WITHSTANDING HARSH OPERATING CONDITIONS

Hohhot Co., Ltd. operates a pump-storage plant (PSP) in Inner Mongolia, China, that supplements a wind farm and provides peak demand power, supplemental power capacity when production is reduced, and energy storage for stand-by emergency power and frequency regulation.

The operating conditions of the Hohhot PSP are harsh and required a specific design of pump turbines and motor-generators that includes:

• Higher stability while operating over a large head range
• Ability to withstand load and thermal cycles due to frequent starts and stops
• Higher availability to cope with demand from the grid.

OBLIQUE ELEMENTS TO ENHANCE PERFORMANCE

GE installed four reversible, 306 MW Francis pump turbines and motor generator units at the PSP plant, and furnished technical and quality support for the unit equipment.

The motor generator’s upper bracket, rotor spider and stator frame were equipped with patented oblique elements that allow thermal expansion without moving parts, resulting in a maintenance free solution. Since this greatly reduces element fatigue and permits smaller clearances, the generators are more compact, efficient and reliable.

The maintenance-free oblique elements increase generator lifetime and—given their smaller foundation – decrease construction costs.

ACHIEVING DESIRED PARAMETERS

The PSP entered commercial operation in 2014 and the customer uses the plant to complement their wind farm production, as well as to provide the electrical network with power for peak demand, supplemental power for periods of reduced production, energy storage for emergency power stand-by and frequency regulation.