Monitoring gas turbines using Speedtronic Mark VI control systems.

Author:Djaidir, Benrabeh
 
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Gas turbine protection systems consist of a number of subsystems, including several run during each stop and normal startup. Other systems and components operate strictly during emergencies and abnormal operating conditions.

The most common type of failure on gas turbines is that of a sensor or the wiring of sensor protection systems, which are configured to detect an alarm.

If the condition is severe enough to completely disable the protection, the turbine will be triggered. It will also respond to more complex settings such as speeding, over-temperature, high-vibration monitoring of combustion and flame loss.

The examined gas turbine considered in this article is a GE MS3002, a mechanical drive machine with double shaft and single-cycle. It uses an actual gas turbine and consists of an axial compressor with 15 floors, six arranged combustion chambers to (90[degrees]) to the axial intake, a high-pressure turbine single floor (first floor), which drives the compressor and auxiliary equipment, as well as a low-pressure turbine (second floor), which drives the load.

The regulation of this turbine is made by start-control functions: sensors monitor the speed of the turbine, the exhaust temperature, compressor discharge pressure and other parameters to determine the operating conditions of the unit. When it is necessary to modify the conditions of operation --due to changes in load conditions or environmental--the regulation is done by control modules installed to the supervision of the gas turbine.

For this article, we studied the speed of the turbine (high and low pressure), vibration (the first tier and fourth tier) and the temperature (exhaust and the wheel space). We used the Speedtronic Mark VI system, which contains a number of systems, controls, protections and timings designed to ensure reliable and safe operation of the MS3002 gas turbine.

Control System

The start of control is passed to the turbine from "speed zero" to safe operating speed by supplying the right amount of fuel to establish the flame speed in a way that minimizes the fatigue cycle down. This requires an adequate sequence of control signals to the accessory device and the start of the fuel-regulating system.

Since a successful startup depends on proper operation of the turbine equipment, it is important to check the status of selected devices in the sequence. A significant amount of control logic circuits is associated not only with operating control devices, but with valid protection...

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