High-capacity non-salient pole nest plate type synchronous generator

Abstract

The invention relates to a large capacity non-salient pole plate fine type synchronous generator, which is characterized in that a main generator is provides with a stator which is sleeved with a motor base split unit and a rotor which is connected with a motor base through an end cover bearing, an exciting end of a rotor rotating shaft is provided with a brushless excitation system with a high pole number, the tail end of the system is provided with a grounding detecting device, and a cooling system comprises a cooling device which is positioned on the main generator, four ducted cooling paths which circulates in multiply return circuits and is formed by a stator ventilating circuit, a rotor ventilating circuit, an air gas ventilating circuit and an exciting dynamo ventilating circuit of the main generator. The generator has the advantages of reasonable design of the whole system, compact structure, complete function of each portion, convenient installation and maintenance, reliable operating property, high quality of voltage and electric current which are produced and the like, which saves manufacturing cost.

Description

technical field [0001] The invention belongs to the technical field of steam turbine generators of large-scale thermal power generation equipment, in particular to a large-capacity hidden-electrode sleeve-type synchronous generator. Background technique [0002] At present, domestic generator production is dominated by small-scale low-pole generators. Due to the small power generation capacity, low energy utilization rate, low pole number, and high output voltage pole-change rate of this type of generator, it is increasingly unsuitable for modern large-scale enterprises. The requirements for power consumption and external networking have gradually developed towards large-scale high-pole generators. However, the large-scale generators in the prior art generally have the following problems: [0003] (1) Due to the large power generation capacity of large generators, the components such as stator and rotor windings, main shaft bearings, and excitation systems generate a lot of...

AI Technical Summary

Problems solved by technology

[0003] (1) Due to the large power generation capacity of large generators, the components such as stator and rotor windings, main shaft bearings, and excitation systems generate a lot of heat during operation. Once reliable and effective cooling is lacking, it is easy to affect the quality of power generation due to burning , and even cause downtime accidents, so effective cooling is one of the main auxiliary functions of generators

In the existing technology, the cooler is usually installed at the bottom of the main generator. When the generator set is installed, a huge installation room must be built below the ground to accommodate the cooler and the installation and maintenance work space. Not only is the installation project complicated , heavy workload, long cycle time, high material consumption

And it brings a lot of trouble to the maintenance of the installation, debugging and use process.

Secondly, due to the long distance between the installation position of the cooler and the stator and rotor of the main cooling part, the cold air transmission distance is long, the pressure and energy loss are high, and the cooling effect is affected

Moreover, there is usually only one heat exchanger in the cooler. Once a failure occurs, it will take a long time to stop for maintenance, which will affect production efficiency; Poor insulation will easily lead to insulation failure and poor operation reliability, especially at the end of the coil, where heat energy is concentrated and covered by a guard ring, which is the most prone to failure; Fourth, exposed air cooling is generally used for the exciter, and the cold air can only be blown to other parts. The surface does not have the effect of heat dissipation inside the exciter, and at the same time, oil and dust are easy to enter the inside of the body, resulting in insulation failure, short circuit and other accidents

Although the cooling system of the generator has been continuously improved in the prior art, the cooling effect is still not ideal. For example, some axial ventilation slots are set at the bottom of the rotor coil, but since the cooling air enters the slot from both ends, it cannot circulate. Difficult to achieve ideal cooling effect

[0004] (2) The base of the generator mostly adopts the integral structure of the stator core and the base, and the adjustment of the air gap is very difficult, which is mainly guaranteed by the machining accuracy of the components, resulting in difficult processing and assembly, and affects the performance of the whole machine

Due to the poor rigidity of this structure, the generator vibrates too much and is prone to heat, which cannot ensure the balance of the air gap during the operation of the generator, and generates vibration harmonic voltage, which has a negative impact on the power grid.

In addition, separate bearing housings and rolling bearings are generally used in the frame structure, which occupy a large axial space for installation and poor sealing, which also affects the rigidity of the stator shaft.

[0005] (3) The stator of the generator usually adopts an internal pressure structure in which the stator and the machine base are integrally connected. Since the stator core is integrated with the machine base, the machine base must be processed first before the stator punching lamination, coil off-line, etc. , unable to work in parallel, resulting in a long production cycle, low efficiency, and cumbersome assembly operations, time-consuming and labor-intensive

Due to the slender structure of the rotor shaft, the production and processing cycle is long, the process is many, the cost is high, the manufacturing process is complicated, and the material utilization rate is low

In order to improve the heat dissipation performance of the rotor, some heat dissipation grooves are set at the bottom of the wire slot under the rotor shaft. However, due to the lack of radial ventilation circulation, the internal heat dissipation is still only transmitted to the rotor surface by conduction, and the heat dissipation performance is not ideal. Require

Secondly, the rotor in the prior art usually adopts a single damping circuit, which has poor anti-interference ability. When the excitation is powered by an external line network, interference is prone to occur due to large fluctuations in voltage and capacitance.

Especially when there is a paroxysmal abnormal operation state, the generator cannot quickly restore the stability of the system, which affects the production power supply quality of the machine

[0007] (5) The current brushless excitation system usually uses a generator with a low number of poles, and the number of magnetic poles is only 4 poles, 6 poles or 8 poles

Therefore, the generated excitation current frequency is low and the voltage pole change rate is high, resulting in poor power generation quality of the main generator

Secondly, the rectification mechanism generally adopts a double-sided installation structure composed of a positive plate, a negative plate and an intermediate insulating partition, the rectification effect is poor, and the structure is not compact

In addition, most of the existing excitation systems lack effective cooling measures, often due to the influence of temperature rise, the stability is not good, the normal operation of the excitation system cannot be guaranteed, and even failures occur

[0008] (6) The collector ring in the generator rotor shaft current grounding detection device is usually installed between the generator bearing and the end cover, and a radial lead hole is set on the shaft. The collector ring has a large volume and the peripheral surface linear velocity If it is too high, the brushes will wear out quickly, requiring frequent maintenance and replacement of brushes

For frequent maintenance and overhaul, the protective cover is often discarded, so that the collector ring is exposed outside, resulting in accelerated wear of the components, especially when the generator is installed outdoors, rainwater, oil, and dust are easy to enter the radial wiring holes, resulting in Lead wire damage, short circuit and other faults, even lead to accidents

In addition, the collector ring body is bulky, labor-intensive and material-intensive to manufacture, takes up a lot of space, and is inconvenient to maintain and overhaul

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