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

22

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

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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