voltagecontrol

Voltage control refers to the set of methods and devices used to regulate electrical voltage levels in electrical systems, ensuring voltages stay within specified limits for safe operation and system performance. In alternating-current power systems, the goal is to maintain bus voltages close to their nominal values while minimizing losses and preserving power quality. Voltage control relies on managing reactive power and network impedance through various technologies and control schemes.

Common methods include transformer tap changing (on-load and off-load) to raise or lower voltage at substations, and the use of reactive power resources such as shunt capacitor banks and reactors. Power electronics-based devices, including STATCOMs, static VAR compensators, and unified power flow controllers, provide fast and flexible voltage support. Generators employ automatic voltage regulators that adjust excitation to maintain terminal voltage. In distribution networks, coordinated reactive power planning and control help balance voltage along feeders and reduce losses.

Control strategies can be centralized or distributed. Voltage measurements feed feedback control loops, which may use proportional-integral or model-predictive approaches. Droop control is common in islanded microgrids, providing decentralized voltage regulation. Advanced methods optimize voltage and reactive power dispatch through operational planning or real-time optimization, especially with high penetrations of distributed generation.

In direct-current systems and microgrids, voltage regulation is achieved with DC-DC converters and regulated DC buses, often paired with energy storage. Challenges include rapid voltage fluctuations from renewable sources, unbalanced loads, and limited reactive power resources, requiring fast, reliable control and careful protection coordination.

See also: voltage stability, reactive power, power quality, automatic voltage regulator, FACTS devices.