CABLES FOR CONTROL AND MONITORING CIRCUITS – EVOLUTION AND SOLUTIONS

На русскую версию

In order to connect transducers and actuating mechanisms with software and hardware facilities of APCS (Automatic Process Control Systems) with MAXI-TEPMI-POINT cables of control and monitoring circuits with pair wise construction are used.

Earlier for this purpose in the systems of general industrial application cables JE-Y(St)Y in accordance with German standard DIN VDE 0815 were widely used.

The mentioned cables have single copper wires with diameter of 0.8 mm twisted to pairs and insulated with vinyl (PVC) blend which in turn were twisted into elementary four pair bundles, which in turn were twisted into strand. Above the strand were in series placed wrapping, screen made of aluminum polymer band, and sheath of PVC plastic compound. Number of pairs in cable is 2, 4, 8, 12, 16, 20, 32, and 40.

General industrial application insulated cables JE-Y(St)Y with sheath of PVC plastic compound are flame-retardant with separate laying; fire-safety class of cables according to GOST 31565-2012 is 01.8.2.5.4.

Besides that, burning and smoldering of the cable emits sufficient amount of smoke and corrosive combustion gases, which may result in damaging of APCS electric equipment.

Today cables JE-Y(St)Y do not comply with requirements of Technical Regulations on fire safety regulations as of July 2, 2008 No. 123-FZ, GOST 31565-2012 and STO 1.1.1.01.001.0902-2013 and therefore can not be used for group laying in the rooms equipped with computerized and microprocessor equipment, in the buildings and structures with massive presence of people.

Taking into account experience of domestic and foreign developments, in accordance with requirements of FSUE «VNIIA», OJSC «VNIIKP» in cooperation with cable producing companies has developed a series of cables for control and monitoring circuits which enable connection on MAXI-TEPMI- POINT technique.

In 2009 were developed cables with single copper and tin-plated cooper wires with diameter of 0.8 mm with insulation and sheath made of halogen-free polymer compounds of КУППнг(А)-HF and КУППлнг(А)-HF grades in accordance with technical specifications TU 3561-411-00217053-2009.

Functional and electric parameters of developed cables are equal to ones of JE-Y(St)Y cables. Mass production has also been developed.

Fire safety characteristics and electric parameters of cables for control and monitoring circuits are shown in Table 1.

Table 1

Parameter name, unit of measurement Parameter value
cable JE-Y(St)Y КУППмнг(А)-HF КУППмнг(А)-FRHF КУППлнг(А)-HF
КУППнг(А)-HF
КУППлнг(А)-FRHF
КУППнг(А)-FRHF
1 2 3 4 5 6
1 Fire safety parameters          
1.1Fire propagation: with separate laying with group laying according to “A” category with group laying according to “A” category with group laying according to “A” category with group laying according to “A” category
1.2Decrease of transparency,%, not exceeding * 40 40 25 40
1.3Characteristics of corrosive activity          
a)gas content of halogenic acids in equivalent of HCl, mg/g, not exceeding * 5.0 5.0 5.0 5.0
b)specific conductivity of aqueous solution with absorbed produces of smoke and gas emission, mqSm/mm, not exceeding * 10.0 10.0 10.0 10.0
c) рНindex, not less than * 4.3 4.3 4.3 4.3
1.4Fire-resistance, not less than, min. * * 90 * 90
2Electric parameters          
2.1Electric resistance of conductor to DC, Ohm/km, not exceeding 36.6 36.6 36.6 36.6 36.6
2.2 Ohmic asymmetry of conductors in operating pair, %, not exceeding * 3.0 3.0 * 3.0
2.3 Electrical insulation resistance of conductor, MOhm∙km, not less than 100 100 100 100 100
2.4 AC test voltage with frequency of 0.05 kHz within 1 minute, V:                  
- between wires
- between wires and shield
800
800
1000
2000
1000
2000
1000
*
1000
1500
2.5 Operating capacitance at the frequency of 0.8 or 1 kHz,nF/km, not exceeding 100 120 120 120 120
2.6 Maximum attenuation rate, dB/km, at the frequencies, kHz:          
0.8
10
39
1000
1.1
*
*
*
1.1
2.9
5.0
30.0
1.1
2.9
5.0
30.0
1.4
*
*
*
1.1
2.7
4.0
20.0
2.7 Characteristic impedance, Ohm, at the frequencies, kHz:
0.8
31.25
1000
 
 
*
*
*
 
 
350 ± 20 %
100 ± 20 %
80 ± 20 %
 
 
350 ± 20 %
100 ± 20 %
80 ± 20 %
 
 
350 ± 15 % *
*
 
 
450 ± 15 %
120 ± 15 %
110 ± 15 %
2.8 Coupling attenuation at close end at the frequency of 0.8 kHz, dB/1000 m, not less than  
 
*
 
 
70
 
 
70
 
 
70
 
 
70
Note:* — not rated.

As a result of implementation of insulation and sheath made of halogen-free polymer compounds in the structure of developed cables fire-safety class of the cables according to GOST 31565-2012 is П 1б.8.1.2.1.

