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1
IndroductionIndroduction
Corrosion Coating Cathodic protection Cathodic protection criteria CP Project
Overview of CP equipment Safety / hazards Routine testing / inspection Routine maintenance General trouble shooting
2
What Is CorrosionWhat Is Corrosion In general, Degradation of materials through environmental
interaction.
In metals, conversion of metals to metal oxide
Metals are put into high energy state during extraction from ores & again want to be in low energy state which is their oxides.
Corrosion is an electrochemical process which involves removal of electrons – Oxidation ( Anodic ) & consumption of electrons – Reduction ( Cathodic ).
3
Corrosion in MetalsCorrosion in Metals
Corrosion Cell ( Due to different soil Resistivity, Oxygen concentration,
Dissimilar Metal )Anode – Positively ChargedCathode – Negatively ChargedElectrolyte – SoilContinuity between Anode & Cathode
– Structure / Pipe
4
Detection of Corrosion MetalsDetection of Corrosion Metals
If we place a metal in the soil, we can measure the voltage between them using a reference cell. ( Also Inside the A/G Water Tanks )
For Mild Steel ( Rusted ) –0.2 to –0.5VFor Mild Steel ( New ) –0.5 to –0.8VRemote Vs Close Interval SurveySoil Resistivity, Line Current Survey
5
Mitigation of CorrosionMitigation of Corrosion
Coating of Metal Surface– Coating will break the contact between metal &
Soil. – Then there will not any path for the corrosion
current to flow.– There are some limitations for coatings such as
damage during installation, coating deformation etc
6
Cathodic ProtectionCathodic Protection
In normal situation in U/G metal, current will flow to soil from metal.
CP is the system which will make the U/G metal to receive the current from the soil.
This is exactly opposite to the corrosion current flow.
Thus the corrosion rate will be reduced. If CP is used for coated metals, required current
will be considerably less.
7
Types of Cathodic ProtectionTypes of Cathodic Protection
Impressed Current Cathodic Protection– DC power source is used– Can be applied to Large Surface Area & long duration.– Surface & Deep Well Ground Bed
Galvanic Cathodic Protection– This is also called Sacrificial CP System.– Can be used for Small Surface Area only & Shorter
duration.– Anode will be active metals such as Magnesium, Al etc
8
9
Transformer RectifiersTransformer Rectifiers
10
Surface Anode Ground BedsSurface Anode Ground Beds
11
12
ApplicationsApplications
External Protection for Underground pipelines, Above Ground Storage Tank Bottom etc
External Protection of offshore Structures etc. Concrete Reinforcement Protection. External protection of Oil & Gas Well Casings. Internal Protection of pipelines & Storage Tanks
etc. (Non Hazardous, Conductive product) Above Ground Pipeline Crossings below roads
etc.
13
Criteria for CPCriteria for CP
-850mV with CP applied100 mV PolarizationNet Current required – Bare or Uncoated &
critical places to measure Close Potential
(E&I Log, CPET for well casings)Over Protection ( More than –1200mV )
14
Cathodic Protection PotentialsCathodic Protection Potentials
Instant “OFF” Potentials ( mV)
Reference Electrode
Cu/CuSo4 Ag/AgCl
Steel in Soil -950 to -1150 -900 to -1100
Steel in Concrete -700 to -1300 -650 to -1250
Steel in Water -850 to -1150 -800 to -1100
