Coordination Strategy of Large-Scale DFIG-Based Wind Farm for Voltage Support With High Converter Capacity Utilization

Abstract

Due to the long-distance transmission, external grid cannot effectively support the access point voltage (APV) of the large-scale wind farm (WF), which thus entails DFIGbased WF to provide its ancillary services on reactive power generation. Considering factors of limited down-sized converter capacity, various operating modes of wind turbines (WTs), and the large pressure of large-scale WF communication on the central governor, this paper proposes a distributed active power and reactive power coordination scheme for APV support. A reactive power self-allocation scheme is developed and operated in each WT for reactive power dispatch. Based on the mechanism of distributed consensus control and aligning with the principle of preferential and proportional utilization of spare reactive power capacity (RPC), the proposed method collaborates the rotor side converters and the grid side converters of all WTs but without the necessity of knowing the total RPC. Further, in case that the total RPC is insufficient for the demand, a coordinating factor for RPC extension is generated to weaken the active power. Through a current-enforced PQ coordinating loop, it guarantees a high utilization of converter capacity as well as an exact compensation on the reactive power imbalance, which thereby reduces the wind power curtailment for the RPC release. Several case studies verify the effectiveness of the proposed method.

Load-Aware Operation Strategy for Wind Turbines Participating in the Joint Day-Ahead Energy and Reserve Market

“…The capability of wind farms to provide reactive power ancillary services is explained in [10] and [11]. Another study presented in [12] explores the coordination strategy of large wind farms for voltage support by the means of high converter capacity. An ancillary services provision method by the means of coordination between wind turbine and electrolysis systems is presented in [13].…”

“…The total load on the wind turbine L is calculated as weighted sum the four individually calculated loads as in (12). Here, a, b, c and d are the weight factors associated with the loads.…”

Multiobjective Ant Lion Optimization for Performance Improvement of Modern Distribution Network

“…This type-III DER is a power plant capable of injecting active power and absorbing reactive power. The type of renewable energy power plant includes an asynchronous generator, for example, a wind power plant that uses an induction generator [39], [40]. The AL parameter used consists of a population of 100, and the maximum number of iterations is 100.…”

An Active Voltage Coordinate Control Strategy of DFIG-Based Wind Farm with Hybrid Energy Storage System

“…Considering the operation demand of the power grid with the high proportion of wind power, it is of great significance to exploit the voltage support capacity of the wind farm to the power grid to improve the reactive power environment and promote the wind power consumption of the power system. The limitation of reactive power (LRP) of DFIGs was used to improve the voltage control strategy in [17,18], and the reactive power support capability of the wind farm was verified. A reactive power dispatch method was proposed in [19], in which the lifetime of the converter was considered to optimize the reactive power environment of the wind farm.…”

“…However, the above methods ignore the influence of active power on LRP and voltage, which may lead to insufficient reactive power reserve in wind farms. The controller structure was modified to improve LRP in [18,24], while the active voltage control of the wind farm was formulated in [25] by adjusting the output active power according to the LRP. Nevertheless, the output active power reduction in a wind farm may lead to the waste of primary energy.…”