Answer / niranjan

· The system earthing and safety earthing are interconnected and therefore fault current flowing through system ground raises the potential of the safety ground and also causes steep potential gradient in and around the Substation. But separating the two earthing systems have disadvantages like higher short circuit current, low current flows through relays and long distance to be covered to separate the two earths. After weighing the merits and demerits in each case, the common practice of common and solid (direct) grounding system designed for effective earthing and safe potential gradients is being adopted.

Answer / siva kumar

during fault conditions the fault current fed from transformer neutral.So the earth pit which is connected to neutral has to supply fault current.
supplying of quantity of fault current by earth pit has limitations such as soil type.CIPipe lengh etc.
if you connect neutral earth pit to substation mat, the mat will supply the fault current.

it is just like earth as big water reservoir and water as current. If more and more parlel pipe lines are laid more quantity of water can be dischrged quickly.

Answer / pankaj agarwal

as the short circuit fault devlops in the system the fault
current flows from fault point into the neutral. in the
absense of interconnection, all the fault current has to
travel through ground which have high resistivity so the EF
current flowing in the system may not be sufficient to
operate the EF trip relay. in the interconnected system EF
current have alternate and less resistive path so fault
gets cleared fast.

Answer / nipesh

but we do metal glanding in secondary side cable termination in both side, transformer and PCC panel (LT Panel), in this case transformer body earthing and substation earthing both are joint through metal gland, is this safe for transformer and other equipment?

Define conversion efficiency of a power amplifier. What is its value for class c power amplifier?

0 Answers  

---

How to select a contactor? How many types of contactors are available

0 Answers   TCS,

---

What is the difference between single core 2 wire and single core 3 wire system? Which application we are using this? and for What purpose we are using this?

0 Answers  

---

Write the force balance equation of m ideal mass element.

0 Answers  

---

How we find the size of cable if we know the current

2 Answers   Gemscab,

---

What is the difference between Welding Transformer and Normal Transformer?.

2 Answers   DAE,

---

what is the formula for backup time of online ups?

1 Answers  

---

how does PLCC work?...

1 Answers  

---

what is the difference betn earthed and unearthed cables which is commanly used why?

2 Answers   Bhel, Power Grid,

---

We have 11kV/110V three phase indoor potential transformer in 66/11kV Sub-station, where the failure of PT is frequently happening and the rating of the PT is 0.2 class accuracy, with primary star and seconday (two cores) star connected. Some experts has suggested to not to connect the PT Primary neutral to the ground because when transformer neutal NCT connection is loose; the faulty current will flow through the PT primary neutral, resulting into failure of PT. My question is: Is it necessary to remove the primary neutral connection of the PT from ground? if not, what would be the reason for failure of PT. Please guide me.

2 Answers   KPTCL,

---

how to calculate the chiller load from TR to KW?

0 Answers  

---

What are the components ofan HT panel in a 11kv power station?

2 Answers   Reliance,

---