Title of Invention	A DEVICE FOR MEASUREMENT OF ENDWINDING VIBRATION OF TURBOGENERATOR STATOR
Abstract	This invention relates to a device for measurement of end-winding vibration on turbogenerator stator comprising a vibration probe (5) on terminal clamp over L-shaped base plate (1), said base plate is mounted on a putty (2) and a textolite sheet (3) laid over bar clamp at HV (4), cables (2) from said base plate and probe assembly are connected through sleeve (7), rubber-textolite-gland (9) and earthed flange assembly (8).

Title of Invention

A DEVICE FOR MEASUREMENT OF ENDWINDING VIBRATION OF TURBOGENERATOR STATOR

Abstract

This invention relates to a device for measurement of end-winding vibration on turbogenerator stator comprising a vibration probe (5) on terminal clamp over L-shaped base plate (1), said base plate is mounted on a putty (2) and a textolite sheet (3) laid over bar clamp at HV (4), cables (2) from said base plate and probe assembly are connected through sleeve (7), rubber-textolite-gland (9) and earthed flange assembly (8).

Full Text	The invention relates to a device for measurement of endwinding vibration on turbogenerator stator. Vibration measurement are being carried out on the endwinding of stator during performance testing of turbogenerator at testing stand or at loading conditions at site. Normally the vibrations are measured on neutral nose joints of ovehang on both the ends of generator namely Exciter and Turbine ends at rated current (short circuit conditi-ions), rated voltage (open circuit condition) and during actual operation of generator at site. PRIOR ART Presently, the vibration measurement is accomplished by mounting a small base-plate of insulating material on neutral nose joints of stator overhang and fixing with special glue(putty). The vibration probe is then screwed on to the base-plate after the putty gets completely cured. The measuring cables connected to each mounted vibration probe are then routed through the generator winding overhang and brought outside through specially designed gland sealing system for connecting the measuring instrumentation system outside the generator. Some of the important tests being performed on the generator winding at works are: High Voltage Test, Dielectric Tests, Sudden Short Circuit Test etc. For carrying out dielectric tests such as Tan£> , Partial Discharge, Dielectric Loss Energy at nominal voltage of specific generator, the vibration probe system on the end winding used to be dismantled in order to avoid electrical discharges/flashover and inturn damage to the low voltage probes due to high voltage application and also any likely fire hazard to the mahine. I Thus, testing of generator winding with external high voltage application is possible only after dismantling of vibration probe system from the generator, There are disadvantages in the present system of performance testing of turbogenerator at the testing stand. Main disadvantage is that during sequential testing of the generator especially at test stand the vibration probe system is dismantled from the generator. - Another disadvantage associated with the present system of performance testing of turbogenerator is that in the case of hydrogen cooled generators, the hydrogen gas filled in for cooling has to be removed from the generator. - Yet another disadvantage associated with the present system of performance testing of turbogenerators is that the generator has to be opened up i.e. end shields of the generator at both the ends have to be removed. It involves extra work, man power and time delay at crucial testing stage. Further disadvantages associated with the present system of performance testing of turbogenerators is that the intended test conditions are not maintained due to dismantling of vibration probe system. SUMMARY OF THE INVENTION; Therefore, the main object of the present invention of performance testing of turbogenerators is to provide a special endwinding vibration measuring system which can withstand external high voltage upto nominal voltage without dismantling the vibration probe thus, eliminates all the disadvantages mentioned above. Another object of the present invention is to provide stator endwinding vibration measuring system on the turbogenerators which are subjected to external high voltage during performance testing. The type of turbogenerators are; Air cooled, Hydrogen cooled, Stator water and hydrogen cooled, rated upto 21kV. Yet another object