Upload
msmonk22
View
220
Download
0
Embed Size (px)
Citation preview
8/6/2019 TRIAD White Paper April 2011 REV4
1/23
CE Power Solutions White Paper April 2011
Reliability Assessment Program Series Paper/Presentation
Electrostatic Precipitator Transformer Rectifier Sets and Power ModulesTransformer Rectifier Insulation Analysis and Diagnostics - TRIAD
Mark S. McCloy Director Marketing CE Power Solutions Cincinnati, OH
PRELUDE
CE Power is developing a series of technical publications, papers and presentations to
further communicate, support and develop condition-based maintenance practices forelectrical power equipment and systems; Reliability Assessment Program (RAP).
ABSTRACT
This paper will provide an informational foundation for the Development,implementation and benefits of applying Condition-based Maintenance protocols and
practices to coal-fired, power generation facilities Electrostatic Precipitators key
components the Transformer Rectifier and Power Modules.
Transformer Rectifiers and Power Modules are utilized in todays electric Utilities coal-
fired Power Plants, as components of the Electrostatic Precipitator System (ESP); the
ESP is the first line of particulate control (extraction) in Emissions Control. ThePrecipitator removes particulate from the flue gas or the smoke from the stacks.
Transformer Rectifiers Power Module
8/6/2019 TRIAD White Paper April 2011 REV4
2/23
Electrostatic Precipitators (ESPs) are critical to the clean delivery of electric power as
well as controlling particulate emissions from various industrial processes. TheEnvironmental Protection Agency has increased the required compliance with its Clean
Air Act. Thus, the importance of ESP performance continues to rise. The
transformer/rectifier (TR) is a key component of the power supply system to the ESPs.
The failure of a TR can limit the performance of the ESP system and therefore limitproduction and output. Many of the existing TRs have been in service for several decades
and therefore are in need of evaluation, repair and/or refurbishment.
TR Maintenance and Inspections are seldom performed and was time based or reactive.
In order to meet the needs of an aging TR fleet, CE Power Solutions has developed aReliability Assessment Program (RAP) specific to TRs. This new program will
incorporate our TRIAD (Transformer Rectifier Insulation Analysis and Diagnostics)
methodology; consisting of specific dielectric fluid sampling and analysis services along
with physical inspections and electrical testing. This comprehensive series of tests,combined with our diagnostic evaluation software, enables us to evaluate the current
condition of your Precipitators transformer/rectifier and power modules to allowprioritization of Maintenance and Replacement Budgets and Tasks based upon thecurrent Operating Condition and Performance of the TR Set and associated Power
Module.
We begin by providing a basic understanding of the Electrostatic Precipitator system.
Electrostatic Precipitator
Electrostatic precipitation has been a reliable technology since the early 1900's.Originally developed to abate serious smoke nuisances, the manufacturers of zinc,
copper, and lead quickly found electric gas cleaning a cost efficient way to recovervaluable product carried out of the stacks from furnace operations. Today electrostaticprecipitators are found mainly on large power plants, cement plants, incinerators, and
various boiler applications.Electrostatic precipitators have taken on considerably greater
importance in recent years, particularly in view of the increased emphasis upon
maintaining a clean environment.
The theory behind the operation of an electrostatic precipitator involves the generation ofa strong electrical field through which stack gases pass, so that the particles carried by the
stack gases can be electrically charged. By charging the particles electrically they can be
separated from the gas stream and collected, and thereby not enter and pollute the
atmosphere. The generation of such electrical fields requires electrical power suppliesthat can provide a high DC voltage to charge the particulate matter and thereby permit its
collection. The existing systems are based upon AC corona theory, using a single phase
transformer-rectifier set to rectify AC power to DC power and provide a high DCpotential between a charging electrode, to charge the particles, and a collection surface,
usually a plate, so that the stack gases are subjected to the maximum current obtainable
through the gas without complete breakdown.
8/6/2019 TRIAD White Paper April 2011 REV4
3/23
That approach is believed to produce the maximum ionization of the particles and thereby
the maximum efficiency in effecting removal of such particles.
