This paper presents the preliminary results of studies aiming to use a battery energy storage system (BESS) in the Brazilian transmission system. The main objective of the BESS is to solve congestion problems caused mainly by the large increase in variable renewable generation in certain system areas. The studies were conducted based on actual forecasted system scenarios using a full representation of the electric grid available from the Brazilian system operator data base. In this work, only the steady-state modeling was considered as this may be the first stage in the assessment of a new technology. A qualitative economic comparison of the BESS application with other possible solutions to the congestion problems is also included.

This paper presents the main concepts of small-signal security assessment of power systems, focusing on the online monitoring of small-signal stability. In this work, a computational tool for online monitoring of oscillation modes (OLMO) in power systems is proposed. The objective of the methodology consists of determining small-signal stability margins, security levels, and corrective measures that can improve the damping factor of oscillation modes present in such systems. These corrective measures can be associated with possible redispatches of power plants. In this context, the Closest Security Boundary for Generation Redispatch using Eigenvalue Sensitivities, known as CSBGRES Method, could be applied to determine an optimized redispatch for the power plants of the system to ensure a desired minimum damping factor, previously chosen, for oscillation modes. The proposed tool can be applied for controlling power plant dispatches on Smart Grids, focusing on the damping factor of oscillation modes. A small test system is used to evaluate the proposed computational feature and the results were presented to demonstrate its importance to power system security. Results of the utilization of OLMO on the Brazilian Interconnected Power System (BIPS) are presented to prove the viability of using this method in large-scale power systems.

LCC-HVDC links are used worldwide for long-distance bulk power transmission in large scale power systems. In this technology, commutation failure phenomena may occur, where transient power interruptions of HVDC links may lead the system to electromechanical instability. For power system simulations with HVDC transmission, the dynamic phasor methodology has advantages for considering simultaneously the electromechanical and electromagnetic transients, in particular, the simulation of commutation failures and their impacts in transient stability. However, when using dynamic phasors, the full harmonic contents of the HVDC variables are missing, which may worsen the accuracy of commutation failure simulations. This paper proposes a methodology, named Synchronous Recovery of Waveforms from Dynamic Phasor Model (SRWDPM) for obtaining accurate waveforms of the HVDC variables from dynamic phasor models. The main benefits of SRWDPM are these accurate waveforms and their use for adequate commutation failure simulations using efficient fundamental frequency dynamic phasor models. These accurate waveforms were previously only available in EMT programs or in expensive dynamic phasor models of high-order harmonics. The methodology is based on numerical integration of a small subsystem of each HVDC converter using instantaneous values obtained from dynamic phasors as input variables. SRWDPM is solved synchronously with the dynamic phasor solution and the waveforms are comparable to those obtained in electromagnetic transient programs with discontinuities and without harmonic truncation. The proposed methodology is general, it can be applied to different dynamic phasor models for improving efficiency or accuracy. A benchmark system is used for illustrating the methodology application.