Gas Turbine Control System Retrofits 

Existing Instrumentation - In most cases, the existing instrumentation on the turbine can be reused. No expensive electric valve upgrades are expected since the system accepts OEM supplied LVDT's, flow divider pickups and servos. Turbine Diagnostic Services, Inc. (TDS) can retain any level of redundancy in the instrumentation supplied by the OEM including LVDT, servo coils and magnetic pickup inputs. 

Flames Scanner Upgrade - Existing UV (Honeywell type) sensors are expensive and require a specialty interface. TDS can upgrade the flame scanner system to a third party supplied system to enhance the reliability of the gas turbine. 

Temperature Control - TDS has implemented standard isothermal exhaust temperature control as well as biased temperature control. Biases include water flow, compressor discharge pressure (CPD), compressor pressure ratio (CPR), ambient temperature, compressor discharge temperature, air humidity, load and fuel demand. The application will determine which biases apply to the turbine. As an option, the customer can specify the exhaust thermocouples be divided over three thermocouple modules so that the failure of one module will have reduced effect on exhaust temperature control. 

Load Control - TDS has implemented algorithms to control load at a pre-selected set point. 

Speed Control - TDS has implemented a proportional speed droop controller as required by IEEE standards. Isochronous speed control, although not as popular on gas turbines, can also be supplied. On DLN machines where due to the non-linarites introduced by multi-valve systems, the droop may not be in accordance with IEEE specifications. Closed loop megawatt droop control is used when online. 

Acceleration Control - TDS has implemented an acceleration controller for gas turbines. This ensures that startup of the machine occurs in a controlled and predictable way. The acceleration set point is adjusted during startup to stay within the capabilities of the machine. 

Surge Control - TDS has implemented control algorithms that will control bleed heat, IGV's and fuel in order to control compressor surging. This type of control is only applicable to larger frame machines. 

Inlet Bleed Heat - TDS has implemented control algorithms that will control inlet bleed heat in the same way as the OEM. This includes open loop controllers (old style manifold) and closed loop control (new style manifold). 

IGV Temperature Control - TDS has implemented control algorithms that can modulate hydraulic IGV's in order to maintain exhaust temperature control as high as possible. On combined cycle machines, this provides a boost in efficiency. On DLN machines, this is required to enable the machine to operate in low emissions (Pre-Mix Steady State or PM6) mode in as low a load as possible. 

IGV Temperature Matching - TDS has implemented algorithms necessary to control exhaust temperature to an external temperature set point. This will in turn allow the exhaust temperature to be controlled to match the steam outlet temperature to the steam turbine chest temperature. This allows for minimized stresses in the boiler and steam turbine as well as faster startups.