6.8.1. Maintenance and repair of means of electrochemical protection of underground gas pipelines from corrosion, control over the efficiency of ECP and development of measures to prevent corrosion damage to gas pipelines are carried out by personnel of specialized structural divisions operating organizations or specialized organizations.
6.8.2. The frequency of performance of work on maintenance, repair and verification of the efficiency of the ECP is established by PB 12-529. It is allowed to combine measurements of potentials when checking the efficiency of ECP with planned measurements of electrical potentials on gas pipelines in the coverage area of ECP facilities.
6.8.3. Maintenance and repair of insulating flanges and ECP installations are carried out according to schedules approved in the prescribed manner by the technical management of organizations - owners of electrical protective installations. During the operation of ECP facilities, their failures in operation and downtime are recorded.
6.8.4. Maintenance of ECP cathode units includes:
Loop Status Check protective earth(re-grounding of the neutral wire) and supply lines. An external inspection checks the reliability of the visible contact of the ground conductor with the body of the electrical protective installation, the absence of a break in the supply wires on the overhead line support and the reliability of the contact of the neutral wire with the body of the electrical protective installation;
Inspection of the condition of all elements of cathodic protection equipment in order to establish the serviceability of the fuses, the reliability of the contacts, the absence of traces of overheating and burns;
Cleaning equipment and contact devices from dust, dirt, snow, checking the presence and compliance of anchor marks, the condition of carpets and contact device wells;
Measurement of voltage, current value at the output of the converter, potential on the protected gas pipeline at the connection point with the electrochemical protection unit turned on and off. In case of discrepancy between the parameters of the electrical protective installation and the commissioning data, its operating mode should be adjusted;
Making appropriate entries in the operating log.
6.8.5. Maintenance of tread units includes:
Measurement of the tread potential relative to the ground with the tread off;
Measurement of the potential "gas pipeline-ground" with the protector on and off;
The value of the current in the circuit "protector - protected structure".
6.8.6. Maintenance of insulating flange joints includes cleaning the flanges from dust and dirt, measuring the potential difference "gas pipeline-ground" before and after the flange, voltage drop across the flange. In the zone of influence of stray currents, the measurement of the potential difference "gas pipeline-ground" before and after the flange should be performed synchronously.
6.8.7. The condition of adjustable and unregulated jumpers is checked by measuring the potential difference "structure-to-ground" at the jumper connection points (or at the nearest measuring points on underground structures), as well as by measuring the magnitude and direction of the current (on adjustable and detachable jumpers).
6.8.8. When checking the efficiency of the operation of electrochemical protection installations, in addition to the work performed during the technical inspection, the potentials are measured on the protected gas pipeline at reference points (at the boundaries of the protection zone) and at points located along the gas pipeline route, every 200 m in settlements and every 500 m on straight sections of inter-settlement gas pipelines.
6.8.9. The current repair of the ECP includes:
All types of technical inspection works with performance checks;
Measurement of insulation resistance of current-carrying parts;
Repair of the rectifier and other circuit elements;
Elimination of breaks in drainage lines.
6.8.10. The overhaul of ECP installations includes work related to the replacement of anode ground electrodes, drainage and supply lines.
After the overhaul, the main equipment of electrochemical protection is checked in operation under load for the time specified by the manufacturer, but not less than 24 hours.
Moscow, 1981
"Instructions for the design of electrochemical protection of underground metal structures and communication cables against corrosion" was developed by military unit 33859, agreed with the State Expertise of Projects, Central Military Project, military unit 14262, military unit 54240, military unit 44011, military unit 52678, military unit 52686 and the Office on protection against electrocorrosion of underground structures and networks" UGH Moscow region.
Design organizations involved in the design of protection of underground metal structures against corrosion must be guided by this Instruction.
1. Introduction
This manual has been developed on the basis of instructions from the Technical Department capital construction Ministry of Defense of 1979 in accordance with the requirements of GOST 9.015-74 "Instructions for the protection of urban underground pipelines from electrochemical corrosion" and " Safety rules in the gas industry".
When developing the instructions, the experience of operating electrical protection devices built according to projects developed by military unit 33859 was used to protect various underground metal structures (PMS), as well as many years of experience of organizations operating different kinds electrical protective installations in the Moscow region.
This instruction applies to the operation of installations for drainage, cathodic and sacrificial protection of pipelines, communication cables, tanks and reservoirs.
When operating protective installations, it is necessary to take into account the departmental and territorial instructions in force in certain regions of the USSR for the operation of PMS electrical protection against corrosion.
The types of work and the frequency of their implementation was adopted in accordance with the current regulatory documentation.
2. General instructions
2.1. Protective devices are put into operation after completion of commissioning and stability testing for 72 hours.
2.2. Before acceptance and inclusion of electrical protection in operation, it is necessary to make sure that the construction and installation work is carried out correctly.
2.3. Installation of electrical protection must be carried out in accordance with the design documentation. All deviations from the project must be agreed with the design and other interested organizations.
2.4. The electrical parameters of the external circuit of the electrical protective installation must comply with the data specified in the technical documentation of the installation.
2.5. Mounted electrical protection installations must include all the necessary elements provided for by the project and the terms of the project approvals.
2.6. The electrical protective installation is put into operation only if it is installed in accordance with the safety regulations and the "Electrical Installation Rules" (PUE).
2.7. Before switching on the protective installation, along the entire length of the protection zone of the protected and adjacent PMS, measurements of the potentials "Is-z" are performed in the normal mode (i.e. without turning on the electrical protective installation).
2.8. Acceptance of electrical protection for operation is carried out by a commission consisting of:
customer representative;
Representative construction organization;
Representative of the commissioning organization;
Representative of the operating organization;
Representative of the office "Podzemmetallzaschita, where necessary and allowed by the conditions of the regime;
Representative of the design organization (if necessary).
