A static var compensator is a parallel combination of a controlled reactor and a fixed shunt capacitor, as shown in the figure below. The thyristor switch assembly in the static var compensator controls the reactor. The firing angle of the thyristor controls the voltage across the inductor, which in turn controls the current flowing through the inductor. In this way, the reactive power consumption of the inductor can be controlled. The static reactive power compensator enables stepless adjustment of reactive power in an infinite range without any delay. It improves system stability and system power factor.
The main components of the traditional type of static var compensator (static var compensator) are reactive power generating capacitors and reactive power absorbing inductors. In order to provide operation in both generating and absorbing modes, both elements must be used; in order to replicate the dynamics of the synchronous compensator, at least one of them must be rapidly variable. Capacitor elements do not provide stepless change: therefore, if a smooth continuous change is required over a range, the capacitor bank must be rated to supply at least the current IC must be connected and the variable element must be inductive with a current rating at least equal to IC+ IL.
What are the advantages of static var compensator? The static var compensator improves the transmission capacity of the transmission line. The static reactive power compensator improves the transient stability of the system. Static var compensators control steady-state and temporary overvoltages. Static var compensators improve load power factor, thus reducing line losses and increasing system capability. Static var compensators have no rotating parts and are used for surge impedance compensation and segmented long transmission line compensation.
A static var compensator is an electrical device used to provide fast-reacting reactive power on high-voltage transmission networks. Static var compensators are part of the Flexible AC Transmission Systems family of devices (FACTS) that regulate voltage and stabilize systems.
Static var compensators in wind farms, due to the increase in wind energy, transmission system operators (TSOs) have imposed grid code requirements on wind farms to ensure grid stability, such as reactive power control and ride-through capability. A central static var compensator located at the point of common coupling (PCC) can be used to solve these problems in wind farms with the following advantages: voltage regulation, fault ride-through (FRT), reactive power balancing, flicker reduction.