A precipitator is a relatively simple device. The main components are as follows:
An insulated and lagged shell
Collection plates or tubes
Discharge electrodes
Collection Plate Rappers/Electrode Vibrators
Hoppers
Power: A typical precipitator will take 480 volt AC and with the assistance of
transformer/rectifier converts the power to operated the discharge electrode's at 55-70 kV
DC. This leads most inquirers to conclude they are huge electricity consumers. In reality,the electrostatic precipitator is the lower power consumer available to accomplish the job.
Electrostatic forces are applied directly to the particles and not the entire gas stream.
Combining this feature with the low-pressure drop (0.5" wc) across the system results in
power requirements approximately 50% of comparable wet systems and 25% ofequivalent bag filter systems.
Power Supplies and Controls
The power supply system is designed to provide voltage to the electrical field (or bus
section) at the highest possible level. The voltage must be controlled to avoid causingsustained arcing or sparking between the electrodes and the collecting plates.
8/6/2019 TRIAD White Paper April 2011 REV4
4/23
Electrically, a precipitator is divided into a grid, with electrical fields in series (in the
direction of the gas flow) and one or more bus sections in parallel (cross-wise to the gasflow). When electrical fields are in series, the power supply for each field can be adjusted
to optimize operation of that field. Likewise, having more than one electrical bus section
in parallel allows adjustments to compensate for their differences, so that power input can
be optimized. The power supply system has four basic components:
Automatic voltage control
Step-up transformerHigh-voltage rectifier
Sensing device
Voltage Control
Automatic voltage control varies the power to the transformer-rectifier in response tosignals received from sensors in the precipitator and the transformer-rectifier itself. It
monitors the electrical conditions inside the precipitator, protects the internal components
8/6/2019 TRIAD White Paper April 2011 REV4
5/23
from arc-over damages, and protects the transformer-rectifier and other components in
the primary circuit.
The ideal automatic voltage control would produce the maximum collecting efficiency by
holding the operating voltage of the precipitator at a level just below the spark-over
voltage. However, this level cannot be achieved given that conditions change frommoment to moment. Instead, the automatic voltage control increases output from the
transformer-rectifier until a spark occurs. Then the control resets to a lower power level,and the power increases again until the next spark occurs.
Transformer-Rectifiers
The transformer-rectifier rating should be matched to the load imposed by the electrical
field or bus section. The power supply will perform best when the transformer-rectifiersoperate at 70 - 90% of the rated capacity, without excessive sparking. This reduces the
maximum continuous-load voltage and corona power inputs. Practical operating voltagesfor transformer-rectifiers depend on:
Collecting plate spacing
Gas and dust conditionsCollecting plate and discharge electrode geometry
8/6/2019 TRIAD White Paper April 2011 REV4
6/23
At secondary current levels over 1500 mA, internal impedance of a transformer-rectifieris low, which makes stable automatic voltage control more difficult to achieve. The
design of the transformer-rectifier should call for the highest possible impedance that is
corresponding with the application and performance requirements. Often, this limits the
size of the electrical field or bus section.
It is general practice to add additional impedance in the form of a current-limiting reactorin the primary circuit. This reactor will limit the primary current during arcing and also
improve the wave shape of the voltage/current fed into the transformer-rectifier.
Inductance
The unit of measure for reactors is the henry. The ability of a reactor to impede the flowof AC current is termed inductance. The inductance of CLRs is usually from 5 to 20
millihenries (.005H to .020H).The CLR value that is required is based upon the totalsystem impedance that is desired for the power supply. This system impedance limits themaximum amount of current that can flow in the primary circuit and is usually specified
as percent impedance. A value of from 30% to 50% is usually employed. The impedance
of the reactor can be calculated by:
Zclr = L x (2 x x f) = L x 377 where Zclr = impedance in ohms L = inductance in
henries = 3.1415 f= frequency in hertz
The percent impedance that the CLR provides is calculated by:
%Z = L x 377 x I x 100/V where %Z = percent impedance L = inductance in henries
I = rated primary current V = system voltage (typically 480 or 575 VAC)
The same formula can be used for calculating the inductance required for a desired %impedance by:
L = V x %Z / I x 377 x 100
The system impedance also includes the reactance of the transformer, which is typically
5% to 10%. A system impedance of 50% limits the maximum AC current to twice the
rated current. At 33% the limit is three times the rated current. When specifying the CLR,the inductance in henries, the primary rated current, and the anticipated spark rate must
be given. Since the ESP will periodically spark, the actual average current that the CLR
will need to withstand is greater than the T/R rated current.