2.9. When putting the protective installation into operation, the commission must be presented by the customer with the following documentation:
Project for the construction of electrical protection;
Acts for the performance of construction and installation works;
Executive drawings M 1:500 and diagrams with the application of the protection zone 1:2000;
Information about the results of the adjustment of the protective installation;
Information on the impact of the protective installation on adjacent PMS;
Passports of electrical protective installations;
Permission to connect power to the electrical network;
Acts for hidden work;
Acts for checking the insulation resistance of cables;
Acts for checking the spreading resistance of the anode and protective grounding circuits;
Acts for the acceptance of electrical protective installations into operation.
2.10. After reviewing the as-built documentation, the selection committee checks the effectiveness of the protective installations. To do this, the electrical parameters of the installations and the potentials of the PMS are measured in the area where, in accordance with the commissioning report, the protective potentials are fixed.
2.11. The effect of protection on adjacent PMS is determined by the magnitude of the potentials of these PMS at the points specified in the commissioning report.
2.12. The acceptance into operation of the protective installation is formalized by an act, which reflects:
Deviations from the project and imperfections, if any;
List of executive documentation;
Operating parameters of electrical protection;
Values of PMS potentials within the protected area;
Impact of protection on related ICPs.
2.13. In the event that deviations from the design or imperfections adversely affect the effectiveness of the protection, or contradict the requirements of operation, the act indicates the methods and terms for their elimination, as well as the deadlines for submitting the protective installation for re-submission.
2.14. In case of detection of the inefficiency of the constructed protection or its harmful effect on adjacent PMS, the organization, the author of the protection project, develops additional design documentation that provides for the elimination of the identified deficiencies.
2.15. Each protective installation accepted for operation is assigned a serial number and a special log is started, in which the data of acceptance tests are entered. The log is also used during the planned operation of the protective installation.
3. Equipment for the operation of electrical protective installations
3.1. The operation service must have the following minimum measuring equipment and materials:
Grounding meter "M-416" (MS-08, MS-07) for measuring the spreading resistance of anode, protective grounding circuits and soil resistivity;
Ampervoltmeter "M-231" for visual measurements of potentials "PMS - earth";
Millivoltmeter "N-399" (N-39); for measurements and automatic recording of potentials "PMS - earth" and detection of stray currents;
Polar planimeter, for calculating recorder tapes;
Combined device "Ts-4313" (Ts-4315) for measuring voltage, current and resistance;
Megger M-1101;
Voltage indicator MIN-1 (UNN-90);
Steel reference electrodes for measuring potentials in the zone of stray currents at "I PMS-z" > 1 V;
Copper sulfate reference electrodes for measuring potentials on cable sheaths and pipelines at "I PMS-z"< 1 В;
Electrodes for measuring soil resistivity and spreading resistance of ground loops;
Wire of various sections and grades for the assembly of electrical measuring circuits;
Table No. 1
The values of the minimum polarization (protective) potentials
|
metal structures |
The value of the minimum polarization (protective) potential, V, in relation to the copper sulfate reference electrode |
Wednesday |
|
Steel |
0,85 |
Any |
|
Lead |
0,50 |
Sour |
|
0,72 |
alkaline |
|
|
Aluminum |
0,85 |
Any |
The values of the maximum polarization (protective) potentials
|
metal structures |
Protective coatings |
The value of the maximum polarization (protective) potential, V, in relation to the copper sulfate reference electrode |
Wednesday |
|
Steel |
With protective coating |
1,10 |
Any |
|
Steel |
Without protective coating |
Not limited |
Any |
|
Lead |
With and without protective coating |
1,10 |
Sour |
|
1,30 |
alkaline |
||
|
Aluminum |
Partially damaged finish |
1,38 |
Any |
Corrosive activity of soils in relation to carbon steel depending on their electrical resistivity
|
Name of indicator |
Specific electrical resistance ground, Ohm |
||||
|
St. 100 |
St. 20 to 100 |
St. 10 to 20 |
St. 5 to 10 |
Up to 5 |
|
|
Corrosivity |
Low |
Medium |
Increased |
high |
Very high |
|
Corrosivity |
Low |
Medium |
Increased |
high |
Very high |
6. Methodology for performing electrometric work
6.1. The control of the value of the protective current and the output voltage is carried out according to the instruments of the electrical protection of the installation. Checking of these devices is carried out within the time limits stipulated by the manufacturer's instructions. In the absence of the above devices, the magnitude of the current and output voltage are measured with portable devices.
6.2. The measurement of the potential difference "structure - ground" when checking the operating mode of the cathode station or drainage and when taking a general potential characteristic (once every three months) is carried out by devices of the type "M-231" and "N-39" (N-399).
6.3. The positive terminal of the devices is connected to the protected structure (pipeline, cable, etc.), the negative terminal is connected to the reference electrode.
6.4. Connecting the connecting wire from the positive terminal of the device to the protected structure is carried out at the points indicated on the plans and in the tables of the report on the adjustment of the electrical protection of underground metal structures against corrosion.
6.5. The reference electrode is installed as close as possible to the underground structure. If the electrode is installed on the surface of the earth, then it is placed above the axis of the structure. The steel reference electrode is driven into the ground to a depth of 15 - 20 cm.
6.6. It is recommended to measure the potentials "I PMS - earth" in wells filled with water using the portable electrode method, i.e. when connecting the measuring device to the PMS in the well, the reference electrode is along the PMS route at a distance of 50 - 80 m from the well.
6.7. When measuring with a copper sulfate electrode in dry weather, the place where the electrode is placed on the ground is moistened with water. The soil at the place of installation of the electrode is cleared of litter, grass, etc.
6.8. Measurement of the potential difference "structure - ground" is carried out in the following sequence:
The device "M-231" is installed in a horizontal position;
The arrow of the device is set to zero by the corrector;
The wires from the underground structure and the reference electrode are connected to the M-231 device;
Such a necessary measurement limit is set at which the arrow of the device noticeably deviates, which makes it possible to read the readings of the device;
Instrument readings are recorded.
