FACTSapparaten

FACTSapparaten, in English commonly termed FACTS devices, refers to a family of power-electronic controllers designed to increase the flexibility, controllability, and stability of AC transmission systems. By manipulating reactive power, voltage magnitude, and the effective impedance of transmission paths, FACTSapparaten can raise transfer limits, improve voltage profiles, and damp dynamic oscillations without constructing new lines.

The devices are typically categorized by their function and connection point. Shunt devices, such as STATCOMs, inject or absorb reactive power at a bus to regulate voltage. Series devices, like SSSCs and Thyristor-Controlled Series Capacitors (TCSCs), adjust the impedance along a transmission corridor to control power flow. More comprehensive controllers, such as the Unified Power Flow Controller (UPFC) and Interline Power Flow Controllers (IPFC), combine multiple capabilities to control voltage, impedance, and phase angle across one or more lines.

FACTSapparaten are powered by solid-state converters, often using IGBTs or similar switches, and are governed by fast-acting control systems that respond within milliseconds to grid conditions. They are typically installed at substations or along strategic links in the transmission network to alleviate congestion, enhance transient and small-signal stability, and reduce losses.

Advantages of FACTSapparaten include enhanced controllability of power flow, improved voltage stability, and increased transmission capacity without new conductors. Limitations include high capital cost, complex protection and coordination requirements, and the need for reliable power-electronics hardware and control schemes in harsh grid environments.

See also: Flexible AC Transmission Systems, STATCOM, SSSC, UPFC, IPFC, power electronics, grid stability.