Grid Ancillary Services From Doubly Fed Induction Generator-Based Wind Energy Conversion System: A Review

Abstract

Modern electrical grids face serious challenges to maintain healthy operational conditions. The nominal voltage and frequency, for instance, are affected by huge load changes and renewable energy integration. Renewable energy conversion systems are traditionally installed to provide active power. Fortunately, advanced renewable energy conversion systems have the ability to provide other facilities such as reactive power control and harmonic mitigation. In fact, recent grid codes obligate renewable energy systems to serve other duties such as generating reactive power rather than just simply supply active power, participate in fault ride through, for instance. This paper presents a comprehensive study on the doubly fed induction generator (DFIG)-based wind energy conversion system (WECS), which provides ancillary services to the grid along with performing its regular duties. These services include reactive power control, voltage ride through, power quality improvement, frequency control, and power oscillation damping. The literature survey and comparative studies show that the DFIG-based WECS has the ability to support electrical grid during normal and transient conditions, and it can also help in the large-scale renewable energy penetration to the power grid. The effect of different industrial and nonlinear controllers on DFIG performance in extracting grid ancillary services is highlighted. INDEX TERMS Doubly fed induction generator (DFIG), frequency control, grid ancillary services, power oscillation damping, power quality improvement, reactive power control, voltage ride through, wind energy conversion system (WECS).

Optimal feedforward torque control for nonlinear induction machines considering stator & rotor copper losses and current & voltage limits

“…An operation management was designed for a doubly-fed induction machine (DFIM) which saturates the 2 Actually, the reactive power reference at the point of common coupling (PCC) of WECS depends on the grid demand. However, unitary power factor operation with i q s = 0 is commonly considered, but using the grid-side converter (GSC) for reactive power control is also an option [15]. For OFTC, it is assumed that the GSC compensates the reactive power of the DFIG at the PCC (if required).…”

Review and Comparison of Grid-Tied Inverter Controllers in Microgrids

“…Microgrids are expected to present specific features concerning stability, flexibility, scalability, and grid supporting capabilities [16], [110]- [112]. In particular, microgrids should i) present adequate stability margins in both steady-state and transient conditions; ii) be able to automatically react to faults to allow prompt restoration of normal operating conditions for loads and sources; iii) extend operation by transitioning to the islanded mode; iv) offer the possibility to seamlessly add, or remove, loads and sources; v) provide services like grid-support, dispatchability, data-logging, remote diagnostic.…”

“…Standards like [3], [105], [107]- [109], [113] define a set of versatile functionalities to be implemented by grid-tied inverters. Others have been identified and proposed in the literature, like [18], [111], [112], [114]- [116]. Altogether, the set of functionalities can be categorized by referring to four circumstances of operation, denoted in Fig.…”

An Analytical Model for Detailed Transient Fault Analysis of Doubly-Fed Induction Machines

“…The doubly-fed induction machine (DFIM) is applied in a wide variety of power generation facilities. In general, there are issues related to the mechanical design, the control design, as well as to the interplay with the power grid [1], where transients can be induced. The machine current and torque transients are critical machine-related issues, as their maximum values determine the mechanical design.…”

“…The current and torque amplitudes of these phenomena are lower than for a terminal short-circuit fault so, i.e., they do not significantly impact the mechanical design of the generator (local ones are more severe). The grid faults are normally simulated using numerical simulation software like SIMSEN 1 , as the grid topology is different for every project.…”