Synchronous hydro generators up to 100 MVA

More than 60 years IHB Electric JSC supplies hydro generators for hydro power plants in wide range of speed, vertical or horizontal form of execution for Francis, Kaplan and Pelton turbine types. As of today worldwide there are new and modernized hydro generators with total installed capacity of more than 3000 MVA.

Our hydro generators distinguish robust design and construction, high efficiency and long operational life. This has been accomplished thanks to the experience and traditions, calculations and models used, using of modern technologies, optimized manufacturing process, permanent monitoring and control of every manufacturing stage and using of materials of highest quality. In the manufacturing and rehabilitation processes we have implemented and use proven insulation systems Global VPI and Resin Rich. 

Every single project is taken into consideration by our designers, resulting in individual solution which meets the specifications of the overall project and las but not least - to meet the customer's expectations. Therefore every customer gets technically grounded recommendation for additional accessories and auxiliary equipment, needed to fully accomplish the project.

The permanent research and development combined with the performed electrical and dynamic tests in our laboratories and on site result in complete technical solution for the project, which corresponds both to needs of the project itself and the customer's expectations, which is also in accordance with the latest tendencies in hydro generators manufacturing.

IHB Electric has design and manufacturing capabilities for synchronous hydro generators with the following parameters:

Applicationfor all hydro turbine types
Rated power (kVA)100 - 100000
Rated voltage (V)380 - 19500
Rated speed (min-1)75 - 1500
Frequency (Hz)50 - 60
Isolation classF - H
Degree of protectionIP 23 - IP55
Bearingsrolling; sleeve
 

STATOR FRAME

The stator frames of the manufactured rotating machines are welded construction made of rolled structural steel for the large dimensions. The sufficient mechanical strength is reached by using transverse and longitudinal ribs, which forms channels for the cooling air. Welds are performed by highly qualified specialists, using latest welding equipment and best technology and the quality control is done by specialized X-ray and ultrasonic equipment. In certain cases, after the performance of welding operations, tempering or vibration of the housings is done in order to remove residual mechanical stresses. Machining of the base surface is carried out by vertical and horizontal drills and lathes which are capable of handling stator frames of rotating machines with a capacity of 250 MVA. Stator core is installed on the stator frame by means of guiding beams with T-heads and tightening bolt connections. For the smaller dimensions frames of iron castings are used. 

 

STATOR CORE     

Stator core is built up from laminations (steel punching or laser cut) made of high grade steel with low level of specific losses and high magnetic conductivity. The factory has high quality machines for bilateral varnish coating with a thickness of 0.004 to 0.02 μm, which allows to achieve good filling with steel of the stator package with guaranteed insulation between segments. Technology used to built up the stator core allows to achieve high accuracy of geometric dimensions and guaranteed excellent magnetic properties.  The ready stator core is checked for local areas of overheating by thermal vision, control of the inner cylindrical surface by laser tracker.

 

INSULATION SYSTEMS

Stator winding, depending on the capacity of the electrical machine is executed like coils or stator bars. IHB Electric JSC has the equipment and technology for the implementation of the winding insulation with heat resistance class F and H. Insulation systems are made on technology lines for hydro-vacuum pressing or Global VPI for voltage of  hydro generators and other rotating electrical machines up to 20 kV.

The company has established its own "Know-how" as it is obvious from registered patent No. 65201-2007.  Based on this patent IHB Electric JSC has rehabilitated more than twenty four hydro generators so far and increased their efficiency up to 14, 2 %. Resin Rich insulation system is used for large dimensions and production of high voltage stator bars. Consolidation of the tapes is carried out in a deep vacuum process and under HVP. VPI technology is used for electric machines with medium and small dimensions. Both technologies use special insulation tapes, supplied by leading manufacturers in this field of industry. IHB Electric JSC apply the main insulation in the active part and the coils front parts by using specially dedicated machine equipment. Automated preparation of insulation system ensures even distribution of input materials along the section and even strength, which leads to the production of main insulation homogeneous distribution which guarantees equally distributed in the volume electrical field. Depending on the operating voltage there is crown protection made by selecting conductive and semi-conducting tape with suitable V / A characteristic. The both technology insulation systems are characterized by low levels of partial discharge and leakage current, high dielectric strength, coefficient of stock ks = 2 ÷ 3, ks =Ubr.v/Utest),(Utest=3.5*Unom). When we put all in one it  predetermined operational resources of about 20 ÷ 30 years.

