We all know how complex is gas turbine protection system is. At each halt and startup, they must run a number of subsystems. These are backed up by backup systems that activate as needed. The gas turbine protection systems consist of several parts that function during each stop and normal startup. During emergencies and abnormal operating situations, other systems and components perform precisely.
The most common type of failure on gas turbines is a sensor or the wiring of sensor protection systems, which are designed to detect an alarm. If the problem is severe enough to disable the protection, the turbine will be turned on. It will also react to more complicated settings like speeding, overheating, high-vibration combustion monitoring, and flame loss.
Throughout this article, we will consider the GE MS3002, a mechanical drive machine with a double shaft and a single cycle. It employs a real gas turbine with 15 floors, six combustion chambers positioned at 90 degrees to the axial intake, a high-pressure turbine single floor (first floor) that powers the compressor and ancillary equipment, and a low-pressure turbine (second floor) that drives the load.
Start-control functions regulate this turbine. Sensors monitor the turbine’s speed, exhaust temperature, compressor discharge pressure, and other factors. This is to determine the unit’s working conditions. Control modules attached to the gas turbine’s supervision are used to adjust the operating conditions as needed – due to changes in load or the environment.
Mark VI GE: Control From Zero Speed to Operating Speed
By providing the right amount of fuel to set the flame speed in such a way that the fatigue cycle is reduced. The turbine may be controlled from “zero” to a safe working speed. This necessitates a proper sequence of control signals to the auxiliary device. Also to start of the fuel management system. As the appropriate operation of the turbine equipment is required for a successful restart. It is critical to monitor the status of chosen components in the sequence. Not only are there many control logic circuits associated with running control devices. But there are also many control logic circuits associated with valid protecting circuits and setting permissive circumstances before proceeding. This ensures turbine control while in operation.
The turbine control system will modify the flow to the combustion chambers. This is in response to the fuel stroke reference signal for the fuel gas control system (FSR). The machine begins with a servo-drive system. It compares the setpoint to the feedback signal and converts the result to a valve position.
Some of the protective systems and components in this duty function through the control system’s protection circuit and master control Speedtronic. While others are mechanical and operate directly on the turbine components. In each scenario, the fuel control valve (RST) and the inlet of the liquid fuel valve are essentially distinct paths for stopping the flow of fuel (FSV).
Each protection system is developed separately from the control system to avoid the risk of the control system disabling protective devices. The Speedtronic Mark VI is designed to protect the gas turbine from damage caused by a fast-spinning turbine rotor. Under normal operating conditions, the speed control regulates the rotor speed.
Mark VI GE: Real-life Fail-Safes
In real-life conditions, the Mark VI system includes an over-temperature device to protect the gas turbine from a spark. It takes over if the temperature-control system fails. The exhaust temperature control system will also control fuel flow when ignition temperature limits are reached. Under normal functioning conditions, this happens. The fuel flow rate can, however, exceed control limitations if the turbine is in failure mode. The area of the turbine flow rate will reach its maximum if this occurs.
Within the turbine exhaust chamber, twelve thermocouples are fitted in the Mark VI system. Latching and alerting are determined by averaging data from these thermocouples.
GE created the Mark VI with a central Control Module that used passive signal conditioning to collect inputs through termination boards. IS200EACFG1B, IS200EXHSG1A, IS200BLIGH1A are few among the components under the Mark VI series.
For this article, we examined turbine speed (high and low pressure), vibration (first tier and fourth tier), and temperature (exhaust and the wheel space). We employed the Speedtronic Mark VI system, which includes several systems, controls, protections, and timings that ensure the MS3002 gas turbine operates reliably and safely.