6.9. If the readings of the device are not more than 10 ÷ 15% of the total number of divisions of the scale, you should switch to a lower measurement limit.
6.10. Start measurements only from large limits, moving, as needed, to a smaller one.
6.11. Potential measurements are made by two performers. One monitors the position of the instrument pointer and at regular intervals (5 ÷ 10 sec.) on command reads the instrument readings aloud. In this case, not the maximum and minimum values of the potentials for the elapsed 5 - 10 seconds are recorded, but the actual position of the instrument pointer at the moment of reading. The second performer watches the time and after 5 ÷ 10 sec. gives the command to count. In total, 90 - 120 readings are recorded at each measurement point.
6.12. Each reading (in volts) is recorded in the protocol, which indicates the address of the measurement point, its number, type and number of the device, measurement mode (with or without protection), number and time of measurements, type of underground structure.
6.13. In the presence of stray currents on structures, automatic recording potentials by recording (self-recording) devices such as "H-39" or "H-399".
Measurements are made at the points specified in the report on the adjustment of electrical protection equipment, as well as at the points of connection of the drain cable to the protected structure and at points with the lowest protective potential. Measurements are made during the period of taking a general potential characteristic.
6.14. The recording of potentials is made within 2 - 4 hours. Preparation of the device, its connection and processing of tapes for recording potentials is carried out in accordance with the instructions of the manufacturer of the device.
6.15. Measurement of the spreading resistance of anode grounding is carried out by instruments of the "MS-08" or "M-416" type in accordance with the instructions of the instrument manufacturer.
7. Processing of measurement results
7.1. Processing the results of measurements of potentials and currents is to determine the average, maximum and minimum values during the measurement.
7.2. When processing the results of measurements of potentials with respect to the ground, performed with a steel reference electrode with visual instruments in the zones of influence of stray currents, the average values of the potentials over the measurement period are determined by the formulas:
where And cf. (+) and And cf. (-) - respectively, the average positive and negative values of the measured values;
And - respectively, the sum of the instantaneous values of the measured values of positive and negative signs;
n- total number of readings;
l, m- the number of readings, respectively, of a positive or negative sign.
7.3. When using a non-polarizable copper sulfate reference electrode, the potential difference between the PMS laid in the field of stray currents and the ground (AND PMS - ground) is determined by the formula
And pms-z \u003d ± And meas - (-0.55) \u003d I meas + 0.55,
And mes - the potential of steel, measured in the field of stray currents, V;
0.55 - the average value of the potentials of steel in soils relative to the copper sulfate reference electrode.
7.4. The calculation of the average values of the potentials measured using copper sulfate is performed:
For all instantaneous values of the measured values of positive and negative signs, less in absolute value than 0.55 V, according to the formula:
And cf. (+) - the average positive value of the PMS potential in relation to the earth B;
AND i- all instantaneous values of the measured potential of a positive or negative sign, less in absolute value than 0.55 V;
n- the total number of readings.
For instantaneous measured values with a negative sign that exceed 0.55 V in absolute value
And cf(-) - the average negative value of the PMS potential in relation to the earth, V;
AND i- instantaneous values of the measured potential of a negative sign, exceeding 0.55 V in absolute value;
m- the number of readings of a negative sign, exceeding 0.55 V in absolute value;
n- the total number of readings.
7.5. Determination of the average values of potentials and currents on recording tapes by recording instruments is performed by a scale ruler of the instrument or by the method of planometry of tapes.
The method of area planning is given in the instructions attached to the planimeter.
8. Reference electrodes
8.1. Steel and non-polarizable copper-sulfate electrodes are used as reference electrodes for measuring "PMS - ground" potentials.
8.2. The steel electrode, made of the same steel as the PMS, is driven into the ground to a depth of 15 - 20 cm above the structure.
8.3. The copper sulphate electrode is installed on the surface of the earth.
8.4. Before measurements with a copper sulfate electrode, the following is required:
clean the copper rod from dirt and oxide films;
a day before measurements, pour the electrode with a saturated solution of pure blue vitriol in distilled or boiled water;
place the filled and assembled electrode in a vessel (glass or enameled) with a saturated solution of copper sulfate so that the porous plug is completely immersed in the solution.
8.5. Electrodes are manufactured in accordance with the recommendations set out in " Instructions for the protection of urban underground pipelines from electrochemical corrosion"or in accordance with the appendix Fig. No. 3.
9. Safety precautions for electrical measurements and operation of electrical protection installations
9.1. Persons who have the right to work with electrical installations with voltage up to 1000 V are allowed to operate cathodic protection stations and drainages. Persons at least 18 years old who know the safety regulations in the gas industry and the rules of technology are allowed to perform electrical measurements on underground metal structures, rail tracks and suction cables safety during electrometric work. In particular, the worker must be familiar with the following safety rules:
Electrical measurements on underground metal structures, rail tracks of electrified transport, etc. produced only by a group of at least two people;
Manhole covers, wells and carpets should be opened and closed only with special hooks;
When performing work in collectors, wells and on the roadway, install fences that prevent movement in this place;
When working in wells and collectors, there must be people on the surface to observe, communicate and, if necessary, provide assistance;
When measuring potentials on the suction cables of traction substations, the instrument terminals are connected only by employees of traction substations;
When measuring potentials on the rails of electrified vehicles, traction substations and transformer substations, it is forbidden to approach closer than 2 m to the contact network, unshielded conductors and other current-carrying parts of the contact network, touch the broken wires of the contact network, climb the supports of the contact network, perform installation work related to with air passage through the wires of the contact network;
Measurements on rail tracks to ensure traffic safety are made only after agreement with the relevant services;
Measurements on the roadway are carried out by two people, one of whom must monitor the safety of work by monitoring traffic; for long-term measurements and heavy traffic, the devices are taken out to a safe area.
9.2. Measurement of potentials in gas wells is carried out using a rod or a team of at least three people: one working in the well and two observing him from the surface of the earth, the observers hold a rope tied to the protective belt of the worker in the well, so that, if necessary, quickly lift it up.
