Power transformer Y-D Y grounded
Power transformer Y-D Y grounded
(OP)
Are there any benefits from grounding the neutral on a Y-D transformer? This is a small 750 KVA, 13.8KV to 2.3 KV. The secoundary, 2300 volt side is ungrounded. The 13.8KV that supplies this transformer is grounded.






RE: Power transformer Y-D Y grounded
There may be potential problems, per IEEE C62.92.4-1991 …Application of Neutral Grounding… §4.3 If the wye-delta neutral of the transformer bank is connected to the primary neutral, the transformer bank may:
1) Circulate current in an attempt to balance any unbalanced primary phase-to-neutral loads
2) Act as a grounding bank and supplying fault current to any fault on the circuit
3) Circulate triplen harmonic currents in the delta.
An ungrounded secondary winding is subject to damaging transient ground overvoltage.
RE: Power transformer Y-D Y grounded
Are there any benefits from grounding the neutral on a Y-D transformer? This is a small 750 KVA, 13.8KV to 2.3 KV. The secondary, 2300 volt side is ungrounded. The 13.8KV that supplies this transformer is grounded.
///It depends. How is system grounding upstream?
What is the transformer load in terms of the transformer availability and cost of the process or load downtime?
In some applications, the ungrounded power distribution systems are used since they can survive one fault to ground that is alarm only without any tripping. Also, any overvoltages caused by arcing may be suppressed and alarmed. This way the availability of the ungrounded power supply is high. This is usually referred to as a power supply for a dedicated load, or dedicated power supply.
If the above is not the case, then the grounding will limit overvoltage transients caused by arcing, cause positive trips of protective relays on fault conditions, break or modify the zero sequence current path, etc.\\\
RE: Power transformer Y-D Y grounded
RE: Power transformer Y-D Y grounded
RE: Power transformer Y-D Y grounded
When the source (grounding upstream) is efectively grounded, a line fault eliminates one phase voltage regardless of the connections of the step down bank.
When the source is isolated, and the source impedance is negligible , in case of a line-to-ground fault, the primary voltages are maintained. This points up the fact that an isolated system can not be effectively grounded by grounding the neutral of a small Y-delta bank capable of drawing only a small short-circuit current in case of a line-to-ground fault.
RE: Power transformer Y-D Y grounded