Models of reactive power‐related wind park losses for application in power system load flow studies

Abstract

In power system load flow studies, it is common to ignore wind park (WP) losses completely, since WPs are obliged to provide reactive power as a free-of-charge ancillary service. Strongly simplified WP loss estimations are also widespread. Prevailing loss modelling approaches may result in substantial and so far usually ignored reactive power allocation inefficiencies. The innovation of this paper lies in demonstrating this and in presenting an alternative modelling approach that combines speed, ease-of-use and accuracy. Calculations are based on a generic WP connected to 110 kV. It is simulated once using gearless permanent magnet synchronous generators and once using doubly fed induction generators. In this way, for the first time, the consequences of neglecting differences between wind generator types when calculating reactive power-related losses are systematically quantified. Loss-minimal dispatch is assessed using heuristic optimal power flow. Relevance of findings is demonstrated for the application of reducing system losses based on reactive power control of WPs in closed-loop optimal power flow schemes. It is shown that non-consideration of WP losses may lead to dispatch decisions where the increase in WP losses outweighs the achieved loss reduction in the 110 kV system by 400%. The study facilitates comparing reactive power ancillary services from WPs to that of other technologies from an economic perspective. It concludes by a benchmarking overview of pros and cons of modelling alternatives

Competitive cross‐voltage level procurement of reactive power considering reliable capacity from wind and photovoltaics

“…Values refer to VRPP collector systems connected to PCC via HV cables. For a discussion of DFIG connected via overhead lines refer to Kaempf and Braun ().…”

“…It tries to characterize the distribution systems' capability to adapt P/Q exchange at the T/D interface such that it can be integrated into transmission‐level operational Q planning (Cuffe, Smith, & Keane, ). Silva et al () suggest to estimate a cost map of PQ flexibility provision at the T/D interface, which is suitable to integrate maps of Q cost such as introduced in Kaempf and Braun (). Such maps are also likely to ensue from distribution level flexibility markets as suggested in Ntakou ().…”

Reactive Power Capability Model of Wind Power Plant Using Aggregated Wind Power Collection System

“…In power system operation studies, reactive power capabilities of WPPs have been used for load flow studies in [7,8]. Zhang et al have applied reactive power capability curves of IEC 61400-27-1 Type 3 (also known as doubly fed induction generator (DFIG)) WT for loss minimisation in WPP [9].…”