Water-cooled Stator Research Articles

Design and Analysis of in-Wheel Permanent Magnet Synchronous Motor Cooling System of Mining Dump Truck

In-wheel motor is an important power unit of electric drive mining trucks, a variety of dynamic performance and thermal issues have important impacts on the whole vehicle performance. In this paper, a model of permanent magnet brushless DC motor (BLDC) cooling system with water-cooled stator structure of electric drive mine dump truck is built. Considering the actual cooling systems, the author modeled the bldc motor and completed the electromagnetic simulation with ansoft software to determine the motor heat source and boundary conditions. This paper simulates the cooling water jacket temperature field with fluent software, and finally validated the feasibility of the design of the motor and its cooling system by experiments.

흡습된 수냉각 발전기 고정자 권선의 전기적 특성

Insulation breakdown of water-cooled generator stator windings occurs frequently due to leakage of cooling water and absorption into the insulation material. Leakage and absorption problems of water-cooled stator windings are often found during regular preventive maintenance. To evaluate cooling water leakage and absorption, diagnostic tests were performed on two water-cooled turbine generators, which have been in service for 13 and 17 years, respectively. The test results of the measured electrical properties such as dissipation factor(<TEX>$tan{\delta}$</TEX>), capacitance and AC leakage current for water-cooled generator stator windings with wet bars are reported in this paper.

Analysis of Leak and Water Absorption Test Results for Water-Cooled Generator Stator Windings

Cases of insulation breakdown damage of water-cooled generator stator windings occur frequently due to coolant leakage and water absorption worldwide. Such serious accidents may cause not only enormous economic loss but also very serious grid accidents in terms of stable supply of electric power. More than 50 % of domestic generators have been operated for more than 15 years, and leak and water absorption problem of windings are often found during the planned preventive maintenance period. Since 2005, leak and water absorption tests have been performed for total watercooled stator windings after fully drying the inside of the windings. The results are then comprehensively analyzed. The result of the test performed by GE, a foreign manufacturer, for 141 generators showed failures in 80 of them (failure rate: 57 %), whereas in the tests carried out in Korean domestic power plants, only 14 out of 50 generators showed failures (failure rate: 28 %).

Development of a capacitance measuring robot for the water-cooled stator winding of turbine generators

When water permeates the winding insulation in large-scale direct water-cooled turbine generators, dielectric strength drops steeply due to wet heat deterioration. To ensure operational reliability, it is essential to know whether or not water has permeated the insulation, and if so, to determine accurately the degree of deterioration. We have developed a capacitance measuring robot which enables measurement near the stator core end without removing the rotor, and confirmed good results in the field. The robot travelling along the retaining ring can be accurately positioned, and measured capacitances are stable and reproducible. The robot minimizes the extent of disassembly and reassembly, thus greatly reducing the out-of-operation period. Further, because the insulation condition can be accurately determined through its periodical use, we believe that it will contribute to both preventing accidents and assuring generators with high reliability.

UKI-03 device for checking the generator water-cooled stator winding insulation

A diagnostic microprocessor device for checking the generator water-cooled stator winding insulation, realizing semiautomatic measuring of the level of resistance and absorption coefficient of the stator winding insulation, in which case the shunting effect of the water hoses is eliminated, was developed and is operating successfully.

Integrated End-Winding Ring Support For Water-Cooled Stator Winding Design Features, Analysis, Test Results and Experience

An integrated stator end-winding support design which differs from conventional support systems is described in this paper. This design is called system and features stiff end-winding support by forming a solid, resin-filled end-winding arc with the bar ends bolted to a funnel-shaped backing ring. The backing ring encircles the end winding and is mounted on heavy brackets that allow only movement in the axial direction from thermal expansion. The short-circuit analysis outlined reveals an approximately tenfold reduction of end-winding deflections and stresses due to the stiffness of the composite end-winding arc and backing ring structure. The design is described in detail and considerable information from factory and field tests is presented. The paper also provides information on the operating experience with two-pole and four-pole generators up to ratings of 1530 MVA demonstrating the effectiveness of the Ringbloc system.

Integrated End-Winding Ring Support for Water-Cooled Stator Winding: Design Features, Analysis, Test Results and Experience

Integrated End-Winding Ring Support for Water-Cooled Stator Winding: Design Features, Analysis, Test Results and Experience

Twenty-one Year Development in Turbine-Generators with Water-Cooled Stator and Rotor Windings

This paper gives an account of turbine- generators with water-cooled stator and rotor windings made by Shanghai Electrical Machinery Mfg. Works. It emphasizes especially the special features of water cooling of the rotor windings. This tckhnique, as far as we know, vas first applied by us in the world manufacturing history of turbine-generators. More than 100 units of such kind of generators are now successful in operation in the power stations of our country. The first unit has been in service for 21 years and has operated for 130,000 hours. The largest rating is of 300 MW. The paper also gives the future prospects of such a new technique. Typical operating data are given in Appendix I.

Twenty-One Year Development in Turbine-Generators with Water-Cooled Stator and Rotor Windings

Twenty-One Year Development in Turbine-Generators with Water-Cooled Stator and Rotor Windings

Test results of the world's largest four-pole generators with water-cooled stator and rotor windings

Two turbogenerators, the largest ever produced with direct water-cooling of both rotor and stator windings, were completed and tested early in 1974. Their losses and efficiency from test, together with temperatures in critical areas and cooling circuit behavior are described. Vibration of coil ends was measured at rated voltage and during sudden short circuit using a newly perfected photo cell technique. Based on the test results, it is estimated that generators can now be built in ratings up to 2400 MVA at 1800 rpm using presently available rotor forgings with water-cooled windings.

Electrical Features of Raccoon Mountain Pumped-Storage Plant

This paper describes unique features of the electrical equipment and some of the considerations involved in its selection for a 1,700-MVA underground pumped-storage project with four reversible pump/turbines. Considerations of cost and maintenance of the machines, transmission system, and powerhouse construction led to selection of generator/motors with direct water-cooled stator and rotor windings, static-converter synchronous starting of pumps with synchronous dynamic braking, use of generator circuit breakers, and underground main transformers with self-contained 161-kV single-section cables having 1,100-ft change in elevation.