Work in gas wells alone is prohibited:
9.2.1. Before lowering the worker, the lid of the well must be open for ventilation for at least five minutes. Checking the presence of gas is carried out by a gas analyzer and by smell.
9.2.2. It is strictly forbidden to use open fire in wells! It is allowed to turn on and off portable electric lamps and lanterns powered by batteries and accumulators only on the surface of the earth.
9.2.3. During work related to the disconnection of the gas pipeline, the existing electrical protection must be turned off.
9.3.1. In order to avoid sparking when performing work at these facilities related to breaking the pipeline circuit (installation of gate valves, connector of flange connections, etc.), the following safety measures must be provided:
Turn off all electrical protection installations;
The detachable parts of the pipelines are connected by a cable jumper, the jumper is grounded. Removal of the jumper is allowed only after the completion of work;
When switching on electrical protective installations, the load is connected first, and then alternating current, shutdown is performed in the reverse order;
The packet switches are only adjustable when the protective installation is de-energized.
1 - PMS; 2 - instrumentation; 3 - device M-231; 4 - reference electrode.
Rice. No. 1. Scheme for measuring the potential difference "PMS - earth"
(a) - at the instrument connection point; b) - by the method of a portable electrode)
1 - device M-416 (MS-08); 2 - ground electrode
Rice. No. 2. Scheme for measuring soil resistivity
Rice. No. 3. Copper sulfate and steel reference electrodes
Commissioning of electrical protective installations. All newly installed devices and installations for electrical protection of gas pipelines against corrosion are accepted for operation by a commission consisting of representatives:
Ш offices or management protection services;
Ш operational trust or office;
Sh customer;
Sh construction and installation organization.
When accepting installations, the contractor submits to the commission the following as-built technical documentation:
Ш executive plan for the placement of electrical protection installations with references on a scale of 1: 500;
Ш passport for the installation of electrical protection;
Ш acts for hidden work on laying a drainage cable, on installing an anode ground loop (for cathodic protection stations), on installing a protective ground loop, on checking the spreading resistance of an anode ground loop (for cathodic protection stations), on installing power lines, etc .;
Ш permission of the power supply organization to connect the installation to the power line.
In the presence of members of the commission, testing of the electrical protection installation with appropriate measurements should be carried out. Commissioning of protective devices and installations is permitted on the basis of acts of acceptance committees. When the plant is put into operation, its influence on neighboring metal structures. Such verification should be carried out in the presence of representatives of the owners of these facilities.
Maintenance and repair of electrochemical protection installations
Operation of drainage installations consists in the maintenance (inspection) of installations, monitoring their operation and, if necessary, changing the operating mode, as well as periodic control measurements on protected gas pipelines.
During maintenance (inspection) of drainage installations, they are carried out at least four times a month and include:
Ø external inspection of all drainage elements in order to identify external defects;
Ш Checking the health of the fuses;
Ш Checking the status of the contacts on the relays available on the drainage;
Ш cleaning relay contacts, as well as cleaning the drainage (cabinet) from dust, snow, dirt, etc.
When monitoring the operation of drainage installations, the following is carried out:
Ш measurement of the average value of the current passing in the drainage circuit, and determining the direction of the current in which the drainage works;
Ø measurement of the magnitude and sign of the potential difference between the protected structure and the rails (negative bus), at which polarized drainage is triggered;
Ш determination of the average value of this potential difference;
Ш measurement of the potential difference between the protected structure and the ground at the point of connection of the drainage.
During the operation of cathode stations, a technical inspection and control over their work is carried out.
The technical inspection includes:
Ш check of serviceability of installation of fuses;
Ø cleaning of units from snow, dust and dirt.
Inspection is carried out at least twice a month according to the schedule. The results of the inspection are recorded in the journal.
Control over the operation of the cathodic protection station (CPS) of gas pipelines consists in measuring:
Ш value of current RMS;
Ш value of the output voltage of the cathode station;
Ш potential difference gas pipeline - earth.
The operation of protectors consists in technical inspection and control of their work.
The technical inspection of the tread units is carried out once every six months, and the performance control is carried out twice a year.
When monitoring the operation of tread installations, the following measurements are taken:
Ш potentials of the protected gas pipeline in relation to the ground, both at the points of connection of the protectors, and in the sections between the protectors;
Ш current strength in the circuit protector - gas pipeline;
Ш electrochemical potential of the protector in relation to the ground.
The protector is considered unsuitable for further use if its wear is 90%. Such protectors are replaced with new ones.
The current repair of protective installations is carried out during operation on the basis of the conclusions of the technical inspection.
Current repair of electrochemical protection installations includes:
Ш all types of technical inspection and maintenance works with checking the efficiency of electrochemical protection installations;
Ш repair of the rectifier and other elements of the circuit;
Ш measurement of insulation resistance of current-carrying parts;
Ø elimination of breaks in drainage lines;
Ø carrying out a complete audit of the equipment.
Overhaul installations of electrochemical protection are carried out approximately once every five years and include work on the replacement of anode ground electrodes, drainage and supply lines. After a major overhaul, the main electrical protection equipment is checked in operation under load for a period specified by the manufacturer, but not less than 24 hours. For the period of maintenance and overhaul, the installations are dismantled and replaced with similar ones from the reserve.
7 Requirements for the maintenance and repair of ECP installations during operation
7.1 Maintenance and repair of ECP units during operation are carried out to keep them in full working order, prevent premature wear and failures in operation and are carried out in accordance with the schedule of maintenance and scheduled preventive repairs.
7.2 The schedule of maintenance and scheduled preventive repairs should include the definition of the types and scope of maintenance and repair work, the timing of their implementation, instructions on the organization of accounting and reporting on the work performed
7.3 At each protective installation, it is necessary to have a control log in which the results of inspection and measurements are entered, Appendix G.
