Askellujännitteet

Askellujännitteet refers to the voltage drops that occur across the legs of a transformer, specifically during the energization of the transformer. This phenomenon is primarily observed in three-phase transformers. When a three-phase transformer is initially energized, the currents flowing through the windings are not uniformly distributed. This uneven current flow leads to transient voltage drops within the transformer's internal impedance.

These askellujännitteet can cause temporary voltage imbalances and distortions on the power system connected to the transformer. The magnitude and duration of these voltage drops depend on several factors, including the transformer's design, the source impedance of the power grid, and the pre-energization state of the system. In some cases, these transient voltages can affect sensitive connected equipment.

Mitigation strategies for askellujännitteet often involve controlled energization techniques. One common method is pre-insertion, where a small resistor is momentarily inserted into the circuit along with the breaker. This resistor limits the initial inrush current, thereby reducing the severity of the voltage drops. Another approach is the use of synchronous closing of the circuit breaker, which aims to close the contacts at a specific point in the voltage waveform to minimize the transient effects. Understanding and managing askellujännitteet is important for ensuring the stable operation of power systems and the protection of connected assets.