nomentary paralalling

kinjalpatel1899

hello, i want to know what is nomentary paralalling?

Ayman Elotaify

kinjalpatel1899

hello, i want to know what is nomentary paralalling?

Momentary Paralalling or Parallel Operation:

of transformers or more than one power source to fed large loads.

ATS (Automatic Transfer Switch) work to switch between transformer and standby generator in case of transformer incomming fails. duration of this transition is in arround 100 ms typically. So most loads like inductive loadand PCs do not feel that there is power failure for a period of 100 ms.

Hope this helps.

PISCEAN 2010

Ayman Elotaify

kinjalpatel1899

hello, i want to know what is nomentary paralalling?

Momentary Paralalling or Parallel Operation:

of transformers or more than one power source to fed large loads.

ATS (Automatic Transfer Switch) work to switch between transformer and standby generator in case of transformer incomming fails. duration of this transition is in arround 100 ms typically. So most loads like inductive loadand PCs do not feel that there is power failure for a period of 100 ms.

Hope this helps.

Hello,
In this case, is it necessary to keep DG set running contineously? Because for any circuit,to sense the power failuer & switch on the DG, it requires some time mostly more than 100 ms. Then how this is achieved or this, 100 msis the only operatingtime of ATS switch ?

Hello

Momentary paralleling ( As the name suggests ) is paralleling of two power sources for a small duration ( could range from say 100 ms to sometimes 5-10 seconds ). This is Different from automatic Transfer switch ( ATS ) described by Ayman Elotaify

Momentary parallelingis carried out to change the power from one source to another without tripping any of the downstream loads where continuous paralleling of the two sources is either not feasible or not required.

Momentary paralleling can be done between two transformers or a Transformer and a DG.
In either case the Voltage and frequency and Phase angle of the two sources has to be matched.
This is checked using a check synchronising relay.

If all the three parameters are within permissible range then the Incoming source is switched ON. As soon as the Incoming source is closed ( Or after a short delay ) the existing source feeding the bus is disconnected. This way the load is bumplessly switched from one source to another.

Most common uses of Momentary Paralleling are :

a) Switching Load bumplessly from one transformer to another. Both transformes should be similarly rated and of same vector group . Also they are being fed by the same upstream source .
This is because we cannot control the Frequency / phase angle of either source. Voltage can be adjusted if the Transformer has OLTC ( On Load Tap Changer )

b) Switching Load from Grid Supply to ( Already running ) DG supply - e.g. in case of a planned changeover or vice-versa. In this case the DG Voltage / frequency and phase angle have to be controlled to match the Grid supply using a Auto / Manual synchroniser.

Hope this helps

Cheers

Navnag

kinjalpatel1899

hello, i want to know what is nomentary paralalling?

kinjalpatel1899

hello, i want to know what is nomentary paralalling?

New question published by MVN_1983 is split to a separate thread with the subject Paralleling the Multiple DG Set with utility source and any philosophy of operation.

Best regards
Jen_Moderator