Electrical Power Exchange in GMS and Its Influence on Power Systems in Vietnam and Thailand

The paper aims to identify the development of power interconnection network in the Greater Mekong Sub-region (GMS) which is a part of the major energy infrastructure mandated by ASEAN delegates in 1997. An overview of power systems in the region is introduced. The combined load curve for Vietnam and Thailand are formed to show the benefit of power grid interconnection of GMS. The paper also concentrates on simulation, analysis and evaluation of power transfer in 500kV and 220kV interconnection transmission lines in GMS for the planning horizon of 2010-2020. Reliability and environmental benefits of the interconnection are discussed due to interconnection. Based on the simulation results few recommendations are given

Examination of effective VAr with respect to dynamic voltage stability in renewable rich power grids

High penetrations of inverter-based renewable resources (IBRs) diminish the resilience that traditional power systems had due to constant research and developments for many years. In particular, dynamic voltage stability becomes one of the major concerns for transmission system operators due to the limited capabilities of IBRs (i.e., voltage and frequency regulation). A heavily loaded renewable-rich network is susceptible to fault-induced delayed voltage recovery (FIDVR) due to insufficient effective reactive power (E-VAr) in power grids. Hence, it is crucial to thoroughly scrutinize each VAr resources' participation in E-VAr under various operating conditions. Moreover, it is essential to investigate the influence of E-VAr on system post-fault performance. The E-VAr investigation would help in determining the optimal location and sizing of grid-connected IBRs and allow more renewable energy integration. Furthermore, it would enrich decision-making about adopting additional grid support devices. In this paper, a comprehensive assessment framework is utilized to assess the E-VAr of a power system with a large-scale photovoltaic power. Plant under different realistic operating conditions. Several indices quantifying the contribution of VAr resources and load bus voltage recovery assists to explore the transient response and voltage trajectories. The recovery indices help have a better understanding of the factors affecting E-VAr. The proposed framework has been tested in the New England (IEEE 39 bus system) through simulation by DIgSILENT Power Factory. © 2013 IEEE

Exploring the Dynamic Voltage Signature of Renewable Rich Weak Power System

Large-scale renewable energy-based power plants are becoming attractive technically and economically for generation mix around the world. Nevertheless, network operation has significantly changed due to the rapid integration of renewable energy in supply side. The integration of more renewable resources, especially inverter-based generation, deteriorates power system resilience to disturbances and substantially affects stable operations. The dynamic voltage stability becomes one of the major concerns for the transmission system operators (TSOs) due to the limited capabilities of inverter-based resources (IBRs). A heavily loaded and stressed renewable rich grid is susceptible to fault-induced delayed voltage recovery. Hence, it is crucial to examine the system response upon disturbances, to understand the voltage signature, to determine the optimal location and sizing of grid-connected IBRs. Moreover, the IBRs fault contribution mechanism investigation is essential in adopting additional grid support devices, control coordination, and the selection of appropriate corrective control schemes. This article utilizes a comprehensive assessment framework to assess power systems' dynamic voltage signature with large-scale PV under different realistic operating conditions. Several indices quantifying load bus voltage recovery have been used to explore the system' s steady-state, transient response, and voltage trajectories. The recovery indices help extricate the signature and influence of IBRs. The proposed framework's applicability is carried out on the New England IEEE-39 bus test system using the DIgSILENT platform. © 2013 IEEE

Sizing HESS as inertial and primary frequency reserve in low inertia power system

Energy storage systems are recognised as the potential solution to alleviate the impacts of reduced inertia and intermittency in power systems due to the integration of renewable energy sources. Several energy storage technologies are available in the market with diverse power and energy characteristics, operational limitations, and costs. Besides, frequency regulations in power systems have different requirements, for example, inertial response requires high power for a short period while primary frequency regulation requires steady power for a longer time. Thus, it is crucial to find out the optimum sizes and types of storage technologies for these services. In this paper, a methodology for sizing fast responsive energy storage technologies for inertial response, primary frequency regulation, and both inertial response and primary frequency regulation is developed. The sizing of storage systems for inertial response, primary frequency regulation, and both inertial response and primary frequency regulation is done separately. The sizing of storage for inertial response is done in two steps. A region reduction iterative algorithm is proposed to estimate the storage size for inertial response. The sizing of the storage system for primary frequency regulation is done analytically. The sizing methodology incorporates the frequency dynamics of storage, converters, and other associated controls that affect the frequency response. Moreover, an economic analysis is carried out to find the optimum combination of storage technologies for inertial response, primary frequency regulation, and both inertial response and primary frequency regulation services. The accuracy of the proposed sizing method has been compared with the metaheuristic algorithm based technique. The effectiveness of the proposed method is also compared with those in the literature. Simulation results show that the proposed method outperforms the existing methods in the literature. Finally, the non‐linear simulations revealed the validity of the optimal solutions

Stability of renewable energy based microgrid in autonomous operation

This paper develops a comprehensive small-signal model of hybrid renewable-energy-based microgrid (MG) in an attempt to perceive oscillatory stability performance and capture the potential interaction between low-frequency critical modes within the MG. Trajectories of sensitive modes due to controller gain variations were evaluated in order to determine the stability boundaries. It was noticeable that various power-sharing schemes significantly influenced the small-signal stability of MG. Moreover, modal interaction emerged due to the proximity of RES-based DG units and non-linear dynamic behaviour of the sensitive modes. The interaction may result in a more oscillatory situation which potentially leads to instability of MG. The low-frequency critical modes obtained from eigenvalues analysis were then verified with the help of nonlinear time domain simulations. The presented work contributes to enhance the design and tuning of controller gain and propose appropriate power-sharing scheme within MG

Forced oscillation in power systems with converter controlled-based resources- a survey with case studies

In future power systems, conventional synchronous generators will be replaced by converter controlled-based generations (CCGs), i.e., wind and solar generations, and battery energy storage systems. Thus, the paradigm shift in power systems will lead to the inferior system strength and inertia scarcity. Therefore, the problems of forced oscillation (FO) will emerge with new features of the CCGs. The state-of-the-art review in this paper emphasizes previous strategies for FO detection, source identification, and mitigation. Moreover, the effect of FO is investigated in a power system with CCGs. In its conclusion, this paper also highlights important findings and provides suggestions for subsequent research in this important topic of future power systems. © 2013 IEEE

Comparison of Battery Energy Storage Models for Small Signal Stability in Power System

Abstract— In the 21st century, integration of large-scale renewable energy sources (RESs) is increasing significantly. Although RESs provide clean and sustainable energy, they may adversely affect the performance of power system due to their distinct dynamic characteristics and intermittent power output. It is apparent that the integration of battery energy storage system (BESS) in power system is inevitable to accommodate more RESs. BESS could provide additional active and reactive power to the grid to overcome the energy shortfall. It is reported that the dynamics associated with BESS may significantly influence the low-frequency oscillation of the system. Therefore, it is important to analyze the various models of BESS for power system small signal stability studies. This paper investigates various models of BESS and their impacts on low-frequency oscillation for high penetration of RESs. Analysis has been conducted using Two-area power system for which the benchmark results are available for comparison purpose. Both the eigenvalue and time-domain analyses are employed in this paper to assess the impacts of various BESS models on low-frequency oscillation. From the simulation results, it is evident that the detailed model of BESS (i.e. 5th order model) could reflect the complete influence of BESS controller on low-frequency oscillation. Keywords- BESS, damping ratio, eigenvalue, small signal stability, time domain simulation