of the present invention is to provide stator endwindings vibration measuring system for turbogenerators whih is simple and the main component of the system comprises piezolectric vibration probes (accelerators), probe mounting base plates, cables, gland sealing system etc. Further object of the present invention is to provide stator endwindings vibration measuring system for turbogenerators in which the mounting device is the base plate made of monolithic electrical insulating material, compact in shape and size and is used for mounting vibration probe. The base plate is installed inside the turbogenerator on the stator overhang at specific locations with special glue for carrying out endwinding vibration measurement. Yet a further object of the present invention is to provide a device with a vibration probe to withstand the rated high voltage of the respective turbogenerator without any flashover or electrical discharges during the application of external high voltage for dielectric measurement like Tan , PD or DLE on the winding. With this there is no need for dismantling of vibratio probe system from the generator while carrying out these tests reducing time and man power. Still a further object of the present invention is to provide stator endwindings vibration measuring system for turbogenerators wherein the 'base-plate-vibration probe system can withstand electrical potential upto 15.kV when the connecting leads are grounded and upto 21 kV when the connecting leads are kept floated individually without adverse effect on the machine. According to the present invention there is provided a device for measurement of endwinding vibration of turbo- generator stator comprising a L shaped bar plate said base—plate is mounted ono texto- lite sheet by a over a by joint cables from said prose late rubber-texto-assembly having rubber -texto lite-gland and an earthed flange The nature of the invention, its objective and further advantages residing in the same will be apparent from the following description made with reference to nonlimiting exemplary embodiments of the invention represented in the accompanying drawings: Figure 1 shows the front and side elevation of the base plate; Figure 2 shows the base plate of the invention in isometric view; Figure 3 shows the device of the invention for the test for TARI/THRI Turbogenerator; Figure 4 shows the device of the invention for the test 500 MW Turbogenerator. DETAILED DESCRIPTION OF THE INVENTION Figures 1 and 2 show details of the base plate (1) of the invention. Figures 3 and 4 show tw variants of the device of the endwinding vibration system which consists of piezo type accelerometer probes (5), probe mounting base plates (1), double screened minature cables (6) and especially designed textolite-rubber based gland sealing system (9,10) for plugging the leakage of circulating coolant (Hydrogen) inside generator stator body. The probes (5) are charge type accelerometers. The base-plate (1) for mounting the probes (5) is made of epoxy-glass insulating material and its shape and size are as per drawing attached. It has two SS studs fixed at the holes (12) for screwing the vibration probes (5) . The holes with SS studs are made void free by filling resin-hardener mixture. This, additionally helps to avoid loosening of the studs. The whole base-plate (1) is then coated with red enamel paint to make it moisture resistant and avoid tracking problem. The base plate (1) for mounting the probes (5) is made up of epoxy-glass insulating material and its shape and size has been indicated in Figures 1 and 2. The base plate (1) has two SS studs fixed at holes (12) for screwing the vibration probes(5). The holes (12) with SS studs are made void free by filling resin-hardener mixture. This additionally helps to avoid loosening of the studs. The whole base-plate (1) is then coated with red enamel paint Valfeh to make it moisture resistant and avlid-tracking problem. The striking feature of this base -plate (1) is its configuration which has been optimally arrived at after exhaustive experimentation .Moreover, it has monolithic construction and compactnes to withstand the application of external rated high voltage of the machine (during dielectric testing) without any flashover or electrical discharges when it is mounted on the end winding of the stator. Single base-plate (1) is used for fixing two vibration probes (5); one at radial and the other at tangential direction. This, in