Wind Power Reserve Research Articles

Modeling the Reserve Capacity of Wind Power and the Inherent Decision-Dependent Uncertainty in the Power System Economic Dispatch

The ever-increasing penetration of renewable generation is demanding additional flexibility for the operation of power systems. In this sense, it has been proved that wind power generators (WPGs) can provide part of the required operating reserve through pitch angle control (PAC) under a deloaded strategy. Unlike conventional operating reserve sources, however, the operating reserve provided by WPGs can't always be considered reliable, which renders the power system dispatch more challenging. In this research, the reserve capacity of the WPGs is modeled considering the decision-dependent uncertainty (DDU). The random wind speed introduces uncertainty to the available reserve capacity of the WPGs while the decisions on the deloading degrees of the WPGs directly affect their coefficients between wind speed and usable wind power, making the uncertainty decision-dependent. Moreover, the operational technical limits of the WPGs and the multiple possible wind speed scenarios are also considered in the wind power reserve capacity modeling. Then, a two-stage reliability constrained stochastic economic dispatch model with WPGs' reserve provision (SED-WRP) is developed to jointly dispatch the generation and reserve. A group-based multi-cut Benders decomposition method is applied to improve the convergence performance of the solution algorithm. Case studies are solved to quantify the impact of considering the reserve provision of WPGs and the inherent DDU in power system dispatch decisions.

Synergetic Scheduling Energy and Reserve of Wind Farms for Power Systems with High-Share Wind Power

With wind and other variable renewable energy (VRE) generation gradually becoming the main power source, it is difficult to ensure the flexible and secure operation of the system by completely relying on conventional sources to balance the uncertainty and volatility of VRE. The increase of VRE penetration leads to the shortage of operation reserves, and wind power is allowed to participate in reserve services. However, the output of wind power is uncertain, and how to ensure the reliability and sustainability of wind power reserves is still an open question. A robust energy and reserve dispatch method considering the flexibility of wind power is proposed to solve this problem. To effectively measure the output and reserve margin of wind power under uncertain scenarios, (1) the grid connection coefficient of wind turbine generators (WTGs) is defined, and the uncertainty set considering active wind power curtailment is established; and (2) based on two kinds of WTG control methods, the reserve model of wind farms is established. The model links the reserve capacity between the base scenario and uncertain scenarios through the reserve coefficient, which ensures that the wind power reserve determined in the base scenario is still deliverable in any uncertain scenario. The robust scheduling model determines the optimal dispatching and reserve plan of conventional units and wind farms by balancing the system operation economy and the schedulable reserve of wind power. The column-and-constraint generation algorithm is used to solve the model. The effectiveness of the proposed model is verified by the illustrative results of the IEEE normal system.

A Frequency Security Constrained Scheduling Approach Considering Wind Farm Providing Frequency Support and Reserve

The proposal of the “carbon neutrality” target promotes the rapid development of variable renewable energy, which leads to the reduction of inertia and the deficiency of flexible reserve in power systems. Wind turbines (WTs) now are asked for providing frequency support and reserve through proper control strategy. This proposes a new issue on how to coordinate the operation of conventional units and WTs. This paper proposes a frequency security constrained scheduling approach considering wind farms providing frequency support and reserve. Two dynamic frequency indices: RoCoF and nadir, are derived and introduced into the scheduling model. The frequency support capability of wind farm is accurately quantified by considering the real grid-connected WT capacity and wake effect. A wind power reserve model considering uncertainty is established by linking the reserve under the forecasted scenario and uncertain scenarios through reserve auxiliary variables. The contribution of wind farms to power system frequency support and reserve is quantified in the robust scheduling model. Case studies show that the frequency support and reserve from wind farms can effectively reduce the whole operation cost and VRE curtailment. Moreover, the value of wind farms in CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> emission reduction is properly quantified.

Analysis of the Implementation of the Primary and/or Inertial Frequency Control in Variable Speed Wind Turbines in an Isolated Power System with High Renewable Penetration. Case Study: El Hierro Power System

With high levels of wind energy penetration, the frequency response of isolated power systems is more likely to be affected in the event of a sudden frequency disturbance or fluctuating wind conditions. In order to minimize excessive frequency deviations, several techniques and control strategies involving Variable Speed Wind Turbines (VSWTs) have been investigated in isolated power systems. In this paper, the main benefits and disadvantages of introducing VSWTs—both their inertial contribution and primary frequency regulation—in an exclusively renewable isolated power system have been analyzed. Special attention has been paid to the influence of the delays of control signals in the wind farm when VSWTs provide primary regulation as well as to the wind power reserve value which is needed. To achieve this objective, a methodology has been proposed and applied to a case study: El Hierro power system. A mathematical dynamic model of the isolated power system, including exclusively renewable technologies, has been described. Representative generation schedules and wind speed signals have been fixed according to the observed system. Finally, in order to obtain conclusions, realistic system events such as fluctuations in wind speed and the outage of the generation unit with the higher assigned power in the power system have been simulated.

