Virtual Inertia: Current Trends and Future Directions

Abstract

Abstract:The modern power system is progressing from a synchronous machine-based system towards an inverter-dominated system, with large-scale penetration of renewable energy sources (RESs) like wind and photovoltaics. RES units today represent a major share of the generation, and the traditional approach of integrating them as grid following units can lead to frequency instability. Many researchers have pointed towards using inverters with virtual inertia control algorithms so that they appear as synchronous generators to the grid, maintaining and enhancing system stability. This paper presents a literature review of the current state-of-the-art of virtual inertia implementation techniques, and explores potential research directions and challenges. The major virtual inertia topologies are compared and classified. Through literature review and simulations of some selected topologies it has been shown that similar inertial response can be achieved by relating the parameters of these topologies through time constants and inertia constants, although the exact frequency dynamics may vary slightly. The suitability of a topology depends on system control architecture and desired level of detail in replication of the dynamics of synchronous generators. A discussion on the challenges and research directions points out several research needs, especially for systems level integration of virtual inertia systems.

Virtual Inertia Control Application to Enhance Frequency Stability of Interconnected Power Systems with High Renewable Energy Penetration

“…To overcome such a problem, the concept of virtual inertia control is implemented. Implementing virtual inertia control, the action of the prime mover is imitated to enhance system inertia and frequency stability [7,8]. If active power via power electronic converters of energy storage systems (ESS) is proportionally controlled by the derivative of the system frequency, the virtual inertia power can be virtually imitated, which contributes to improving the inertial response of the system against the variations in RESs penetration and power demand.…”

“…In order to overcome the problem introduced by power electronic-based RESs, one of the recent solutions is to imitate the synchronous generator behavior virtually in the power system, enhancing system inertia and stability [5]. It is called a virtual synchronous generator (VSG), which imitates the important behavior of prime movers (e.g., inertia characteristic) and synchronous machines, as well as providing ancillary service to the system [6,7]. Implementing virtual inertia control, the action of the prime mover is imitated for frequency control support.…”

“…Recently, considerable research has been proposed regarding virtual inertia control designs [5][6][7][8][9][10][11][12][13][14]. Reference [8] compared the dynamic characteristics of VSG and droop control methods to imitate inertia in the power system.…”

A Time-Varying Potential-Based Demand Response Method for Mitigating the Impacts of Wind Power Forecasting Errors

“…Wind power is one of the most mature renewable energies around the world [1], but the wind power forecasting error (WPFE) can be up to 10-15% with a look-ahead time of 1 h. The variability and unpredictability of wind power generation increase the amplitude and occurrence rate of power imbalance in the power system [2][3][4], which is mainly regulated by automatic generation control (AGC) units in real-time. At present, the base output of AGC units is confirmed in the process of formulating the dispatching plan based on the forecasting information of load and wind, which is optimized every 15 min.…”

Special Issue on Advances in Integrated Energy Systems Design, Control and Optimization

“…Afterwards, they verify the effectiveness and applicability of the proposed method by an empirical system in the eastern regions of South Korea. Last but not least, U. Tamrakar, D. Shrestha, M. Maharjan, B. Bhattarai, T. Hansen, and R. Tonkoski review the recent literature on the control of modern power systems (which are on the verge of transition from synchronous machine-based systems towards inverter-dominated systems) and describe the current state-of-the-art in such virtual inertia systems under high renewable energy penetration [11]. They also suggest potential research directions and challenges in this subject area.…”