turn, is fixed on the end winding of turbogenerator stator overhang basket for carrying out endwinding vibration measurements during performance testing at works as well as during actual operation at site. The signal cables (6) used in the endwinding vibration measuring system are coated with graphite in order to reduce the extraneous electromagnetic noise. These cables are meticulously routed through the overhang system without any hindrance to other components and at the same time keeping a safe clearance against high voltage. The gland sealing system (9,10) consists of two textolite circular plates (9) with necessary holes and a sealing rubber plate, silicon rubber gland (10) also with holes sandwiched between them. The cables (6) from the probes (5) are taken out of the generator body through this sealing system. This gland sealing system (9,10) ensures proper sealing of the out coming cables (6). Turbogenerator stator end winding vibrations are being carried out during performance testing of the machine at test bed, to meet specific customer requirement and also for generat ing reference OEM data. Base plate (1) of epoxy insulating material are fixed with special putty (2) on neutral nose joints (12) of stator windings on both sides; turbine and exciter end of the generator. The probes (5) are screwed on these base plate (1) and connecting leads are taken out from respect probe (5) and routed through the overhang basket and finally through a special gland sealing arrangement (9,10) of stator body for connecting to measuring instrument. Thus, the vibration measurement are carried out during performance testing/normal operation of the machine. The dielectric measurements like Tanb , DLE and PD are required to be carried out upto Un as per customer's quality plan during shop testing and also during overhauling of the machine at site. During these test, external high voltag (HV) is applied to all the windings of respective phases separately. Consequently, under the application of HV, the probes (5) alongwith base plates (1) already mounted on neutral bars of the end-windings for vibration measurement purpose are subjected to certain level of high voltage depending on the capacitive distribution of base plate (1) insulation. In order to avoid any electrical discharges around the 'probe-base plate assembly' a special base plate (1) of epoxy-glass material has been designed after exhaustive mock-up tests under HV application. The drawing is as per Figure 1 and 2. The new base plate-probe assembly (15) with cables 16 developed obviates the need for dismantling of vibration probes during the testing of Tanb , DLE and pd at works and also during overhauling of the machine at site wherein external HV is applied. DETAILS OF EXPERIMENTATION; DEVELOPMENT OF BASE PLATE INVOLVED EXHAUSTIVE SIMULATION STUDIES: A: FOR TARI TYPE AIR COOLED AND THRI TYPE HYDROGEN COOLED TGs 7.11 For the purpose of simulation study for establishing the design of base plate (1) exhaustive experimentation was conducted simulating a nose joint by using two numbers THRI 210 MW bars. Bar overhangs were finished with stress grading tape. Slot portion of the bar was wrapped with aluminum foil and was earthed. 7.1.2 Vibration probes (5) (accelerometers) of Bruel & Kjaer type 4383 were used for experimentation. 7.1.3 High voltage tests were conducted on the bars with different variants of base plate (1) alongwith the radial and tangential vibration probes (5) and a final variant of L shaped Base plate (1) (Figures 1 & 2) was established alongwith its associated cables-gland sealing assembly (9,10) wich ensured discharge free phenomena upto 20 kV.(Figures 3 & 4). B. FOR 500 MW TG: For the purpose of simulation study for establishing the desi-gn of base plate (1) for use in 500 MW TG, one number 210 MW TG bar was taken and the actual terminal clamp of 500 MW TG was clamped at the lug portion. Different variants of vibration probes mounting at the terminal were adopted. After conducting number of trials as per mock up arrangement, four variants of mounting arrangements were short listed. The brief details of the variants are: Variant-1: Vibration probe (5) mounted on terminal clamp (4) of 500 MW over L shaped base plate (1) of thickness 20 mm. Cables (6) were taken through 'rubber - textolite-gland (9,10), and earthed flange (8) assembly. Clamp at HV Cables at earth potential; Discharge phenomena was observed (under dark conditions.) This arrangement was