Inertial Response Identification Algorithm for the Development of Dynamic Equivalent Model of DFIG-Based Wind Power Plant

As the wind power penetration increases, the frequency stability of the power system is deteriorating. Thus, it is expected that the wind power plants (WPPs) will be required to produce the inertial response during the short-term large-scale frequency disturbances. To study the effects of the inertial response of the WPP, the dynamic equivalent model (DEM) of the WPP should be able to emulate the inertial response of the actual WPP. Otherwise, the simulated system frequency would be different from the actual one. Therefore, the inertial response identification algorithm (IRIA) is proposed in this paper. The IRIA is able to identify the values of the droop gain and the inertia constants of the WPP according to the actual system frequency and the active power output of the actual WPP. The simulation results demonstrate that the DEM of the WPP and the actual WPP have similar responses of the active power output and the rotor speed under two frequency disturbances. In addition, the FNs of the simulated and actual system frequencies are very close. As a results, the effectiveness of the IRIA is successfully proved.

With the continuous increase in wind power penetration, doubly fed wind turbines can quickly respond to changes in grid frequency, and have particularly important inertia-response characteristics. This article starts with the excitation control principle of a doubly fed induction generator, compares the transient frequency characteristics of the synchronous generator under fault, and proposes that the doubly fed induction generator can control the speed or active power of the generator through excitation. It proves the unique “active power transient frequency characteristics” of doubly fed induction generators. Under different wind speeds, the inertia response capability of the wind turbine is quantified, and the degrees of influence of the inertia time constant and frequency characteristic slope of the doubly fed induction generator on the transient change process are analyzed. Finally, simulation and experiments verify the correctness of the above theory, which provides a basis for significantly improving the transient stability of the power system and realizing the controllability of the transient stability of the power system.

As wind power penetration into power systems increases, it poses a growing challenge to power system operation and stability. This is partly because wind power is highly time variable and cannot inherently contribute to power system frequency regulation. The provision of frequency support from wind turbines under changing wind conditions is examined in this paper. A simplified variable speed wind turbine model is developed. A modified turbine controller to deliver inertial and droop response is proposed. The interaction between inertial and droop response from wind turbines is examined under varying wind.

Optimization of wind power generation to minimize operation costs in the daily scheduling of hydrothermal systems

As the wind power penetration level increases, the inertial response of a wind power plant (WPP) is important to the grid under load and generation imbalance. In this paper, we present coordinated WPP control for frequency support under wake effects. By de-loading the power from a WPP, the inertial response can be obtained from the kinetic energy of wind turbine rotors. The coordinated WPP control considering wake effects improves the inertial response of WPP by preventing the rotor speed recovery period, which is unfavorable during a frequency drop. The proposed frequency support scheme could prevent large generation reduction right after an inertial response. In addition, more power generation is available when a WPP uses both primary and secondary control. To validate the performance, a WPP with three wind turbines was used as a case study with wake, turbine, and generator models.

Increasing wind power penetration and the size of Wind Power Plants (WPPs) brings challenges to the operation and control of power systems. Most of WPPs are located far from load centers and the short circuit ratio (SCR) at the Point of Connection (POC) is low, which means that fluctuations of the wind power can cause voltage variations. An optimal voltage control scheme for WPPs with STATCOMs is presented in the paper. It ensures that the voltages within the WPPs and at the high voltage side of the WPPs are within the limits and maximizes the dynamic Var reserve of the WPPs. Case studies were conducted with the simplified Anholt offshore WPP and the case study results demonstrate the efficacy of the proposed optimal voltage control scheme.

Wind power is still the most promising renewable energy source in the year of 2014. Wind power is considered feasible replacement of fossil fuels and energy production using this resource is increasing with the passage of time. Growing wind power production has impacts on the systems synchronized with these wind turbines. As the wind power penetration increases to the main power grids systems, the respective power system operators are more concerned about the reliability and stability of their systems. This increase of wind power penetration in system means that the wind turbines are replacing conventional power plants that usually control and stabilize the system. If this power penetration surpasses a certain level, control tasks for wind turbine system also needs to be considered. If the wind speed increases, much power is produced through turbines. The main problem we are facing in wind power production is that even after generating more than enough power to meet the load demands, surplus energy is being dissipated by dump load, otherwise it can create threat for power system stability as surplus power can have adverse effect on the frequency and voltages. In normal cases, surplus power is dissipated by using dump load. But enough portion of produced power is being wasted this way. In this study, an efficient controller for effectual wind turbine operation by controlling dump load is proposed to keep the system stable and the surplus dumped power is also consumed in productive way through heat generating system which increases the power system overall efficiency.

