Answer / amit shankar choudhary

Tan Delta, also called Loss Angle or Dissipation Factor
testing, is a diagnostic method of testing
cables to determine the quality of the cable insulation.
This is done to try to predict the
remaining life expectancy and in order to prioritize cable
replacement and/or injection. It is also
useful for determining what other tests may be worthwhile.
How Does It Work?
If the insulation of a cable is free from defects, like
water trees, electrical trees, moisture and air
pockets, etc., the cable approaches the properties of a
perfect capacitor. It is very similar to a
parallel plate capacitor with the conductor and the neutral
being the two plates separated by the
insulation material.
In a perfect capacitor, the voltage and current are phase
shifted 90 degrees and the current
through the insulation is capacitive. If there are
impurities in the insulation, like those mentioned
above, the resistance of the insulation decreases, resulting
in an increase in resistive current
through the insulation. It is no longer a perfect capacitor.
The current and voltage will no longer
be shifted 90 degrees. It will be something less than 90
degrees. The extent to which the phase
shift is less than 90 degrees is indicative of the level of
insulation contamination, hence
quality/reliability. This “Loss Angle” is measured and analyzed.

Answer / wareagle

Its tan delta. Not ten delta. You can google that for
yourself.

we done magnetic balance test for 33KV /440V transformer in our company , but the ratio out is confusing us Voltage applied in RY = 440 , at RB = 320 and YB = 60 RY 440 = ( RB + YB ) 380 only Please let me know what type of problem is it.

2 Answers  

---

In Transmission System if the potential difference at the two end of line are same then is the transmission of power will continue ? if yes then how.

1 Answers   IOCL,

---

What is the difference between earthed and unearthed cable

5 Answers   FT, L&T, Suzlon,

---

why lightning arrestor are made in two stack of insulator but why not cvt

0 Answers  

---

how to calculate short circuit breaking capacity KA for 2500kva 33kv transformer.

0 Answers  

---

---

1.Can we use 6.6/11KV 300sq mm xlpe 3core cable for LT use (415 Volt). 2. If we use it for LT then what is the current rating

0 Answers  

---

what is the essential resistance of r y b phase short citcuit ? Eg in star connection we doing this kind of short circuit oly

0 Answers  

---

1.why ACB is not connected in HT side what Happens? 2.how much voltage maintained in ACB breaker? 3.OLTC is connected in primary side in case secondary side connected what happened?

3 Answers   L&T,

---

What is the physical significant of power factor?

0 Answers   Cooper,

---

What is the meaning of electricity? How it is being produced? Can we store the electricity? When we produce electricity what is the capacity of voltage current we are getting? If we need 440 volts how to get it? In case, if we want lower than 440 volts how to change it? Please answer?

1 Answers  

---

in electric lamp what is ballast. y its needed to start & stop lamp. what is ballast ckt.

0 Answers  

---

How to calculate pitch, gauge of winding wire, and No. of turns for 30HP, 3 phase, 4 poles 50Hz, 380V induction motors

0 Answers  

---