not considered. Variant-2: Vibration probe (5) mounted on terminal clamp(A) of 500 MwJSver L shaped Base plate (1) of thickness 20 mm. Cables (6) were taken through 'rubber- textolite gland (9,10) and earthed flange' assembly. Clamp at HV Cables floated;- Discharge phenomena was observed (under dark conditions). This arrangement was also not considered. Variant-3: An insulating epoxy laminate sheet (3) of 100x100 nin and 2 mm thick was fixed on the terminal clamp (4). The L shaded base plate (11) of thickness 2C mir> alongwith vibration probes (5) was mounted on tis laminate sheet (3). Cables were taken 'through 'rubber - textolite gland (9,10) and earthed flange (8) assembly. Clamp at HV; Cables floated; Did not pass the required HV withstand satisfactorily. Variant-4: 1. An insulating epoxy laminate sheet (3) of 100x100 men and 2 mm thick was fixed oh the terminal clamp (4). The L shaped base plate (1"> alongwith vibration probes (5) was again mounted on this laminate sheet (3). Thickness of base plate being 25 mm 2. The vibration probe assembly (5) alogwith base plate (1) wrapped with glass tape and anchored with the clamp (3), The cables (6) through *rubber-textolite gland(9,10) and earthed flange' assembly. Clamp at HV; Cables floated: 21 kV on the terminal - withstood for more than 10 min. 25 kV on the terminal - withstood for 3 min. No visible discharges Potential measured on the pickups when cables were under floating condition : (clamp at hv) At 21 kV on the terminal, The surface voltage on radial pick up was approx 0.5 kV. The surface voltage on tangential pick up was about 3 kV. System was considered acceptable. Based on the simulation studies conducted, the system for mounting the vibration probes on turbo generator end windings of TARI, THRI type TGs as well 500 MW TGs (along with associated cable routing and sealing arrangement), for the purpose of endwinding vibration measurement, has been established for the suitability of external high voltage application (during dielectric test). Same has been successfully installed and proved 'on TARI type turbogenerators like Kayamkulam I,II,III, Faridabad i; and 500 MW. THW type Vindhyachal VIII. The invention described hereinabove is in relation to a non-limiting embodiment and as defined by the accompanying claims. WE CLAIM: 1. A device for measurement of endwinding vibration turbogenerator stator comprising a L-shaped baseplate (1), Vibration Probes (2), said base-plate is mounted on a Textolitesheet (5) by a Glue (Putty) (3) laid over on a Bar Joint (9), Cables (8) from probe-base-plate assembly having Sleeve (4) being connected through gas sealing system of Rubber-Textolite-Gland (7) and an earthed Flange (6). 2. A device for measurement of endwinding vibration on turbogenerator stator as claimed in Claim 1 wherein said base-plate (1) and vibration probes (2) system withstand electrical potential upto 15.7 kV with connecting cables (8) ground and upto 21 kV with connecting cables (8) kept floated individually. 3. A device for measurement of endwinding vibration on turbogenerator stator as claimed in Claim 1 wherein said vibration probes are piezoelectric type accelerometer probe. 4. A device for measurement of endwinding vibration on turbogenerator stator as claimed in Claim 1 wherein said L-shaped base plate for mounting said vibration probes is made up of epoxy-glass insulating material. 5. A device for measurement of endwinding vibration on turbogenerator stator as claimed in Claim 4 wherein said base-plate is provided with two holes for screwing said vibration probes with two SS studs fixed at holes. 6. A device for measurement of endwinding vibration on turbogenerator stator as claimed in Claim 5 wherein said holes with two SS studs are made void free by filling resin-hardner mixture and whole of said base-plate is coated with red enamel paint to make it moisture resistant and avoid tracking error. 7. A device for measurement of end winding vibration on turbogenerator stator as claimed in Claim 1 wherein single base-plate (1) is used for fixing of two vibration probes (2) one at radial and other at tangential direction (with respect to rotor axis) and is fixed on the end winding nose joint of turbogenerator stator overhand for carrying out vibration measurerment during works testing as well as during actual operation. 8. A device for measurement of end winding vibration on turbogenerator stator as herein described and illustrated in Figs. 3 and 4.

