The stray current (stray current) of the subway has a great corrosive effect on urban buildings and the subway itself. In order to effectively limit the stray current of the subway, reduce and eliminate its adverse effects, and ensure that the subway has good overall social and economic benefits, this regulation is formulated. This regulation is applicable to all aspects of the design, construction, operation and maintenance of subway systems that use DC power traction and running rail return current. CJJ 49-1992 Technical Regulations for Corrosion Protection of Stray Current in Subways CJJ49-1992 Standard download decompression password: www.bzxz.net

Engineering Construction Standards Full Text Information System
Industry Standards of the People's Republic of China
Metro Stray Current Corrosion Protection
Technical Regulations
Engineering Construction Standards Full Text Information System
Engineering Construction Standards Full Text Information System
Industry Standards of the People's Republic of China
Metro Stray Current Corrosion Protection
Technical Regulations
Editor: Beijing Institute of Metro Science and Technology Approval Department: Ministry of Construction of the People's Republic of China Implementation Date: 1993 ... Document Information System
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Engineering Construction Standard Full Text Information System
Notice on the Release of the Industry Standard "Technical Regulations for Corrosion Protection of Stray Current in Subways"
Jianbiao [1992] No. 477
According to the requirements of the former Ministry of Urban and Rural Construction and Environmental Protection (88) Chengbiaozi No. 141, the "Technical Regulations for Corrosion Protection of Stray Current in Subways" compiled by the Beijing Institute of Metro Science and Technology has been reviewed and approved as an industry standard, numbered CJJ49-92, and will be implemented from April 1, 1993.
This standard is managed by the Ministry of Construction's Urban Construction Standards and Technology Management Unit, the Ministry of Construction's Urban Construction Research Institute, and its specific interpretation work is the responsibility of the Beijing Institute of Metro Science and Technology.
This standard is organized and published by the Ministry of Construction's Standard and Quota Research Institute. Ministry of Construction of the People's Republic of China
July 25, 1992
Engineering Construction Standards Full Text Information System
Engineering Construction Standards Full Text Information System
Chapter 1 General
Chapter 2
Basic Principles
Chapter 3
Chapter 4
Section 1
Section 2
Section 3
Chapter 6
Section 1
Section 2
Chapter 7
Appendix 2
Appendix 3
Hazard Indicators of Corrosion of Metro Structures and Equipment by Stray Current
Metro Limitation of stray current value
Metro traction power supply system·
Metro running rail return system·
Protection of metal pipeline structures along the subway
Metro main structure
Cable and pipeline structure
Metro and depot structure and facilities
Protection monitoring
General provisions
Monitoring points and measuring rooms
Acceptance and inspection test
Explanation of terms in this code
Test measurement and instrumentation for corrosion and protection of stray current in subway
Explanation of terms used in this code
Additional explanation
Appendix: Explanation of clauses·
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Chapter I General Provisions
Article 1.0.1 The stray current (stray current) of the subway has a great corrosive effect on urban buildings and the subway itself. In order to effectively limit the stray current of the subway, reduce and eliminate its adverse effects, and ensure that the subway has good overall social and economic benefits, this regulation is formulated. Article 1.0.2 This regulation applies to the design, construction, operation and maintenance of subway systems that use DC power traction and running rail return. It mainly includes:
1. Measures related to limiting and reducing the value of stray current in the DC traction power supply system of the subway;
2. Structures and equipment in the subway that may be corroded by stray current or affect its leakage;
3. Anti-corrosion measures in the subway system.
This regulation does not apply to temporary measures taken during the construction of the subway. Article 1.0.3 The engineering design of the subway shall include the content of stray current corrosion protection (active protection and passive protection measures). Article 1.0.4 The construction of the subway must complete various measures to limit stray current and corrosion protection and monitoring facilities of the subway structure in accordance with the requirements of the engineering design, and shall be included in the content of the project acceptance. During the construction process, the construction quality shall be checked in a timely manner section by section to ensure that the technical indicators are met.
Article 1.0.5 Metro lines that operate normally all year round should strive to reduce the stray current value in their operating mode. The subway lines and line superstructures should always be in a clean, dry and well-insulated state.
Article 1.0.6 In addition to complying with this regulation, the stray current corrosion protection of the subway shall also comply with the provisions of the relevant current national standards. Engineering Construction Standard Full-text Information System
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Chapter 2 Basic Principles
Article 2.0.1 The basic principles of subway stray current (stray current) corrosion protection should comply with the following provisions:
, first, focus on treating the root cause and reduce the subway stray current to a minimum; second, limit the spread of stray current to the outside of the subway; third, underground metal pipeline structures near the subway should take effective anti-corrosion measures separately.