15
100 mV Potential Criteria100 mV Potential Criteria
Polarization build up Polarization DecayPolarization Decay
0
200
400
600
800
1000
1200
1400
Time
Pote
ntia
l (-m
V)
Polarized Potential
Instant Off
> 100 mV> 100 mV
0
200
400
600
800
1000
1200
1400
Time
Pote
ntia
l (-m
V)
Polarized Potential
Instant On
> 100 mV
16
Bare Surfaces
Bare steel in contact with soil 22mA/m2
Bare steel in contact with concrete 20mA/m2 Bare steel in contact with fresh water 30mA/m2 Bare steel in contact with saline water 65mA/m2 Bare Steel Well Casing 1-20MicroAmp/cm2 or As per NACE RP0186
Coated Surface
Coated with coal tar urethanes or FBE 0.02 – 0.05 mA/m2 Coated with 3-Layer polyolefin system 0.005- 0.01 mA/m2
Current Density Current Density ( At 30( At 300 0 C, 25% Increase in Every 10C, 25% Increase in Every 100 0 C )C )
17
General Arrangement Of General Arrangement Of EquipmentEquipment
18
ANODE JUNCTION BOX
10” SURFACE CASING
WATER LEVEL
DC POWER SUPPLY
10
AN
OD
ES
20
AN
OD
ES
WELLHEAD
5 M
25
M
51
M
NEGATIVE CABLE CONNECTION TO WELLHEAD
POSITIVE CABLE CONNECTION TO ANODES
Typical Deep Anode Groundbed
CP Current
WELL CASING
19
Anode Lead Junction BoxAnode Lead Junction Box Individual circuits 10 or 20 terminals Calibrated shunts Stainless steel enclosure IP 65 rated
20
21
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Typical Stray CurrentTypical Stray CurrentCathodically ProtectedSection of Foreign Pipeline
Accelerated Corrosionon Foreign Pipeline
Protected Pipeline
Rectifier
Foreign Pipeline
23
Potential Testing of Foreign Potential Testing of Foreign StructuresStructures
Use multimeter with 100 megohm input impedance
Measurements taken with current cycled on and off
Project criteria: +50 mV shift with current applied
24
Interference Vs. Potential Interference Vs. Potential ValuesValues
Negative potentials shifts on a foreign structure with system “ON” indicates areas where the current is collecting on the structure to the soil. (No problem)
Positive potential shifts on a foreign structure with system “ON” indicates areas where the current is discharging from the structure to the soil. (Possible interference problem)
25
General Phases Of CP General Phases Of CP ProgramProgram
Front end engineering design Field investigation Detailed design engineering Procurement of equipment Construction System commissioning System turn over
26
ADCO CP ProjectADCO CP Project
ADCO Well Casing Cathodic Protection Project
ADCO Contract No. 5922.01/EC
27
Basic Design PhilosophyBasic Design Philosophy Protect 1 or 2 well clusters per CP system Standardized system capacity at 15 amp / casing
(plus 5 amp for flow line) 20 year design life Integrated system (no insulating devices) Deep and surface groundbeds (50 amp max) Ground beds positioned remote (150 m from
wellhead) Use rectifier and solar power supplies Extend 415 VAC power up to 500 meters Use exiting CP equipment where possible
28
Limitations Of Cathodic Limitations Of Cathodic Protection In Oil & Gas WellsProtection In Oil & Gas Wells
Cathodic protection can only be applied to the external surfaces of the conductor and outer casing.
Where conductors are electrically shorted to surface casing, CP will only protect the outside of the casing.
Corrosion protection in the annulus between the conductor and surface casing is provided by the proper cementing techniques.
