DECS-250 / DECS-250N — digital excitation control systems for generators and synchronous motors
A full-featured digital excitation control system in a compact case for synchronous generators and motors. The power stage is 15 A, and the DECS-250N has a 20 A rectifier bridge with positive and negative forcing. Used on hydro, thermal and diesel generating stations, synchronous motors and condensers.
- Power stage
- PWM 15 A (DECS-250); 20 A rectifier bridge with positive and negative forcing (DECS-250N)
- Supply
- shunt, auxiliary winding, PMG or DC
- Regulation
- voltage, reactive power, power factor; RMS measurement
- PSS
- built-in system stabilizer (option)
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
DECS-250 is a digital excitation control system in a compact case for synchronous generators and motors. It regulates voltage, reactive power and power factor precisely, responds quickly, and has a full set of generator and motor protections. The system is used on hydro, thermal and diesel generating stations, as well as on synchronous motors and condensers.
The 15 A pulse-width modulated power stage gives a high initial response to load steps. It can easily be adapted to any excitation supply scheme: shunt, auxiliary winding, permanent magnet generator or DC source. RMS measurement and a robust power stage keep operation stable with strongly distorted voltage waveforms caused by non-linear loads. The DECS-250N version has a 20 A rectifier bridge with positive and negative field forcing, which is especially useful together with a PSS stabilizer.
The PSS system stabilizer is available as an option. It helps meet strict grid code requirements without external devices or additional installation, and the component itself is certified to the German standard VDE-AR-N 4110. The DECS-250 CGCM version is a ready replacement for the 1407-CGCM module, with an emulation mode for integration with ControlLogix systems. The Network Load Sharing function simplifies building complex parallel operation systems.
Setup is done in BESTCOMSPlus® with graphical programmable BESTlogic™Plus logic, automatic PID tuning and self-tuning. A built-in offline simulator checks the logic without hardware. The interface is multilingual, so fewer errors occur during setup. There are many communication interfaces, for example Modbus for communication with the station's distributed control system. Four hydro units of a small American utility were switched to operation without permanent staff in 2019, and this system was used there. It was commissioned in December 2019 and the documentation was handed over in February 2020.
The following options are offered for the regulator: IDP-801 and IDP-1201 operator panels, CEM-2020 contact and AEM-2020 analog signal expansion modules, ICRM inrush current limiting modules, isolation power transformers, and a control power transformer for two regulators in a redundant scheme. Based on DECS-250, ready-made SGC-250 and SMC-250 systems are produced. The equipment ships from the plant in Highland, Illinois, USA.
Technical specifications
| Power stage | PWM 15 A (DECS-250); 20 A rectifier bridge with positive and negative forcing (DECS-250N) |
|---|---|
| Supply | shunt, auxiliary winding, PMG or DC |
| Regulation | voltage, reactive power, power factor; RMS measurement |
| PSS | built-in system stabilizer (option) |
| Protection | full set of generator and motor protections |
| Grid requirements | component certified to VDE-AR-N 4110 |
| Load sharing | network (Network Load Sharing) |
| Software | BESTCOMSPlus®, BESTlogic™Plus |
| Variant | DECS-250 CGCM is a replacement for the 1407-CGCM module |
Request a price and lead time
DECS-250 / DECS-250N — digital excitation control systems for generators and synchronous motors. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Questions and answers
What is the difference between DECS-250 and DECS-250N?
DECS-250 has a 15 A pulse-width modulated power stage. DECS-250N has a 20 A rectifier bridge with positive and negative field forcing.
Which excitation supply schemes does the DECS-250 support?
The system adapts to shunt excitation, supply from an auxiliary winding, a permanent magnet generator and a DC source.
Does the DECS-250 meet grid code requirements?
The optional built-in PSS stabilizer helps meet strict grid code requirements without external devices. The component is certified to the German standard VDE-AR-N 4110.
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