Asynchronous generators, including doubly-fed rotors, are widely used in wind farms. During voltage drops, any slight speed deviation of these rotors consumes large amounts of reactive energy. Due to the large demand for reactive power during significant voltage drops, FRT regulations have been implemented in many modern grid codes.
A typical voltage drop event is the result of a short circuit on one of the network branches. It takes at least 100-200 ms to isolate the faulty substation, potentially deteriorating the voltage stability. The majority of modern grid standards require reactive energy to be generated by local networks during a fault.
The most reliable reactive energy solutions are based on capacitor banks, Static VAR Compensation (SVC). However, utilising a SVC as a ride-through solution has its disadvantages. The provided reactive current is proportional to the voltage, while the reactive power is proportional to the second power of the voltage (V²).
Fault Ride Through Solution
The Equalizer RT system is the Elspec Ride Through solution for asynchronous Turbine which is based on Elspec Real Time Static VAR Compensation technology which is used worldwide.
The Equalizer is a transient free static compensation system which has been modified in order to boost supplied kVAr capacity for short time voltage dips applications and is based on the following features
- Transient-free connection of capacitors
- Voltage Control operation mode – optimised to fulfil the Spanish PO12.3 Grid Code requirements.
- Ultra fast acquisition time – full compensation within less than 10mSec