29
Electrical IsolationElectrical Isolation
Integrated system selected Casings and flow lines electrically continuous Minimizes interference and balancing problems Eliminates maintenance and current leakage
problems across insulators
30
CP Current RequirementCP Current Requirement NACE RP0186 criteria: net flow of current to the
casing eliminates anodic areas Data analysis:
Corrosion potential evaluation tool (CPET) E-log I testing Current density calculations Current attenuation modeling
FEED recommended 15 amps per casing 5 amp allowed for flow lines
31
Corrosion Potential Corrosion Potential Evaluation Tool (CPET) Evaluation Tool (CPET)
LoggingLogging Recommended in the FEED for project Typically conducted during well work overs Only way to determine down hole anodic and
cathodic areas on a casing (interference) Tool includes 4 sets of 3 electrodes which make
contact with the casing Potentials are measured between electrodes to
determine magnitude and direction of CP current flow
Shah field is good candidate for CPET logging
32
CPET Tool and LogsCPET Tool and Logs
33
E-log-i TestingE-log-i Testing
1 amp intervals / 3 minute cycle / remote ground bed 37 tests conducted in FEED CP current ranged from 12 to 18 amp
34
CP Current AttenuationCP Current Attenuation
9 5/8 inch casing 15 amp total current to casing
-8,000
-7,000
-6,000
-5,000
-4,000
-3,000
-2,000
-1,000
0
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
CURRENT (DC AMPERES)
CA
SIN
G S
EG
ME
NT
DE
PT
H (
FE
ET
)
35
Current Density Per SegmentCurrent Density Per Segment
-8,000
-7,000
-6,000
-5,000
-4,000
-3,000
-2,000
-1,000
0
0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00
CURRENT DENSITY (DC MILLIAMPERES PER SQUARE FOOT)
CA
SIN
G S
EG
ME
NT
DE
PT
H (F
EE
T)
9-5/8” casing 15 amp total current
36
Groundbed DetailsGroundbed Details Deep and surface groundbeds used Located 150 to 200 meters from wellhead 20 year design life 25 or 50 amp rating 10 or 20 anodes per ground bed Titanium / MMO anodes Individual anode lead wires Coke breeze backfill Design circuit resistance: 0.25 - 0.60 ohm
37
200
MTR
S.
150 MTRS.
MIN.
OPTIMUM GROUNDBED LOCATION
-ANODE TO BE LOCATED 180 +/- 90 FROM FLOWLINE.
-ANODE TO BE POSTION 75M FROM UNDERGROUND METALLIC STRUCTURES
FLOWLINE
90
90
Preferred Groundbed LocationPreferred Groundbed Location
38
Determining Borehole DepthsDetermining Borehole Depths
Drill Stem Resistance (ohms)
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60
Depth (m)
Resis
tance
(ohm
s) Use drill stem resistance measurements Drill stem simulates ground bed resistance values Theoretical target resistance established Anode installed below water level (10-60 m)
Drill Rig Wellhead
Megger
39
40
Drill RigsDrill Rigs Two types of rigs used Truck mounted Track mounted
41
42
Deep Anode Groundbed Deep Anode Groundbed DetailsDetails
200 mm diameter borehole 30 to 100 meter depth 6 meter surface casing Anodes installed in water MMO anodes Coke breeze backfill 25 mm dia vent pipe Centralizers
43
Cross Section Of Deep Anode Cross Section Of Deep Anode GroundbedGroundbed
44
Titanium / MMO AnodesTitanium / MMO Anodes
32 mm dia x 1220 mm long Individual lead wires 20 year G/B design life 8 amp max output per anode With centralizers
45
Coke Breeze BackfillCoke Breeze Backfill Used for surface and deep
anodes 98% carbon content Small particle size Lowers anode to earth
resistance Promotes uniform current
discharge from anodes
46
Anode / Vent Pipe LoadingAnode / Vent Pipe Loading
Anode
Vent Pipe
Centralizer
Tremmy Pipe
47
Deep Anode Installation RigDeep Anode Installation Rig
Coke breeze mixing tank Tremmy tube “A” frame for lowering
anode assemblies
48
Coke Breeze Pumping OperationCoke Breeze Pumping Operation
Coke breeze mixed in slurry Pumped from the bottom up
thru flexible PE pipe
49
Power SuppliesPower Supplies
• Use existing power supplies when possible
• Use air cooled rectifiers where 415 VAC power is within 500 meters
• No extension of 33 KV power lines
• Use solar power supplies where AC power is not available
50
Transformer RectifiersTransformer Rectifiers