7.4 Maintenance and scheduled preventive repairs are carried out:
maintenance - 2 times a month for cathodic, 4 times a month - for drainage installations and 1 time in 3 months - for galvanic protection installations (in the absence of telemechanical control). If there are means of telemechanical control, the timing of technical inspections is established by the management of the OETS, taking into account data on the reliability of telemechanics devices;
maintenance with efficiency check - 1 time in 6 months;
maintenance - 1 time per year;
overhaul - 1 time in 5 years
inspection of all elements of the installation in order to identify external defects, check the density of contacts, serviceability of installation, absence mechanical damage individual elements, the absence of burn marks and traces of overheating, the absence of excavations along the route of drainage cables and anode grounding;
checking the health of the fuses (if any);
cleaning the housing of the drainage and cathode converter, the unit of joint protection from the outside and inside;
measurement of current and voltage at the converter output or between galvanic anodes (protectors) and pipes;
measuring the potential of the pipeline at the connection point of the installation;
production of an entry in the installation log about the results of the work performed;
elimination of defects and malfunctions identified during the inspection that do not require additional organizational and technical measures.
all technical inspection works;
measurements of potentials in permanently fixed strong points.
7.7 Maintenance includes:
all technical inspection works with efficiency checks;
measurement of insulation resistance of supply cables;
one or two of the following works: repair of power lines (up to 20% of the length), repair of the rectifier unit, repair of the control unit, repair of the measuring unit, repair of the unit body and attachment points, repair of the drainage cable (up to 20% of the length), repair of the contact device anode ground loop, repair of an anode ground loop (in the amount of less than 20%).
all works on technical inspection with verification of the effectiveness of the ECP;
more than two works from the list of repairs listed in clause 7.7 of this standard, or repairs in the amount of more than 20% - the length of the power line, drainage cable, anode ground loop.
7.10 In order to promptly perform unscheduled repairs and reduce interruptions in the operation of ECP, organizations operating ECP devices should have a reserve fund of converters for cathodic and drainage protection at the rate of 1 backup converter for 10 operating ones.
8 Requirements for methods for monitoring the efficiency of ECP installations during operation.
8.1 ECP efficiency control of pipelines of heating networks is carried out at least 2 times a year (with an interval of at least 4 months), as well as when changing the operating parameters of ECP installations and when changing corrosion conditions associated with:
laying new underground structures;
in connection with the repair work on heating networks;
ECP installation on adjacent underground utilities.
8.2 When checking the parameters of electrical drainage protection, the drainage current is measured, the absence of current in the drainage circuit is established when the polarity of the pipeline is reversed relative to the rails, the drainage response threshold is determined (if there is a relay in the drainage circuit or control circuit), as well as resistance in the electrical drainage circuit.
8.3 When checking the operation parameters of the cathode station, the cathodic protection current, the voltage at the output terminals of the cathode station and the potential of the pipeline at the contact device are measured.
8.4 When checking the parameters of the galvanic protection installation (when the protectors are located in channels or chambers), the following is measured:
current strength in the circuit between the protector sections and pipelines;
the magnitude of the shift in the potential difference between the pipeline and the measuring electrodes before and after connecting the protector sections to the pipelines.
channelless and channel laying with the placement of the AZ outside the channel is carried out according to the potential difference between the pipeline and the MES installed in a stationary or non-stationary instrumentation (in the latter case, using a portable MES).
8.6 A diagram of a portable MES is shown in Figure 4 of Appendix A STO-117-2007 “Heat network pipelines. Corrosion protection. Creation conditions. Norms and requirements”, scheme and specifications MES of the ENES and ESN-MS types, installed in stationary instrumentation, are given in Appendix P STO-117-2007 “Pipes of heating networks. Corrosion protection. Creation conditions. Norms and requirements".
8.7 Stationary instrumentation should be installed in areas of heat networks where the minimum and maximum allowable values of protective potentials are expected, at the intersection of heat networks with rails of electrified transport
8.8 In the absence of stationary instrumentation, a portable MES is installed on the surface of the earth between pipelines (in plan), at the bottom of the thermal chamber (if there is water in it). Before installing the electrodes, the soil must be loosened to a depth of 4-5 cm and solid inclusions larger than 3 mm must be removed from it. If the soil is dry, it should be moistened until it is completely saturated with tap water. For measurements, devices such as EV 2234, 43313.1, PKI-02 are used.
8.9 The duration of measurements in the absence of stray currents should be at least 10 minutes with continuous recording or with manual recording of the results every 10 seconds. In the presence of stray tram currents with a frequency of 15-20 pairs per hour, measurements must be carried out during the hours of morning or evening peak load of electric transport.
In the zone of influence of stray currents of electrified railways the measurement period should cover the starting moments and the time of passage of electric trains in both directions between the two nearest stations.
8.10 The values of the potential difference between the pipelines and the MES in the protection zone can be in the range from minus 1.1 to minus 3.5 V.
8.11 The average value of the potential difference U cf (V) is calculated by the formula:
U cf = U i / n, (8.1)
where U i is the sum of the values of the potential difference; n is the total number of readings.
The measurement results are recorded in the protocol (Appendix I of this standard), and also recorded on the maps of heat networks.
8.12 If inefficient operation of cathodic or drainage protection installations is detected (their coverage areas are reduced, potentials differ from permissible protective ones), it is necessary to regulate the operation mode of ECP installations.
8.13 AZ current spreading resistance should be determined in all cases when the operating mode of the cathode station changes dramatically, but at least once a year. The current spreading resistance of the AZ is determined as the quotient of dividing the voltage at the output of the cathode installation by its output current or when the AZ is located outside the channel using devices such as M-416, F-416, F 4103-M1 and steel electrodes according to the scheme shown on rice. 1. Measurements should be made during the driest time of the year. The drain wire (6) must be disconnected for the duration of the measurements. With a length Laz, the supply electrode (5) is referred to a distance of 3Laz, the auxiliary electrode (4) - to a distance a 2Laz.