Article 2.0.2 The engineering design of newly built subway lines shall include the following contents related to stray current corrosion protection: 1. Measures to limit stray current in the traction power supply and return system of the subway; 2. Tunnel insulation and waterproofing measures with reasonable design, reliable and durable performance; 3. Protection measures for the main structural steel bars and metal pipeline structures; 4. The various cables, water pipes and other pipeline structures laid along the subway line shall be selected with materials, structural design and construction methods that meet the requirements of stray current corrosion protection; 5. The setting plan of anti-corrosion monitoring points along the line and at stations; 6. Demonstration and implementation plan of special protection methods for stray current corrosion. Article 2.0.3 When designing "stray current corrosion protection" for existing subway lines, the results of on-site measurements and investigations shall be used as the basis. Engineering 2 Construction Standard Full Text Information System
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Chapter 3
Metro Structure and Equipment Corrosion Hazard Index by Stray Current
Article 3.0.1 Corresponding electrical measurements shall be made on the subway buildings, structures and equipment in operation to determine the extent of their corrosion by stray current. Article 3.0.2 The hazard index of subway structures and equipment corrosion by stray current shall be determined by the current density leaking from the structure surface to the surrounding electrolyte and the potential polarization shift caused by it.
Article 3.0.3 The leakage current density, a direct quantitative indicator of the risk of electrical corrosion, shall comply with the provisions of Table 3.0.3. Allowable leakage current density of subway structures
Reinforcement in concrete structures
Steel structures
Note: ① The table lists the 1h average value during the peak of train operation; ② The calculation method of leakage current density is shown in Appendix 2. Table 3.0.3
Allowable leakage current density
(mA/dm2)
Article 3.0.4 Indirect indicators of corrosion risk The potential polarization offset (voltage) value of the structure caused by the leakage current shall be the hourly average value measured during the peak train operation time.
Article 3.0.5
The control indicator of the damage of stray current corrosion on the outer surface of the tunnel structure is the deviation of the structural voltage caused by the leakage current from its natural potential value. For the steel bars of the reinforced concrete subway main structure, the average value of the positive offset of the above polarization voltage shall not exceed 0.5V.
Article 3.0.6 For metal armored cables directly buried in the soil, the dangerous voltage caused by stray current corrosion shall not be greater than the values ​​listed in Table 3.0.6. Cable metal outer armor dangerous voltage
"Dangerous voltage" value (V)
Iron grounding electrode
Copper sulfate measurement reference electrode
Note: The table lists the 1h average value during the peak of train operation. Engineering Construction Standard Full Text Information System
Soil resistivity p
(Q·m)
100~500
500~1000
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Limitation of subway stray current value
Chapter 4
Section 1 Metro traction power supply system
Article 4.1.1 In the DC traction power supply system using running rail return, the overhead line should be connected to the positive busbar of the traction substation, and the return running rail should be connected to the negative busbar.
Article 4.1.2 The traction power supply system of the newly built subway line should adopt a higher traction voltage and a distributed traction power supply scheme. The DC traction feeding distance should be shortened. Article 4.1.Article 3 Under normal operation, the subway overhead line should implement bilateral power supply. The no-load voltage value on the DC busbar of the traction substation on both sides of the feeder section should be kept consistent, and cross-area power supply should not occur.
Article 4.1.4 Traction power supply shall not be provided from one traction substation to different subway lines.
Article 4.1.5 The negative return line of the traction substation shall use cables, and the number of cables shall not be less than two. The withstand voltage level shall not be lower than 5kv of the power frequency. Article 4.1.6 Metal pipeline structures such as subway structural steel bars, water pipes and cable metal outer armor shall not have direct electrical connection with the return running rails and the negative pole of the power supply.
A polarity discharge protection system may be set up after demonstration. Article 4.1.7 The negative return line of the traction substation shall be connected to the running rails of the main line, and it shall be ensured that the traction current can flow back in both directions in any line section of the running rails. Only the single-line section with a length of no more than 12.5m on the station line and the connecting lines in the depot yard and maintenance depot, etc., can allow unidirectional return flow. Article 4.1.8 The traction power supply network in the subway depot should have the main power supply from the traction substation of this section and the backup traction power supply from the main line. At the junction of the two power sources, the contact network and the return rail should be electrically disconnected and equipped with corresponding circuit breakers and disconnectors, and the two should be able to achieve synchronous operation. Article 4.1.9 The connection and transition sections between different subway lines should obtain the main power supply from the contact network of one subway line, and the other line should provide backup power. The contact network and running rails of the backup power supply line should be electrically disconnected from the contact network and running rails of the transition section from the backup power supply side, and special circuit breakers and disconnectors should be installed, and operation interlocking should be achieved.
