When we use air circuit breaker, it has O/L protection ,time delay SC protection, Instataneous SC protection & ground fault protection. They all have some setting range. But what is the suitable/allowable setting for the above protection which will be safe for the equipment? For example-O/L protection setting have a range of (0.4,0.45,0.5,0.55,0.6,0.65,0.7,0.8,0.9,1.0)xIn Time delay SC protection have a range of (1.25,1.5,2,3,4,6,8,10,12)xIn Time delay setting is 0.02,0.1,0.2,0.3,0.4 Instataneous setting is fixed to 20xIn Gound fault setting is given 100A,300A,600A,900A,1200A This setting are for 2500A ACB. So what will be the basic allowable setting for the above protection? is there any formulae to calculate this<
1769Why the meters sonnected to metering core of CT are not damagedon event of a fault??? Explain the phenomena??
1 4384How to determine earth fault level to set relay for a normal distribution system of 11 kV , 100 A load????????
TCS,
1 3654Why the Transformer connection is changing in different transformer?(Like Star & Delta,Delta & Delta,Star & Star,Delta Star) From that connection where it is used?
2 62501)What will happen when 240 VDC supply is connected to 240VAC supply(DC supply +ve is connected to phase of AC supply & DC supply is to neutral of AC supply). 2)Also what will happen when 240 VDC supply is connected to 240 VAC supply in reverse polarity as of Sr. No 1.
2 4168What will happen when more than one star neutral points at same voltage level are connected to earth by metallic conductor?
TCS,
1 3491What is the unit of inertia constant of rotating machines? Which has more inertia constant between turboalternator and hydroaltermanor and why?
2 15782Can the efficiency of transformer be measured with the help of wattmeter readings taken at primary and secondary side? Support the answer.
2 3916Classical power system stability was mainly focussed on rotor angle stability but modern power system stability has more focus on voltage stability.Why?
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