Full Text

The invention relates to a device for measurement of endwinding vibration on turbogenerator stator.
Vibration measurement are being carried out on the endwinding of stator during performance testing of turbogenerator at testing stand or at loading conditions at site. Normally the vibrations are measured on neutral nose joints of ovehang on both the ends of generator namely Exciter and Turbine ends at rated current (short circuit conditi-ions), rated voltage (open circuit condition) and during actual operation of generator at site.
PRIOR ART
Presently, the vibration measurement is accomplished by mounting a small base-plate of insulating material on neutral nose joints of stator overhang and fixing with special glue(putty). The vibration probe is then screwed on to the base-plate after the putty gets completely cured. The measuring cables connected to each mounted vibration probe are then routed through the generator winding overhang and brought outside through specially designed gland sealing system for connecting the measuring instrumentation system outside the generator.

Some of the important tests being performed on the generator winding at works are: High Voltage Test, Dielectric Tests, Sudden Short Circuit Test etc. For carrying out dielectric tests such as Tan£> , Partial Discharge, Dielectric Loss Energy at nominal voltage of specific generator, the vibration probe system on the end winding used to be dismantled in order to avoid electrical discharges/flashover and inturn damage to the low voltage probes due to high voltage application and also any likely fire hazard to the mahine. I Thus, testing of generator winding with external
high voltage application is possible only after dismantling

of vibration probe system from the generator,
There are disadvantages in the present system of performance testing of turbogenerator at the testing stand.
Main disadvantage is that during sequential testing of the generator especially at test stand the vibration probe system is dismantled from the generator. - Another disadvantage associated with the present system of performance testing of turbogenerator is that in the case of hydrogen cooled generators, the hydrogen gas filled in for cooling has to be removed from the generator.

- Yet another disadvantage associated with the present system of performance testing of turbogenerators is that the generator has to be opened up i.e. end shields of the generator at both the ends have to be removed. It involves extra work, man power and time delay at crucial testing stage.
Further disadvantages associated with the present system of performance testing of turbogenerators is that the intended test conditions are not maintained due to dismantling of vibration probe system.
SUMMARY OF THE INVENTION;
Therefore, the main object of the present invention of performance testing of turbogenerators is to provide a special endwinding vibration measuring system which can withstand external high voltage upto nominal voltage without dismantling the vibration probe thus, eliminates all the disadvantages mentioned above.
Another object of the present invention is to provide stator endwinding vibration measuring system on the turbogenerators which are subjected to external high voltage during performance testing. The type of turbogenerators are; Air cooled, Hydrogen cooled, Stator water and hydrogen cooled, rated upto 21kV.

Yet another object of the present invention is to
provide stator endwindings vibration measuring system for
turbogenerators whih is simple and the main component of
the system comprises piezolectric vibration probes (accelerators), probe mounting base plates, cables, gland sealing system etc.
Further object of the present invention is to provide stator endwindings vibration measuring system for turbogenerators in which the mounting device is the base plate made of monolithic electrical insulating material, compact in shape and size and is used for mounting vibration probe. The base plate is installed inside the turbogenerator on the stator overhang at specific locations with special glue for carrying out endwinding vibration measurement.
Yet a further object of the present invention is to provide a device with a vibration probe to withstand the rated high voltage of the respective turbogenerator without any flashover or electrical discharges during the application of external high voltage for dielectric measurement like Tan , PD or DLE on the winding. With this there is no need for dismantling of vibratio probe system from the generator while carrying out these tests reducing time and man power.

Still a further object of the present invention is to provide stator endwindings vibration measuring system for turbogenerators wherein the 'base-plate-vibration probe system can withstand electrical potential upto 15.kV when the connecting leads are grounded and upto 21 kV when the connecting leads are kept floated individually without adverse effect on the machine.
According to the present invention there is provided
a device for measurement of endwinding vibration of turbo-
generator stator comprising a L shaped bar plate said base—plate is mounted ono texto-
lite sheet by a over a by joint cables from said prose late

rubber-texto-assembly having rubber -texto
lite-gland and an earthed flange
The nature of the invention, its objective and further advantages residing in the same will be apparent from the following description made with reference to nonlimiting exemplary embodiments of the invention represented in the accompanying drawings:
Figure 1 shows the front and side elevation of the base plate;
Figure 2 shows the base plate of the invention in isometric view;
Figure 3 shows the device of the invention for the test for TARI/THRI Turbogenerator;
Figure 4 shows the device of the invention for the test 500 MW Turbogenerator.