415 volt AC input 25 or 50 amp capacity Air cooled (NEMA 3R) Constant voltage type Manual output control via taps Data loggers provided Installed with sun shade
51
Solar Power SuppliesSolar Power Supplies
240 watt output capacity (0-24 volt) 26 photovoltaic modules per system Typically located adjacent ground bed
52
Solar Power ControllerSolar Power Controller Automatic CP current control Data logging capability Interrupting circuit
53
Storage BatteriesStorage Batteries Lead acid type 1680 amp-hr capacity 5 day autonomy Housed in stainless steel
enclosure
54
Negative Connection To WellNegative Connection To Well Bracket for cable connection Removed during work overs
55
Special ToolsSpecial Tools
Multimeter (digital high input impedance) Cu/cuso4 reference electrode Clamp on ammeter Current interrupter Variable resistor for dummy load PC with software for data loggers Test reel and test leads
56
Project CP CriteriaProject CP Criteria Primary
– 15 ampere per well casing per feed recommendations
Secondary– 100 mV polarization shift
Interference to foreign structures– Limited to +50 mV shift with current “on”
57
Assessment Of CP Current Assessment Of CP Current To CasingTo Casing
It = total current output of power supply
Is = current drain from structures connected to wellhead (measured using swain meter)
Current to casing = it - is
58
Commissioning ActivitiesCommissioning Activities Pre-commissioning check list Power supplies energize per manufacturers
recommendations Set power supplies at desired current output Allow casing and flow lines to polarize Re-test after 24 hours (polarization shift) Download data loggers Investigate and mitigate interference
59
General SafetyGeneral Safety
The CP equipment presents various hazards that can cause injury to personnel
Only qualified personnel should be allowed to work on CP systems
Personnel working on CP equipment should be thoroughly familiar with the manufacturers O & M manuals
60
PPE And Safety EquipmentPPE And Safety Equipment
Helmet Eye protection Steel tip boots Rubber gloves (recommended by battery
manufacturer
61
Safety HazardsSafety Hazards Batteries present spark, burn and acid hazards
High DC current from the solar panels and batteries which can cause burn and shock hazards
415 VAC input to rectifier presents lethal shock hazard
Disconnection of negative connection at well provides explosion hazard at wellhead if combustible gases are present
62
The End The End Thank YouThank You
63
TestingTesting
64
Routine TestingRoutine Testing Solar power supplies Transformer rectifier power supplies Adjustment of the DC output Measure current to casings (dual sites) Measure anode output currents Remote on / off potential of well casing Potential of flow line Current measurement through flow lines Down loading of date loggers (every 60 days)
65
AC Input Measurement Of AC Input Measurement Of RectifierRectifier
AC power measurements must be done by qualified personnel
Use multimeter with insulated test leads
415 volts between phases (+/- 10%)
66
DC Current Output Of DC Current Output Of RectifierRectifier
DC current output of panel ammeter can be verified by using: Clamp on ammeter Panel shunt
67
DC Voltage Output of DC Voltage Output of RectifiersRectifiers
Accuracy of the panel volt meter can be determined using a multimeter
68
Measure and Balance CP Current To Well Casings Measure and Balance CP Current To Well Casings (Dual Sites)(Dual Sites)
Dual sites provided with current control box (CCB)
Resistance added to well with highest CP current as required to balance the current
Variable resistors rated at 0.1 to 0.5 ohms (interchangeable)
69
Tap Adjustment Of RectifierTap Adjustment Of Rectifier Fixed voltage type Manual tap adjustments (25) Course (A-E) and fine (1-5) tap for
each phase Taps must be the same for each phase Tap increments of 4% - DC voltage
rating 1.2 volt for 30 volt units 2.4 volt for 60 volt units
Shock hazard – power off while making adjustments
Correct Correct
WrongWrong
70
General Components Solar General Components Solar Power Supplies for CPPower Supplies for CP
Solar Panels Batteries Controller
