Robust coordinated damping control of power systems with multi-terminal vsc-hvdc system and facts

This thesis investigates the robust and coordinated design of multiple damping controllers to ameliorate the damping characteristics of a bulky power system. A new methodology is proposed in this thesis for VSC-MTDC and FACTS damping controllers based on multiple control objectives and system multi-model. The key feature of the methodology is the robust and coordinated performance of the damping controllers. The formulated BMI-based optimization problem is solved systematically via a two- step approach. System multi-model is established in the design for the robustness of the controllers under system disturbances and changing operating conditions. The sequential design of a series of SISO controllers with properly selected feedback signals minimizes the negative interactions among the controllers. The approach is applied to a three-terminal VSC-MTDC and subsequently exerted with one terminal of VSC-MTDC and a TCSC to incorporate multiple devices and examine the generality and feasibility of the design. Given the flexible internal control configuration of VSC converter, the assessment of the impact of the d-q decoupled control modes on the effectiveness and flexibility of the damping controllers is carried out. Real-Time Digital Simulator is used to examine the effectiveness and robustness of the damping controllers under various system operating conditions and disturbances

An Advance Distributed Control Design for Wide-Area Power System Stability

The development of control of a power system that supply electricity is a major concern in the world. Some trends have led to power systems becoming overstated including the rapid growth in the demand for electrical power, the increasing penetration of the system from renewable energy, and uncertainties in power schedules and transfers. To deal with these challenges, power control has to overcome several structural hurdles, a major one of which is dealing with the high dimensionality of the system. Dimensionality reduction of the controller structure produces effective control signals with reduced computational load. In most of the existing studies, the topology of the control and communication structure is known prior to synthesis, and the design of distributed control is performed subject to this particular structure. However, in this thesis we present an advanced model of design for distributed control in which the control systems and their communication structure are designed simultaneously. In such cases, a structure optimization problem is solved involving the incorporation of communication constraints that will punish any communication complexity in the interconnection and thus will be topology dependent. This structure optimization problem can be formulated in the context of Linear Matrix Inequalities and l1-minimization. Interconnected power systems typically show multiple dominant inter-area low-frequency oscillations which lead to widespread blackouts. In this thesis, the specific goal of stability control is to suppress these inter-area oscillations. Simulation results on large-scale power system are presented to show how an optimal structure of distributed control would be designed. Then, this structure is compared with fixed control structures, a completely decentralized control structure and a centralized control structure

A survey on fopid controllers for lfo damping in power systems using synchronous generators, facts devices and inverter-based power plants

In recent decades, various types of control techniques have been proposed for use in power systems. Among them, the use of a proportional–integral–derivative (PID) controller is widely recognized as an effective technique. The generalized type of this controller is the fractional-order PID (FOPID) controller. This type of controller provides a wider range of stability area due to the fractional orders of integrals and derivatives. These types of controllers have been significantly considered as a new approach in power engineering that can enhance the operation and stability of power systems. This paper represents a comprehensive overview of the FOPID controller and its applications in modern power systems for enhancing low-frequency oscillation (LFO) damping. In addition, the performance of this type of controller has been evaluated in a benchmark test system. It can be a driver for the development of FOPID controller applications in modern power systems. Investigation of different pieces of research shows that FOPID controllers, as robust controllers, can play an efficient role in modern power systems

Robust damping of multiple swing modes employing global stabilizing signals with a TCSC

Published versio

Robust damping control of power systems with FACTS

Power systems are under greater stress today due to the rapid growing demand and market-oriented activities. Operation of the existing system networks is gradually approaching their transmission limits and this raises a lot of stability problems which could potentially result in series consequences. The advent of FACTS provides new solutions to the reinforcement of the existing networks. Furthermore, the integration of FACTS also creates additional opportunities for the enhancement of system dynamic stability. This thesis presents the robust damping control of power systems with FACTS for the purpose of improving system small-signal dynamic stability. A Novel BMI-based methodology is proposed for the design of robust FACTS damping controllers. Different from most of the existing method, the proposed method is capable of managing multiple control objectives under several preselected operating points which could guarantee controller robustness in a broader range. The generality and feasibility of the proposed method is validated by controller designs on a two-area four-generator system and a five-area 16-generator 68-bus system with different FACTS devices. As an extension of the proposed BMI-based method, a coordinated design approach for multiple FACTS damping controllers is developed to address the damping problem with respect to multiple dominant oscillatory modes in large interconnected power systems. To reduce the adverse interactions between different FACTS devices, multiple SISO controllers are designed in a sequential manner with cautiously selected feedback signals. The coordinated design approach is then applied on a five-area 16-generator 68-bus system with an SVC and a TCSC to evaluate its effectiveness

