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How change Dyn11 to Dyn3?
DYn1 = Delta connected highside winding, Wye connected lowside winding, neutral brought out, lowside lagging by 30 degrees DYn11 = delta connected highside winding, Wye connected lowside winding, neutral brought out, lowside leading by 30 degrees In a DYn1, the lowside A phase is coupled to the highside A-B leg. In a DYn11, the lowside A phase is coupled to the highside C-A leg. So to convert one to another, you must physically change this coupling, which would require rewiring the internal connections of the transfomer delta.
How to parallel the Dyn1 and Dyn11 Transformer?
you keep the hv & lv on the dyn11 tx straight in phasing. you then put a cross on any two phases on the hv side of the dyn1 tx, and do the same cross with the phases on the lv side of the tx. for instance lets say we cross a & c phases on the hv & lv sides of the dyn1 tx. now draw a diagram with the four tx, split them up, 2 x dyn1, 2 x dyn11. now on the diagram where you have dyn1 tx, change the the phase plates to read cba left to right, also change the lv side to match. leave the phase plates on the dyn11 tx alone to read abc left to right on both sides. now draw the cables going between them on the hv & lv sides. now if a phase always goes to a phase and b & c phases do the same it will all tie in. prove it to yourself and follow a phase threw all the tx's, do the same will b & c phases. I do it all the time at my job, works every time.
What is the difference between transformer vector group Dyn11 Dyn1 Dyn5?
They all have delta primaries and star secondaries, possibly earthed. The number is the angle of the secondary voltage's lag behind the primary's, expressed as an hour on a clock-face. 11 --> Secondary leads primary by 30 degrees 1 --> Secondary lags primary by 30 degrees 5 --> Secondary lags primary by 150 degrees, making the red secondary voltage lag the yellow primary by 30 degrees (using UK Red/Yellow/Blue phases) Dyn11 and Dyn1 are much more common than DYn5
Why there is a phase shift of 30degree in Dyn11 3 phase transformer?
The phase shift is caused by inductance in the transformer. Any inductance from magnetic flux that fails to link both windings is called leakage flux, and the resulting inductance is called leakage inductance.
How can you test the vector group DYn11 and vector diagram?
connect the neutral point of the star (secondary) to u phase of primary, and now apply voltage to primary and measure the voltage between V&R, W&B, V&Y and V&B. when you measure voltage b/w 1. V&R the voltage must be maximum, 2. W&B Should be minimum and 3. voltage between V&Y and V&B should be same U.V&W are primary (Delta) R,Y&B are secondary (Star)
Can a 3-phase DYN 1 transfomer be connected in parallel with a DYN11?
No
How change Dyn11 to Dyn3?
DYn1 = Delta connected highside winding, Wye connected lowside winding, neutral brought out, lowside lagging by 30 degrees DYn11 = delta connected highside winding, Wye connected lowside winding, neutral brought out, lowside leading by 30 degrees In a DYn1, the lowside A phase is coupled to the highside A-B leg. In a DYn11, the lowside A phase is coupled to the highside C-A leg. So to convert one to another, you must physically change this coupling, which would require rewiring the internal connections of the transfomer delta.
How to parallel the Dyn1 and Dyn11 Transformer?
you keep the hv & lv on the dyn11 tx straight in phasing. you then put a cross on any two phases on the hv side of the dyn1 tx, and do the same cross with the phases on the lv side of the tx. for instance lets say we cross a & c phases on the hv & lv sides of the dyn1 tx. now draw a diagram with the four tx, split them up, 2 x dyn1, 2 x dyn11. now on the diagram where you have dyn1 tx, change the the phase plates to read cba left to right, also change the lv side to match. leave the phase plates on the dyn11 tx alone to read abc left to right on both sides. now draw the cables going between them on the hv & lv sides. now if a phase always goes to a phase and b & c phases do the same it will all tie in. prove it to yourself and follow a phase threw all the tx's, do the same will b & c phases. I do it all the time at my job, works every time.
What is the difference between transformer vector group Dyn11 Dyn1 Dyn5?
They all have delta primaries and star secondaries, possibly earthed. The number is the angle of the secondary voltage's lag behind the primary's, expressed as an hour on a clock-face. 11 --> Secondary leads primary by 30 degrees 1 --> Secondary lags primary by 30 degrees 5 --> Secondary lags primary by 150 degrees, making the red secondary voltage lag the yellow primary by 30 degrees (using UK Red/Yellow/Blue phases) Dyn11 and Dyn1 are much more common than DYn5
What is DYN11 of a transformer?