DETAILED DESCRIPTION OF THE INVENTION
Figures 1 and 2 show details of the base plate (1) of the invention. Figures 3 and 4 show tw variants of the device of the endwinding vibration system which consists of piezo type accelerometer probes (5), probe mounting base plates (1), double screened minature cables (6) and especially designed textolite-rubber based gland sealing system (9,10) for plugging the leakage of circulating coolant (Hydrogen) inside generator stator body. The probes (5) are charge type accelerometers. The base-plate (1) for mounting the probes (5) is made of epoxy-glass insulating material and its shape and size are as per drawing attached. It has two SS studs fixed at the holes (12) for screwing the vibration probes (5) . The holes with SS studs are made void free by filling resin-hardener mixture. This, additionally helps to avoid loosening of the studs. The whole base-plate (1) is then coated with red enamel paint to make it moisture resistant and avoid tracking problem.
The base plate (1) for mounting the probes (5) is made up of epoxy-glass insulating material and its shape and size has been indicated in Figures 1 and 2.

The base plate (1) has two SS studs fixed at holes (12) for screwing the vibration probes(5). The holes (12) with SS studs are made void free by filling resin-hardener mixture. This additionally helps to avoid loosening of the studs.
The whole base-plate (1) is then coated with red enamel paint
Valfeh
to make it moisture resistant and avlid-tracking problem.
The striking feature of this base -plate (1) is its configuration which has been optimally arrived at after exhaustive experimentation .Moreover, it has monolithic construction and compactnes to withstand the application of external rated high voltage of the machine (during dielectric testing) without any flashover or electrical discharges when it is mounted on the end winding of the stator.
Single base-plate (1) is used for fixing two vibration probes (5); one at radial and the other at tangential direction. This, in turn, is fixed on the end winding of turbogenerator stator overhang basket for carrying out endwinding vibration measurements during performance testing at works as well as during actual operation at site.
The signal cables (6) used in the endwinding vibration measuring system are coated with graphite in order to reduce the extraneous electromagnetic noise. These cables are meticulously routed through the overhang system without any hindrance to other components and at the same time keeping a safe clearance against high voltage.

The gland sealing system (9,10) consists of two textolite circular plates (9) with necessary holes and a sealing rubber plate, silicon rubber gland (10) also with holes sandwiched between them. The cables (6) from the probes (5) are taken out of the generator body through this sealing system. This gland sealing system (9,10) ensures proper sealing of the out coming cables (6).
Turbogenerator stator end winding vibrations are being carried out during performance testing of the machine at test bed, to meet specific customer requirement and also for generat ing reference OEM data.
Base plate (1) of epoxy insulating material are fixed with special putty (2) on neutral nose joints (12) of stator windings on both sides; turbine and exciter end of the generator. The probes (5) are screwed on these base plate (1) and connecting leads are taken out from respect probe (5) and routed through the overhang basket and finally through a special gland sealing arrangement (9,10) of stator body for connecting to measuring instrument. Thus, the vibration measurement are carried out during performance testing/normal operation of the machine.