Decentralized and Fault-Tolerant Control of Power Systems with High Levels of Renewables

Inter-area oscillations have been identified as a major problem faced by most power systems and stability of these oscillations are of vital concern due to the potential for equipment damage and resulting restrictions on available transmission capacity. In recent years, wide-area measurement systems (WAMSs) have been deployed that allow inter-area modes to be observed and identified.Power grids consist of interconnections of many subsystems which may interact with their neighbors and include several sensors and actuator arrays. Modern grids are spatially distributed and centralized strategies are computationally expensive and might be impractical in terms of hardware limitations such as communication speed. Hence, decentralized control strategies are more desirable.Recently, the use of HVDC links, FACTS devices and renewable sources for damping of inter-area oscillations have been discussed in the literature. However, very few such systems have been deployed in practice partly due to the high level of robustness and reliability requirements for any closed loop power system controls. For instance, weather dependent sources such as distributed winds have the ability to provide services only within a narrow range and might not always be available due to weather, maintenance or communication failures.Given this background, the motivation of this work is to ensure power grid resiliency and improve overall grid reliability. The first consideration is the design of optimal decentralized controllers where decisions are based on a subset of total information. The second consideration is to design controllers that incorporate actuator limitations to guarantee the stability and performance of the system. The third consideration is to build robust controllers to ensure resiliency to different actuator failures and availabilities. The fourth consideration is to design distributed, fault-tolerant and cooperative controllers to address above issues at the same time. Finally, stability problem of these controllers with intermittent information transmission is investigated.To validate the feasibility and demonstrate the design principles, a set of comprehensive case studies are conducted based on different power system models including 39-bus New England system and modified Western Electricity Coordinating Council (WECC) system with different operating points, renewable penetration and failures

Passivity - Based Control and Stability Analysis for Hydro-Solar Power Systems

Los sistemas de energía modernos se están transformando debido a la inclusión de renovables no convencionales fuentes de energía como la generación eólica y fotovoltaica. A pesar de que estas fuentes de energía son buenas alternativas para el aprovechamiento sostenible de la energía, afectan el funcionamiento y la estabilidad del sistema de energía, debido a su naturaleza inherentemente estocástica y dependencia de las condiciones climáticas. Además, los parques solares y eólicos tienen una capacidad de inercia reducida que debe ser compensada por grandes generadores síncronos en sistemas hidro térmicos convencionales, o por almacenamiento de energía dispositivos. En este contexto, la interacción dinámica entre fuentes convencionales y renovables debe ser estudiado en detalle. Para 2030, el Gobierno de Colombia proyecta que el poder colombiano El sistema integrará en su matriz energética al menos 1,2 GW de generación solar fotovoltaica. Por esta razón, es necesario diseñar controladores robustos que mejoren la estabilidad en los sistemas de energía. Con alta penetración de generación fotovoltaica e hidroeléctrica. Esta disertación estudia nuevas alternativas para mejorar el sistema de potencia de respuesta dinámica durante y después de grandes perturbaciones usando pasividad control basado. Esto se debe a que los componentes del sistema de alimentación son inherentemente pasivos y permiten formulaciones hamiltonianas, explotando así las propiedades de pasividad de sistemas eléctricos. Las principales contribuciones de esta disertación son: una pasividad descentralizada basada control de los sistemas de control de turbinas hidráulicas para sistemas de energía de múltiples máquinas para estabilizar el rotor acelerar y regular el voltaje terminal de cada sistema de control de turbinas hidráulicas en el sistema como, así como un control basado en PI pasividad para las plantas solares fotovoltaicas