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Retrofit Turbine Generator Controls

The TCG400 electronic turbine generator control system utilizes the robust and reliable Allen-Bradley SLC500 series Programmable Logic Controller for precise automatic turbine speed control and has the following salient features:

• Automated startup and critical speed avoidance
• Automated KW trim control to avoid running generator above rated capacity
• Electronic and Mechanical overspeed testing capabilities
• Alpha Numerical Operator Interface for ease of operation.
• Redundant speed and load sensors for improved reliability
• Automatic Extraction Pressure Control
• Alarm Output and interface screen

Turbine Speed is measured via two passive magnetic speed sensors and a sixty pulse per revolution speed disk coupled to the turbine shaft.

Generator load is measured via one Yokogawa Digital Panel Watt Meter and one M-System model LWT Watt Meter.

Governor Valve V1 is controlled by a Fisher type 667 size 40 actuator together with a Fisher model 3582i I/Z positioner.

Extraction Grid Valve V3 is controlled by a Fisher type 667 size 40 actuator together with a Fisher model 3582i I/Z positioner.

Extraction pressure is measured with a GP50 model 311B-PP-2-CJ/GJ 0-15 psig transmitter located in the junction box mounted on the extraction actuator pedestal.

Power for the control system is supplied from the 125 VDC bus circuit breaker 5.  This circuit breaker in turn supplies fuses 13FU located in the control room cabinet.

This power source energizes the following components:

Allen-Bradley SLC500 series PLC
24 VDC power supply for operator interface
12 VDC power supply for speed pickup amplifiers.
M-Systems LWT KW Transducer

Power for the Yokogawa Panel meter is supplied from lighting panel circuit breaker number 14 which in turn supplies fuse 15A-FU located in the control room cabinet.

Allen-Bradley model 1746-P5 power supply generates 24 VDC for field actuators and transmitters.

Application:
            General Electric 7500 KW Turbine Generator with LP Extraction
            Turbine:
                        Rating:
                                    7500 KW
                                    3600 RPM 12 stage
                                    400 psig inlet steam pressure
                                    700 deg. F Final Turbine Temp
                                    2” abs Exhaust Pressure
                                    10 psig extraction pressure

            Generator:
                        Rating:
                                    ATB-HL-9375 KVA
                                    3600 RPM
                                    13,800 Volts
                                    0.8 Power Factor