Impact of Reduced Share of Rotary Frequency Converters in a Low Frequency Synchronous Railway Grid : A Transient Stability Study

• Most low-frequency AC single-phase railway grids have both power-electronic based Static Frequency Converters (SFCs) and electrical-machine based Rotary Frequency Converters (RFCs) connecting them to the three-phase public grid.Already today, in some such grids, a majority of the power conversion is from SFCs. As railway traffic (and thus power demand) increases, more SFCs are installed for capacity increase, while the number of RFCs remains (almost) constant. Thus, the share of SFCs is expected to increase, and the ratio of installed rotational inertia over installed power to decrease.This paper investigates how different shares of SFCs affect the transient stability of low-frequency AC railway grids when having a mix of RFCs and SFCs converting three-phase AC power to single-phase AC power. Results from numerical simulations of the interactions that occur between converters when and after the grid is subject to a fault are presented.The numerical studies show that with an increased share of SFCs there is an increased oscillatory behavior, for example in the voltage magnitude and active power after fault clearance.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik -- Annan elektroteknik och elektronik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering -- Other Electrical Engineering, Electronic Engineering, Information Engineering (hsv//eng)

Nyckelord

Railroads

Stability

Transients (Dynamics)

Alternating current (Electricity)

Clearances (Engineering)

Computer simulation

Energy conversion

Machinery

Rotational inertia

Traffic

Electric Power Engineering

Elkraftteknik

Publikations- och innehållstyp

vet (ämneskategori)

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