Investigating the impact of stability constraints on the future GB transmission system

High penetration of wind power is anticipated in order to increase the share of renewable energy sources up to 20% in 2020. Therefore, in the future there will be major changes to the GB generation profile, both in terms of equipment type and geographical location, which will result in the need to transfer large amounts of renewable energy from the north of Scotland to the mainland demand centers in the GB south. Due to the fact that the existing network has insufficient transmission capacity to accommodate the increasing power transfer, the GB system operator and owners are required to introduce new reinforcements as well as maximizing the use of existing transmission lines to avoid constraining some generators and also at the same time improve the stability limits. In this paper the capability of several new transmission technologies such as Thyristor Controlled Series Capacitor (TCSC) and embedded High Voltage DC (HVDC) links are investigated with regard to increasing power transfer limits and their effect on dynamic stability control is also investigated. Initially, this study proposes a hierarchical Control Strategies for co-ordinated control of the TCSC and HVDC links for all operational point. Finally, the main objective of the study is to analyse and develop an operational stability control system (SCS) that will be able to provide fully co-ordinated control of TCSC and HVDC links in order to achieve best dynamic performance and make the stability limits less binding factor than the thermal limit under all operating conditions using a stabilising feedback control system. This implies that the intertrip actions will be reduced as well as maintaining and enhancing the stability for every dispatched operating point.