Masachika Ishimaru

Robust thyristor-controlled series capacitor controller design based on linear matrix inequality for a multi-machine power system

Abstract Power system stabilizing control has an important role in maintaining synchronism in power systems during major disturbances resulting from sudden changes of load and configuration. The thyristor-controlled series capacitor (TCSC) is one of the representative devices in flexible AC transmission systems. In this paper, robust TCSC controllers are applied to suppress disturbances in realistic power systems. H ∞ control is adopted as the methodology of the robust controller design along with a linear matrix inequality (LMI), which solves the Lyapunov inequality without the weighting coefficients used in other control theories. In the proposed design, load changes are treated as a system uncertainty in the LMI approach. The proposed LMI-based approach is shown to be effective in the design of TCSC controllers to enhance robustness and response by simulations on a test system.

Cost-benefit analysis of reliability management by transmission expansion planning in the competitive electric power market

Recently, a competitive electricity market has been introduced in many countries to improve the economic efficiency of power system operation. From the viewpoint of economic efficiency in the market, the establishment of a new rule for power system operation is indispensable for realizing open-access to the existing transmission network by nonutility generators. The overall objective of this study is to analyze planning for long-term transmission expansion for network reliability in the competitive market, and to assess transmission tariffs with regard to long-term and short-term economic efficiency. In this paper, a transmission expansion strategy for assuring network reliability is proposed in a hypothetical perfect competitive electricity market. The influence on social welfare of planned expansion of the transmission system and of congestion management operation of the network for the purpose of securing reliability is examined. The economic benefit of newly participating generators was shown when effective reliability maintenance measures were implemented.

Allocation and design of robust TCSC controllers based on power system stability index

Stabilizing control for power system stability has been applied to generators equipped with an excitation controller and speed governor. Power electronics-based control devices have been the focus of research and development for the improvement of transient stability. Power electronics control devices are utilized for control of the power flow on a transmission line or the reactive power in a power system. In that case, they have no constraint of setting point in a power system. On the other hand, the total number of these devices to be equipped has economical constraints, because their prices are very expensive; therefore, the allocation problem of these controllers is worth studying. This paper proposes an approach to determine the numbers and locations of thyristor-controlled series capacitors (TCSC) in a multi-machine power system. The index of optimal allocation of the controllers is the power system stability. First, the steady-state stability is considered, and then the transient stability is examined to find a robust allocation of the TCSC controllers.

PADES: an analytical tool for designing power system stabilizer for cross-compound unit

In this paper, an analytical method for design of power system stabilizers (PSS) that will be equipped in cross-compound units is proposed, and a simple and practical design tool based on a frequency response method is presented. An extended Heffron-Phillips model which has been developed for two machines-to-infinite-bus power system model is employed for dynamic stability analysis. The effects of PSS on damping of both inter-area and inter-machine electromechanical modes are described.

Allocation and Design of Power System Stabilizers for Mitigating Low-Frequency Oscillations in the Eastern Interconnected Power System in Japan

Abstract To analyze and solve the problem of long-term low damping oscillation phenomena, a method is presented to find the best allocation and to design a power system stabilizer (PSS) for damping inter-area power oscillations. The method is based on the single-machine-infinite-bus models derived from the multi-machine power system by coherency-based reduction technique. Dynamic simulations using a 10-machine power system model are presented in order to show the effectiveness of the PSS designed according to the proposed method.

Output feedback TCSC controller design making use of linear matrix inequality

Power system stabilizing control plays an important role to remain in synchronism during major disturbances resulting from sudden or sustained load changes. TCSC (thyristor controlled series capacitor) is one of the representative devices of FACTS (flexible AC transmission system), in this paper, a design method for an output feedback TCSC controller using a detailed model has been applied to suppress system disturbances in large-scale power systems. As the methodology of robust controller design, H/sub /spl infin// control has been adopted. Currently, LMI (linear matrix inequality) is very effective, since it solves the Lyapunov inequality without considering the weighting coefficients used in other control theories. In the proposed approach, the load change is treated as a system uncertainty in the LMI approach. The proposed LMI-based approach is proved to be applicable for the design of TCSC controllers to enhance robustness and response by simulations on a test system.

Stabilizing control for long-term low damping oscillation in multi-regional power system

To analyze and solve the problem of long-term low damping oscillation phenomena, a method is presented to find the best allocation and to design a power system stabilizer (PSS) for damping inter-area power oscillations. The method is based on the single-machine-infinite-bus models derived from the multi-machine power system by coherency-based reduction technique. Dynamic simulations using a 10-machine power system model are presented in order to show the effectiveness of the PSS designed according to the proposed method.