8/6/2019 TRIAD White Paper April 2011 REV4
7/23
In an electrostatic precipitator, the polluted gas is conducted between electrodes
connected to a high-voltage rectifier. Usually, this is a high-voltage transformer withthyristor control on the primary side and a rectifier bridge on the secondary side. This
arrangement is connected to the ordinary AC mains and thus is supplied at a frequency,
which is 50 or 60 Hz.The power control is effected by varying the firing angles of the thyristors. The smaller
the firing angle, i.e. the longer conducting period, the more current supplied to the
precipitator and the higher the voltage between the electrodes of the precipitator.
When separating dust of low or moderate resistivity, the degree of separation increases as
the voltage between the electrodes increases. However, the possible voltage is not only
restricted by the construction of the high-voltage rectifier, but also by the fact that at
sufficiently high voltage, there will be flashover between the electrodes in theprecipitator.
This is effected by slowly increasing the current until flashover occurs. Subsequently, thecurrent is reduced in a predetermined manner and then again slowly increased until the
next flashover. The process is repeated periodically. If the circumstances result in a
highly varying flashover limit, more than 100 flashovers a minute may be acceptable. In
more stable processes, 10 flashovers a minute may be involved. In certain processes, thebest separation is however obtained at very high flashover frequencies although the
operation is very stable.
8/6/2019 TRIAD White Paper April 2011 REV4
8/23
In case of flashover, the current is interrupted during a first time interval, and then the
current is rapidly increased from zero, during a second time interval after which it isincreased slowly when a given value, depending on the value before the flashover, has
been achieved.
To ensure that the flashover does not lead to a permanent arc and, thus, sets the
precipitator out of operation for a long time, the first time interval, during which the
current is interrupted, must be at least a half-cycle of the mains voltage. The current is
usually interrupted during an entire cycle of the mains voltage, partly because otherwisethe excitation of the transformer, when reconnected, yields a very high overload on the
mains and increases the losses in the transformer windings.
This technique therefore implies that the precipitator is dead for 20 milliseconds up to100 times a minute or even more frequently. Moreover, it will be appreciated that the
separation is not fully effective also during the second time interval, when the precipitator
is being recharged and the voltage between the electrodes is essentially below the value atwhich the flashover occurred. If the second time interval is estimated at about 100
milliseconds, the precipitator may, in extreme cases, be out of operation during almost as
much as 10% of the total time. This is a strongly restricting factor at a high flashoverfrequency.In conventional thyristor-controlled rectifiers, the current cannot be interrupted until the
next zero point of the mains voltage. This means that the precipitator can function as a
short-circuit load for a considerable time, between the flashover and the next zero pointof the mains voltage. If the flashover occurs early during the half-cycle, this state can
prevail for almost 10 milliseconds.
Transformer
The step-up transformer is the major component of the T/R system. Transformers
designed for ESP applications employ design techniques specifically developed for thisuse. ESP transformer coils must be capable of withstanding repeated sparking and arcing
of the load. Disruptions such as these, along with occasional shorted fields, cause current
surges well above the system ratings. These surges cause the windings of the transformerto exert considerable physical force on the system insulation and support mechanism. If
not properly accounted for, these forces will eventually cause premature destruction ofthe insulation and system failure.
8/6/2019 TRIAD White Paper April 2011 REV4
9/23
The transformer is typically the most reliable component in the system. Failures of
transformers, however, do occur and can often be placed in two general categories. Thefirst is degenerative failure that is caused by the long term breakdown of a component
part. If the transformer is used within its rated parameters, then degenerative failure is
most likely due to a defect of material or workmanship. The second failure category is
overstress failure. Overstress failure is caused by subjecting the transformer to eitherexcessive voltage or excessive current. Overstress failure is usually the case for
transformers that fail between five and twenty years of operation.Of the components and materials used on T/Rs, the layer insulation on the transformer
winding determines the life expectancy of the system. Modern designs use Kraft
insulation. The life expectancy of the insulation is a function of stress level (voltageacross the insulation) and temperature of the insulation material. The operating
temperature of the insulation is usually assumed to be 10 (C) higher than the overall
temperature rise of the winding. The 10 margin is based upon the assumption that heat
transfer between the coils and the oil can never be absolutely uniform. The expected lifeof the insulation for modern designs is 34 years if the unit is continuously subjected to
rated current and rated voltage (REF ANSI C57.91.1981). Degenerative insulation failureafter less than 15 years, although possible is statistically very unlikely, unless there areother contributing factors. Degenerative insulation failure can be caused by abrasion
caused by excessive vibration and physical movement of the transformer windings.
