Optimized Reactive Power Capability of Wind Power Plants With Tap-Changing Transformers

Abstract

With the recent advancements in power electronics for wind turbines, wind power plants (WPPs) have become valuable assets for reactive power support of bulk power systems. In this paper, we present a methodology to optimize the WPP's reactive power capability as seen from the point of common coupling (PCC). To this end, the proposed methodology determines the configuration of the tap-changing transformers within the WPP that maximizes the amount of reactive power the WPP can either consume or inject into the network, considering uncertain levels of wind power generation and voltage magnitude at the PCC. The optimized reactive power capability (ORPC) problem is initially formulated as a mixed-integer nonlinear programming (MINLP) model. Then, a set of efficient linearization techniques are used to obtain a mixed-integer linear programming (MILP) model that can be solved via off-the-shelf mathematical programming solvers. The results demonstrate that the proposed MILP model is a scalable, flexible and accurate method to maximize the reactive power capability of WPP as seen from the PCC.

A novel control technique for on‐load tap changer to enlarge the reactive power capability of wind power plants

“…The methodology proposed in [18] determines the tap position to maximize either generation or consumption of reactive power considering uncertain levels of active power and voltage at point of common coupling. A mixed-integer nonlinear programming model is used for offline optimization of reactive power capability.…”

Reactive Power Potential of Converter-Connected Renewables Using Convex Power Flow Optimization

“…Thus, a complete converter model including not only the rated current but also converter voltage limits has to be considered. The fully rated converter-connected RES model with current and minimum and maximum voltage limits are developed in [36][37][38][39][40]. A complete doubly fed induction generator model is used in [41] to account for the reactive power from a wind power plant (WPP), while [42] uses models of the converter with maximum current and maximum voltage limits only.…”

“…A complete doubly fed induction generator model is used in [41] to account for the reactive power from a wind power plant (WPP), while [42] uses models of the converter with maximum current and maximum voltage limits only. More recently, authors in [40] propose to enhance the reactive power potential of a WPP using the complete converter constraint model as suggested in [36][37][38]. However, a linearization approach for the constraints based on Taylor series expansion is used for all the reactive power constraints of the WPP.…”

“…However, such methods lack the guarantee for a globally optimal solution. Two other popular methods existing in literature to solve the problem of optimizing active distribution network operation are analytical, as pointed out in [30,32,44], or based on linearization of the power flow equations and/or converter constraints, as demonstrated by [19,40,46].…”