1 - anode ground electrodes; 2 - control and measuring point; 3 - measuring device; 4 - auxiliary electrode; 5 - supply electrode; 6 - drainage wire.
Figure 1 - Measurement of spreading resistance of anode grounding
When the AZ is located in the channels, the current spreading resistance of the AZ is determined when the channel is flooded or silted up to the level of the insulating structure of the pipes. If there are several AZ arms, their resistance to current spreading is determined separately.
8.14 Monitoring the effectiveness of the action of ECP means on pipelines of thermal networks of channel laying when the AZ and galvanic anodes (protectors) are located directly in the channels is carried out by the value of the displacement of the potential difference between the pipeline and the RE installed on its surface (or heat-insulating structure) towards negative values within the limits 0.3 to 0.8 V.
For ECP using magnesium alloy protectors, the potential difference between the SE and the pipeline must be at least 0.2 V.
8.15 Prior to the start of measurement work in a given zone of the ECP, the levels of flooding of the channel and chambers are determined, if possible, visually or by an instrumental method. In the latter case, the level of flooding is determined, reaching the points of installation of the RE on the supply and return pipelines - at the level of the lower generatrix of the heat-insulating structure.
8.16 Checking the presence of water at the level of the DE installation is carried out in the following sequence:
Cathodic protection stations are turned off (protectors are not turned off when they are used);
A megaohmmeter is connected to the conductor from the pipeline at the instrumentation and VE;
With the jumper removed on the instrumentation between the pipeline and the SE, the electrical resistance R is measured.
The value R 10.0 kOhm indicates the presence of water in the channel (chamber) at the level of the installation of the SE or above it.
Similar measurements are made at other points where VEs are installed.
8.17 Measurement of the potential of pipelines in relation to the SE in areas where the channel is flooded at the level of the SE installation or above it (after the technical inspection of the ECP installations) is carried out in the following sequence:
When the RMS is off, connect a voltmeter to the terminals of the control point: the positive clamp of the voltmeter - to the terminal "T" (pipeline), the negative - to the terminal of the auxiliary electrode. For measurements, a voltmeter with an input resistance of at least 200 kOhm per 1.0 V of the instrument scale is used (multimeter type 43313.1, voltammeter type EV 2234). The toggle switch or jumper must be open.
Not less than 30 minutes after the disconnection of the RMS, fix the initial value of the potential difference between the pipeline and the SE (I ref.) taking into account the polarity (sign).
Turn on the RMS by setting its operation mode at the minimum current and voltage values.
By increasing the current strength in the SKZ circuit, set its value when the potential difference between the pipeline and the SE is reached: And ' t-v.e. within the range from minus 600 to minus 900 mV (not earlier than 10 minutes after setting the current value).
Calculate I t-w.e. taking into account I ref.
And t-w.e. = I t-w.e. – And ref. , mV
Calculation example No. 1 .
And ref. \u003d -120 mV, I’ t-we. = -800 mV.
And t-w.e. = -800 - (-120) = -680 mV.
Calculation example No. 2 .
And ref. \u003d + 120 mV, I’ t-we. = -800 mV
And t-w.e. -800 - (120) = -920 mV.
8.18 If the obtained values of And t-w.e. on the instrumentation, the protection coverage areas (in areas of flooding or channel drift with soil) are not within the range of minus 300–800 mV, the converter current strength is adjusted.
Note. The increase in the current strength of the converter must be carried out taking into account the maximum permissible value of the voltage at the output of the converter, equal to 12.0 V.
8.19 Upon completion of the measurement work, if the CE is made of carbon steel, the CE is closed with the pipeline. If the CE is made of stainless steel, the CE is not connected to the pipeline.
8.20 In case of malfunctions of the SE (damage to conductors, fastenings to the pipeline of the SE), at accessible points, a portable SE is installed near the surface of the heat-insulating structure, with the help of which the above measurement work is performed.
8.21 If sections of pipelines are found that are not subject to flooding and are not in contact with the drift soil in the area of a separate arm of the anode earth electrode, it is advisable to disconnect the indicated section (arm) from the ECP system until the channel is flooded in this section. After turning off the specified section, additional adjustment of the operating mode of the SKZ is necessary. It is advisable to re-equip the SKZ by using a device for automatic start or shutdown of the SPCS (or individual sections of pipelines) depending on the level of canal flooding in these sections.
8.22 Control of the effectiveness of the ECP with the use of galvanic anodes (protectors) made of magnesium alloys placed on the bottom or walls of the channels is carried out after the work specified in paragraphs 8.15-8.16 of this standard.
8.23 When fixing the flooding of the channel at the installation site of the DE, the operation of the sacrificial protection is checked by measuring:
Current strengths in the circuit of the link (group) "protectors - pipeline";
The potential of the protector or a group of protectors disconnected from the pipeline, relative to the copper-sulfate reference electrode installed at the bottom of the channel (if possible) or above the channel in the installation area of the controlled group of protectors;
The potential of the pipeline in relation to SE with the group of protectors switched off and on. The data are recorded in the protocol given in Appendix K of this standard.
Measurements of these parameters are carried out only if it is possible to disconnect a group of protectors from pipelines and connect measuring instruments.
The presence of current in the circuit "protectors - pipeline" indicates the integrity of this circuit;
The potentials of the protectors disconnected from the pipeline, the values of which (in absolute value) are not lower than 1.2 V, characterize the protectors as serviceable (the potentials of the protectors are measured only in the presence of electrolytic contact of the protectors with electrolyte - water at the bottom of the channel);
The potential difference between the pipeline and the SE with the group of protectors on and off, which is at least 0.2 V, characterizes the effectiveness of the protector protection of pipelines.