Vibration is induced by the 60 cycle AC current while coil movement is induced bycurrent surges. ESPs by nature present a harsh load for transformers due to the sparks and
arcs that are expected. T/Rs designed for such applications must therefore employ
extraordinary measures to tolerate such conditions. If such measures are not employed or
improperly employed, then the abrasion of the coils will occur.
The main problem that results from operating a precipitator at a level at which sparking
occurs is that the automatic controller for the transformer-rectifier set must sense an arcand immediately reduce the voltage on the precipitator collector plate, because any spark
can quickly create an arc between the plate and the electrode, with a resultant high
current flow. The high current flow can cause severe damage to the precipitator grid orplate, or it can cause the transformer-rectifier set to fail. Any of those incidents will cause
a section of the precipitator to be temporarily off-line, until the failures have been
repaired. Repair can be a matter of minutes, or it can be weeks if the transformer-rectifier
set has to be replaced.
Reliability Assessment Program (RAP) Development
As stated above, degenerative insulation failure is the primary root cause to TR failures in
todays ESP systems. A method of measuring and trending the integrity of the insulation
system in a TR can be developed and implemented, based upon the extremely effectiveand time-proven methods developed in the utilities Transmission and Distribution
8/6/2019 TRIAD White Paper April 2011 REV4
10/23
departments and the management of traditional substation-class, oil-filled power
transformers.
Transformer Rectifier Insulation Analysis or TRIAD; was developed to assist in
identifying several TR fault/failure modes. These include various modes of degenerative
failure, such as:
Overheating of TR ComponentsPartial Discharge within the TR
Arcing within the TR
The first and very key component of the TRIAD program is the TR fluid analysis.
Under normal operating conditions very little decomposition of the insulating oil or
insulating cellulose occurs. However, when degenerative faults occur, the oil and
cellulose insulation will undergo chemical degradation. The fault-induced breakdownproducts, indicated below, are low molecular weight gaseous compounds that are soluble
in the oil.
Hydrogen - H2 Methane - CH4 Ethane - C2H6 Ethylene - C2H4
Acetylene - C2H2 Carbon Monoxide CO Carbon Dioxide - CO2
Quantitative analysis of the gases present in the oil DGA (Dissolved Gas Analysis)
allows one to identify fault processes such as Partial Discharge, Sparking, Overheatingand Arcing.
In addition to the DGA, it is also important to understand the physical condition of thedielectric fluid. TRIAD incorporates several fluid analyses that measure the dielectric
fluids insulation quality, fluid characteristics, fluid degradation and impurity content.
Table 1 illustrates how these various tests can be used to identify failure modes in yourTR.
Failure Diagnostic Tools
Overloading DGA
Moisture moisture dielectric color/visual
Partial Discharge DGA
Carbon dielectric breakdown color/visual
AVC (overvoltage) DGA
Failing / Failed Diodes (Arcing) DGASludging IFT acid color/visual
High Contact Resistance DGA
Deteriorated paper insulation DGA
Table 1
8/6/2019 TRIAD White Paper April 2011 REV4
11/23
TRIAD Overall Compilation Report
Bank OE
M
SampleDate Fluid kV
A
Volts H2 CH
4
C2H6 C2H4 C2H2 CO CO2 N2 O2 TDG TDC
G
HS EqTCG%
TRA6 N
W
L
5/25/07 Silicone
Fluid
1
0
9
46
0
1
5
9
10
5
11 0 11 16
08
13
20
2
154
242
23
94
6
193
284
18
94
0.8663
TRA4 N
W
L
5/25/07 Silicone
Fluid
1
0
9
46
0
1
1
9
47 11 3 1 22
15
11
17
2
145
118
21
11
8
179
804
23
96
1.1486
TRA5 N
W
L
5/25/07 Silicone
Fluid
1
0
9
46
0
1
3
7
18 9 25 2 78
6
88
89
120
157
38
65
0
168
673
97
7
0.5719
TRA3 N
W
L
5/25/07 Silicone
Fluid
1
0
9
46
0
0 2 1 1 0 59 55
14
122
638
51
92
4
180
139
63 0.0288
8/6/2019 TRIAD White Paper April 2011 REV4
12/23
Individual Insulating Fluid Sampling Results
TESTRESULTS
AlternativeTechnologies, Inc. Serial Number:
