شرح کلی سیستم:
Generator start-up system or Static Frequency Converter (SFC) has long been integrated into MECO products. MECO has recently developed its domestically-produced system called MAPLCI.
SFC Advantages
- Reducing equipment and system complexity
- Allowing unlimited generation of varying frequencies
- Significantly reducing maintenance costs
- Increasing accuracy in supplying varying frequencies
General system description:
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.
Specifications:
- Installing driver system components such as thyristor racks, and inductive reactor to reduce output distortion and control equipment in separate panels to optimize system performance in terms of safety and noise immunity
- Using optical fibers for better isolation and separation of the control field from the power field
- Using control equipment such as AC motor drive, and SINAMICS GL150 to generate suitable firing pulses for thyristor bridges using CU320 processor
- Ensuring smooth operation of the starter system control and protection loops to reduce current fluctuations during start-up on the line side and prevent adverse effects on the feeder short circuit level
- Establishing signal communication between the starter system and excitation via the Profibus protocol
- Providing significant efficiency savings for starting and switching between multiple generators through a single SFC by connecting to the cross-board system
- Eliminating the need for mechanical accessories on the rotor monitor and using open and closed loop controllers on the SFC to increase its maintainability
- Enabling the turbine and generator to accelerate at lower speeds using DC-link pulsing method
SFC Start-Up System Specifications | |
DC-link output power | 2.9 MW |
Rated power | 3.7 MVA |
DC-link start-up current | 1850 A |
Input voltage | 1400 V |
DC-link voltage | 1560 V |
Line thrystor type | T1551 N52 |
Rated loss | 36kW |
Circulating cooling air flow | 7.200 M3/h |
Noise pollution intensity |
|
Weight | 2,400 kg |
DC-link single-line reactor Rated current |
1,120 A |