Modern switchgear (RC) of power plants
and substations are increasingly being performed using rigid structures
tubular tires (rigid tires). Rigid busbar type OJ-AL
manufactured by the company LLC “ALIT” is designed to perform
electrical connection of high-voltage equipment in open and closed
three-phase ac industrial switchgear
frequencies of 50 and 60 Hz in networks with a nominal voltage of 35-750 kV and a nominal
current up to 5000 A.
OJ-AL is a system of current-carrying parts – prefabricated tires
or intra-cell bonds made of pressed pipes made of
made of aluminum alloy for electrical purposes. As a material
Rigid tires use aluminum alloys having a high
Strength with good electrical conductivity. Every phase of prefabricated
tires and intra-cell connections is a tire structure,
made of a number of single-span tires that can reach 24 meters.
A rigid tire can be used in conjunction with a flexible one, for example, in the form of
combinations of rigid prefabricated tires with flexible intra-cell ties.
As part of the rigid tire production of LLC “ALIT” are used
unique, in terms of reliability, connecting elements – cast
bus holders with flexible connections. Cast tire holders are used
to connect the buses to each other, to connect to the equipment and to create
reliable electrical contacts between current-carrying parts, serve
for the perception of mechanical forces that occur in the connection nodes.
In rigid-tire switchgear, the use of cast fasteners compensates for
Temperature deformation and effectively suppresses wind resonance oscillations.
The completeness of the supply of OJ-AL is determined according to the specific order. In general, the composition of OJ-AL includes
the following elements:
• Cast tire holders with fastening points of the tire to the support insulators;
• Connecting units for connecting flexible descents;
• Tire holders for intra-cell connections;
• Current compensators;
• End plugs;
• Damping elements (vibration dampers);
• Metal structures (to order).
The use of rigid tires produced by ALIT LLC in switchgear has a number of advantages:
• Lower construction cost, reduced area and construction time of RU compared to flexible
• Ease of maintenance (due to a lower installation height);
• Possibility to compensate for deviations of the foundations: tire holders provide the possibility of free
movement of tires with small deviations of the foundations, arising during construction and operation;
• Increased reliability: the use of bolted joints instead of welded ones during the installation of tires avoided
the danger of “annealing” metal and reducing the mechanical strength of tires in areas with welded seams;
• High operational reliability of electrical contacts of cast bus holders: since all mechanical
the forces arising at the bus junctions are perceived by the cast bus holders, this eliminates the
the negative impact of such efforts on the state of electrical contacts, which are provided by flexible connections;
• High speed and ease of installation: the tires supplied to the site have a high degree of factory readiness.
The use of cast tire holders and bolted connections allows for the installation of the tire quickly and without
the use of welding technology;
• Ability to quickly replace tires if you need to increase throughput.
The strength of all elements of rigid tires corresponds to the expected electrodynamic, air, ice
loads, as well as the load from the own weight of the tire and branches.
The quality of the tire and its elements produced by ALIT LLC is confirmed by the relevant qualification
tests and calculations. When delivered to the facility, the rigid tire is checked for completeness and assemblability.