– Charge controller– CP controller
71
Electronic Components Of Electronic Components Of Solar ControllerSolar Controller
MSRx array switch PCB assembly (input power)
MSRx control PCB (input controller)
CPU20 power PCB assembly (output power)
CPU20 control PCB (output control)
Shunt PCB assembly (feedback)
72
Solar Power Alarm SettingsSolar Power Alarm Settings Controller has 12 individual alarms Regulator Fault (RF) will occur if any alarm is
activated Low, high and load disconnect voltages are set
per manufacturer recommendation Controller senses battery voltage and temperature The CP alarm will be activated below a preset
current value
73
Controller Alarm LED’sController Alarm LED’s
High voltage Low voltage Charge fault Regulator fault CP alarm Fire alarm Low voltage disconnect
Alarms can be simulated in test menu Alarms can be simulated in test menu
74
CP Controller AdjustmentsCP Controller Adjustments
Constant current / voltage mode selected by rotary switch
Limits are adjustable via 10 turn potentiometer
Set and actual values displayed on LED
75
Normal Operating DisplayNormal Operating Display
76
Shunt RatingsShunt Ratings
Individual battery input and output shunts provide data for charge current control and amp-hour calculations
77
Shunt Rating / ConversionsShunt Rating / Conversions
EQUIPMENT SHUNT RATING CONVERSION60 V / 50 A Rectifier 60 amp / 50 mV 1 mV = 1.2 amp
30 V / 25 A Rectifier 30 amp / 50 mV 1 mV = 0.6 amp
Solar input array 100 amp / 60 mV 1 mV = 1.66 amp
Solar load 60 amp / 60 mV 1 mV = 1 amp
Anode Junction Box .01 ohm 10 mV = 1 amp
Current Control Box 50 amp / 50 mV 1 mV = 1 amp
78
Anode Current MeasurementsAnode Current Measurements
Individual anode lead wires terminated in anode j-box
Each anode circuit includes calibrated shunts rated at .01 ohm
Multimeter used to measure the voltage drop across the shunt– 10 mV = 1 amp
79
Flowline Current MeasurementsFlowline Current Measurements
Swain type DC ammeter used to measure current flow on flow lines
Magnitude and direction of current must be recorded
80
Interrupting Current Output of Interrupting Current Output of RectifierRectifier
Rectifier includes relay & contact to interrupt DC output
Separate current interrupter required Terminal strip on front panel allows
access to relay contacts
81
Sample Interference Test Sample Interference Test DataData
Test LocationP/S Potential (mV)
ResultsOn Off Change
Foreign Pipeline 150 m from Groundbed
- 990 - 980 -10 No interference
Flowline of well -1120 -1010 - 110 No interference
Earthing electrode located 40 m from ground bed
-550 -550 0 No interference
Shallow water well located 50 m from ground bed
-640 -650 + 10 Little Interference
82
Set-up and Down Loading of Set-up and Down Loading of Data LoggersData Loggers
Rectifiers and solar power supplies provided with data loggers
Specification requires that voltage and current be monitored on regular basis
60 day storage required Software for data loggers installed on ADCO pc’s
83
Data Logger on RectifiersData Logger on Rectifiers
Data sampled hourly DC output voltage & current of
rectifier stored Data should be down loaded to PC
every 60 days Data logger equipped with RS 232
port required for down load ADCO specific software provided
84
Rectifier Data Logger ConnectionRectifier Data Logger Connection
Standard RS-232 Port
85
Set-up of Rectifier Data LoggerSet-up of Rectifier Data Logger
CRM software has been installed in the ADCO pc’s for data logger communications
Rectifier data loggers are setup in the office and the information is then transferred on site with PC
The setup information includes TR serial number, site name, site number, channel and recording settings
Data transfer is two way communication, information can be sent and received with a PC
86
Data Logger Set-up WindowData Logger Set-up Window(General)(General)
Name: well no. Password: N/A. Company: ADCO. Site address: power source
(cluster / RDS / ETC). Description: CP configuration. Communication type: (unique
no. Per next slide).
87
Communication Type CodesCommunication Type Codes(Unique 5 Digit No.)(Unique 5 Digit No.)
