Rigid busbar
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:
• Tires;
• 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:
• Reduction of construction cost, reduction of construction area and time compared to flexible busbar
• 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 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 assimilability.