8.24 Direct assessment of the risk of corrosion and the effectiveness of the ECP of pipelines of thermal networks of channel laying and in the areas of their laying in cases can be carried out using corrosion rate indicators of the BPI-1 or BPI-2 type. The essence of the method of direct assessment of the risk of corrosion and the effectiveness of the ECP, methods of data processing when examining the state of the surface of BPI-1, when BPI-2 is triggered, are set out in section 11 STO-117-2007 “Pipes of heating networks. Corrosion protection. Creation conditions. Norms and requirements»
8.25 The serviceability of the EIS is checked at least once a year. For this purpose, special certified indicators of the quality of electrically insulating connections are used. In the absence of such indicators, the voltage drop across the electrically insulating joint or synchronously the potentials of the pipe on both sides of the electrically insulating joint are measured. Measurements are carried out using two millivoltmeters. With a good electrically insulating connection, the synchronous measurement shows a potential jump. The results of the check are drawn up in a protocol in accordance with Appendix L of this standard.
8.26 If six or more failures in the operation of the converter were observed at the operating ECP installation during the year, the latter must be replaced. To determine the possibility further use The transducer must be tested to the extent stipulated by the requirements of pre-installation control.
8.27 In the event that the total number of failures in its operation exceeds 12 during the entire operation of the ECP installation, it is necessary to conduct a survey of the technical condition of pipelines along the entire length of the protective zone.
8.28 The total if the duration of interruptions in the operation of ECP installations should not exceed 14 days during the year.
8.29 In cases where, in the coverage area of a failed ECP installation, the protective potential of the pipeline is provided by neighboring ECP installations (overlapping of protection zones), then the time limit for eliminating the malfunction is determined by the management of the operating organization.
8.30 Organizations operating ECP installations must annually compile a report on failures in their work.
9 Requirements for the organization of control and maintenance of protective coatings during operation
9.1 During the operation of the protective coatings of pipelines of heating networks, their condition is periodically monitored
9.2 Protective coatings of pipelines of heating networks located in accessible areas are subject to mandatory control and maintenance:
Overhead pipelines;
Pipelines in thermal chambers;
Pipelines in through channels and collectors;
Pipelines in manholes.
9.3 Control of the condition of the protective coatings of pipelines of heat networks located in impassable, semi-passage channels, as well as pipelines of heat networks of channelless laying, is carried out during control openings of heat networks. Maintenance and repair of coatings on these sections of pipelines is carried out during emergency repairs
9.4 Methods for checking quality indicators and eliminating detected defects in protective coatings in the field are given in section 9 STO-117-2007 “Heat network pipelines. Corrosion protection. Creation conditions. Norms and requirements".
9.5 The choice of a protective coating for the implementation of repairs is determined by the purpose * of the heat pipeline (main heat networks, quarterly (distribution) heat networks ) and types of work carried out, which are aimed at ensuring the operational reliability of heating networks, table 1.
9.6 The quality of protective anti-corrosion coatings applied in the course of repair work is checked with the drawing up of Acts of hidden work and entering the results of quality control in the Anti-corrosion work log in accordance with Appendix M of this standard
Types of protective coatings
Table 1
| The purpose of heating networks and the type of recommended coatings |
|||
| Types of work carried out on heating networks | Main heat networks | Central heating networks | Hot water networks |
| Anti-corrosion protection of newly constructed heating networks | Paint and varnish Silicate enamel** Metallization** Alumino-ceramic** | Paint and varnish | Paint and varnish Silicatnoema-left** |
| Anti-corrosion protection during renovation and overhaul heating networks | Paint and varnish Silicate enamel** Metallization** Alumino-ceramic** | Paint and varnish | Paint and varnish Silicatnoema-left** |
| Corrosion protection at current repair and elimination of damage to heating networks | Paint and varnish | Paint and varnish | Paint and varnish |
Notes.
* Within the framework of this Standard, the following division of heat networks is applied depending on their purpose:
main heating networks, serving large residential areas and groups of industrial enterprises - from a heat source to a central heating substation or ITP;
quarterly (distribution) heating networks(hot water and central heating systems) serving a group of buildings or an industrial enterprise, from the central heating or ITP to connecting individual buildings to the networks.
** When applying these coatings, subsequent anti-corrosion protection of welded joints and pipeline elements of heating networks is required with paints and varnishes.
10 Safety requirements when working with protective anti-corrosion
coatings and during the operation of electrochemical protection devices
10.1 When performing work to protect pipelines of the heating network from external corrosion using protective anti-corrosion coatings, the safety requirements given in specifications for anti-corrosion materials and protective anti-corrosion coatings, GOST 12.3.005-75, GOST 12.3.016-87, as well as in existing normative documents.
10.2 Only persons trained in safe methods works that have been instructed and passed the exam in the prescribed manner.
10.3 The working personnel should be aware of the degree of toxicity of the substances used, methods of protection against their effects and first aid measures in case of poisoning.
10.4 When applying and testing protective anti-corrosion coatings containing toxic materials (toluene, solvent, ethyl cellosolve, etc.), the safety and industrial hygiene rules, sanitary and hygienic requirements for production equipment in accordance with current regulatory documents must be observed
10.5 Contents harmful substances in the air working area when applying protective anti-corrosion coatings on pipes, it should not exceed the MPC, according to GOST 12.1.005-88:
toluene - 50 mg / m 3, solvent - 100 mg / m 3, aluminum - 2 mg / m 3, aluminum oxide - 6 mg / m 3, ethyl cellosolve - 10 mg / m 3, xylene - 50 mg / m 3, gasoline - 100 mg / m 3, acetone - 200 mg / m 3, white spirit - 300 mg / m 3,
10.6 All work related to the application of protective anti-corrosion coatings containing toxic substances must be carried out in workshops equipped with supply and exhaust and local ventilation in accordance with GOST 12.3.005-75.
10.7 When working with protective anti-corrosion coatings containing toxic substances, individual protective equipment should be used to prevent toxic substances from entering the skin, mucous membranes, respiratory and digestive organs in accordance with GOST 12.4.011-89 and GOST 12.4.103-83.
10.8 When performing installation, repair, adjustment of ECP installations and electrical measurements on heating networks, it is necessary to comply with the requirements of GOST 9.602, Rules for the production and acceptance of work, sanitary and hygienic requirements.