The dielectric measurements like Tanb , DLE and PD are required to be carried out upto Un as per customer's quality plan during shop testing and also during overhauling of the machine at site. During these test, external high voltag (HV) is applied to all the windings of respective phases separately. Consequently, under the application of HV, the probes (5) alongwith base plates (1) already mounted on neutral bars of the end-windings for vibration measurement purpose are subjected to certain level of high voltage depending on the capacitive distribution of base plate (1) insulation.
In order to avoid any electrical discharges around the 'probe-base plate assembly' a special base plate (1) of epoxy-glass material has been designed after exhaustive mock-up tests under HV application. The drawing is as per Figure 1 and 2. The new base plate-probe assembly (15) with cables 16 developed obviates the need for dismantling of vibration probes during the testing of Tanb , DLE and pd at works and also during overhauling of the machine at site wherein external HV is applied.
DETAILS OF EXPERIMENTATION;
DEVELOPMENT OF BASE PLATE INVOLVED EXHAUSTIVE SIMULATION STUDIES:
A: FOR TARI TYPE AIR COOLED AND THRI TYPE HYDROGEN COOLED TGs
7.11 For the purpose of simulation study for establishing
the design of base plate (1) exhaustive experimentation was conducted simulating a nose joint by using two numbers THRI 210 MW bars.
Bar overhangs were finished with stress grading tape. Slot portion of the bar was wrapped with aluminum foil and was earthed.
7.1.2 Vibration probes (5) (accelerometers) of Bruel & Kjaer
type 4383 were used for experimentation.
7.1.3 High voltage tests were conducted on the bars with
different variants of base plate (1) alongwith the
radial and tangential vibration probes (5) and a final
variant of L shaped Base plate (1) (Figures 1 & 2)
was established alongwith its associated cables-gland sealing assembly (9,10) wich ensured discharge free phenomena upto 20 kV.(Figures 3 & 4).
B. FOR 500 MW TG:
For the purpose of simulation study for establishing the desi-gn of base plate (1) for use in 500 MW TG, one number 210 MW TG bar was taken and the actual terminal clamp of 500 MW TG was clamped at the lug portion. Different variants of vibration probes mounting at the terminal were adopted.
After conducting number of trials as per mock up arrangement, four variants of mounting arrangements were short listed. The brief details of the variants are:
Variant-1:
Vibration probe (5) mounted on terminal clamp (4) of 500 MW over L shaped base plate (1) of thickness 20 mm. Cables (6) were taken through 'rubber - textolite-gland (9,10), and earthed flange (8) assembly.
Clamp at HV Cables at earth potential; Discharge
phenomena was observed (under dark conditions.) This arrangement was not considered.
Variant-2:
Vibration probe (5) mounted on terminal clamp(A) of 500 MwJSver L shaped Base plate (1) of thickness 20 mm. Cables (6) were taken through 'rubber- textolite gland (9,10) and earthed flange' assembly.
Clamp at HV Cables floated;- Discharge phenomena was observed (under dark conditions). This arrangement was also not considered.
Variant-3:
An insulating epoxy laminate sheet (3) of 100x100 nin and 2 mm thick was fixed on the terminal clamp (4). The L shaded base plate (11) of thickness 2C mir> alongwith vibration probes (5) was mounted on tis laminate sheet (3). Cables were taken 'through 'rubber - textolite gland (9,10) and earthed flange (8) assembly.
Clamp at HV; Cables floated; Did not pass the required HV withstand satisfactorily.
Variant-4:
1. An insulating epoxy laminate sheet (3) of 100x100 men
and 2 mm thick was fixed oh the terminal clamp (4). The
L shaped base plate (1"> alongwith vibration probes (5)
was again mounted on this laminate sheet (3).
Thickness of base plate being 25 mm
2. The vibration probe assembly (5) alogwith base plate
(1) wrapped with glass tape and anchored with the clamp
(3), The cables (6) through *rubber-textolite gland(9,10)
and earthed flange' assembly.
Clamp at HV; Cables floated:
21 kV on the terminal - withstood for more than 10 min. 25 kV on the terminal - withstood for 3 min.
No visible discharges
Potential measured on the pickups when cables were under floating condition : (clamp at hv)
At 21 kV on the terminal,
The surface voltage on radial pick up was approx 0.5 kV. The surface voltage on tangential pick up was about 3 kV.
System was considered acceptable.
Based on the simulation studies conducted, the system for mounting the vibration probes on turbo generator end windings of TARI, THRI type TGs as well 500 MW TGs (along with associated cable routing and sealing arrangement), for the purpose of endwinding vibration measurement, has been established for the suitability of external high voltage application (during dielectric test).
Same has been successfully installed and proved 'on TARI type turbogenerators like Kayamkulam I,II,III, Faridabad i; and 500 MW. THW type Vindhyachal VIII.
The invention described hereinabove is in relation to a non-limiting embodiment and as defined by the accompanying claims.