First digit - area – 1 = Sahil– 2 = Asab– 3 = shah– 4 = Bab– 5 = Buhasa
Second digit – well type– 1 = water– 2 = oil – 3 = gas– 4 = observation
Digits 3-5 – well number (123)
88
Data Logger Set-up WindowData Logger Set-up Window(Channel Tab)(Channel Tab)
Channel 1: N/A (ref cell potential) Channel 2: DC output voltage Channel 3: DC output current (shunt multiplier required)
89
Data Logger Set-up WindowData Logger Set-up Window(Rectifier Tab)(Rectifier Tab)
Rectifier information.– Manufacturer.– Model no.– Class (Nema 4X).– Serial no.– DC output rating.
Relay set-up:– Standard.– Instant off delay: 500
milsec.– Recovery: 2 seconds.
90
Data Logger Set-up WindowData Logger Set-up Window(Recording Tab)(Recording Tab)
Sample Intervals: 1 / hour Duration: Indefinite Start Date: Actual (future) Time: Actual Type: “On” Title: “One Hour Recordings” Enable Channels: Tick 2 & 3
91
Down Loading Data LoggerDown Loading Data Logger(Status and Tools Window)(Status and Tools Window)
The relevant T/R is selected from the “Site Selection”
The “Status and Tools” window present options
The download is performed by the “Auto Report” menu
92
Down Loading Data LoggerDown Loading Data Logger(Auto Report Window)(Auto Report Window)
Click “options” button opens Auto Reporting Options Window
Memory: Transfer or Transfer & Clear as desired
Return to Auto Reporting window to begin data transfer
93
Generating ReportGenerating Report Choose “reports” file from CRM folder Enter file name of report desired
– *.LAH for low average high report– *.CSV for one hour recording report
Select and open file for desired site Select “de-limited” for original data type Tick “comma” as delimiter Select “finish” to generate excel report
94
Sample Rectifier Data Logger Sample Rectifier Data Logger ReportReport
Title: , Interrupter: Idle, Type: On, Start: Scheduled, Transfer Time: 07/23/04 13:19
Date Time , TS, S. Rate, 1(V DC), 2(V DC), 3(A DC),
07/21/04 10:00:00, Y, 1 Hour(s), , 5.8800, 9.7980, , , , , ,
07/21/04 11:00:00, , 1 Hour(s), , 5.9000, 9.9300, , , , , ,
07/21/04 12:00:00, , 1 Hour(s), , 5.8200, 9.8040, , , , , ,
07/21/04 13:00:00, , 1 Hour(s), , 5.7600, 9.6840, , , , , ,
07/21/04 14:00:00, , 1 Hour(s), , 5.8500, 9.7260, , , , , ,
07/21/04 15:00:00, , 1 Hour(s), , 5.9300, 9.8820, , , , , ,
07/21/04 16:00:00, , 1 Hour(s), , 5.8000, 9.8220, , , , , ,
07/21/04 17:00:00, , 1 Hour(s), , 5.8700, 9.7800, , , , , ,
RMU SYSTEM (by RCS)SITE REPORT CUMULATIVE
SITE NAME: Bb-123COMMUNICATION No.: 6COMPANY: ADCOADDRESS: Cluster 21DESCRIPTION:
RECTIFIER No: 1 of 1RELAY NO.: 1MANUFACTURER: CorrpowerMODEL CSAY 30 -25SERIAL NO.: 123456CLASS: Nema 3RRATING: 30 Volt / 25 Amp
Title: , Interrupter: Idle, Type: On, Start: Scheduled, Transfer Time: 07/23/04 13:1901 01 01 02 02 02 03 03 03
Min. Ave. Max. Min. Ave. Max. Min. Ave. Max.(V DC) (V DC) (V DC) (V DC) (V DC) (V DC) (A DC) (A DC) (A DC)
7/21/2004 / 10:00:00 AM 5.75 5.88 6.01 15.22 15.65 15.877/21/2004 / 11:00:00 AM 5.82 5.91 6.12 15.31 15.81 15.987/21/2004 / 12:00:00 PM 5.75 5.88 6.01 15.22 15.65 15.877/21/2004 / 1:00:00 PM 5.82 5.91 6.12 15.31 15.81 15.987/21/2004 / 2:00:00 PM 5.75 5.88 6.01 15.22 15.65 15.877/21/2004 / 3:00:00 PM 5.82 5.91 6.12 15.31 15.81 15.98
Date / Time
95