10.9 During the technical inspection of ECP installations, the mains voltage must be turned off and the drainage circuit open.
10.10 During the entire period of operation of the experimental cathodic protection station, which is switched on for the test period (2-3 hours), there must be a person on duty at the anode earthing circuit, not allowing unauthorized persons to the anode earth electrode, and warning signs must be installed in accordance with GOST 12.4. 026-76.
10.11 In case of electrochemical protection of pipelines of heating networks with the location of anode grounding devices directly in the channels, the DC voltage at the output of the cathodic protection station (converter, rectifier) should not exceed 12 V.
10.12 On sections of pipelines of heating networks to which a cathodic protection station is connected, and anode earth electrodes are installed directly in the channels, signs with the inscription “Attention! The channels are cathodic protected.
Requirements for the handling of production and consumption waste generated during the protection of pipelines of heating networks from external corrosion
11.1 Production and consumption waste generated during the protection of pipelines of heating networks from external corrosion at the stage of acceptance into operation and operation should be considered:
Materials used in the production of anti-corrosion coatings that have lost their consumer properties ( paints and varnishes, solvents, hardeners);
Non-ferrous metal wires used in the production of electrochemical protection devices and which have lost their consumer properties.
11.2 The procedure for handling waste generated during the protection of pipelines of heating networks from external corrosion is determined in accordance with the section “Requirements for the handling of production and consumption waste at the stages of construction and operation” STO-118a-02-2007 “Heat supply systems. Delivery conditions. Norms and requirements".
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TYPICAL INSTRUCTION ON LABOR SAFETY
in the repair and operation of deviceselectrochemical protection of gas pipelines
TOI R-39-004-96
Developer: company "Gazobezopasnost" JSC "Gazprom"
Coming into effect
Validity
1.GENERAL SAFETY REQUIREMENTS
1.1. The following persons are allowed to work on the maintenance and repair of electrochemical protection devices (ECP):
- not younger than 18 years old;
- passed a medical examination;
- having special training;
— who have passed the exam on PEEP and PTB in electrical installations of consumers in the prescribed manner and have a certificate for admission to work with electrical installations;
— who received an introductory briefing on labor protection and safety briefing at the workplace with a corresponding entry in the briefing log.
Maintenance and repair of ECP devices can be performed by ECP fitters who have group 3 for electrical safety in electrical installations up to 1000 V and not less than group 4 when working in electrical installations above 1000 V and are allowed to work independently.
1.2. All work on maintenance and repair of devices of ECP facilities is managed by an ECP engineer who is responsible for organizational and technical measures that ensure the safety of work.
1.3. The head of the department is obliged to issue a copy of the instruction to each worker, who is obliged to study it, if any item is not clear, check its contents with the head.
1.4. Dangerous and harmful factors in the production of works are:
- location workplace on high,
- explosion and fire hazard;
- transported cargo;
— moving machines and mechanisms;
- insufficient illumination of the workplace,
— gas contamination of the working area air,
- increased / decreased air temperature of the working area,
- Availability electric current in electrical installations and electrical networks.
1.5. Employees who violate the safety requirements for the production of work set forth in the instructions are liable in accordance with applicable law.
1.6. Fire and explosion safety requirements:
1.6.1. Fire safety of ECP devices must be ensured by proper technical condition equipment, completeness and maintenance of fire extinguishing means in good condition; compliance with fire safety regulations.
1.6.2. Fires in electrical installations, cable channels are eliminated with the help of carbon dioxide fire extinguishers; it is forbidden to use foam fire extinguishers and water to extinguish electrical equipment, live cables.
1.6.3. Spilled flammable liquid extinguish with sand, any foam fire extinguisher, felt mat.
1.6.4. Carry out preventive inspection and repair of electrical equipment in explosive premises only after establishing the absence of gas pollution in the environment.
1.7. The working personnel of the ECP service must be provided with overalls:
cotton suit with water-repellent impregnation,
tarpaulin boots,
combined gloves,
waterproof raincoat,
padded jacket,
trousers with insulated lining,
felted boots.
1.8. In the process of work, personnel must comply with the rules of internal work schedule enterprises.
1.9. ECP devices must meet the following safety requirements:
1.9.1. The installation of cathodic protection must be equipped with a separate ground circuit in accordance with the requirements of the "Electrical Installation Rules".
1.9.2. Protective earth resistance must not exceed 4 ohms.
1.9.3. During the operation of electrochemical protection installations, periodic monitoring of the state of protective grounding should be carried out by opening and inspecting grounding devices; measurement of protective grounding resistance must be carried out at least once a year.
1.9.4. Personnel taking instrument readings are prohibited from independently carrying out work in the cabinets of installations, climbing the supports of pole transformer substations, touching arresters and other current-carrying parts.
1.9.5. A switching device (knife switch, batch switch, automatic machine) must be installed on the supply to the cathode station.
1.9.6. Cathodic protection devices must have guards, warning posters, and be locked.
1.10. Staff should be trained in how to provide first aid injured.
2.SAFETY REQUIREMENTS BEFORE STARTING WORK
2.1. Before starting work, all employees must:
2.1.1. Receive a safety briefing.
2.1.2. Get a job assignment. Have a firm grasp of the amount of work assigned.
2.1.3. Prepare essential tool, overalls, protective and safety devices.
2.1.4. Check the serviceability of protective devices (tools with insulated handles, dielectric gloves, claws, belt).
2.1.5. Produce necessary shutdowns breaker, switch, automatic. Post appropriate posters (“Do not turn on. People are working”, “Do not turn on - work on the line”).
2.2. It is not allowed to use a faulty tool, devices, protective devices, the period of verification (testing) of which has expired.
2.3. Shutdown air lines transmission lines (TL) 10 kV must be carried out by the organization serving this power line and must be confirmed by an official statement from this organization. After receiving confirmation that the power line has been disconnected, before starting work, use a pointer using dielectric gloves to check the absence of voltage in the line and apply a portable ground.
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