Make Electrical Easy

 Given Data: Annual consumption = 700800 units Maximum demand  = 200 KW  Solution: Load factor = Average load / Maximum demand Average load = Annual consumption / Hours in Day * Number of days in a year                            = 700800 / 24*365                            = 79.8                             = 79.8 / 200                             = 0.4%

Given data: R= 4ohm MVA = 100 KV = 10  Solution: Find the base impedance Zb = (10)^2 / 100 = 1             = 4/1     = 4ohm

 Solution: The reactors can apply all type of voltage. We can install the reactors both indoor and outdoor. It provides high safety factor against flash over. No magnetic field in the outside of the tank avoiding heating and forces in adjacent reactors. Shielded reactors provides high thermal capacity to avoid excessive heating.

Solution:  Reduce the reactance . Reduce the voltage gradient. Reduce the corona loss. Reduce the radio interference. Reduce the search impedance. Increase power stability.

Solution:  Pin insulator (Upto 33KV) Suspension type insulator (More than 33KV) Strain insulator (Less than 11KV) Shackle insulator (Low voltage)

 Solution: It reduce the transmission line efficiency It cause inductive interference with communication lines More loss of energy Ozone produce corrosion of the conductor Non-sinusoidal voltage drop occurs It attenuates lightning surges 

 Solution:  Due to corona,the air surrounding the conductor becomes conducting and hence virtual diameter of the conductor is increased.The increased diameter reduces the electro static stresses between the conductor It reduce the effect of transient  It reduce the magnitude of high voltage It reduce the effect of surge 

 Solution: 1.By increasing conductor size. 2. By increasing conductor spacing. 3.By using hollow and bundled conductor 4.By reducing current density in a conductor

 Solution: The phenomenon of violet glow,Hissing noise and protection of ozone gas is an overhead transmission line. Corona occurs only when the electric field intensity is greater than dielectric strength of air. Reason for Corona: 1. Electrical power transmission is at higher operating voltage. 2.Number of free electron in the spacing surrounding the power conductor or more due to radio activity.

 Solution: Surge Impedance: Impedance of the transmission line without losses is called Surge Impedance. Zs = √(L/C). Surge Impedance Loading: The power delivered by the line to a purely resistive load equal to it's surge impedance or the load at which inductive and capacitive,reactive volte amphere are equal and opposite this is called surge impedance loading. SIL = VsVr / Zs

 Solution: During the current chopping a very high voltage may appear across circuit breaker contact.These voltage may danger the operation of the system.To reduce these voltage a shunt resistor across the circuit are used. This resistor depends on operation of circuit breaker and it's performed to reduce the RRRV(Rate of Rise of Restriking Voltage),Reduce the transient voltage (Maximum voltage at short period)..                                             R = 0.5  √(L/C)

 Solution: The device detect the fault and initiate the operation of the circuit breaker to isolate the defective element from the power system. Types:  1. Directional relay     i.Induction type over current relay     ii.Induction type reverse power relay 2. Differential relay 3. Distance relay (Based on transmission line distance)     i.Impedance relay     ii.Reactance relay     iii.Admittance relay

 Solution: The device used for switching, controlling and protecting the electrical circuits and equipments. Example: 1.Fuse 2.Circuit breaker 3.Relay 4.Switches