The contact rails of unimportant transition sections can achieve traction power supply from one subway line.
Section 2 Subway Running Rail Return System
Article 4.2.1 The transition resistance between the subway running rail used as return and the main structure of the tunnel (or the earth) (measured in sections according to the blocked section and converted to the resistance value of 1km length) should not be less than 15Q·km for newly built lines and should not be less than 32·km for operating lines.
Article 4.2.2 Wooden sleepers must be treated with insulating preservatives first. The end faces and threaded spike holes of the sleeper must be insulated or a special insulating layer must be set.
Threaded spike holes should not be through. The gap between the bottom of the rail and the roadbed shall not be less than 30mm.
The tunnel lining structure and steel structure of the subway should not be used as return. Article 4.2.3
Article 4.2.4 The current transformers, turnouts, etc. in the running rail loop should have good insulation from the roadbed, pavement concrete and main structure of the line. There should also be good insulation between the metal outer armor of the control cable of the turnout transfer device and the turnout body. The insulation requirements for the plastic connecting cable of the choke transformer and the plastic cable for the flow line between the tracks should be the same as those for the negative return cable. Article 4.2.5 In the maintenance and parking garage of the vehicle depot, the running rails of each line should be isolated from the running rails of the yard line by using insulating joints. An isolating switch should be installed at the insulating joint to ensure that the train can drive out of the parking position. There should be good insulation between the track and the grounding loop. There should also be good insulation between the track and metal structures, pipelines, cable outer armor shells, concrete steel bars, etc. Article 4.2.6 There shall be no metal connection between the various metal facilities and equipment in and along the subway tunnel, the rails in the temporary storage hole, spare materials and equipment, etc. and the running rails.
Article 4.2.7 The thickness of the plain concrete layer of the ballast under the rails should not be less than 0.4m.
Article 4.2.8 The structure of the subway line should ensure that the ballast, the upper structure of the line and the track are not corroded and polluted by water flow and water accumulation. The tunnel structure shall not leak or accumulate water, and shall have a good drainage system. It is strictly forbidden to adopt the design and operation mode of directly discharging wastewater into the tunnel.
Article 4.2.9 The return running rail shall be welded into a long rail, and its connection quality shall comply with the relevant standards and meet the requirements of the longitudinal resistance value of the corresponding grade of rails. Article 4.2.10 The connection between the turnout and the turnout in the subway line shall be equipped with a copper lead wire, the cross-sectional area of ​​which shall not be less than 120mm, and the copper lead wire shall be welded to the rail, and the joint resistance shall not exceed the resistance value of a complete track of 1m long. Article 4.2.11 In the return track system, the resistance value added by each current transformer should not exceed the equivalent resistance of a 36m long track. The connection between the choke transformer and the track should use a copper core plastic cable with a withstand voltage level not less than 5kV at the power frequency. Article 4.2.12 In the double-track subway, an inter-track equalizing line should be set up. The insulation level and cross-section of the cable used for the inter-track equalizing line are the same as those of the return cable. In stations with traction substations, the function of the inter-track equalizing line can be achieved by connecting the negative return cable to each track.
Article 4.2.13 In the interval section of the subway line, the setting and distribution of the inter-track equalizing line and the separable breakpoints of the running track should comply with the technical requirements of the stray current test and signal system.
Article 4.2.14 The following parts of the subway running track should be electrically isolated. 1. Between all electrified and non-electrified sections; 2. Between the subway's operating line and the line section under construction; 3. Between the subway and the ground railway line; 4. Between the car stop device of each track of the terminal line and the electrified track.Article 5 In the maintenance and parking garage of the vehicle depot, the running rails of each line should be isolated from the running rails of the yard line by using insulating joints. An isolating switch should be installed at the insulating joint to ensure that the train can drive out of the parking position. There should be good insulation between the track and the grounding loop. There should also be good insulation between the track and metal structures, pipelines, cable outer armor shells, concrete steel bars, etc. Article 4.2.6 There shall be no metal connection between the various metal facilities and equipment in and along the subway tunnel, the rails in the temporary storage hole, spare materials and equipment, etc. and the running rails.
Article 4.2.7 The thickness of the plain concrete layer of the ballast under the rails should not be less than 0.4m.
