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If voltage surge represented by 5/50 ┬╡s then at 50 ┬╡s value of voltage will be
Zero
Peak
Half of the Peak
None of above
Half of the Peak
A voltage surge or impulse wave is defined by its rise time and tail time. In the notation T1тАЛ/T2тАЛ╬╝s, T1тАЛ represents the time to reach the peak value (virtual front time), and T2тАЛ represents the time taken for the voltage to decrease to half of its peak value (virtual tail time).
A voltage surge or impulse wave is defined by its rise time and tail time. In the notation T1тАЛ/T2тАЛ╬╝s, T1тАЛ represents the time to reach the peak value (virtual front time), and T2тАЛ represents the time taken for the voltage to decrease to half of its peak value (virtual tail time).
V(t)=V0тАЛ(eтИТ╬▒tтИТeтИТ╬▓t) тАФ represents the standard impulse voltage wave equation
The impulse voltage waveform is generated in high-voltage laboratories to simulate lightning surges. The wave rises rapidly to a crest value VpeakтАЛ and decays exponentially. By standard international convention (IEC), the tail time T2тАЛ is defined as the time interval between the virtual origin and the instant the voltage falls to 50% of the peak amplitude on the tail portion of the wave.
A 5/50╬╝s wave means the virtual front time is 5╬╝s.
The virtual tail time is 50╬╝s.
Standard testing impulse waves are defined by these two parameters to ensure consistency in insulation breakdown testing.
The virtual origin is determined by the intersection of the line through the 30% and 90% points on the front of the wave with the zero axis.
Provides standardized stress testing for high-voltage equipment
Allows simulation of lightning strokes in a controlled laboratory environment
Requires high-cost impulse generators
Extreme precision needed for pulse shaping circuits
Testing transformers for Basic Insulation Level (BIL)
Dielectric strength testing of power cables and switchgear
The 5/50 ┬╡s wave is a common standard wave used for lightning impulse testing of electrical equipment.
Option B is incorrect because the peak occurs at T1тАЛ (5 ┬╡s), not at the tail time.
C is correct тАФ By convention, the second number in the impulse notation denotes the time at which the voltage magnitude decays to 50% of its peak value.
Remember that in lightning impulse notation, the first number is always shorter than the second; if you see a notation like 1.2/50, it is the standard lightning impulse wave.