Software takes tighter control of turbines

Advanced turbine control applications help power generators improve turbine operation, performance and reliability.

Emerson Process Management has announced the availability of additional advanced Ovation turbine control applications.

Leveraging Emerson's significant expertise in both turbine controls and mechanical turbine control equipment, these applications are designed to help power generators improve turbine operation, performance, and reliability.

"No other control system supplier can match Emerson's ability to offer comprehensive turbine solutions that address both the control and mechanical aspects of turbine operation", said Bob Yeager, President of the Power and Water Solutions Division of Emerson.

"With this combination of expertise, power generators can be assured that Emerson's turbine solutions translate into efficient operation, tighter control and the highest reliability and safety".

A new Startup Sequencing application within the Ovation system is composed of two functional pieces - the turbine startup sequencer (TSQ) and the turbine stress evaluator (TSE).

The TSQ enables the turbine to more closely follow the parameters of the OEM-recommended loading curves, while the TSE adjusts the curves based on calculations regarding actual turbine operations, further improving turbine startup.

The interaction of the TSQ and TSE translates into more consistent turbine operation by reducing turbine startup and loading times, turbine stress, and the time needed to reach the desired turbine speed or load.

A new Mechanical Trip Protection Replacement application replaces the overspeed mechanical bolt that trips the unit in the event of excessive turbine speeds.

Emerson's solution, which utilises a combination of Ovation control logic and sensor technology, provides better, more reliable turbine protection.

Switching from the previous low-tech, mechanical approach to Emerson's automated solution also eliminates costly overspeed bolt testing and maintenance.

The Trip Protection Upgrades application uses a combination of Ovation applied logic and sensors to better manage trip logic so that the unit trips when necessary to prevent equipment damage, yet is less prone to false/unnecessary trips.

Emerson has developed Trip Protection Upgrades that are customised specifically for GE and Westinghouse turbines.

The GE Trip Protection Upgrade is a patent-pending application featuring three speed signals that are processed and interrogated on separate Ovation Speed Detector I/O modules.

In the event of a turbine over-speed, a testable dump manifold (TDM) trips the turbine by rapidly de-pressurising the turbine hydraulic trip header.

For greater reliability, the manifold assembly is fully redundant and testable while the turbine is online without requiring an actual unit trip.

The Westinghouse Trip Protection Upgrade replaces the "Mystery Box" found in Westinghouse turbines with a pressure status manifold (PSM).

The PSM monitors critical pressures and provides the Ovation control system with three independent analogue signals.

Two out of three voting logic is used in the control system to generate trip signals based on the PSM signal monitoring.

Each of the three transmitters has a pressure-blocking valve and a pressure drain valve which allow the transmitters to be tested individually, and provide instrument isolation for on-line replacement.

A patent is pending for this application.

Emerson's turbine control solution, which is in operation on more than 1100 steam and combustion turbines around the world, is based on the company's Ovation expert control technology.

Ovation, a key component of Emerson's PlantWeb digital architecture, was designed specifically to meet the challenges of the power generation industry.

Leading power generators worldwide rely on Ovation to monitor and control critical processes/equipment, including the turbine, burner management system, balance of plant equipment, the combustion process, scrubbers, and more.

Use of the Ovation system to control both the boiler and turbine results in fully co-ordinated control that enables utilities to improve unit stability, responsiveness and thermal efficiencies; achieve tighter overall control of plant operations; and obtain a concise view of key plant and turbine parameters.

"Our comprehensive turbine control and mechanical retrofit capabilities are based on decades of power generation industry experience providing mechanical hydraulic control, and electrohydraulic control and equipment for gas and steam turbines from virtually every turbine OEM", said Bob Yeager, President of the Power and Water Solutions Division of Emerson.

"Based on our significant in-house expertise and successful track record, power generators can continue to trust Emerson to provide valuable turbine solutions".

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