Down Loading of Solar Power Down Loading of Solar Power Data LoggerData Logger
Hardware connection is from lap-top com-port via RS232 connector
Opening the BP-download software a window will request site and operator name
Clicking the “download historical data” tab will start the data transfer. The download data window will open automatically after transfer completion
96
Solar Power Data Logger Solar Power Data Logger ConnectionConnection
Standard RS-232 port
97
Download MenuDownload Menu
98
Sample Readout of Solar Sample Readout of Solar Power Data LoggerPower Data Logger
Site: Bu191 Operator: Anis Downloaded: 29-Jul-2004 at 09:30
Date Time Regulator Status CP Status Alarms
yyyy-mm-dd hh:mm Mode BV Temp A I L ICP V
CP IRC V
DIS
HVA
LVA
LVD
AY1
AY2
LC
FA
RF
CP
BS
TS
2004-07-29 9:25CP Interrupt Timer Stop
2004-07-29 9:21CP Interrupt Timer Start
2004-07-29 9:00 F 26.2 37.4 0.0 2.7 3.8 15.0 0.0
2004-07-29 8:00 F 26.3 36.8 8.8 2.6 3.8 15.0 0.0
2004-07-29 7:00 F 25.6 35.5 5.0 2.7 3.8 15.0 0.0
2004-07-29 6:00 N 25.3 35.2 0.0 2.7 3.7 15.0 0.0
2004-07-29 5:00 N 25.2 35.5 0.0 2.7 3.7 15.0 0.0
2004-07-29 4:00 N 25.3 35.8 0.0 2.7 3.7 15.0 0.0
2004-07-29 3:00 N 25.3 36.2 0.0 2.7 3.7 15.0 0.0
2004-07-29 2:00 N 25.3 36.5 0.0 2.7 3.7 15.0 0.0
99
MaintenanceMaintenance
100
Routine MaintenanceRoutine Maintenance Visually inspect accessible equipment and make
repairs as necessary.
Clean the glass and frames of the solar panels.
Check and clean electrical cable connections.
Inspect and clean sand from rectifiers, data loggers, junction boxes and battery enclosures.
Remove sand accumulation around CP equipment.
101
Trouble ShootingTrouble Shooting Trouble shooting should be carried out by
qualified personnel with cathodic protection experience
The technician must be familiar with the CP system
Drawings, manufacturers manuals and historical operating records should be available
102
Problem of TR SystemProblem of TR System The problem of a AC powered CP system can be
into the following basic areas:
– AC power to rectifier– DC output of power supply– External CP cables– Anode junction box– Groundbed – Structure
103
AC Power ProblemAC Power Problem
Check voltage of input terminal of rectifier
If no voltage present, problem is with the AC power source
104
No DC VoltageNo DC Voltage
Use portable meter to confirm AC power to rectifier
Use portable meter to confirm no DC voltage
If AC exists but no DC voltage present, problem lays within rectifier
Check circuit breaker Check DC fuses Carry out T/R trouble shooting
procedures
105
DC Voltage But No DC DC Voltage But No DC Current From T/RCurrent From T/R
Usually a problem with the external DC circuit
Use dummy load to confirm fault is external of T/R
Check negative connection at wellhead
Check positive connection at Anode J-Box
Conduct continuity test of DC cables
106
Dummy Load Across Power Dummy Load Across Power SupplySupply
A portable resistor can be used to simulate the external CP load
Connecting a dummy load across the T/R output can assist in isolating problem
107
Internal Transformer Rectifier Internal Transformer Rectifier ProblemsProblems
For internal T/R problems use schematic diagram, O & M manual and normal electrical trouble shooting procedures.
