TDP - Prevention of Water Damage to Steam Turbines Used for Electric Power Generation: Fossil Fueled Plants

ASME’s TDP-1 Standard provides recommended practices for the prevention of water damage to steam turbines used in fossil-fuel-fired electrical power generation. These practices address damage due to water, wet steam, and steam backflow into a steam turbine and are applicable to conventional steam cycle, combined cycle and cogeneration plants. They cover design, operation, inspection, testing, and maintenance of those aspects of the following power plant systems and equipment concerned with preventing the induction of water into steam turbines and associated systems and equipment:

• motive steam systems;
• steam attemperation systems;
• turbine extraction/ admission systems;
• feedwater heaters;
• turbine drain systems;
• turbine steam seal systems;
• start-up systems;
• condenser steam and water dumps;
• steam generator sources.

Any connection to the turbine is a potential source of water either by induction from external equipment or by accumulation of condensed steam. The sources treated herein specifically are those found to be most frequently involved in causing damage to turbines. Although water induction into the high and intermediate pressure turbines have historically been recognized as the most damaging, experience has shown that water induction in low pressure turbines can cause significant damage.

Key changes to this revision include:

• inclusion of mandatory language throughout document;
• requirements for power-operated block valve closures;
• parameters for feedwater heater testing;
• considerations for vertical flash tanks;
• requirements for continuous drains;
• requirements for spray control valves and attemperator block valves;
• requirements for feedwater block valve backflow;
• addition of section on control systems and instrumentation;
• addition of section on excess steam routed to feedwater heater or condenser.

Intended for anyone engaged in the safety of steam turbines and fossil fuel power plants, including those responsible for: design, engineering and manufacture; operation, testing, maintenance, and monitoring; inspection and regulation; insurance and liability; facilities and plant management; and emergency response.

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