Rakibuzzaman Shah

Large-Scale PV Plant With a Robust Controller Considering Power Oscillation Damping

Transmission voltage-level photovoltaic (PV) plants are becoming reality in many developed and developing countries around the world. Studies suggest that large-scale PV plants could have either positive or negative influence on low-frequency oscillation (LFO) depending on their locations and sizes. Given the fact that these plants cannot be placed in ideal locations to minimize their impact on LFO, it is important to consider designing a damping controller for flawless integration. In this paper, a minimax linear quadratic Gaussian-based power oscillation damper (POD) for a large-scale PV plant is proposed for interarea oscillation damping. A benchmark power system prone to power system oscillations is used to demonstrate the damping performance of the designed controller considering feedback signal transmission delay. The performance of the designed controller is evaluated under different operating conditions as compared to the classical POD at PV plant. Simulation results demonstrate that the proposed controller for a PV plant provides sufficient damping to the interarea mode for a wide range of operating conditions.

Impact of large-scale PV penetration on power system oscillatory stability

This paper presents the impact of large-scale photovoltaic (PV) generation on power system oscillatory instability. Two models of PV generation systems, namely detailed dynamic and simplified models, have been studied in IEEE-14 bus test system typically used for power system oscillatory instability studies. Influence of radiation pattern, and size and location of PV generating system on the power system stability issue is thoroughly investigated. In PV generation penetration, two scenarios, namely concentrated and scattered are examined. Simulation shows that the increased penetration of PV system enhances power system oscillatory stability.

Contribution of PV systems with ultra capacitor energy storage on inter-area oscillation

In this paper, the effect of increased solar power penetration by three Photovoltaic (PV) generator systems on inter-area oscillation is investigated. With the help of an illustrative example, it is shown that general trends for PV generator is to increase the damping of inter-area mode oscillation. However, there are exceptions for certain types of system, location and penetration for which PV generator can reduce damping of the inter-area mode. Analysis of different PV generator systems contribution to the damping of inter-area mode has been carried out by a two-area test system. Eigenvalue analysis has been employed for detailed study along with participation factor and eigenvalue sensitivity analysis. Performance measures such as damping ratio and line performance index (LPI) are also used for further analysis of the contributions of PV systems on inter-area oscillation and the system performance.

Small-Disturbance Angle Stability Control With High Penetration of Renewable Generations

Growth and penetration of renewable energy has been remarkable during the last few years in many power systems around the world. Essentially, there are two major technologies responsible for the growth, namely wind and photovoltaic. The technologies involved in harnessing energy from wind and sun are distinctly different in dynamic characteristics and limitations. Consequently, their influence on stability of power system should not be overlooked. This paper examines the small-disturbance angle stability with high penetration of renewable energy and proposes a methodology to control. The hierarchical principal component analysis, which is a clustering method corresponding to the eigenvalue sensitivity of reactive power control, is utilized to select the renewable generator clusters for different reactive power control scheme. Then, the framework based on structured singular value has been employed, in which the reactive power controls of renewable generator clusters are selected such that the desired robust stability criterion is satisfied. Results obtained in 16-machine 68-bus test system (typically used for small-signal angle stability studies) show the effectiveness of the proposed methodology.

Power system voltage stability as affected by large-scale PV penetration

Voltage instability is considered as one of the main threats to secure operation of power system networks around the world. Grid connected renewable energy-based generation are developing in recent years for many economic and environmental reasons. This type of generation could have significant impact on power system voltage stability given the nature of the primary source of generation and the technology used to energy conversion. This paper examines the impact of large-scale photovoltaic (PV) generation on power system voltage stability. A comprehensive model of large-scale PV generation in IEEE-14 bus test system has been used for the investigation. Various performance measures including critical eigenvalues of Q-V modal matrix, bus participation factor and loading margin (LM), are used to analyze the impact of PV generator on power system static voltage stability.

Design of robust power oscillation damping controller for large-scale PV plant

Large-scale photovoltaic (PV) plants are becoming a reality in many countries. Studies suggest that the large-scale PV plants can have either a positive or negative influence on power system oscillation, which depends on many factors, including their location and sizes. Given the fact that these plants cannot be located in their ideal location for placement in power system, it is important to consider designing controllers for flawless integration. In this paper, a minimax Linear Quadratic Gaussian (LQG) based power oscillation damper (POD) for large-scale PV plant is proposed for oscillation damping. As a benchmark system for oscillatory stability analysis, the two-area test system is used to demonstrate the system performance with the designed controller. The robustness of the designed controller is verified under different operating conditions by eigenvalue analysis and non-linear power system simulation. Simulation results demonstrate that the proposed controller for PV plant improves the damping of inter-area mode for a wide range of operating conditions.

Low-order robust damping controller design for large-scale PV power plants

The paper presents a method of designing a low order robust wide-area damping controller (WADC) for large-scale photovoltaic (PV) power plants. The controller design procedure is focused on designing a second-order wide-area damping controller by convex optimization method. A Hankel singular value (HSV) based hybrid signal selection method is also proposed for optimal selection of the control signal. The performance of the synthesized controller is investigated on a 16-machine 68-bus system, typically used for power system oscillation studies.

Performance assessment of solar thermal power plants: A case study in Queensland

Recent and ongoing improvements make the concentrated solar thermal power (CSP) as one of the promising sources to replace fossil fuel based power plants. CSP plants are already commercially being exploited in some countries such as Spain and USA. Australia is also expecting increasing penetration of CSP in near future in order to meet the renewable energy target of 20% by 2020. Among the states and territories of Australia, Queensland is one of the promising states for the large-scale deployment of CSP plants. In such a case, it is important to analyze the performance of different CSP technologies in Queenslands climatic condition. Therefore, this paper compares the performance of four available large-scale CSP technologies at some potential sites for CSP deployment in Queensland. The aim of this paper is to report the performance of these technologies by means of output analysis. The effects of different design parameters on the performance are also analyzed and reported in this paper.

Test systems for dynamic stability studies in electric power system

Electric power system is one of the largest and complex infrastructures made by mankind during the last century. The total investment associated with it in trillions of dollars. As it is a very expensive, large and complex physical system, secure network operation without having any system wide instability issue and catastrophic consequences is sought. As a result power system educators and researchers are constantly scrutinizing power system with changing scenarios and coming up with the new solutions to keep the most important infrastructure intact in order to make the economy and society sustainable. It is tough, but not impossible, and expensive to build physical test power systems to perform various researches. Hence, the test power systems models have been playing a key role for better understanding, development, and deployment of new solutions in power system problems. There have been many test systems with varying complexities and sizes used all around the world. However, there is no common platform where the most of these test systems are documented so that the educators and researchers can chose an appropriate test system suitable for their studies. The paper presents a collection of commonly used test systems for various dynamic stability studies.

Dual-loop primary frequency regulation controller for VSC-HVDC system

This paper presents a frequency control mechanism for an AC system through the active and reactive power loops of a VSC-HVDC system. The proposed scheme makes use of the reactive power loop for inertia support by exploiting the voltage-power sensitivity of loads, and active power droop control has been used to provide governor-like support following the large-disturbance. The performance of the presented controller is evaluated through various simulation case studies in DIgSILENT Power Factory including small-perturbation to demonstrate the effect of the frequency controller in system electromechanical mode damping. From the set of case studies it can be found that the proposed dual-loop control has favorable effects on the frequency behaviour and the inter-area mode damping of the system.