Static silicon controlled excitation

Product Overview

Characteristic of main parts of generator

1)Rotor machining

The generator shaft is forged from an integral high-quality alloy steel and has an axial groove formed thereon for fitting a rotor coil and an air groove or a crescent groove is made in the large tooth to enhance the cooling of the main body and the coil end. The slots are processed by special machine for generator rotor processing, Tacchi high precision horizontal slotting and milling machine made in Italy, to ensure the high efficiency of generator.

The generator rotor must be subjected to high-speed dynamic balancing experiment and dynamic impedance experiment before delivery to verify the mechanical strength of the rotor and ensure excellent inter-turn insulation of the rotor windings.

2) Models

Mainly produce the following models of steam turbine generator and the specifications are as follows:

 3) Cooling type

QNP steam turbine generator uses closed-loop air self-circulation ventilation. 

The rotors of turbo-generator under 50MW adopt indirect ventilation cooling method;

The rotors of 50MW and above turbo-generator is directly ventilated and cooled; an auxiliary groove is machined under the rotor winding trunking; air vents are machined on the rotor windings; with the action of the fan head and the centrifugal pressure head of the air vents, the rotor windings are directly cooled by air from the auxiliary groove and air vents.

4)Excitation methods

QNP’s steam turbine generator can adopt static silicon controlled excitation, two-pole AC brushless excitation and three-pole AC brushless excitation.

5)Insulation system

QNP adopts class F insulation materials and insulation structure, during running time, assess the system according to class B insulation grade, meanwhile some margin has been kept.

6)Design and acceptance criteria

Designing, manufacturing and inspection are conducted according to relevant national standards, at the same time meet the latest International Electrotechnical Commission IEC34-1 standards. QNP’s steam turbine generator can also be designed, manufactured and accepted according to ANSI, NEMA and other international standards upon customer’s requirement.

Technical performance analysis

1.Output margin

The series of steam turbine generator of QNP retain 10% output margin.

2.Loss and efficiency

The steam turbine generator of QNP optimized its design and farthest minimized the additional loss and wind abrasion of generator under no-load and short-circuit condition, improved the efficiency of the generator, in general, QNP steam turbine generator’s efficiency is 0.2% higher than domestic similar models in this industry. It is higher than the national efficiency standard on the same capacity level. For example: QNP 15MW steam turbine generator’s efficiency value can reach 97.65%, and the national standard value is 97%.

3.Operational reliability 

QNP’s steam turbine generator adopts advanced manufacturing technology, especially the rotor’s overspeed test uses high-speed dynamic balancer, the rotor’s balance precision has been greatly improved, and the rotor’s vibration value is decreased. So that the steam turbine generator’s running availability factor has been improved, and the unit’s forced outage rate is decreased. At present, the availability factor of the steam turbine generator can reach about 99%, and the forced outage rate fell to 0.04% to 0.4%. Overhaul interval is up to 5 years. And the unit life can reach to 35 to 40 years.

Model Description

 Parameters 

(Remarks: The above units are data with double-layer layout and power factor of 0.8. The voltage level only provides part of the commonly used. Due to the limited space, they cannot be provided one by one; they can be designed and manufactured separately according to domestic and foreign customers; Separate notice)