In several countries, the wind power penetration increased tremendously in recent years. To ensure the proper functioning of the power system, some grid operators already require the capability to provide inertial response or primary control with wind turbines. This paper discusses the emulated inertial response with wind turbines by means of the synthetic inertia and the droop control strategy. The behavior of the synthetic inertia strategy is determined by the inertial and the droop constant, whereas droop control only has a droop constant. When these strategies are used, it is important to tune the control parameters depending on the power system to which the wind turbines are connected. Simulations show that it is possible to enhance but also to deteriorate the frequency response of the system, dependent on these parameters. For different power system compositions, the optimal inertial constant is always close to zero. This way, the synthetic inertia strategy reduces to a fast droop control strategy. This is an important outcome, as it means that no differentiation of the frequency is needed to obtain an optimal inertial response from the wind turbines, which is beneficial in terms of robustness. Consequently, droop control is a viable alternative for the synthetic inertia.

The grid connection of large-scale wind power will reduce the equivalent inertia and damping of the system, resulting in a decrease in system frequency stability. The directly-driven permanent magnet synchronous generators (D-PMSG)-based wind turbine (WT) usually uses conventional PD control to support frequency, however, the related controller parameters are difficult to design, reducing economic benefits of WT power generation and slowing speed recovery. To this end, based on the analysis of the dynamic response of D-PMSG grid-tied system, this paper studies the dynamic influence and variation law of controller parameters on system frequency. A WT control strategy based on frequency trajectory planning (FTP) is proposed. The frequency fixed value determined by the power grid regulation is directly taken as the control target to carry out the FTP, and the WT auxiliary power output is controlled according to the planned frequency trajectory. The system frequency is supported quickly in the transient process, ensuring the safe and stable operation of the grid while realizing the economy of WT power generation. The effectiveness and economy of the proposed control strategy is verified by RT-LAB experiment.

According to the characteristics of double fed asynchronous generator rotor energy flow, research and design based on the DSP control with two-way flow of energy function of Dual PWM converter and discusses the grid side converter control method of Dual PWM converter in particular. The wind turbine simulation model is established by using the electromagnetic transient PSCAD/EMTDC software. The simulation system is used to simulate the P, Q decoupling control and maximum wind energy tracking control of the generator. Wind is a natural phenomenon generated by the solar radiation heat, the earth's surface caused by uneven heating of the atmosphere. It is estimated that only 1% of the wind on the ground will be able to meet the needs of the world's energy. With the continuous improvement of the level of wind power generation technology, the cost of wind power gradually reduced, considering environmental benefits, the cost will be close to the cost of coal-fired power generation. Therefore, great efforts to develop wind energy as the representative of the renewable energy and new energy, to achieve sustainable development, has become the consensus of the whole society, strategic choice to solve the energy crisis and environmental problems. 2.Overview of control technology of doubly fed wind power gener ation Wind power is the kinetic energy contained in the natural wind into electrical energy in the process, the wind turbine wind energy capture and convert it into mechanical energy, driven by rotary generator, and the generator for converting mechanical energy conversion into electrical energy. As countries around the world pay more attention to wind power, wind power has become the world's fastest, most widely studied and applied new energy technology. With the development of wind power technology, wind turbine, wind turbine generator, converter and its control system and the way of the wind turbine, there are different types of. Among them, the doubly fed wind power generation system due to the converter control capacity is small, the speed of operation range wide characteristics become currently the world's most widely used VSCF wind power generation system. Variable speed constant frequency generator in asynchronous generator rotor side applied three-phase low frequency current to realize AC excitation, the output power is constant frequency and constant voltage amplitude, frequency, phase of the exciting current control. At the same time, the active power and reactive power decoupling control of the generator is realized by using the vector control technology. Control active power capable of adjusting the rotation speed of the wind turbine, to capture the maximum wind power tracking control; regulation of reactive power adjustable power factor and improve the dynamic and static stability of the wind turbine and power system operation. In addition, the VSCF wind power generation technology, so to achieve good flexible connection between the generator and power grid system, compared with the traditional constant speed constant frequency generation system easier to achieve grid connected operation and operation

