Generator Start-up System

In gas-fired power plants, the compressor needs to provide enough air for combustion, but it cannot accelerate fast enough when the engine starts. Therefore, a starter helps the gas unit turbines to start initially. The starter is an advanced frequency converter that turns the synchronous generator into a synchronous motor for the first few minutes, and supplies the initial power for the gas generator. This system is designed and manufactured by MECO to run the V94.2 gas turbine using an advanced SFC control system.

Thus, at first, after receiving electrical energy from the grid, the generator is used as an electric motor and the gas turbine is started. The SFC converts the AC input from the grid to DC power and then back to AC power with a variable frequency that matches the turbine speed in the start-up phase. This way, the SFC adjusts the input power to the generator as a starter. The SFC is an AC/DC/AC converter with an input frequency of 50 Hz and an output frequency of 0 to 35 Hz.

The start-up operation begins with the SFC from zero speed or turning gear and continues until 600 rpm, when fuel injection, flame ignition and acceleration happen simultaneously in the turbine. The SFC stops when the turbine reaches 2100 rpm and starts producing mechanical energy. After that, the generator switches to its main function, which is generating electrical energy.