WE CLAIM:
1. A device for measurement of endwinding vibration turbogenerator stator comprising a L-shaped baseplate (1), Vibration Probes (2), said base-plate is mounted on a Textolitesheet (5) by a Glue (Putty) (3) laid over on a Bar Joint (9), Cables (8) from probe-base-plate assembly having Sleeve (4) being connected through gas sealing system of Rubber-Textolite-Gland (7) and an earthed Flange (6).
2. A device for measurement of endwinding vibration on
turbogenerator stator as claimed in Claim 1 wherein said base-plate (1)
and vibration probes (2) system withstand electrical potential upto 15.7
kV with connecting cables (8) ground and upto 21 kV with connecting
cables (8) kept floated individually.
3. A device for measurement of endwinding vibration on
turbogenerator stator as claimed in Claim 1 wherein said vibration probes
are piezoelectric type accelerometer probe.
4. A device for measurement of endwinding vibration on
turbogenerator stator as claimed in Claim 1 wherein said L-shaped base
plate for mounting said vibration probes is made up of epoxy-glass
insulating material.

5. A device for measurement of endwinding vibration on
turbogenerator stator as claimed in Claim 4 wherein said base-plate is
provided with two holes for screwing said vibration probes with two SS
studs fixed at holes.
6. A device for measurement of endwinding vibration on
turbogenerator stator as claimed in Claim 5 wherein said holes with two
SS studs are made void free by filling resin-hardner mixture and whole of
said base-plate is coated with red enamel paint to make it moisture resistant
and avoid tracking error.
7. A device for measurement of end winding vibration on
turbogenerator stator as claimed in Claim 1 wherein single base-plate (1)
is used for fixing of two vibration probes (2) one at radial
and other at tangential direction (with respect to rotor axis) and is fixed on
the end winding nose joint of turbogenerator stator overhand for
carrying out vibration measurerment during works testing as well as during
actual operation.
8. A device for measurement of end winding vibration on
turbogenerator stator as herein described and illustrated in Figs. 3 and 4.

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Patent Number

217836

Indian Patent Application Number

747/DEL/2001

PG Journal Number

17/2008

Publication Date

25-Apr-2008

Grant Date

29-Mar-2008

Date of Filing

09-Jul-2001

Name of Patentee

BHARAT HEAVY ELECTRICALS LTD

Applicant Address

BHEL HOUSE, SIRI FORT, NEW DELHI-110049, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	AEKBOTE K.L. RAO	CORPORATE RESEARCH & DEVELOPMENT, VIKAS NAGAR HYDERABAD 500093, A.P.INDIA.
2	RAM SEWAK	C/O BHART HEAY ELECTRICALS LIMITED (A GOVERNEMNT OF INDIA UNDERTAKING), CORPORATE RESEARCH & DEVELOPMENT, VIKAS NAGAR HYDERABAD 500093, A.P.INDIA.
3	RAJESH RANJAN	C/O BHART HEAY ELECTRICALS LIMITED (A GOVERNEMNT OF INDIA UNDERTAKING), CORPORATE RESEARCH & DEVELOPMENT, VIKAS NAGAR HYDERABAD 500093, A.P.INDIA.

PCT International Classification Number

H 02K 03/30

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA