Let_QPS_be_your_Guardian_Angel(1)_updateML[1] (FILEminimizer)

Let QPS be your guardian Angel to your turbine Generators:

Let QPS be your guardian Angel to your turbine Generators Launching a new product line November 2009

Objectives:

Objectives Failure Mechanism in a typical generator Electrically induced Vibration Relating Vibration amplitudes to looseness Relating PD to local temperature rise Introducing our new VibroFibre™ Sensors measuring both vibration and temperature Our recent installation of a TG Guard system at AEP’s Pirkey Power Plant

Failure Mechanism in a typical generator:

Failure Mechanism in a typical generator Sequence of events: Electrically induced Vibration Loose windings-- increased amplitudes Rubbing & Abrasion of the insulating layer Partial discharge starts Shorted turns Short circuit to ground Stator failure

Structure inside the Generator:

Structure inside the Generator The stator contains a number of coils wound around and through the stator slots There are many slots. Coils are intertwined, once energized, set up a rotating magnetic field In a 3 phase machine, 3 coils will form 2 magnetic poles with line frequency of 60Hz Whereas a 4 poles (6 coils) will have a rotating field of 1800 RPM (30Hz)

Electrically induced Vibration :

Electrically induced Vibration It is always there and its signal frequency is two times the line frequency Caused by electromagnetic forces interacting between the rotor and the stator Found in all electrical devices: motors, generators and transformers Disappears as soon as power is turned off

Details of this electrically induced Vibration:

Details of this electrically induced Vibration Depends on line frequency For 50Hz system, this magnetic signal will become 100 Hz Whereas a 60Hz system, this magnetic signal would become 120 Hz

Relationship between Vibration amplitudes & looseness inside the generator:

Relationship between Vibration amplitudes & looseness inside the generator Looseness will allow the amplitude of these electromagnetic vibrations to increase It might be caused by wedges that are not tight Or windings that are not tied down Or cracks in the stator bars The end windings act like a mechanical amplifier to make these vibrations easier to measure

Proof of this relationship:

Proof of this relationship The experiment consisted of sandwiching a wedge element, a ripple spring under an iron block And impact signal is generated by tapping one end of the wedge: an unpackaged VibroFibre™ sensor is mounted on a thin epoxy reed touching the other end of the wedge at a slight angle We study how the intensity of the vibration signal is affected by the force we apply to the sandwich structure ( simulating tightness)

Simulated wedge structure:

Simulated wedge structure

Experimental setup:

Experimental setup

When the wedge is tight :

When the wedge is tight

Then the wedge is let loose :

Then the wedge is let loose The impact signal amplitudes suddenly become larger The next slide shows data recorded on the same system, same sensor, almost the same tapping force. See the difference in amplitude When it is loose, the peak went from 0.5 volts to 1.3 volts, a 2.5 times increase

When the wedge becomes loose :

When the wedge becomes loose

Comparing the two Spectra:

Comparing the two Spectra Slot looseness produces stronger low frequency components: 60, 80, 100, 120 Hz These component were down 30 db when the slot was tight Tightness can therefore be quantified by the magnitude of these low frequency components. Tightness can also be related to the Maximum amplitude of the triangular impulse response This is in fact, similar to the bump test standard

Important to detect these loose wedges:

Important to detect these loose wedges

Stator wedge loose on GE generator 49.5 MW Machine :

Stator wedge loose on GE generator 49.5 MW Machine

Another cause of looseness:

Another cause of looseness

Abrasion of the insulating layer can be seen :

Abrasion of the insulating layer can be seen

What is partial discharge (PD)?:

What is partial discharge (PD)? They are arcing events that take place inside the turbine generators When PD occurs, it is a sign that the insulating layers on the windings have been compromised As an analogy in human terms, our hearts might skip a few beats, event is hard to detect but has long term consequence to our lives if we ignore these symptoms

PD Measurement is complicated:

PD Measurement is complicated

PD inspection on Alstom 87.5 MVA needed to remove 18 top bars completely from their slots :

PD inspection on Alstom 87.5 MVA needed to remove 18 top bars completely from their slots

Relating PD to local temperature rise :

Relating PD to local temperature rise Since PD are local discharge or arcing events When PD occur, there will always be a high current spikes in the general area Statistical significant PD activities would cause a local rise in temperature around the windings most susceptible – one with the highest voltage Instead of detecting PD , one could do a rapid temperature measurement (say 4Hz )and detect small temperature changes at the critical winding, it would show the cumulative and equivalent results of all these arcing events

Local temperature rise measurement Could replace PD measurement :

Local temperature rise measurement Could replace PD measurement PD data are hard to interpret PD installation is complex Would be nice if there is a easier way to monitor the health of you Generators? We will now explain how our advanced VibroFibre TM can help

Advanced VibroFibre TM Sensor:

Advanced VibroFibre TM Sensor

They work with our new TG guard system:

They work with our new TG guard system Can measure vibration signal ranging from 20 to >1000 Hz Can work at higher temperature of up to 250 degrees C measuring vibration without change in calibration Most importantly, the same sensor can measure the local temperature rise in the critical windings where it is more susceptible to PD

Basic Building Block of the VibroFibreTM is structure showing a triangular spectrum:

Basic Building Block of the VibroFibre TM is structure showing a triangular spectrum reflectivity