Sensitivity‐based reliability coordination for power systems considering wind power reserve based on hybrid correlation control method for wind power forecast error

Sensitivity‐based reliability coordination for power systems considering wind power reserve based on hybrid correlation control method for wind power forecast error

A Multi-Source Coordinated Optimal Operation Model Considering the Risk of Nuclear Power Peak Shaving and Wind Power Consumption

In view of the development trend of nuclear power and offshore wind power in China’s coastal areas, as well as the current situation of peak shaving pressure brought by reverse peak shaving of wind power to the power grid. In this paper, according to the number of failures and power loss per year in each region, the risk of peak load regulation is calculated comprehensively and quantitatively, and the risk cost increment of nuclear power peak shaving is calculated and evaluated. Optimize and linearize the constraints, and the relatively complete constraint conditions are established. Thus, the traditional peak shaving model of fixed gear nuclear power dispatch is improved, and the peak shaving depth is continuous within the safety regulation range of nuclear power. Then, based on the peak shaving operation model of nuclear power safety constraints, considering the nuclear power risk and wind power consumption, taking into account the operation cost, risk cost, environmental cost and safe operation constraints of various types of power supply, a multi-source optimal scheduling model of wind-nuclear-thermal-storage-gas is established. Based on the calculation example of the actual regional power grid, the security, low carbon and economy of the model are analyzed, and the sensitivity analysis of the risk cost coefficient and wind power reserve coefficient in the dispatching model is carried out. It can be concluded that the nuclear power has a little safety impact on the reactor core and coolant circulation system after participating in the peak shaving operation, and the increase in the probability of man-made misoperation is not obvious. The main source of the risk cost increase is the benefit loss of selling electricity, so that it can properly participate in the peak shaving of the system. When the nuclear safety risk is low and the risk of wind abandonment is high, the nuclear power peak shaving has a stronger economic advantage. The dynamic optimal allocation of wind power reserve capacity can further reduce the abandonment of nuclear power and improve the operation economy of the system.

An Endogenous Approach to Quantifying the Wind Power Reserve

Due to inherent uncertainty and volatility, large-scale wind power integration requires additional reserves for power balancing. However, it remains an open question as to how to quantify the required reserves corresponding to different uncertainties and penetration scales of wind power. This paper addresses this problem with an improved endogenous reserve determination method. Multiple uncertainties, including wind power outputs, load fluctuations, and generator failures, especially power flow uncertainties caused by wind power fluctuations and generator faults, are comprehensively integrated into a security and network-constrained economic dispatch (S&NCED) model to jointly schedule the generation and reserve. Affinely adjustable robust optimization (AARO) is adopted to address wind power and load uncertainties. Then the model is transformed into a two-stage (normal state optimization and fault verification) S&NCED model for iterative solving with the aid of Benders decomposition, and auxiliary constraints are designed to accelerate the convergence. Results of 6-bus and IEEE118-bus systems show that the proposed method can effectively provide a more economical and robust generation-reserve dispatch scheme and can clearly specify the reserve capacity required by wind power.

A Distributionally Robust Co-Ordinated Reserve Scheduling Model Considering CVaR-Based Wind Power Reserve Requirements

The reserve scheduling problem becomes more difficult to handle when wind power is increasing at a rapid rate in power systems and the complete information on the stochasticity of wind power is hard to be obtained. In this paper, considering the uncertainty on the probability distribution (PD) of the wind power forecast error (WPFE), a distributionally robust co-ordinated reserve scheduling (DRCRS) model is proposed, aiming to minimize the total procurement cost of conventional generation and reserve, while satisfying the security requirement over all possible PDs of WPFE. In this model, a distributionally robust formulation based on the concept of conditional value-at-risk (CVaR) is presented to obtain the reserve requirement of wind power. In addition, to achieve tractability of the scheduling model, the random variable that refers to WPFE in the scheduling model is eliminated, equivalently converting the stochastic model into a deterministic bilinear matrix inequality problem that can be effectively solved. Case studies based on the IEEE-39 bus system are used to verify the effectiveness of the proposed method. The results are compared with the normal distribution based co-ordinated reserve scheduling (NDCRS) method that assumes WPFE is of normal distribution.

Impacts of High Wind Power Penetration on the Frequency Response Considering Wind Power Reserve

With high wind power penetration, imbalance between generation and consumption is increased, and as a consequence the frequency deviation from the nominal value will be magnified. For frequency control purpose in conventional power systems, the synchronous generators are only responsible. However, it is expected that the renewable energy sources (RESs) are also needed to contribute in frequency control issue in near future. In this paper, impacts of high wind penetration on the frequency control are studied, and an approach is introduced for creating the secondary reserve for doubly fed induction generator (DFIG) wind turbines. This reserve can contribute to load frequency control (LFC) task. Simulation results on updated standard IEEE 39-bus system are presented and it is shown that the wind turbines can contribute in LFC service, successfully.