MidCura 6, 10 и 15 кВ

MidCura series round Segregated Phase Bus Ducts (hereinafter referred to as SPB) for nominal current up to 5,000 A are designed for electrical connections at power plants and substations and for applications in 50 and 60 Hz AC networks, voltage up to 15 kV.

SPB are manufactured for outdoor use with the nominal values of climatic factors according to GOST 15150, GOST 15543.1 of the NF climatic version, Т category of location 1.

• maximum installation elevation above the sea level - up to 1,000 m;
• maximum operating value of ambient temperature for of the NF climatic version, category of location 1 plus 45°C (limit value - plus 50°C); 
• minimum value of operating ambient temperature for of the NF climatic version, category of location 1 minus 60°С (limit value - minus 70°C); 
• maximum operating value of ambient temperature for climatic version Т, category of location 1 plus 55°C (limit value - plus 65°C); 
• minimum value of operating ambient temperature for climatic version Т, category of location 1 minus 10°С (limit value - minus 10°C); 
• relative air humidity 60% at 20°С (mean annual value); top operating value of relative air humidity 80% at 25°С, for of the NF climatic version, category of location 1;
• relative air humidity 80% at 27°С (mean annual value); top operating value of relative air humidity 100% at 35°С, for climatic version Т, category of location 1.

SPB of the NF climatic version, category of location 1, shall be operational under ice deposit up to 20 mm and wind speed up to 15 m/sec, and in case there is no ice deposit – at the wind speed up to 40 m/sec.

Normal operation mode of bus ducts under working conditions shall be ensured for the II, III and IV atmosphere types according to GOST 15150. Concentration of water vapors and current conducting dust in the environment shall not affect performance of bus ducts, and the environment shall not be explosive.

Nominal operating values of external mechanical impact factors are according to GOST 17516.1 for the M5 mechanical version group. Seismic resistance is 8 points MSK at the height of 25 m, 9 points MSK at the height of 10 m.

Protection degree of bus ducts is IP67 according to GOST 14254.

Segregated Phase Bus ducts MidCura consist of the shell (1) shared by three phases and conduct buses (2) of appropriate profiles and sections. The SBP are fixed on the insulators (3) inside the shells, at the tops of an equilateral triangle, by means of special bus holders. MidCura CS have inter-phase metal partitions (4). The partitions are designed to prevent a single-phase shell short circuit from turning into an inter-phase short circuit.

At the installation site, all sections are connected and arc welded in protective gas environment.

Depending on route configurations and applications, elements of bus ducts are subdivided into following connecting sections and assemblies:

• rectangular;
• angular;
• Z-shaped;
• tee-shaped;
• with phase transposition;
• with phase rotation;
• with integrated equipment (current transformers, charge arresters, bushing insulators, voltage limiters, etc.);
• connection block to switchboard cabinets;
• connection block to transformers;
• butt coupling units between sections and buses, compensators, etc.

General views of bus ducts including overall, mounting and connecting dimensions

Fig. 1B. The busduct closed with an enclosure of the round form, without dividing partitions (NSPB - Non Segragated Phase Busduct) , MIDCURA-C series, on rated voltage of 6 kV and rated current to 1600, 2000A

Fig. 2В. The busduct closed with an enclosure of the round form, without dividing partitions, MIDCURA-C series, on rated voltage of 10 kV and rated current to 4000A (NSPB - Non Segragated Phase Busduct) ; and the busduct closed with an enclosure of the round form, with dividing partitions of the MIDCURA-CS series, on rated voltage of 6 kV and rated current to 1600, 2000A (SPB - Segragated Phase Busduct).

Fig.3В. The busduct closed with an enclosure of the round form, without dividing partitions, MIDCURA-C series, on rated voltage of 10 kV and rated current to 5000A (NSPB - Non Segragated Phase Busduct) ; and the busduct closed with an enclosure of the round form, with dividing partitions of the MIDCURA-CS series, on rated voltage of 6 kV and rated current to 4000A (SPB - Segragated Phase Busduct).

Fig.4В. The busduct closed with an enclosure of the round form, with dividing partitions, MIDCURA-C series, on rated voltage of 10 kV and rated current to 5000A.

In accordance with the circuit diagram, following units are installed together with bus ducts:

1. Generator circuit breakers of various types:

• vacuum circuit breakers 3AH37, nominal current up to 6,300 А, voltage up to 10.5 kV.

Current transformers of various types including ТВ-ЭК, ТШЛ as well as AOС. These transformers are manufactured according to accuracy classes from 10Р to 0,2S, nominal protection accuracy limit of secondary windings – 5 to 100, and measuring instrument safety rating of secondary windings – FS50 to FS2. Nominal load on secondary windings at cos φ=0.8 ranges from 2.5 VA to 60 VA.

3. Voltage transformers type CTY, secondary windings options – from 100:3V to 110V, as well as the ЗНОЛП transformers that Russian customers are used to.

4. Compact disconnectors and earthing devices 10.5 kV for nominal current up to 5,000 A, with manual and motor drives.

Bushing insulators of various types, with porcelain or polymeric insulation, for current up to 5,000 A.

6. Contact joint temperature monitoring system.

7. Overheating indicators and alarm devices.

8. Air drying system.

9. Impact sensors for transportation purposes.