Comparison of two voltage control strategies for a wind power plant

Abstract

Larger percentages of wind power penetration\ud translate to more demanding requirements from grid codes.\ud Recently, voltage support at the point of connection has been\ud introduced by several grid codes from around the world, thus,\ud making it important to analyze this control when applied to wind\ud power plants.\ud This paper addresses the analysis of two different voltage\ud control strategies for a wind power plant, i.e. decentralized and\ud centralized voltage control schemes.\ud The analysis has been performed using the equivalent and\ud simplified transfer functions of the system. Using this\ud representation, it is possible to investigate the influence of the\ud plant control gain, short circuit ratio, and time delays on the\ud system stability, as well as the fulfillment of the design\ud requirements.Peer ReviewedPostprint (published version

Enhanced Voltage Control of VSC-HVDC-Connected Offshore Wind Farms Based on Model Predictive Control

“…Suppose the active and reactive power references and current measurements of the WTG are , , and where is the current time, and . Considering the effects of time delay of the communication system and dynamic response of the WTG control system, the dynamic behavior of the power control loops of WTGs could be described by a first-order lag function [13], [15], (15) (16) where and are the time constants, which are in the range of 1~10 s [34]. Accordingly, the continuous state space of a wind farm with WTGs can be formulated as, ,…”

“…In [11], [14], the set-point of reactive power was calculated based on the voltage at the POC and then dispatched to each WTG based on the PD strategy which is similar to the active power dispatch. Centralized and decentralized voltage control schemes were discussed in [15], which are distinguished by the outer control loop of WTGs. The decentralized control scheme performs better considering the negligible delay between wind farm controller and WTGs.…”

Decentralized Coordinated Voltage Control for VSC-HVDC Connected Wind Farms Based on ADMM

“…The voltage and reactive power management of wind farms, as one of the major topics of regarding wind power integration, has motivated a great number of studies. For conventional acconnected wind farms, several voltage/reactive power control strategies were designed to regulate the voltage at the point of connection (POC) [7]- [8], in which the total required reactive power is calculated based on the voltage at the POC using the slope-based function or using the proportionalintegral (PI) controller and then proportionally dispatched to each wind turbine (WT) according to their available reactive power capability. In recent years, the optimization-based control strategies have been developed to pursue the optimized control performance.…”

Distributed coordinated active and reactive power control of wind farms based on model predictive control

“…For reactive power control of wind farms, the main aim is to maintain the voltage at the point of connection (POC) within the feasible range, which is specified in many grid codes. Several reactive power dispatch strategies based on the proportional distribution and PI controller have been proposed in [4], [10]- [11], which depend on the voltage at the POC and available reactive power capability of WTs while the terminal voltages of WTs are not considered. The optimizationbased reactive power/voltage control strategies have also been proposed [12]- [14].…”