92-1204
12350 River RidgeBlvd.
Client Number:10001171
Burnsville,MN 55337
Date Received:6-7-2007
Telephone (800) 255-8656 or(952) 894-3455
Report Date:6-14-2007
Type /Tank:
TRN PO: 14621
KVA:109 JOB: 400025
KevinCarter
Voltage:
460
Location: UNIT 5
CE PowerSolutions
Gallons:
135
Bank &Phase: TRA6
P.O. Box147
ManufDate:
Manufacturer: NWL
Lake Hamilton, FL33851
FluidType:
SiliconeFluid
Container No.: AB244
DISSOLVED GAS IN OIL
ANALYSIS
Date:
25-May-07
Tem
p:60C
Hydrogen (H2) 159 ppm
Methane (CH4) 105 ppm
Ethane (C2H6) 11 ppmEthylene
(C2H4) 0 ppmAcetylene(C2H2) 11 ppmCarbon
Monoxide (CO) 1608 ppmCarbon Dioxide
(CO2) 13202 ppm
Nitrogen (N2) 154242 ppm
Oxygen (O2) 23946 ppm
TotalGas 193284 ppmTotalCombustible
Gas 1894 ppm
Equivalent TCG Reading 0.8663 %
8/6/2019 TRIAD White Paper April 2011 REV4
13/23
Comm
ents:
Presence of Acetylene may indicate arcing in
Silicone FluidRecommen
ded Retest:
Investigate
Immediately
PHYSICAL AND CHEMICALTESTS
Date
:
25-May-
07
Moisture in Oil 19 ppmInterfacial
Tension 36.9 dynes/cm
Acid Number
8/6/2019 TRIAD White Paper April 2011 REV4
14/23
TEST RESULTS
Alternative Technologies, Inc.Serial Number: NA
12350 River Ridge Blvd.Client Number:
10001
167
Burnsville, MN55337
Date Received:6-7-2007
Telephone (800) 255-8656 or (952) 894-3455 Report Date: 6-14-2007
Type /Tank:
TRN PO: 14621
KVA: 109 JOB: 400025
Kevin Carter Voltage: 460 Location: UNIT 5CE Power
Solutions Gallons: 135
Bank &
Phase: TRA4
P.O. Box 147
Manuf
Date:
Manufactu
rer: NWL
Lake Hamilton, FL
33851
Fluid
Type:
Silicone
Fluid
Container
No.: AM186
DISSOLVED GAS IN OIL
ANALYSIS
Date:
25-May-07
Tem
p:60C
Hydrogen (H2) 119 ppm
Methane (CH4) 47 ppm
Ethane (C2H6) 11 ppmEthylene
(C2H4) 3 ppmAcetylene(C2H2) 1 ppmCarbon
Monoxide (CO) 2215 ppm
Carbon Dioxide(CO2) 11172 ppm
Nitrogen (N2) 145118 ppm
Oxygen (O2) 21118 ppm
Total
Gas 179804 ppmTotal
CombustibleGas 2396 ppm
Equivalent TCG Reading 1.1486 %
Comm
ents:
Presence of Acetylene may indicate arcing in
Silicone Fluid
Recommen
ded Retest:
Investigate
Immediately
8/6/2019 TRIAD White Paper April 2011 REV4
15/23
PHYSICAL AND CHEMICAL
TESTS
Date:
25-May-07
Moisture in Oil 13 ppmInterfacial
Tension 36.9 dynes/cm
Acid Number
8/6/2019 TRIAD White Paper April 2011 REV4
16/23
TEST RESULTS
Alternative Technologies, Inc.Serial Number:
92-
1200
12350 River Ridge Blvd.Client Number:
10001169
Burnsville, MN
55337Date Received:
6-7-
2007
