Power factor- In ac circuit there is some phase difference between the voltage and current. The cosine of this angle phase difference is called Power factor or PF. Popularly defined as cosφ. Power factor types- Leading power factor- Current leads voltage. Happens with Capacitive load circuit, Lagging power factor- Current lags behind voltage. Happens with Inductive load circuit.Value of Power factor– As power factor is a cos function its possible value ranges from -1 to +1 Active and reactive component of power factor: I cosφ is called active or watt full component, I sinφ called reactive or watt less component.Reactive component is very much important for power factor measurement and control. It has a inverse relationship with power factor. The less the reactive component the more is the power factor. Active, reactive and apparent power-
• S² = P² + Q², where S = Apparent Power, kVA P = Active Power, kW Q = Reactive Power, kvar • cos φ = P/S=PF, power factor which tells us what is the proportion between the active and the apparent power, how much there is active power in apparent power. [alva]
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BBT or Bus Bar Trunking system is a replacement to traditional cable and panel distribution. MCB, MCCB in BBT is plugin component as bus is extended to consumer area.
Busbar Trunking System is a not that new technology, in 1930 it was first introduced in USA. Comparing with the conventional wire or cable BBT is far better. In some modern construction, people are now preferring BBT other than cable. What is Busbar Trunking System: We know about bus bar. Three phase incomer from generator or a source at first comes to a three phase bus bar by cable or wire, then circuit breaker or other device connection is made with cable from bus bar , circuit breaker / protection device and bus bar stays in the panel board. Load is out side in use area, connected with cable from circuit breaker/ protection device.So bus bar is receiving and supplying power by cable or wire.But with Busbar Trunking System, there is no cable or wire at all. There is no panel. Bus bar is extended through the use area. A circuit breaker / protection device can just plug in the Busbar Trunking and connect load from the circuit breaker. Types of Electrical cable according to the protection from Electromagnetic pick up and radiation are Twisted Pair cable, Co-axial cable, Sheathed cable. And according to materials used Copper cable, aluminum cable. Coaxial cable is a type of cable that has an inner conductor surrounded by a tubular insulating layer, surrounded by a tubular conducting shield.Many coaxial cables also have an insulating outer sheath or jacket.The term coaxial comes from the inner conductor and the outer shield sharing a geometric axis. Coaxial design helps to further reduce low-frequency magnetic transmission and pickup. In this design the foil or mesh shield has a circular cross section and the inner conductor is exactly at its center. This causes the voltages induced by a magnetic field between the shield and the core conductor to consist of two nearly equal magnitudes which cancel each other. Copper cable
Electrical devices often contain copper conductors because of their multiple beneficial properties, including their high electrical conductivity, tensile strength, ductility, creep resistance, corrosion resistance, thermal conductivity, coefficient of thermal expansion, solderability, resistance to electrical overloads, compatibility with electrical insulators, and ease of installation. Aluminum cable Aluminum conductor is cheaper and weigh less than copper but because of its greater resistivity, aluminum wiring requires larger conductors than copper.Disadvantages- Cold flow tendency– tendency of a solid material to move slowly or deform permanently under the influence of stresses / pressure.Aluminium forms an insulating oxide layer on the surface. |
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