UniGear ZS2 (ABB Technology) 36 kV, 3150A, 31.5 kA Medium voltage, arc-proof, air insulated switchgear

UniGear type ZS2 (former Unisafe 36) is a medium voltage, metal-clad switchgear suitable for indoor installations. It is a modular apparatus made of aligned standard units. Metal sheets segregate each compartment and the energized components are air insulated.

All the startup, maintenance and service operations can be carried out from the front of the unit. The switchgear and the earthing switches are operated from the front with the door closed. The switchgear can be wall-mounted. The range of apparatus available for UniGear ZS2 switchgear is the most complete on the market, including vacuum and gas circuit-breakers.

Characteristics of UniGear ZS2 switchgear:
Each UniGear ZS2 panel consists of a single unit which can be equipped with a circuit-breaker, withdrawable fused device, off load disconnector, as well as with all the accessories available for conventional switchgear units.
  • The panel incorporates a compartment in its upper level to house the auxiliary instrumentation.
  • Units can be coupled together directly with double busbar units, with the possibility for further extension on both sides of the switchgear.
  • The switchgear does not require rear access for installation or maintenance.
  • All the service operations are carried out from the front.
Utilities and Power Plants
  • Power generation stations
  • Transformer stations
  • Main and auxiliary switchgear
• Pulp and Paper
• Cement
• Textiles
• Chemicals
• Food
• Automotive
• Petrochemical
• Quarrying
• Oil and gas pipelines
• Metallurgy
• Rolling mills
• Mines
• Airports
• Ports
• Railways
• Underground transport
• Supermarkets
• Shopping malls
• Hospitals
• Large infrastructure and civil works
From power stations down to distribution substations, ABB provides a reliable, high quality solutions for products, systems and services.
As a single source partner, ABB is the world’s largest and most complete supplier of switchgear and systems for electric power transmission and distribution applications.
ABB substations, cables, transformers, control systems and switchgear enable our customers to make efficient and effective use of electric power.
As a word-leading company in research, development and innovation, ABB is able to provide the most comprehensive and suitable range of solutions to meet the present and future needs of producers, distributors and users of electric power.
Medium voltage switchgear is one of the most important links in the electric distribution chain and ABB has developed the UniGear ZS2 switchgear with the aim of satisfying all requirements. UniGear ZS2 combines consolidated solutions and innovative components, based on ABB’s leading-edge technology.
UniGear ZS2 is medium voltage metal-clad switchgear with a metal enclosure, suitable for indoor installations.
Metal partitions segregate the compartments from each other and the live parts are air-insulated.The switchgear is modular and this provides a coordinated approach that enables the ideal solution for each installation to be built up by placing standardised units side by side.
The switchgear is simple to configure and selection of the correct apparatus and instruments for specific applications does not require dedicated solutions.
The functional units of the switchgear are guaranteed arc proof in accordance with the IEC 62271-200 Standards, appendix AA, class A accessibility, criteria 1 to 5. All the startup, maintenance and service operations can be carried out from the front of the unit. The switchgear and the earthing switches are operated from the front with the door closed.
The switchgear can be wall-mounted. The range of apparatus available for UniGear ZS2 switchgear is the most complete on the market, including vacuum and gas circuit-breakers. All this apparatus is interchangeable inside the same switchgear unit. This makes it possible to offer a single switchgearuser interface, with the same service and maintenance procedures and operations. The switchgear can be fitted with conventional (transformers and releases) or innovative (sensors and multi-purpose unit) measurement and protection components.
Apart from the traditional functional units, the UniGear ZS2 switchgear is fitted with double busbar systems. The use of these units allows extremely efficient use of space.
The switchboard and main apparatus it contains comply with the following Standards:
• IEC 62271-1 for general purposes.
• IEC 62271-200 for the switchgear.
• IEC 62271-102 for the earthing switch.
• IEC 60071-2 for the insulation coordination.
• IEC 62271-100 for the circuit-breakers.
• IEC 60529 for degree of protection.
Normal service conditions
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 24h average of relative humidity 95% RH
- Maximum 24h average of water vapour pressure 2.2 kPa
- Maximum monthly average of relative humidity 90% RH
- Maximum monthly average of water vapour pressure 1.8 kPa
• The normal operation site altitude is up to 1000 m above sea level.
Presence of normal, non-corrosive and uncontaminated atmosphere.
Rated voltage kV
Rated insulation voltage
kV 1min
Rated power frequency withstand voltage
Rated lightning impulse withstand voltage
Rated frequency
kA 3
Rated short time withstand current
Peak current
kA 1 s
Internal arc withstand current
Main busbars rated current
Branch connections rated current
Branch connection rated current with forced ventilation with fan
Branch connection rated current with forced ventilation  with fans ( available only with VD4 vacuum Circuit Breaker)
The electrical characteristics of the switchboard can vary for ambient conditions other than those described in the previous section and also if a higher degree of protection is used.
Degrees of protection
The degrees of protection of the switchgear conform with IEC 60529 Standards.
UniGear ZS2 switchgear is normally supplied with the following standard degrees of protection:
• IP4X for the enclosure.
• IP2X for the partition between compartments.
On request, the external housing can be supplied with a higher degree of protection; in this case please contact your ABB sales representative.
Colour of the external surfaces
RAL7035 - ligh grey (front doors).
Other colours available on request.
With the release of the IEC 62271-200 standard, new definitions and classifications of Medium Voltage switchgear have been introduced.
One of the most significant changes is that classification of switchgear into metal-clad, compartmented and cubicle types has been abandoned.
The revision of switchgear classification rules has been based on the user’s point of view, in particular on aspects like service and maintenance of the switchgear, according to the requirements and expectations for proper management, from installation to dismantling.
In this context, Loss of Service Continuity (LSC) has been selected as a fundamental parameter for the user.
According to the IEC 62271-200, UniGear ZS2 switchgear can be defined as follows.
1. LSC-2B
The busbars, circuit-breaker and cable compartments are physically and electrically segregated. This is the category that defines the possibility of accessing the circuit-breaker compartment with the busbars and cables energized.
2. Partition Class
Switchgear providing continuous metallic partitions and shutters, intended to be earthed between opened accessible compartments and live parts of the main circuit. Metallic partitions and shutters or metallic parts of them shall be connected to the earthing point of the switchgear.
3. Interlock-controlled accessible compartment
Compartment containing high-voltage parts, intended to be opened for normal operation and/or normal maintenance, in which access is controlled by the integral design of the switchgear.
4. Tool-based accessible compartment
Compartment containing high-voltage parts, that may be opened, but not for normal operation and maintenance. Special procedures are required. Tools are necessary for opening.