For its long-term successful operation and high  performance and quality of insulation systems, IHB Electric JSC was awarded a Gold medal and a Diploma at the International Technical Fair in Plovdiv, Bulgaria.

 

ROTOR

Depending on the power output of the hydro generators the rotor may be implemented with rotor spider which is welded construction, made by rolled structural steel or rotor ring built up by segments. Poles are laminated construction. They are connected to the rotor body. For manufacturing the segments for the rotor spider IHB Electric JSC use a precise laser-cutting machine, allowing to achieve high accuracy in manufacturing of the elements (0.02-0.04 mm). Coils of the rotor poles are made of copper strip with a purity of 99.99%, insulated with high-quality materials and temperature resistance class F and H supplied by world-leading companies in the industry. Exciter’s winding is made of a copper strip with rectangular section. It is pressed by 2000 tons press, providing constructive withstand of the worst emergency duties such as over-speed and short-circuit. Damper coil winding is made of copper or brass.

 

EXCITATION SYSTEM

The power supply of the rotor exciter coil, depending on the client requirements, may be executed in two versions: with slip rings mounted on the shaft and brushes, supplied by static converter and using the inbuilt-exciter with rotating rectifier. IHB Electric JSC has developed a wide range of exciters with rotating rectifier, characterized by high reliability of operation due to lack of rotating electrical outlet. Suitable to be embedded in the body of the generator for external mounting for vertical and horizontal mounting.

 

BEARINGS

Our electrical rotating machines are equipped with bearings, supplied by reputable manufacturers, guarantying reliable operation in heavy duty environment, handling various radial and axial intensions from hydraulic turbines and others. Depending on the design requirements, our machines are being equipped with rolling bearings, sleeve bearings with babbit or teflon contact layer. The lubricant systems are designed in order to guarantee long operational life, possibility for effortless maintenance and controlling the condition of the bearings and their cooling. In manufacturing of hydro generators with higher rated power we use slide bearings with oil high-pressure lubrication, while in the process of making generators with lower rated power we built in the bearings inside bearing shields.

 

TEST PROCEDURES

IHB Electric JSC is certified under International standard for quality management ISO 9001 and applies its System for quality management in the manufacturing process. We are also certified under ISO 14001 and OHSAS 18001. In the manufacturing process of the hydro generators, at all stages of the execution of the separate components, there are control tests held to ensure the quality. A subject of control tests are: geometrical measurements of the details and units of the construction, the performance of the welds, the condition of the insulation of the separate details and produced windings. We pay a special attention of the insulation of the windings by holding a full 100% control of their elements on every technological level from their producing to their installation. The mandatory tests include: high-voltage testing in accordance with the nominal power of the windings and the requirements of the standards. Upon finalizing the installation we take off the performance data from the hydro generator and cautiously verify them with the technical data set in the project.

IHB Electric JSC owns latest technology digital measurement and control equipment: 3D laser tracker – for precise control of geometrical measure accurate to 0.005 µm/35 m and 0.017 µm/70 m; thermo vision cameras – for control and measurement of temperatures; three-phase combined meter of electrical parameters – all types I, U, cosφ, rated and nominal power, analyzing harmonics, pie charts and others, vibrations measurement and balance, including balance in operating mode.

All the electrical machines, manufactured by IHB Electric JSC correspond to requirements of IEC 60034-1(BDS EN 60034-1).