Large-scale integration of renewable generation, usually interfaced to the network through power electronics, has led drastic changes in system dynamics. This paper presents novel insights into stability properties such systems. For that purpose, a high-fidelity dynamic model generic low-inertia been developed. The full-order, state-of-the-art control schemes both synchronous and converter-based generators are included, with latter differentiating between grid-forming grid-following mode...

In this paper, the Unit Commitment (UC) problem in a power network with low levels of rotational inertia is studied. Frequency-related constraints, namely limitation on Rate-of-Change-of-Frequency (RoCoF), frequency nadir and steady-state error, are derived from uniform system response model that incorporates dynamics controls both synchronous generators grid-forming inverters. These constraints then included into stochastic UC formulation accounts for wind equipment contingency...

This paper presents a novel virtual synchronous machine controller for converters in power systems with high share of renewable resources. Using linear quadratic regulator-based optimization technique, the optimal state feedback gain is determined to adaptively adjust emulated inertia and damping constants according frequency disturbance system, while simultaneously preserving tradeoff between critical limits required control effort. Two designs are presented compared against open-loop...

The undergoing transition from conventional to converter-interfaced renewable generation leads significant challenges in maintaining frequency stability due declining system inertia. In this paper, a novel control framework for Synthetic Inertia (SI) provision Wind Turbines (WTs) is proposed, which eliminates the secondary dip and allows dynamics of SI WTs be analytically integrated into dynamics. Furthermore, analytical constraints with are developed incorporated stochastic scheduling...

High penetration of renewable energy sources and the increasing share stochastic loads require explicit representation uncertainty in tools such as optimal power flow (OPF). Current approaches follow either a linearized approach or an iterative approximation non-linearities. This paper proposes semidefinite relaxation chance constrained AC-OPF which is able to provide guarantees for global optimality. Using piecewise affine policy, we can ensure tractability, accurately model large...

Virtual Inertia Emulation (VIE) and traditional Active Power Droop Control (APDC) are among the most common approaches for regulating active power output of inverter-based generators. Furthermore, it has been shown that, under certain conditions, these two methods can be equivalent. However, neither those studies, nor analyses comparing control schemes with respect to their dynamical properties, have investigated impact converter operation mode. This paper explores subject by investigating...

A rapid deployment of renewable generation has led to significant reduction in the rotational system inertia and damping, thus making frequency control power systems more challenging. This paper proposes a novel scheme based on Model Predictive Control (MPC) for converter-interfaced generators operating <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">grid-forming</i> mode, with goal exploiting their fast response capabilities provide service...

When planning the investment in Microgrids (MGs), usually static security constraints are included to ensure their resilience and ability operate islanded mode. However, unscheduled islanding events may trigger cascading disconnections of Distributed Energy Resources (DERs) inside MG due transient response, leading a partial or full loss load. In this paper, min-max-min, hybrid, stochastic-robust model is proposed obtain resilient considering both High-Impact-Low-Frequency (HILF)...

With the current trends in renewable energy integration, concept of a 100% inverter-based power system is becoming more reality. However, existing Voltage Source Converter (VSC) control schemes for such systems focus mostly on operation low-voltage microgrids, which have different requirements from transmission perspective. This paper proposes new classification VSC strategies depending their mode operation. Then, partial grid forming introduced and it shown that with zero rotational inertia...

A large-scale integration of renewable generation,usually interfaced to the network through power electronics,has led an overall decrease in system inertia. This paper presents novel insights on fundamental stability properties such systems. For that purpose, a uniform set Differential-Algebraic Equations (DAEs) describing generic,low-inertia has been developed. full-order, state-of-the-art control scheme both synchronous and converter-based generators are included, with latter...

This paper deals with the small-signal stability analysis of converter control modes in low-inertia power systems. For this purpose, a detailed differential-algebraic equation model voltage source and its scheme is developed. Both grid-forming grid-feeding concepts have been considered, as well different active controllers based on traditional droop virtual inertia emulation. An eigenvalue linearized state-space system conducted performance configurations compared. Furthermore, various...

This paper presents a novel virtual inertia controller for converters in power systems with high share of renewable resources. By combining the analytical study system dynamics and Linear-Quadratic Regulator (LQR)-based optimization technique, optimal state feedback gain is determined, adapting emulated constant according to frequency disturbance system. The optimality achieved through trade-off between critical limits required control effort, i.e. utilization internal energy storage....

An increasing penetration of renewable generation has led to reduced levels rotational inertia and damping in the power network. The consequences are higher vulnerability disturbances deterioration dynamic response system. To overcome these challenges, novel converter control schemes that provide virtual have been introduced, which raises question optimal distribution such devices throughout This paper presents a comprehensive framework for performance-based allocation converter-interfaced...

This paper presents a novel strategy for the synchronization of grid-following Voltage Source Converters (VSCs) in power systems with low rotational inertia.The proposed unit is based on emulating physical properties an induction machine and capitalizes its inherent grid-friendly such as self-synchronization, oscillation damping, standalone capabilities.To this end, mathematical model analyzed reformulated to obtain unknown grid frequency by processing voltage current measurements at...

High penetration of renewable energy sources and the increasing share stochastic loads require explicit representation uncertainty in tools such as optimal power flow (OPF). Current approaches follow either a linearized approach or an iterative approximation non-linearities. This paper proposes semidefinite relaxation chance-constrained AC-OPF which is able to provide guarantees regarding global optimality. Using piecewise affine policy, we can ensure tractability, accurately model large...

This paper presents a novel approach for combined sizing of the DC-side storage capacity and tuning controller gains grid-forming converters, which accounts coupling between installation planning operation parameters unit. Furthermore, it ensures sufficient energy power containing predefined active imbalance preserving frequency within prescribed limits. For this purpose, analytic expressions relevant system metrics as well utilization associated converter unit are incorporated into...

This paper studies the procurement and pricing of inertial response using a frequency-constrained unit commitment formulation, which co-optimizes provision energy inertia services while accounting for their complementary properties. The proposed approach builds on two-step process that allows to differentiate between units being online purposes ones committed additionally solely provision. Subsequently, three novel payment schemes reimburse providers in transparent fair manner according...

The electric grid is undergoing a major transition from fossil fuel-based power generation to renewable energy sources, typically interfaced the via electronics. future systems are thus expected face increased control complexity and challenges pertaining frequency stability due lower levels of inertia damping. As result, development novel ancillary services becoming imperative. This paper proposes data-driven scheme, based on Reinforcement Learning (RL), for grid-forming Voltage Source...

This paper presents a novel virtual synchronous machine controller for converters in power systems with high share of renewable resources. Using an interval-based approach, the emulated inertia and damping constants are adaptively adjusted according to frequency disturbance system, while simultaneously keeping within prescribed limits. Furthermore, sufficient stability conditions control tuning derived. The proposed design is integrated into state-of-the-art converter scheme tested through...

Due to the rising shares of renewable energy sources, future power systems are facing significant changes in control complexity and system inertia, thus making frequency regulation more challenging. This paper proposes a novel scheme based on model predictive for grid-forming Voltage Source Converters (VSCs), with goal exploiting their fast response capabilities available DC-side storage provide service system. An observer support vector machine regression detects estimates disturbances...