Operational analysis and limitations of the VSI-Based multi-line FACTS controllers

Abstract

In this paper, the operational analysis and the main limitations of the VSI-based multi-line FACTS controllers, namely: the GIPFC (Generalized Interline Power Flow Controller) and the IPFC (Interline Power Flow Controller), are analyzed. The GIPFC & IPFC are amongst the newest devices within the FACTS technology. By utilizing these devices an enhanced and nearly instantaneous controllability over independent transmission systems, can be obtained. The steady-state analysis of a GIPFC & IPFC controlling two balanced independent AC systems, is initially modeled. The use of the instantaneous power theory along with the d-q orthogonal co-ordinates showed to be appropriate tools for assessing the GIPFC response towards the operation of both controlled systems. Yet, to observe its dynamic behavior and simultaneously validate the previous steady-state analysis, a phase-shift VSI-based GIPFC was implemented in the ATP program. Where applicable, a comparative evaluation between the GIPFC and the IPFC, is also presented

Advanced Technologies for Future Transmission Grids

“…Power electronics has revolutionised the use of phase shifters in power system control because the replacement of the traditional mechanical tap changers by thyristor valves (to obtain the thyristor-controlled PST or TCPST) has increased the response speed of phase shifters and made them effective for the enhancement of both small disturbance and transient stability (see [184,193,195,11,206] [193]. This element consists of two (or more) SSSCs [206] installed in two (or more) lines and connected at their DC terminals. Thus, in addition to serially compensate the reactive power, each SSSC can provide real power to the common DC link from its own line.…”

“…The IPFC can be considered as a multiline FACTS device -UPFC is the most powerful and versatile FACTS device, able to independently and autonomously control voltage amplitude, and real and reactive power flow. This element consists of a shunt and a series transformer, which are connected via two VSCs, a STATCOM (converter 1 -for the shunt part) and SSSC (converter 2 -for the series part) [206], with a common DC link (capacitor).…”

“…In particular, as a TCSC can vary the series impedance continuously to levels below and up to the line's natural impedance, it can offer a powerful mean to increase and control power transfer. This second-generation FACTS device, which is based on conventional thyristors, can greatly improve power flow control (see [185,193,195,196,203,206] Being able to control voltage and reactive power in a continuous and rapid manner, shunt devices allow damping of system oscillations [200].…”

“…In addition to voltage support and control, there are also benefits that can be realised by allowing generating units to increase real power output by relieving the reactive power requirements through the application of these dynamic compensation technologies. Thus, they can be very suitable for the control of wind farm outputs ( [183,185,193,195,196,203,206]). …”

“…Nowadays, an estimation of worldwide installed SVCs exceeds 600 devices for a total installed power of over 90 GVA [184,204,206].…”