Air insulated switchgears

Medium Voltage Cell (ABB)

Description - UniGear ZS1 is a switchgear of up to 24 KV, 4000 A, 50 KA, manufactured and installed in more than 100 countries. It is part of the group of medium voltage switchgears with a metal enclosure, suitable for indoor installation. It consists of a unit that can be equipped with a circuit-breaker, contactor or switch-disconnector, as well as with any other accessories available for conventional switchgears. It is approved to be used under special conditions such as marine (off-shore oil rigs, ships, container ships, ferries, tankers...), seismic, nuclear, and tested for IEC, GB/DL, GOST and CSA standards. The functional units of the switchgear are guaranteed arc proof in accordance with the IEC 62271-200 standards, appendix AA, accessibility class, criteria 1 to 5.

The switchgear does not require rear access for installation or maintenance, all the operations can be carried out from the front.
The range of the apparatus available for this switchgear is the most complete in the market, including:

  • withdrawable vacuum circuit-breakers with mechanical or magnetic actuator
  • withdrawable SF6 circuit-breakers,
  • withdrawable vacuum contactors with fuses,
  • fixed version of switch-disconnectors

  • The switchgear can be fitted with instrument transformers or sensors for voltage and current measurement and protection, as well as with any type of protection or control unit.
    Benefits for Users
    High level of personnel safety and protective equipment, simple use safe for the environment – no contact with gas during installation, various types of cable connections, integrated protective equipment system

    Switchgear Characteristics

    Range from 12-17.5 kV, …4000 A, …50 kA do 24 kV, …3150 A, …31.5 kA

    Standards

    The switchgear and main apparatus contained in it comply with the following standards:
  • IEC 62271-1 for general purposes.
  • IEC 62271-200 for the switchgear.
  • IEC 62271-102 for grounding switch.
  • IEC 62271-100 for circuit-breakers.
  • IEC 60071-2 for insulation coordination.
  • IEC 60470 for contactors.
  • IEC 60265-1 for switch-disconnectors.
  • IEC 60529 for protection rating


  • Protection Rating

    Protection rating of the switchgear conforms to the IEC 60529 standard. This switchgear is supplied with the following standard degrees of protection:
  • IP4X for enclosure.
  • IP2X for partitions between compartments
  • Upon request, the external housing can be supplied with a higher degree of protection; In this case, please contact your sales representative. IEC electrical characteristics of this medium voltage switchgear - single busbars - are given in the following table.

    Nominal    voltage

    KV

    7.2

    12

    17.5

    24

    nominal    insulation voltage

    KV

    7.2

    12

    17.5

    24

    nominal    short withstand voltage

    KV 1min

    20

    28

    38

    50

    nominal    withstand atmospheric surge wave

    KV

    60

    75

    95

    125

    Nominal frequency     

    Hz

    50/60

    50/60

    50/60

    50/60

    Nominal    short time withstand current

    KA 3s

    ...50

    ...50

    ...50

    ...31.5

    maximum    current

    KA

    ...125

    ...125

    ...125

    ...80

    Short    internal arc withstand current

    KA 1s

    ...50

    ...50

    ...50

    ...31.5

    Nominal    current main bus

    A

    ...4000

    ...4000

    ...4000

    ...3150

     

     

    Nominal current switch

     

     

     

     

     

    A

    630

    630

    630

    630

    1250

    1250

    1250

    1250

    1600

    1600

    1600

    1600

    2000

    2000

    2000

    2000

    2500

    2500

    2500

    2300

    3150

    3150

    3150

    2500

     

    Nominal current switch with    forced ventilation

     

    A

    3600

    3600

    3600

    2500

    4000

    4000

    4000

    3150



    This switchgear is classified as LSC-2B because busbars, circuit-breakers and cable compartments are physically and electrically segregated.
    This category defines the possibility of accessing the circuit-breaker while busbars and cables are energized.
    Metal Partition – PM
    ŠConcerning the type of partitions or shutters between live parts and an open compartment, a distinction is made between two partition classes:
  • PM class (partition made of metal);
  • PI class (partition made of insulating material).

  • Safety

    When developing a modern medium voltage switchgear, personnel safety must necessarily take priority. This is why this switchgear has been designed and tested to withstand an internal arc due to short-circuit. The tests show that the metal housing of this switchgear can protect the personnel near the switchgear in case of a fault which includes striking of an internal arc.
    This switchgear is fitted with all the available interlocks and accessories needed to guarantee the highest level of safety and reliability for both installation and personnel. The range of medium voltage cells for application in electricity distribution meets all the requirements, from the simplest to the most demanding processes. This switchgear is highly reliable and suitable for application in power utility and industrial networks, power plants and infrastructure facilities. This switchgear has been designed for voltages up to 24kV and can be fitted with circuit-breakers or contactors, both the vacuum and the SF6 gas, and it has been designed to ensure safety of the operator and continuity of operation. The cells are accessed from the front and all operations are performed while compartment doors are closed. A system of mechanical blockages prevents operator’s faults and disables insertion of the lever unless it is completely safe to do so.