It's a description of the some of the electrical properties of the transformer. This is a Delta connected highside (the D), wye connected lowside (Y) that is grounded (N) and there is a 330 degree phase shift between the highside and the lowside (the low voltage is leading the high voltage by 30 degrees).
What is the meaning of DY 11 on a transformer nameplate?
there is no specification of Dy11.. it will be Dyn11.. it is the vector group of the transformer. capital d means primary winding is delta secondary winding is star(y) and the secondary current lags voltage by 30degree this angle when shown in clock will be looking like 11 o clock
Why there is a phase shift of 30degree in Dyn11 3 phase transformer?
The phase shift is caused by inductance in the transformer. Any inductance from magnetic flux that fails to link both windings is called leakage flux, and the resulting inductance is called leakage inductance.
How can you test the vector group DYn11 and vector diagram?
connect the neutral point of the star (secondary) to u phase of primary, and now apply voltage to primary and measure the voltage between V&R, W&B, V&Y and V&B. when you measure voltage b/w 1. V&R the voltage must be maximum, 2. W&B Should be minimum and 3. voltage between V&Y and V&B should be same U.V&W are primary (Delta) R,Y&B are secondary (Star)
What is standby earth fault protection And how it is to be coordinated with transformer primary overcurrent relayin DYn11 tf?
DYn 11 is a Delta HV winding and star lv with theneutral brought out. At primary substations it is usual to have a neutral ct. The ct is a last line of defence operating a standby earth fault relay which opens the lv circuit breaker (11kV). It may have a stage 2 setting in case the lv breaker fails to open which opens the hV side. If there is no local hV breaker it may operate a fault throw switch. This device shorts one phase directly to earth forcing the protection at the remote end to operate.
How can you test ZNyn11 Vector group transformer?
This vector group test is done to confirm whether the vector group provided in the name plate is correct or not and also to confirm that the winding has not been damaged during transport, installation and erection. Taking a particular example, for Dyn11 transformer we have to apply 3~ 400v to the primary, with primary 'U' & secondary 'u' shorted.... then check the voltage across different terminals such as V-v, V-w, W-w, W-v for Dyn11 configuration (V-v = V-w = W-w)less than W-v.... you can compare the results after drawing the vector diagram for the same...... the purpose of shorting the primary U & secondary u is to nullify the phase shift, to obtain a reference vector...
What is the difference between Dyn-11 and Ynd-11?
Winding connection designations High Voltage Always capital letters Delta - D Star - S Interconnected star - Z Neutral brought out - N Low voltage Always small letters Delta - d Star - s Interconnected star - z Neutral brought out - n Phase displacement Phase rotation is always anti-clockwise. (international adopted convention) Use the hour indicator as the indicating phase displacement angle. Because there are 12 hours on a clock, and a circle consists out of 360°, each hour represents 30°. Thus 1 = 30°, 2 = 60°, 3 = 90°, 6 = 180° and 12 = 0° or 360°. The minute hand is set on 12 o'clock and replaces the line to neutral voltage (sometimes imaginary) of the HV winding. This position is always the reference point. Because rotation is anti-clockwise, 1 = 30° lagging (LV lags HV with 30°)and 11 = 330° lagging or 30° leading (LV leads HV with 30°) To summarise: Dd0 Delta connected HV winding, delta connected LV winding, no phase shift between HV and LV. Dyn11 Delta connected HV winding, star connected LV winding with neutral brought out, LV is leading HV with 30° YNd5 Star connected HV winding with neutral brought out, delta connected LV winding, LV lags HV with 150° " So there is no specification of Dy11.. it will be Dyn11 "
How do you calculation of selecting Neutral Earthing Transformer?
iT IS ISMILAR TO THE GROUND RESITOR CALCULATION FOR TRANSFOMER THE TYPICAL EXAMPLE WAS ANSWERED EARLIER FOR TRANSFORMER DT.19-06-2009 Neutral of transformer can be grounded solidly earthed OR with Neutral Grounded with Resistance. Typical shunt calculations fro 5 MAV 11/6.6 kv transformer neutral are as :_ Transformer rating = 5 MVA Voltage ratio = 11/6.6 KV Vector Group = Dyn11 (6.6 KV ground through Resistor) During Earth fault voltage between Neutral & Earth = 6.6/√3 = 3.81 KV Earth Fault current will be limited to = 5 x 10³ /(√3 x 6.6) = 437.38Amp. N.G.R. value in ohm = V / I = (3.81 x 10³) / 437.38 = 8.71 Ohm Value of N.G.R. is 437.38 Amp, 8.71 Ohm., 10 Sec NGR are inserted On Higher voltage to restrict earth fault current BY SRI
