are derived.The objective function with the constraints is formed as a quadratic mathematical programming problem.For robust design,the parameters of the stabilizer are calculated under various operating conditions.Two types of SSSC-based stabilizer have been presented and designed.Numerical results including eigenvalue analysis and the nonlinear simulations on the 4-and 50-machine power systems are pre-sented to show the effectiveness of the proposed method.
文摘为了提升光纤的传输性能,设计了一种空气孔-沟槽辅助六芯光纤结构。六芯光纤中每根纤芯被一层低折射率沟槽包围,纤芯与沟槽之间存在一层包层,同时光纤周围环绕着空气孔辅助结构。基于光纤的耦合模式理论,对光纤的串扰、模场面积以及弯曲损耗3种传输特性进行了深入分析。研究结果表明:带有空气孔-沟槽辅助结构的光纤在芯间串扰方面表现最佳,串扰值达到最低约-55 d B;而单沟槽辅助结构则有效增大了光纤的模场面积,达到最大值约390μm^(2)。然而,不同结构下光纤的弯曲损耗变化并未呈现明显规律,但其对数取值集中在4~9 d B/m。