Telephone (800) 255-8656 or (952) 894-3455
Report Date:6-14-2007
Type /
Tank:
TR
N PO: 14621
KVA: 109 JOB: 400025
Kevin Carter Voltage: 460 Location: UNIT 5
CE PowerSolutions Gallons: 135
Bank &Phase: TRA5
P.O. Box 147Manuf
Date:Manufactu
rer: NWL
Lake Hamilton, FL
33851
Fluid
Type:
Silicone
Fluid
Container
No.: AL170
DISSOLVED GAS IN OILANALYSIS
Date
:
25-May-
07Tem
p:60C
Hydrogen (H2) 137 ppm
Methane (CH4) 18 ppm
Ethane (C2H6) 9 ppmEthylene
(C2H4) 25 ppmAcetylene
(C2H2) 2 ppmCarbon
Monoxide (CO) 786 ppm
Carbon Dioxide(CO2) 8889 ppm
Nitrogen (N2) 120157 ppm
Oxygen (O2) 38650 ppm
Total
Gas 168673 ppmTotal
Combustible
Gas 977 ppm
Equivalent TCG Reading 0.5719 %
Comm
ents:
Presence of Acetylene may indicate arcing in
Silicone Fluid
Recommen
ded Retest:
Investigate
Immediately
8/6/2019 TRIAD White Paper April 2011 REV4
17/23
PHYSICAL AND CHEMICAL
TESTS
Date:
25-May-07
Moisture in Oil 26 ppmInterfacial
Tension 37.3 dynes/cm
Acid Number
8/6/2019 TRIAD White Paper April 2011 REV4
18/23
TEST RESULTS
Alternative Technologies, Inc.Serial Number:
92-
1201
12350 River Ridge Blvd.Client Number:
10001166
Burnsville, MN
55337Date Received:
6-7-
2007
Telephone (800) 255-8656 or (952) 894-3455
Report Date:6-14-2007
Type /
Tank:
TR
N PO: 14621
KVA: 109 JOB: 400025
Kevin Carter Voltage: 460 Location: UNIT 5
CE PowerSolutions Gallons: 135
Bank &Phase: TRA3
P.O. Box 147Manuf
Date:Manufactu
rer: NWL
Lake Hamilton, FL
33851
Fluid
Type:
Silicone
Fluid
Container
No.: 0353
DISSOLVED GAS IN OIL
ANALYSIS
Date
:
25-May-
07
Temp:
25C
Hydrogen (H2) 0 ppm
Methane (CH4) 2 ppm
Ethane (C2H6) 1 ppmEthylene
(C2H4) 1 ppm
Acetylene(C2H2) 0 ppmCarbonMonoxide (CO) 59 ppmCarbon Dioxide
(CO2) 5514 ppm
Nitrogen (N2) 122638 ppm
Oxygen (O2) 51924 ppm
Total
Gas 180139 ppmTotalCombustible
Gas 63 ppm
Equivalent TCG Reading 0.0288 %
Comments:
All gases at acceptableconcentrations for Silicone Fluid
Recommended Retest: 1 Year
8/6/2019 TRIAD White Paper April 2011 REV4
19/23
PHYSICAL AND CHEMICAL
TESTS
Date:
25-May-07
Moisture in Oil 42 ppmInterfacial
Tension 36.6 dynes/cm
Acid Number
8/6/2019 TRIAD White Paper April 2011 REV4
20/23
In addition to the fluid analysis, a detailed physical inspection of the TR is performed
along with electrical performance tests that include TTR, Megger & Continuity andWinding Resistance. This comprehensive group of tests and analysis provide the current
condition of your TR asset.
