Emulation Strategies and Economic Dispatch for Inverter-Based Renewable Generation under VSG Control Participating in Multiple Temporal Frequency Control

Abstract

As the increasing penetration of inverter-based generation (IBG) and the consequent displacement of traditional synchronous generators (SGs), the system stability and reliability deteriorate for two reasons: first, the overall inertia decreases since the power electronic interfaces (PEIs) are almost inertia-less; second, renewable generation profiles are largely influenced by stochastic meteorological conditions. To strengthen power systems, the concept of the virtual synchronous generator (VSG) has been proposed, which controls the external characteristics of PEIs to emulate those of SGs. Currently, PEIs could perform short-term inertial and primary frequency responses through the VSG algorithm. For renewable energy sources (RES), deloading strategies enable the generation units to possess active power reserves for system frequency responses. Additionally, the deloading strategies could provide the potential for renewable generation to possess long-term frequency regulation abilities. This paper focuses on emulation strategies and economic dispatch for IBG units to perform multiple temporal frequency control. By referring to the well-established knowledge systems of generation and operation in conventional power systems, the current VSG algorithm is extended and complemented by the emulation of secondary and tertiary regulations. The reliability criteria are proposed, considering the loss of load probability (LOLP) and renewable spillage probability (RSP). The reliability criteria are presented in two scenarios, including the renewable units operated in maximum power point tracking (MPPT) and VSG modes. A LOLP-based economic dispatch (ED) approach is solved to acquire the generation and reserve schemes. The emulation strategies and the proposed approach are verified by simulation.

Design of Optimal Real Time Emulators for Steam and Wind Turbines for Avoiding Risky Severe Conditions

“…Wind Turbine Characterization The emulation of wind turbine using DC machines of low power and inertia using efficient software programs is the research trend [51,52]. Different control techniques are used with wind turbine emulator to assure its characterization besides the experimental validation of the real wind turbine [53][54][55][56]. Both model predictive and optimal control techniques have been witnessed for controlling wind turbines under various operating conditions [57,58].…”

Advancing Grid-Connected Renewable Generation Systems

“…The authors in [1] present a solution for inverter-based generation (IBG) systems using virtual synchronous generator (VSG) control, which controls the external characteristics of power electronic interfaces (PEIs) to emulate the concept of synchronous generators (SGs), in order to replace the traditional SGs and to establish the modern power systems. For the power system, the main challenges are stability and reliability, because renewable energy generation (REG) is unpredictable or depends on meteorological conditions and the PEIs suffer from being almost inertia-less.…”

Multi-Energy Cooperative Primary Frequency Regulation Analysis of a Hybrid Plant Station for Wind Power and Hydrogen Production Based on Ensemble Empirical-Mode Decomposition Algorithm

“…However, because wind turbines do not have a coupling relationship with system frequency [3], they do not possess the ability to regulate grid-connected frequency, which is similar to synchronous generators [4]. As a result, large-scale grid-connected wind turbines will decrease frequency stability, which will have an impact on the power system's ability to operate safely and steadily [5]. In order to address the issue of weak grid-connected frequency regulation capabilities of wind turbines, China's power grid laws stipulate that grid-connected wind turbines should possess the same frequency control capabilities as synchronous generators [6].…”