    The rated characteristics of the switchgear are guaranteed under the following ambient conditions:
  • minimum ambient temperature: -5 °C
  • maximum ambient temperature: +40 °C
  • Ambient humidity:
  • maximum daily average of relative humidity 95% RH
  • maximum average of water vapor pressure 2.2 KPa
  • maximum monthly average of relative humidity 90% RH
  • maximum monthly average of water vapor pressure 1.8 KPa
  • normal operating altitude is up to 1,000 m above the sea level. For installation at higher altitudes, please contact your sales representative.

    Vacuum Circuit-Breaker

    Vacuum circuit-breakers cover a wide range of switchgears, and therefore also a whole spectrum of applications. Many years of experience gained in developing and using vacuum interrupters is reflected today in a wide range of the applications of this type of circuit-breaker, which stand out for their exceptional electrical and mechanical characteristics, long life, minimum maintenance, compactness and use of highly innovative construction techniques. Interrupters of various manufacturers can be used in our switchgears.

    VD4 Vacuum Circuit-Breaker

    The VD4 medium voltage interrupters use vacuum to extinguish the electric arc and as the insulating medium. The VD4 interrupters have wide application and are used for protection of cables, overhead lines, motors, transformers, generators and capacitor banks.

    The front part of the interrupter provides a user interface and features the following equipment:
  • ON pushbutton.
  • OFF pushbutton.
  • operation counter
  • Indicator of circuit-breaker state (open or closed).
  • Indicator of the charged or discharged state of the operating mechanism.
  • manual charging device for the operating mechanism.
  • Override selector of the undervoltage release (optional)
  • eVD4 Circuit-Breaker

    This is a traditional circuit-breaker concept where one device can perform the functions of breaking, measurement, protection, control and communication. The EVD4 circuit-breaker is derived from the VD4 series of circuit-breakers.
    The eVD4 integrates the ABB Relion® family RBX615 protection devices with combined current and voltage sensors. The EVD4 is available in fixed and withdrawable versions for this switchgear and it is mechanically interchangeable with the VD4 circuit-breaker

    VM1 Circuit-Breaker

    All the characteristics of circuit-breakers described above remain unchanged, except for the very procedure of functioning of mechanisms of the VM1 circuit-breaker. The operating mechanism is based on a much lower number of components.

    SF6 Circuit-Breakers

    This switchgear can also be fitted with the SF6 circuit-breakers. The ABB vacuum and SF6 series of circuit-breakers are mechanically interchangeable and the same switchgear can therefore take any type of circuit-breaker. Only ABB can offer the circuit-breakers of both the above series for the whole range of applications, voltage levels (12-17.5-24 kV), rated current (630 ... 4000) and breaking capacity (16 ... 50 ka). Long practical experience shows that both types of circuit-breakers are equally valid and complementary.

    HD4 Circuit-Breaker

    The HD4 medium voltage circuit-breakers use sulfur-hexafluoride gas (SF6) as the insulating medium and to extinguish the arc. This type of circuit-breaker is available for all electric power distribution applications. They are even particularly recommended for use on capacitor banks, motors, transformers insulated in oil and in installations with components particularly sensitive to dielectric and dynamic stresses (for example, old cables or transformers). The HD4 circuit-breaker poles use the SF6 autopuffer technology for arc interruption, by combining the compression and self-blast techniques in a single solution. The autopuffer system is the most innovative technique in the field of circuit-breakers using SF6 gas as the insulating medium, and it originates from the high voltage area.

    HD4- HXA

    The HD4- HXA for breaking strong unidirectional components. The range of the HD4 circuit-breakers is extended by the application of the HD4 – HXA series of circuit-breakers. This series of circuit-breakers reflects all the characteristics mentioned for the HD4 circuit-breaker series, but it is notable also for its ability to break a load with strong unidirectional components.

    Instrument Transformers

    The current transformers with epoxy resin insulation are used to supply measurement devices and protection instruments. These transformers can have a wound core or a bushing bar with one or more cores, with all performances required for the needs of the installation of the switchgear.
    They conform to the IEC 60044-1 standards

    Voltage Transformers

    Voltage transformers with epoxy resin insulation are used to supply measurement and protection devices. They are available for fixed assembly or for installation on removable and withdrawable trucks. They can have one or two poles, and come with all required performances and classes for the needs of the measuring and protection instruments of the switchgearjenja
    They conform to the IEC 60044-2 standards

    Protection and Relays (Intelligent Electronic Devices)

    This switchgear is fitted with the IED (Intelligent Electronic Devices) protection which is delivered to more than 70 countries. There are various types of relays with diverse properties of protection, measurement and control. Depending on the requests of buyers and projects, the selected relays are dispatched from our factory with the desired set values. Operating speed, sensitivity, selectivity and reliability are the integral elements of a protection system, and there is a strong link between the protection response speed, and damage and danger caused by the appearance of a fault in the network. The protection system must have a high degree of reliability, which also means that if, for example, a circuit-breaker fails, the backup protection must identify the fault and respond. Relays of various manufacturers can be used in our switchgears.

    Electric Arc Protection

    A robust and reliable make of a compact switchgear, resistant to external influences, guarantees a very small probability of failure in the device. However, in order to achieve maximum personnel safety, the switchgear can withstand an arc caused by short-circuit current for 1 s, without danger for the personnel. In case of pressure growth due to the arc, a flap of the cabinet opens. Damage caused by the appearance of the electric arc as a function of the duration of the electric arc is shown in the following figure