In preparation for the electric mobility technological transition in Colombia, an impact assessment of the electric power system is required, considering the increasing loading that must be able to be managed in the future. In this paper, a plug-in electric vehicle (PEV) charging simulation methodology is developed in order to dimension the impact of this type of load on power grids. PEV electric properties, user charging behaviors, geographic location, trip distances, and other variables of interest are modeled from empirical or known probability distributions and later evaluated in different scenarios using Monte Carlo simulation and load flow analysis. This methodology is later applied to the transmission network of Antioquia (a department of Colombia) resulting in load increases of up to 40% on transmission lines and 20% on transformers in a high PEV penetration scenario in 2030, increases that are well within the expected grid capacity for that year, avoiding the need for additional upgrades.

The frequency of an electrical power system can be interpreted as an indicator of the equilibrium between generation and demand. Under fault conditions where this balance is disrupted, the Under-Frequency Load Shedding scheme is typically the ultimate resource employed to prevent the frequency from dropping to undesirable thresholds that could lead to a blackout. Smart loads have the capability to dynamically adjust their consumption in response to frequency variations, which has the potential to enhance frequency regulation and mitigate the need for abrupt load disconnection through the Under-Frequency Load Shedding scheme. The objective of this paper is to present a literature review of Under-Frequency Load Shedding schemes, an innovative approach to their classifications, and the introduction of a new category within these schemes that incorporates smart loads. Additionally, an overview of smart loads is included to be potentially employed in the design of new schemes and contribute to a shift in the operation philosophy, considering that the primary mission of electric power systems is to provide energy to loads rather than disconnecting them.

Theory of cutset area is defined in the context of network behavior, as much in steady state as in dynamic operation. With reference to cutset angle theory, a proposed methodology for identifying stress on the network is stated for cutset angle evolution. Potential applications for Phase Measurement Units, PMU, are validated on a Colombian network.

This paper presents a novel methodology for the calculation of angular indexes of an electrical system from stationary analysis, using load flow and nose curves (P–V) in each of the buses of the system to perform control actions and preserve or improve voltage stability. The control actions are proposed considering a novel method based on the concepts of the cutset angle (CA) and center of angle (COA). The target is a fast estimation of voltage-stability margins through an appropriate angular characterization of the whole system and for each load bus with a complete network and N-1 contingency criteria. The most significant enhancement is that the angular characterization is based on the COA, which is related to the angular dynamics of the system, and indirectly reflects the inertia and the respective angles of the generator rotor, as well as the impact on the angular equivalent-system model. Simulations showed that the COA is an important index to determine the location of occurrence of the events. The COA can also help aim where control actions, like the amount of load shedding, should be carried out to remedy the voltage problems. The proposed method is assessed and tested in the benchmark IEEE 39-bus system.

The numerical solution of transient stability problems is a key element for electrical power system operation. The classical model for multi-machine systems is defined as a set of non-linear differential equations for the rotor speed and the generator angle for each electrical machine, this mathematical model is usually known as the swing equations. This paper presents how to use direct Richardson extrapolation of several orders for the numerical solution of the swing equations and compares it with other commonly used implicit and explicit solvers such as Runge-Kutta, trapezoidal, Shampine and Radau methods. A numerical study on a simple three machine system is used to illustrate the performance and implementation of algebraic Richardson extrapolation coupled to several solution methods. Normally, the order of accuracy of any numerical solution can be increased when Richardson Extrapolation is used. A numerical example is provided for an electrical grid consisting of three machines and nine buses undergoing a disturbance. It is shown that in this case Richardson extrapolation effectively increases the order of accuracy of the explicit methods making them competitive with the implicit methods.

In this paper, a new index is proposed to find further information on voltage stability of AC/DC systems and reactive power requirements. The index defines two types of systems from the point of view of voltage stability and reactive power variations, soft and non-soft systems. This approach can assist for considering the reactive compensation, control and operation strategies for AC/DC applications as a function of their strength. Well known networks, including the modified IEEE 14 bus system, are studied with the new index. The short circuit ratio, SCR, is traditionally used for dynamic studies of AC/DC interactions. Since SCR tells about the strength of AC/DC nodes, this relation will be used to qualify static and modal analyses in this work.