PROJECT TITLE :

Dynamic Overload Capability of VSC HVDC Interconnections for Frequency Support - 2017

ABSTRACT:

In future power systems, reduced overall inertia caused by an increased dominance of asynchronous generation and interconnections would build frequency control significantly challenging. As the quantity and power rating of voltage supply converter (VSC) HVDC systems increases, network service provision would be expected from such systems and to try to to thus would need overload capability to be included within the converter specifications. This paper studies the availability of frequency services from modular multilevel converter (MMC)-based VSC HVDC interconnections using temperature-constrained overload capability. Overload of the MMC-based mostly HVDC system is achieved through controlled circulating currents, at the expense of higher losses, and subject to a control theme that dynamically limits the overload on the market so as to keep the semiconductor junction temperatures at intervals operational limits. Two frequency management schemes that use the obtained overload capability to produce frequency response throughout emergency conditions are investigated. The controllers' performance is demonstrated within the context of the longer term Great Britain transmission grid through a reduced equivalent take a look at system. Simulation results show that even modest temperature margins which permit overload of MMC-based HVDC systems for some seconds are effective as a primary frequency reserve and additionally scale back the loss of infeed needs of such interconnections.