However, in comparison with cables JE-Y(St)Y developed cables КУППнг(А)-HF are more rigid and have 1.5 times more allowable bending radius during their laying.

In 2012 were developed fire-resistant cables of КУППлнг(А)-FRHF and КУППнг(А)-FRHF grades in accordance with technical specifications TU 3561-442-00217053-2012 with single copper and tin-plated cooper wires, shielded with aluminum polymer band and contact copper wire.

Mass production of the cables has also been developed. Above conductor there is a thermal barrier and insulation made of halogen-free polymer compound.

Fire-safety class of the cables according to GOST 31565-2012 is П1б.4.1.2.1. The cable survive the earthquake with magnitude of 9 points by MSK provided that they are placed above the ground level at up to 60 m in accordance with GOST 30546.1 and have service life of 30 years.

Based on the experience gained during manufacturing of the first series of cables for control and monitoring circuits as well as on the customers requirements, in 2012 were developed cables of КУППмнг(А)-HF and КУППмнг(А)-FRHF grades, in accordance with technical specifications TU 3561-441-00217053-2012 with stranded conductors, insulated and with sheath made of halogen-free polymer compounds, with screen made as braid from tin-plated copper wires. Mass production has also been developed. Implementation of stranded conductors made possible to reduce rigidity and allowable bending radius of the cable which is 1.5 times less than one of JE-Y(St)Y cable.

Cables with stranded conductors are resistant to 10 installation bends per angle of ±900 around of pair of cylinders with diameter equal to quintuple outer diameter of the cable.

Identification of cable components of developed cables (main and auxiliary color coding of wire insulation, color coding of fasteners of each elementary bundle) improves visual monitoring which eliminates mistakes during installation of the cables.

Insulated wires within pairs of each elementary bundle have main color coding in accordance with one shown in Table 2.

Table 2

Arbitrary number of pair within elementary bundle or core Designation and color code of wire insulation
within a pair
wire “a” wire “b”
1 blue red
2 grey yellow
3 green brown
4 white violet

For the purpose of identification of insulated wires within the strand twisted from several elementary bundles, main color coding of insulation of each elementary bundle has an auxiliary color coding (marking) in the form of a group of black transverse half-rings (stripes).

Number of half-rings (stripes) within the group and their width for each elementary bundle are shown in Table 3. Distance between the groups of transverse half-rings is 50–70 mm. Distance between the half-rings within one group is 4–6 mm.

Table 3

Arbitrary number of elementary bundle

Number of half-rings (stripes)

Half-ring width, mm

Color coding of fasteners of elementary
bundle

1

1

1–2

Blue

2

2

1–2

Orange

3

3

1–2

Green

4

4

1–2

Brown

5

5

1–2

Grey

6

1

7–8

White

7

2

7–8

Red

8

3

7–8

Black

9

4

7–8

Yellow

10

5

7–8

Violet

For the purpose of identification of elementary bundles twisted into cable core each elementary bundle in an open spiral pattern is covered with bracing wrap made of multicolor filaments or narrow synthetic tapes in accordance with Table 3.

Cable marking has auxiliary dimensional marks on the outer sheath which eliminates mistakes when measuring cable length during installation works.

In the early August 2014, SC “Zavod “Energokabel” was holding a meeting of interagency committee with the participation of experts of OJSC “Rosenergoatom Concern”, dedicated to performing of type testing of new cables for control and monitoring circuits of КУПЭфПмнг(А)-HF, and КУПЭфПмнг(А)­FRHF grades with stranded conductors, and shielded with aluminum polymer band.

Application of aluminum polymer band as a shield made it possible to reduce complexity of manufacturing of the cables relative to cables with the shield in the form of braid made of tin-plated copper wires.

Judging by results of type testing the interagency committee has confirmed the expediency of alteration of design and production process of the cables for control and monitoring circuits with stranded conductors on technical specifications TU 3561-441-00217053-2012, as follows:

  • incorporation of new types of cables of КУПЭфПмнг(А)-HF, and КУПЭфПмнг(А)-FRHF grades;
  • determination of fire-resistance requirements for the cables with нг(А)-FRHF index as many as 180 minutes;
  • determination of minimum service life requirements to the cables as 40 years;
  • introduction of requirements on durability to the decontamination fluids for the cables.

According to conclusion made by FSUE «VNIIA» cables with “нг(А)-HF” and “мнг(А)-HF” index allow for installation with MAXI-TEPMI- POINT technique which sufficiently increases connection of transducers and actuating mechanisms with software and hardware facilities of APCS, confirmed by testing and practical experience of installation on Kolskaja NPP and Novovoronezhskaya NPP-2.

This way, series of cables for control and monitoring circuits developed by OJSC “VNIIKP” and being produces by Russian companies provides high level of fire and electrical safety as well as convenience of installation along with high manufacturing quality and reliability of supplied products with competitive price. This series of cables ensures complete import substitution, fully complies with requirements of Russian legislation on fire safety and requirements set out during design of software and hardware facilities of APCS of nuclear power plants.

Prepared by: Candidate of Science (Engineering), Chief of Laboratory of OJSC “VNIIKP” Sholudenko M. V. Chief process engineer of JSC “Zavod “Energokabel” Bekreneva I. S.

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