108
Isolate Problem Of Solar Isolate Problem Of Solar SystemSystem
The problem of a solar CP system can be isolated into the following basic areas:
– Solar panels– Controller– Batteries– External CP cables– Anode junction box– Groundbed – Structure
109
Solar PanelsSolar Panels
Minimum panel voltage is 17 volts
Two panels in series, 7/6 panel pairs in parallel form two separate circuits
Current of individual panels can be measured by short circuit with amp.-Meter
110
General Problems With Solar General Problems With Solar ControllersControllers
Check for burned componentsCheck internal and external electrical
connectionsCheck fuses and breakersConsult the manufacturers O & M manual
111
Solar Power Supply SchematicSolar Power Supply Schematic
J 4
A D C O - M S R x 2 C O N T R O L P C B
A S S E M B L Y 4 0 0 8 4 8
A D C O - M S R x A R R A Y S W I T C H
P C B A S S E M B L Y 4 0 0 9 1 1
A D C O - M S R x 2 S H U N T P C B
A S S E M B L Y 4 0 0 9 1 2
M S R x F U S E P C B
A S S E M B L Y 4 0 0 9 1 6
J 1
J 5
J 7 J 6
J 3
3 0 2 3 0 1 5 0 1 5 0 2
A R R A Y C P U O U T P U T
E 1 E 2 E 3
4
A D C O - C P U 2 0 C O N T R O L P C B
A S S E M B L Y 4 0 0 8 4 9
R E G
F A U L T
C H R G
F A U L T
L O W V
A L A R M
H IG H V
A L A R M
B A T T
S E N S E
S C R
R E F
C E L L
V
IN P U T
C P
F A U L T
J 1
A D C O - C P U 2 0 P O W E R
P C B A S S E M B L Y 4 0 0 9 0 1
J 3
J 2
O /P
1 2 V
O /P
1 2 V
J 2
J 3 J 1
T B 1
T B 1
S E N S O R 1
J 1
5 1 5 3
8
1
1 4
1 2 1 3
2 4
6 7
2 9
2 12 02 2 2 3
1 6
1 7
1 8
1 0 1 1
F 2
4 0 2 4 0 1
- V E - V E - V E+ V E- V E+ V E+ V E+ V E
L I V E C O M C O ML I V E
B A T T E R Y
+ V E
- V E
B A T T E R Y
S E N S E
J 1
SCREE
N
1 9
The schematic diagram in the O & M manual will assist The schematic diagram in the O & M manual will assist trouble shooting procedures. trouble shooting procedures.
112
Problems With Input PowerProblems With Input Power
Visual inspection for burned components
Verify charging current corresponding to switch indicator
113
Problems With Charge Problems With Charge ControllerController
Over charging– Faulty control PCB– Failure of sub-array switch PCB– Faulty internal / external wiring– Excessive charge voltage
Under charging– Extended period of poor weather– Faulty control PCB– Faulty internal / external wiring– Failure of sub-array switch PCB– Excessive load consumption
114
Problems With CP ControllerProblems With CP Controller No output
– Tripped breaker– Faulty controller PCB– Failure of power PCB– Load disconnected due to low battery voltage– Faulty internal / external wiring
No control of output– Faulty controller PCB– Short circuit of power board– In correct control mode selection
115
BatteriesBatteries
Visual check individual connections
Feel batteries for heat with back of hand
Measure individual battery voltages
Minimum open circuit voltage should not fall below 1.9 Volts
116
Anode With Low Output Anode With Low Output Check cable connections in anode junction box
Disconnect adjacent anodes to confirm anode is functional
Operate anode alone with increased TRU output
Water the ground bed
117
Open DC Output Circuit Open DC Output Circuit Check negative cable connections at wellhead.
Check positive cable connection at anode junction box
Conduct continuity test of negative and positive cables
Install temporary above ground cable Use cable locator to determine the position of
the break
118
High Circuit Resistance High Circuit Resistance Review operating history of systems to
establish trend Check positive cable connection and anode lead
wires in anode junction box Check negative cable connection to wellhead Measure the output of each anode Confirm integrity of DC cables Follow NACE standards for RP0572-2001 for
watering ground bed
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