Isolated Phase Bus
An isolated phase bus (IPB) is a mechanism which carries large currents needed for a hydroelectric, steam, gas or nuclear power plants. The IPB is used as a connector between a generator and a GSU (Generator Step-Up Transformer). The individual conductors of the mechanism are each enclosed separately in specialized metal housings. The IPB design was first used in the 1960s.
Suitability for Three-Phase Electric Power
Three-phase electric power, introduced in the 19th century by Nikola Tesla, is the design used for most electrical power systems. The system of conducting power in the three-phase model requires three circuit conductors to transport three alternating currents simultaneously. A fault occurs when the flow of current does not pass through the circuits properly; a short-circuit is a type of fault characterized by current flow bypassing the normal load level. In three-phase power design, faults can occur either between the phase and the ground or between phases. The isolated phase bus design concept, with its separate housing for the conductors, greatly reduces the likelihood of phase-to-phase faults.
Conduction Advantages of IPB
The IPB can manage very high amperage -- up to 44,000 amperes of continuous current. The IPB design reduces the effects of heat on the other equipment connected to it, and can handle rather high short-circuit levels as well. The form of the IPB also reduces wattage loss between phases. Overall, the IPB is considered the most reliable design for conducting current between phases in a three-phase power system.
Other Design Advantages
Isolated phase buses have a weather-resistant construction. Additionally, the installation costs of IPB current conduction systems are lower overall than the currently available alternatives.