Physical Inspections
WORKSCOPE
TRANSFORMER/RECTIFIER ON SITE
DESCRIPTION OF SERVICES
NAME/DATE OF
INSPECTOR
OVERALL T/R SET INSPECTION _______/_________
INITIAL TESTING, MEGGAR, OIL SAMPLEING _______/_________
DOCUMENT SCHEMATIC FOR TEST REPORT _______/_________
NOTE ALL PHYSICAL, MECHANICAL, OR ELECTRICAL PROBLEMS _______/_________
REMOVE OIL FROM VESSEL VIA PRESS OR DEGAS SYSTEM _______/_________
REMOVE ALL NECESSARY GASKETING FOR REPLACEMENT _______/_________
INTERNAL TANK INSPECTION AND TORQUE ALL CONNECTIONS _______/_________
DISCUSS ANY PROBLEMS FOUND WITH CUSTOMER
REMOVE ALLBUSHINGS (IF APPLICABLE) _______/_________
INSPECT DIODE PAK _______/_________
INDIVIDUALCOMPONENT TEST (IF APPLICABLE) _______/_________
REMOVE RADIATORS (IF APPLICABLE) _______/_________
PREP TANK FOR
PAINTING (IF APPLICABLE) _______/_________
RE-WIND
XFMR (IF APPLICABLE) _______/_________
ATTACH LID _______/_________
PRIME AND PAINT
UNIT (IF APPLICABLE) _______/_________
VACUUM FILL APPLICABLE OIL _______/_________
FINAL TEST
T/R SET _______/_________
INSPECT ALL ASSOCIATED INSTRUMENTATION _______/_________
TEST OIL WITH PORTABLE DIELECTRIC SET
PRESSURE TEST FOR
LEAKS _______/_________
ASSIST CUSTOMER WITH START UP _______/_________FINAL OIL SAMPLE AFTER UNIT IS ON LINE _______/_________
LEAD TECH SIGN OFF: _______________________/_________
NOTES:
8/6/2019 TRIAD White Paper April 2011 REV4
21/23
Electrical Tests and Inspections
TRANSFORMER
RECTIFIER TEST REPORT
Customer: Job # Date:
Make: Ser #
INCOMING FWRD REV OUTGOING FWRD REV
H1 to 5 H1 to 5
H1 to 7 H1 to 7
Hi to 10 & 11 Hi to 10 & 11
H1 to G H1 to G
10 to 11
10 to
11
10 & 11 to G 10 & 11 to G
TEST VALUE IS 1,000 VDC ALL READINGS IN MEGOHMS
INCOMING POWER
FACTOR: TTR: Calculated:
FINAL POWER FACTOR: Actual:
HUMIDITY: TEMP:
NOTES:
Test Equipment Serial Number:
Technician ID:
8/6/2019 TRIAD White Paper April 2011 REV4
22/23
Power Module and Diode Stack Performance Improvements through Design
Diode Stacks Power Module
Newly designed Modules typically have half the mass of equivalent older-style Modules,
using hockey puck devices. Hockey puck designs require heat sink and clamp
assemblies that add to the already heavy copper pole face and ceramic body. The fact that
the New, Improved Power Modules do not require a clamp assembly allows for easierrepair and maintenance without special tools. New Power Module heat-sinks are
electrically isolated, which allows for easier mounting without proximity issues
promoting a safer installation.
Heat-sink mounting is common across multiple modules. This allows for minimized
mechanical configurations. Modules feature push-on lead terminals, New Power Modulesare designed for quick installation for all applications. The modules require torque to the
heat sink only. No special bus bars are required and connections can be made directly to
the module.
New Power Modules also feature increased tracking distance between anode and cathodeterminations.
Newly Designed Diode stacks offer high surge current rating. They are compensated to
insure voltage sharing across all internal components enhancing product reliability. New
Diode stacks incorporate a 2X safety factor in current ratings to further insure reliableperformance. New Diode Stacks are manufactured by hand using high quality soldering
techniques that ball the solder joints to minimize potential corona effects.
ConclusionThe loss of ESP fields will eventually affect generation revenue and effective particulate
emissions control. The heart of the ESP system - TR Sets have traditionally beenforgotten or ignored, regarding diligent maintenance and testing for Operating integrity.
Without the implementation of a pro-active Field Service Testing and Maintenance
Program on the ESPs Transformer Rectifiers; it is a certainty that failure will occur; theonly question is when?
8/6/2019 TRIAD White Paper April 2011 REV4
23/23
Applying the protocols of the CE Power Reliability Assessment Program utilizingTRIAD; will proactively avert future failures and potential catastrophes; furthermore it
allow the process of planning future Capital expenditures and assure compliance to
applicable emission controls standards requirements while insuring maximum reliability
and revenue potential.
Monkey Power White Paper