VHzohjaus

VHzohjaus, or VHz-ohjaus, is a term used in Finnish automation engineering to describe control strategies in which voltage and frequency measurements drive regulating actions. The "V" denotes voltage magnitude and "Hz" denotes system frequency, with the objective of maintaining acceptable power quality, stability, and performance in electrical networks and connected processes.

Implementations combine sensors to monitor voltage and frequency, controllers (such as PI/PID or model predictive control), and actuators (converter controls, tap-changing devices, motor drives). Data communication and timing are important to ensure fast and stable response.

Typical applications include grid-connected converters and renewable energy interfaces, motor drive systems requiring tight voltage/frequency regulation, data centers seeking stable power supply, and industrial processes sensitive to power quality.

Benefits include improved regulation, faster disturbance rejection, and better protection against voltage sags and frequency deviations. Challenges involve measurement noise, time delays, nonlinear dynamics, and ensuring stability under varying loading and grid conditions. VHzohjaus is related to broader voltage control and frequency control strategies and is often implemented alongside other control layers in smart grids and automation systems.

See also: Voltage control, Frequency control, Power quality, Model predictive control.