Integrating an offshore wind farm to an existing utility power network via an HVDC collection grid: Alternative topology

Abstract

This study proposes an alternative method for integrating an offshore wind farm into the conventional alternating current (AC) power network. The output power port of wind farm consists of a direct current (DC) collector . The offshore wind farm is integrated with a photovoltaic (PV) source and a battery storage system (BSS). The BSS and PV are needed for counteracting the intermittent power generation from offshore wind farm. The conventional AC power network consists largely of AC loads including few DC loads which are fed through the power converters. It is true that the power converters are the main sources of voltage/current harmonic distortion into the power system, thus affecting significantly the power quality. In this study, an interconnected AC and DC power networks is considered, which feed power separately to AC and low-voltage DC loads. The interchange of power between high-voltage DC link and low-voltage DC loads is facilitated through an automatic adapter. The technical concept of the automatic adapter is introduced in this chapter. The interchange of power between the AC and DC networks is facilitated through a bidirectional AC–DC voltage source converter (VSC). The proposed distributed power network topology reduces the need for large number of power converter into the conventional AC power network to feed DC loads, thus reducing the presence of voltage/current harmonic or ripple and also improving the AC network efficiency. Details of operation of the proposed distributed power network topology is analysed and discussed. The mechanism to control the active and reactive power is clearly explained. To verify the effectiveness of the proposed power network topology, intensive simulations are carried out using the Power Simulator (PSim) software.