What Is the Purpose of Each Stage of Steam Turbine Warm-up?

Low speed warm-up

The purpose of low-speed warm-up is to slowly heat each component of the steam turbine, increase the metal temperature of the cylinder, and reduce the thermal stress caused by the temperature difference in the metal components of the steam turbine.

Medium speed warm-up

The purpose of medium-speed warm-up is to heat the rotor to above the low-temperature brittleness transition temperature (the temperature at the center of the rotor reaches or exceeds 150 degrees) to prevent the occurrence of low-temperature brittleness of the rotor and ensure safe power generation after grid connection.

Low load warm-up

The purpose of low-load warm-up is mainly to control the expansion difference of the steam turbine, so that the steam turbine can be further evenly heated and prevent dynamic and static friction from uneven heating of the steam turbine.

The cold warm-up time is long, and there are several main purposes of increasing the warm-up time:

1. Through the circulation of the lubrication system, the temperature of the lubricating oil is increased to ensure the establishment of the bearing oil film.

2. Slowly increase the metal temperature of the turbine flow part, expand evenly, reduce the temperature difference, prevent dynamic and static friction, increase metal life, prevent thrust tile burning, and avoid shaft system vibration.

3. The generator can also use ventilation to remove moisture, improve insulation, ensure uniform expansion of the wire rods, prevent local stress damage, and prepare the unit for grid connection during the "warming up" process.

The hot warm-up time is short, and the speed should be connected to the grid as soon as possible to prevent the cylinder from cooling too quickly.

When the steam pressure is high and the temperature is normal, look at the changes in the cylinder temperature during rotation. If the cylinder temperature drops and the high-adjustable door opening is small at this time, it means that the steam intake volume of the turbine is too small to satisfy the cylinder heating, and the cylinder is being heated. cool down. At this time, the speed should be increased as soon as possible to increase the steam intake so that the cylinder can be better heated.