Fiber optics cavity (measuring vibration and temperature simultaneously):

Fiber optics cavity (measuring vibration and temperature simultaneously) By placing 2 of these FBGs together in the same optical fiber , separated by a distance, we have constructed an optical cavity full of interference fringes These fringes will move with rising temperature, our tracking algorithm would increase laser drive to follow and maintain its operating point, data on drive current increased are effectively temperature measurement at the sensor head This capability is only available to TG Guard system with MODBUS interface (digital data)

FBG Cavity Reflection Spectrum showing all the fringes:

FBG Cavity Reflection Spectrum showing all the fringes

The fringes have a bandwidth of 48 pm :

The fringes have a bandwidth of 48 pm These fringes will move at the rate of 10 pico meter per degree C The laser drive current will move at 10 pico-meter per mA For larger temperature range –TEC can move at 100 pico-meter /degree C

A mechanical amplifier is formed as a hinged platform to protect the sensor from oil/ dust , by making them thinner, a string of these might fit inside the stator bar :

A mechanical amplifier is formed as a hinged platform to protect the sensor from oil/ dust , by making them thinner, a string of these might fit inside the stator bar

SEW Sensor spectral characteristics:

SEW Sensor spectral characteristics

Good Sensor Linearity:

Good Sensor Linearity

Diagram showing the End Windings and where to measure the fast temperature rise:

Diagram showing the End Windings and where to measure the fast temperature rise

System configuration:

System configuration

Pirkey Power plant:

Pirkey Power plant

Situated in Marshall, Texas:

Situated in Marshall, Texas

Owned by AEP:

Owned by AEP

It is a Westinghouse Machine:

It is a Westinghouse Machine

First we perform bump test to confirm tightness at all the coils:

First we perform bump test to confirm tightness at all the coils

The we form a conformal surface with the end windings using Dacron soaked in resin:

The we form a conformal surface with the end windings using Dacron soaked in resin

Let the resin cure before we wrap up the sensor (8 hours curing time):

Let the resin cure before we wrap up the sensor (8 hours curing time)

This Sensor monitors radial vibration:

This Sensor monitors radial vibration

6 sensors installed on the Exciter side:

6 sensors installed on the Exciter side

7 installed on the turbine end:

7 installed on the turbine end

When everything is done:

When everything is done

Hermetic junction Plate:

Hermetic junction Plate

Cross section of hermetic junction plate:

Cross section of hermetic junction plate

Composite cable with 12 fibers:

Composite cable with 12 fibers

Interconnect between hermetic junction plate and the composite cable:

Interconnect between hermetic junction plate and the composite cable

A team of 3 to install the hermetic junction plate, 2 outside, one inside:

A team of 3 to install the hermetic junction plate, 2 outside, one inside

The portal containing the hermetic junction plate at the Exciter end:

The portal containing the hermetic junction plate at the Exciter end

TG Guard system unit:

TG Guard system unit

Two Lasers:

Two Lasers

Rear Panel of the TG Guard:

Rear Panel of the TG Guard

USB cable connection to PC server:

USB cable connection to PC server

Clean the connector before you insert:

Clean the connector before you insert

Plugging in the optical connector:

Plugging in the optical connector

Click on Cancel for this screen:

Click on Cancel for this screen

Enter your device name:

Enter your device name

Sensor network configuration:

Sensor network configuration

On the exciter end:

On the exciter end

On the turbine end:

On the turbine end

Test and calibrate your sensors:

Test and calibrate your sensors

TEC Control , remote sensor status:

TEC Control , remote sensor status

Looking at time domain signal:

Looking at time domain signal

Real time continuous waveform:

Real time continuous waveform

Selection of your Sampling rate would affect your data size:

Selection of your Sampling rate would affect your data size

FFT Frequency spectrum:

FFT Frequency spectrum

Setting up continuous mode:

Setting up continuous mode

Example of vibration data in time domain and FFT thru TG EYE:

Example of vibration data in time domain and FFT thru TG EYE

Trending of vibration amplitudes:

Trending of vibration amplitudes

Water Fall plot:

Water Fall plot

TG Guard makes the SEW & “PD” process deterministic and simple:

TG Guard makes the SEW & “PD” process deterministic and simple While we monitor growth in vibration amplitudes We also monitor local temperature rise in the critical windings The two effects, taken together, would confirm a real alarm Local temperature rise can be related to partial discharge and arcing events which are caused by deterioration of the insulating layer

Our unique selling proposition:

Our unique selling proposition Easy and rapid installation (one day only!) 5 years warranty One year money back Guarantee 5 years of free TG EYE software upgrade Monitoring service and trending of vibration and temperature during this warranty period via WEB portal to customer’s PC server Customer alert advice for 5 years Alarm reporting during warranty period

Benefits to you:

Benefits to you Expected life of the TG GUARD system and advanced VibroFibre TM sensors 25 years 24/7 acting as Guardian Angel to your turbine generators Long term partnership and technical support QPS has your welfare in Mind!

Slide 80:

vibration measurement with fiber gratings 80 Please contact Peter Kung for the distributor closest to you Telephone 1-514-697-4728 Cell phone 1-514-578-6766 Email peter@qpscom.com SKYPE: peter.kung.qps Thank you for attending this webinar