5　Generator and Excitation Device

5.1　General Provisions

5.1.1　This chapter is applicable to the installation works for the mechanical part of turbo-generator and co-axial excitation device，and equipment and piping of cooling water system of water-cooled generator，gas system of hydrogen-cooled generators.

Turbo-generator units have the following types by cooling mode:

1　Air-cooled:both stator windings and rotor windings are cooled by air.

2　Hydrogen-cooled:both stator windings and rotor windings are cooled by hydrogen.

3　Dual internal water cooled:both stator windings and rotor windings are internally cooled by water.

4　Water-hydrogen-hydrogen cooled:the stator windings are cooled internally with water，rotor windings are cooled internally with hydrogen，and stator core and structural members are cooled by hydrogen on surface.

5.1.2　Transport of large generator stator shall comply with the following provisions:

1　Before transport out of the factory，the loading direction at the factory shall be notified，so that it will be in the same locating direction when arriving on-site.

2　Before transport of generator stator，the signaling devices and the bearing capacity and space dimensional requirements of tunnels，bridges，roads and culverts along the way shall be carefully checked，to ensure meeting the transport demand.

3　Plans for over limit transport shall be formulated，and comprehensive justification be performed on safety，technical and economic aspects，to select the best one.

4　For transport of heavy and large equipment，the transport plan shall include measures against effect of severe weather and environment to the transport operation.

5.1.3　After arrival of generator equipment on-site，parts for connection with turbine rotor shall be inspected as emphasis，and they shall comply with the following provisions:

1　The fitting dimensions of generator rotor coupling and turbine rotor coupling spigot shall be within the specified range.

2　The coupling bolts or bolt blank dimensions shall comply with installation requirements.

3　The bearing pedestals，pad and rotor journal shall match with each other in type and dimensions.

4　The protection layer on core surface，rotor surface and journal shall be complete and be free of damage or rust in appearance check.

5　The water inlet and outlet pipe ends of water-cooled generator stator and rotor shall be enclosed in a sound condition.

5.1.4　Safekeeping of generator equipment after arrival on-site shall comply with the following provisions:

1　Before placing the generator，the bearing capacity of the sleepers，unloading table and platform shall be inspected.

2　Generator rotor and stator should be stored in a clean and dry warehouse or building.

3　When equipment are stored on-site，the surrounding ambient temperature of generator storage place shall comply with the requirements in product technical documents，the storage temperature of a water-cooled generator shall be no lower than 5℃；the internal nitrogen pressure of generator stored with nitrogen filled shall comply with the product storage requirements.

4　The storage location shall have provisions against fire，moisture，dust and sundries intrusion.

5　When rotor are in storage，no force shall be applied to the retaining ring，the gas and water inlet and outlet passages of generator shall be tightly enclosed；the water inside the water-cooled winding shall be completely blown out and dry with compressed air for rotor of water-cooled generator.

6　During storage，no rust is allowed at journal，core and collector rings；the rotor shall be turned periodically as required for product.

7　For the rotor and stator windings of a large generator，the insulation resistance shall be measured periodically with a megohm meter，and when the insulation resistance is found reducing significantly，the cause shall be found out and measures shall be taken.

8　During storage，inspection shall be performed once a month.

5.1.5　The compressed air to be used for generator cleaning or leakage test shall comply with the following provisions:

1　Oil-free compressed air shall be used，and the air shall be dry and clean.

2　Care shall be taken to prevent filter desiccant from being carried into the generator.

3　The purging air pressure should not be higher than 0.3MPa，and purging should no be directed at one place at all times to prevent damage of insulation.

5.1.6　The leakage test of the stator or rotor of a water-cooled generator shall comply with the following provisions:

1　Before hydrostatic test，the insulation resistance value of winding shall be measured，and be compared with the test value at the factory.

2　Qualified demineralized water shall be used as medium in hydrostatic test，and before water filling，a temporary strainer sized not less than 80×80 pores/sq.cm and 200 mesh shall be fitted.

3　Before pressurizing，the air in water circuit shall be completely vented.

4　Pressurizing shall be slow，and be stopped in case of sudden drop or stagnation of pressure，and the cause shall be found out.

5　After the test，water inside shall be removed by blowing.

6　After hydrostatic test，the winding insulation shall be checked and remain unchanged，to ensure that the inside of winding is not moistened.

5.1.7　The foundation，soleplate and pad blocks of generator and excitation device shall comply with the following provisions:

1　Requirements on foundation and preparation for foundation before locating the equipment shall be in accordance with the relevant provisions in 4.2 and 4.3 hereof.

2　The deviation of top elevation of stator soleplate after locating from that of turbine soleplate shall be-5mm-0mm，and other requirements shall comply with the provisions in 4.3 hereof.

3　In the foundation on both sides of generator stator location，relevant anchors shall be embedded，for adjustment of stator center.

4　The secondary grouting of foundation concrete shall comply with relevant provisions in 4.10.

5.1.8　When the generator soleplate is installed without using pad block，the lifting bolts on the generator base and excitation device soleplate and a temporary jack can be used for adjustment，and the relevant provisions are as follows:

1　Preparation for foundation shall comply with the requirements in 4.2，the generator longitudinal and transversal centerlines，and the embedded backing plate for lifting bolts on generator base and soleplate shall have a position deviation less than 3mm and elevation deviation less than±10mm，and the backing plate shall be fixed with concrete，as shown in the figure（Fig.5.1.8-1）.

2　Place the block for lifting bolt，and there shall be no gap between it and the backing plate when checked with a 0.05mm feeler gauge.

3　The linking bolt of soleplate and base is as shown in Fig.5.1.8-2，and it should be tightened when the generator is installed，so that the soleplate is fixed on the base，after secondary grouting has reached the specified strength upon ending of installation，it shall be adjusted according to manufacturer requirements.

4　Before leveling and centering of generator，the lifting bolt shall be in good contact with base plate without warping.

5.1.9　The air chamber and concrete air duct for air-cooled and dual water-cooled generators shall meet the following provisions when handed over for installation:

1　The plastering on the air chamber inner wall and concrete duct inner and outer walls shall comply with the provisions in item 7 of 4.2.1.

2　The air chamber floor shall have a sloping for drainage.

3　There shall be isolation measures between the cold and hot air chambers and between air chambers and outside.

4　The spy hole and iron door of the air chamber shall be tight.

5　The concrete air duct must not hinder the locating of stator；the air duct connection shall match with stator air discharge port in dimensions.

6　The positions and dimensions of reserved openings shall comply with the design drawings.

5.1.10　The bottom of isolating oil pan over generator terminal leads shall be flat and inclining towards drain side，the oil drain pipe shall have sufficient flow section and sloping；the oil pan and drain pipe shall be free of leakage in a water filling or oil permeating test after the end of installation.

It is not necessary to provide an isolating oil pan for a generator with enclosed busbar.

5.1.11　Insulation to isolate shaft current of generator and excitation device shall be smooth and free of warping or defect，in homogeneous thickness and with good insulation performance，the insulation resistance shall comply with manufacturer requirements，and shall be greater than 0.5MΩ when measures with a 1000V megohmmeter if there is no manufacturer requirement.