Article 4.2.8 The structure of the subway line should ensure that the roadbed, the upper structure of the line and the track are not corroded and polluted by water flow and water accumulation. The tunnel structure shall not leak or accumulate water, and shall have a good drainage system. It is strictly forbidden to adopt the design and operation mode of directly discharging wastewater into the tunnel.
Article 4.2.9 The return running rail shall be welded into a long rail, and its connection quality shall comply with the relevant standards and meet the requirements of the longitudinal resistance value of the corresponding grade of rail. Article 4.2.10 The connection between the turnout and the turnout in the subway line shall be equipped with a copper lead connection wire, the cross-sectional area of ​​which shall not be less than 120mm, and the copper lead wire and the rail shall be welded, and the joint resistance shall not exceed the resistance value of a complete track of 1m in length. Article 4.2.11 In the return running rail system, the resistance value added by each choke transformer shall not exceed the equivalent resistance of a track of 36m in length. The connection between the choke transformer and the running rail shall use a copper core plastic cable with a withstand voltage level not less than 5kV at the power frequency. Article 4.2.12 In double-track subways, an inter-track equalizing line shall be set up. The insulation level and cross-section of the cable used for the inter-track equalizing line shall be the same as that of the return cable. In stations with traction substations, the function of the inter-track equalizing line can be realized by connecting the negative return cable to each track.
Article 4.2.13 In the interval section of the subway line, the setting and distribution of the inter-track equalizing line and the separable breakpoints of the running track shall comply with the technical requirements of the stray current test and signal system.
Article 4.2.14 The following parts of the subway running track shall be electrically isolated. 1. Between all electrified and non-electrified sections; Engineering Construction Standard Full Text Information System
Engineering Construction Standard Full Text Information System
2. Between the subway's operating line and the line section under construction; 3. Between the subway and the ground railway line; 4. Between the car stop device of each track of the terminal line and the electrified track. Engineering Construction Standards Full Text Information System
nkAoNirkAcaArticle 5 In the maintenance and parking garage of the vehicle depot, the running rails of each line should be isolated from the running rails of the yard line by using insulating joints. An isolating switch should be installed at the insulating joint to ensure that the train can drive out of the parking position. There should be good insulation between the track and the grounding loop. There should also be good insulation between the track and metal structures, pipelines, cable outer armor shells, concrete steel bars, etc. Article 4.2.6 There shall be no metal connection between the various metal facilities and equipment in and along the subway tunnel, the rails in the temporary storage hole, spare materials and equipment, etc. and the running rails.
Article 4.2.7 The thickness of the plain concrete layer of the ballast under the rails should not be less than 0.4m.
Article 4.2.8 The structure of the subway line should ensure that the roadbed, the upper structure of the line and the track are not corroded and polluted by water flow and water accumulation. The tunnel structure shall not leak or accumulate water, and shall have a good drainage system. It is strictly forbidden to adopt the design and operation mode of directly discharging wastewater into the tunnel.
Article 4.2.9 The return running rail shall be welded into a long rail, and its connection quality shall comply with the relevant standards and meet the requirements of the longitudinal resistance value of the corresponding grade of rail. Article 4.2.10 The connection between the turnout and the turnout in the subway line shall be equipped with a copper lead connection wire, the cross-sectional area of ​​which shall not be less than 120mm, and the copper lead wire and the rail shall be welded, and the joint resistance shall not exceed the resistance value of a complete track of 1m in length. Article 4.2.11 In the return running rail system, the resistance value added by each choke transformer shall not exceed the equivalent resistance of a track of 36m in length. The connection between the choke transformer and the running rail shall use a copper core plastic cable with a withstand voltage level not less than 5kV at the power frequency. Article 4.2.12 In double-track subways, an inter-track equalizing line shall be set up. The insulation level and cross-section of the cable used for the inter-track equalizing line shall be the same as that of the return cable. In stations with traction substations, the function of the inter-track equalizing line can be realized by connecting the negative return cable to each track.
Article 4.2.13 In the interval section of the subway line, the setting and distribution of the inter-track equalizing line and the separable breakpoints of the running track shall comply with the technical requirements of the stray current test and signal system.
Article 4.2.14 The following parts of the subway running track shall be electrically isolated. 1. Between all electrified and non-electrified sections; Engineering Construction Standard Full Text Information System
Engineering Construction Standard Full Text Information System
2. Between the subway's operating line and the line section under construction; 3. Between the subway and the ground railway line; 4. Between the car stop device of each track of the terminal line and the electrified track. Engineering Construction Standards Full Text Information System
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