Spændingsstabiliteten

Spændingsstabiliteten, or voltage stability, refers to the ability of a power system to maintain acceptable voltage levels at all its buses under normal operating conditions, as well as during and after disturbances. A power system is considered to have voltage instability if a disturbance, such as a line outage or a generator trip, causes a progressive and uncontrollable decline in voltage. This decline can lead to the collapse of the entire power system.

Voltage stability is influenced by several factors, including the loading of the system, the reactive power reserves of generators and other equipment, and the impedance of the transmission network. High system loading and insufficient reactive power support are common precursors to voltage instability. When the load demand exceeds the available reactive power supply, voltages tend to drop.

The consequences of voltage instability can be severe, ranging from reduced performance of sensitive equipment to widespread blackouts. Protective relays designed to detect overcurrent or undervoltage conditions can trip in a cascading manner, further exacerbating the voltage decline and leading to system collapse.

Mitigation strategies for voltage instability include increasing reactive power generation, installing flexible AC transmission systems (FACTS) devices like static var compensators (SVCs), and implementing robust voltage control schemes. Careful system planning and operational procedures are crucial to ensure adequate voltage stability margins.