Requirements for inertial response (IR) from wind turbines (WTs) have been implemented or drafted by power systems (PSs) operators worldwide. This is a response to the replacement of conventional power plants using synchronous generators by non‐synchronous, power electronics‐based generation and the resulting effect on frequency dynamics in the case of contingency events. The additional active power provided during operation in IR mode must be drawn from the rotating masses. A re‐acceleration accompanied by reduced active power output follows the activation phase. The allowed depth and duration of the post‐inertial recovery will be regulated in future versions of grid codes, e.g. in Québec and Ireland. This study describes an improved version of an IR control system that enables a more PSs‐friendly provision of such short‐term frequency support. The new controls allow adjusting the duration of the recovery period. Potential negative effects of IR from WTs on the PS in the form of a second frequency nadir during the recovery phase can be minimised. The outcome of simulations and of field testing will be presented. All results shown in this study include the initial and the future inertia emulation performance which allows easy comparison of the two controls.

Due to a large number of grid-connected wind turbines don't have the ability to respond to system frequency changes, problems on frequency stability of power system have become increasingly prominent. At present, the primary frequency regulation of wind turbines is mostly based on the method of additional frequency regulation control to change the reference value of electromagnetic power, so as to realize that wind turbines can participate in the system frequency regulation. However, the method of additional frequency regulation control does not t consider the conflict of power increment between the power tracking controller and the frequency regulation controller, which lead to the power increment required for the primary frequency regulation can't reach the target value. Based on this issue, the paper combines the original power tracking technology of wind turbines with the existing frequency regulation technology, and change the signal of frequency deviation by the power tracking curve of the wind turbine, which realize the inertial response and primary frequency regulation of the unit through the fast active power control of the wind turbine. That the purpose of frequency regulation is realized and the power tracking curve is changed, by converting the active output required for the frequency regulation control into the increment load reduction. The simulation results show that, based on the control method in the paper, the double-fed wind turbine can fully achieve the target increment needed for primary frequency regulation, which makes the wind turbines more reliable and effective to participate in system of frequency regulation.

With increasing wind penetration levels on power systems worldwide, conventional thermal plant, along with the ancillary services they provide are being displaced. To address this issue, modern variable speed wind turbines can offer a short-term controlled response to temporary power imbalances, by harnessing their stored rotational energy, a so called emulated, or synthetic, inertial response. However, unlike conventional frequency response services, the emulated inertial response is dependent on the wind turbine operating condition and provides a response which is distinct to that from synchronously connected plant. While much research has investigated the harnessing of such a response from wind turbines and its effect on system frequency, this paper investigates potential issues associated with the system-wide integration of the technology at scale. The ability for wind generation to provide frequency support through emulated inertia is assessed, as well as the potential for tuning such a distributed response resource to ensure timely and effective frequency recovery under different system conditions. It is shown that the frequency response capability of future systems and the operating protocols for system participants, including wind generation, will require development if emulated inertia technology is adopted at scale.

This paper presents the modular structure of wind turbine models to be published in a new standard IEC 61400-27 for "Electrical simulation models for wind power generation". The purpose of this standardization work is to define generic simulation models for wind turbines (Part 1) and wind power plants (Part 2), which are intended for short-term power system stability analyses. Part 1 has passed the first committee draft stage, whereas Part 2 is in an early stage of development. Initially, the paper describes the interfaces between wind turbine, wind power plant and grid models, and then gives a more detailed description of the modular structure of the types of wind turbines that are included in Part 1.

The article discusses the mathematical model of the Daria small wind power plant. This installation is a type of vertical axis wind turbine named after its inventor, Georges Jean Marie Darrieux. The design consists of a vertically oriented shaft with curved blades or airfoils attached to it, forming a shape similar to an egg whisk. In today’s world, against the backdrop of climate change and steadily increasing energy demand, wind energy acts as a critical pillar of the transition to renewable energy sources. This technology helps reduce carbon emissions and mitigate humanity’s impact on the environment. In this context, wind energy is emerging not only as a means of supplying electricity, but also as a powerful catalyst for building a more sustainable and energy-efficient future. The equation of stationary modes is studied at the value of the external resistance of the dynamic model specified by the simplest equation. Conditions have been found under which relaxation oscillations are observed in the system.