BOLOGNA 2011L. Bizumic, R. Cherkaoui, O. A. Mousavi, A. ArestovaSUMMARY
This paper discusses the plausibility of interconnecting multiple large asynchronously operated power systems by means of HVDC technology. These DC interconnections could be made not only between previously disconnected systems, but also, large power systems could be split into smaller asynchronous areas connected by HVDC lines. The reliability and the security of modern power systems are currently in decline. This claim is supported by the numerous large-scale blackouts that have occurred in recent years. The frequency and the severity of these cascading outages are unprecedented. This is due to many factors, but the main reasons are the growing size and complexity of synchronously operated power systems, rising energy demands, aging equipment, electricity market deregulation and more complex market operation, etc. The standard approach towards mitigating these problems is usually to invest in additional resources, transition lines and interconnections. Unfortunately, these measures also further increase the power system’s size and complexity, so the overall effect may even be reduced reliability and security. This paper proposes that systems should be connected exclusively by HVDC links, instead of further increasing the size of synchronous areas. In this wa y, the interconnected power systems will reap all the benefits of system interconnections, while
at the same time HVDC links will act as a firewall for disturbance propagation between systems. This would enable power systems to be operated more efficiently and reliably. To demonstrate the effectiveness of this approach, a comparison is performed between the response to disturbances of power systems connected by AC lines, and those connected solely by DC lines. In addition, the influence of the sizes of the interconnected synchronous systems is analyzed and discussed. In order to ensure accurate dynamic simulations, realistic network models of the European and Russian power networks, developed within the scope of the ICOEUR project (Intelligent Coordination of Operationand Emergency Control of EU and Russian Power Grids), were used in conjunction with extensively validated software designed for simulating the dynamics of electric power systems.
