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What is the meaning of DYN 11 on a transformer nameplate?
What does Dd0, Dyn11, YNd5 etc. mean?First symbol/symbols, capital letters: HV winding connection.Second symbol/symbols, small letters: LV winding connection.Third symbol, number: Phase displacement expressed as the clock hour number.Winding connection designationsHigh Voltage Always capital lettersDelta - DStar - SInterconnected star - ZNeutral brought out - NLow voltage Always small lettersDelta - dStar - sInterconnected star - zNeutral brought out - nPhase displacementPhase 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:Dd0Delta connected HV winding, delta connected LV winding, no phase shift between HV and LV.Dyn11Delta connected HV winding, star connected LV winding with neutral brought out, LV is leading HV with 30°YNd5Star connected HV winding with neutral brought out, delta connected LV winding, LV lags HV with 150°
What is difference between ICT and Transformers in power system?
A CT is a measuring device but does not step up or step down voltage like a transformer will.
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 does a primary substation do?
Primary substation - when the transformer is HV/MV or MV/MV. e.g. substation designed for 132kV/33kV or 230kV/22kV or 33kV/11kV etc stepped down for MV distribution (mainly for utilities and heacy industries) Secondary substation - when the transformer is HV/LV or MV/LV. e.g. substation designed for 11kV/400V or 6.6kV/400V etc stepped down for LV distribution (mainly for residential, commercial) sometime referred to as a kiosk substation.
Why oc test done in lv side?
In OC test , the equipments are connected in LV side since we need to get rated voltage . if it is cinnected in HV side the value of voltage will be less and current wil be more.Hence the ordinary instruments cannot measure this value of current
How do you convert HV amps to LV amps?
To convert high voltage (HV) amps to low voltage (LV) amps, you can use the formula: HV amps = LV amps x (LV voltage / HV voltage). By rearranging the formula, you can calculate LV amps by dividing HV amps by the ratio of HV voltage to LV voltage.
What is purpose of ten delta test on transformer?
To ascertain the life of insulation, or effectiveness of the insulation (HV to LV, HV to earth and LV to earth) of the transformer
What is difference between VCB and ACB?
VCB (vacuum circuit breaker) is used in HV (high voltage) applications. ACB (air circuit breaker) is used in LV (low votage) applications.
What is the difference between Dyn-11 and Ynd-11?
Dyn-11 refers to a transformer connection where the neutral terminal is not connected to the ground. Ynd-11 refers to a transformer connection where the neutral terminal is connected to the ground. Thus, the key difference lies in how the neutral terminal is treated in each connection scheme.
What is the meaning of 32Yd1 on a transformer?
This is 3 Nos Two Winding Transformers put together to form of Three Phase transformer, HV is Star Connected & LV is Delta Connected in the LV phase is leading by 30 Degree with respect to HV phase
What is the meaning of DYN 11 on a transformer nameplate?
What does Dd0, Dyn11, YNd5 etc. mean?First symbol/symbols, capital letters: HV winding connection.Second symbol/symbols, small letters: LV winding connection.Third symbol, number: Phase displacement expressed as the clock hour number.Winding connection designationsHigh Voltage Always capital lettersDelta - DStar - SInterconnected star - ZNeutral brought out - NLow voltage Always small lettersDelta - dStar - sInterconnected star - zNeutral brought out - nPhase displacementPhase 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:Dd0Delta connected HV winding, delta connected LV winding, no phase shift between HV and LV.Dyn11Delta connected HV winding, star connected LV winding with neutral brought out, LV is leading HV with 30°YNd5Star connected HV winding with neutral brought out, delta connected LV winding, LV lags HV with 150°
How do you carry short circuit test on power transformer?
For carrying Short Circuit Test on Power Transformer Do the following: 1] Isolate the Power Transformer from service. 2] Remove HV/LV Jumps and Disconnect Neutral from Earth/Ground. 3] Short LV Phases by Cu/Al plate which could withstand short circuit current and connect these short circuited terminals to Neutral 4] Energise HV side by LV supply (440 3ph Supply) with OLTC tap position on Normal. 5] Measure Current in Neutral, LV line voltages, HV Volatage and HV Line Currents on various OLTC Tap position. Analysis: If Neutral current is near to zero transformer windings are OK If Neutral current is higher or equal to Line current between LV Phase one of the winding is Open.
Why tappings are always provided in HV winding of power transformers?
in hv side, current will be less; so if we vary the rheostate, than thetre is less arcing with respect to lv side, so we always put the tap changer in hv side.
How do you carry out short circuit test on power transformers?
For carrying Short Circuit Test on Power Transformer Do the following: 1] Isolate the Power Transformer from service. 2] Remove HV/LV Jumps and Disconnect Neutral from Earth/Ground. 3] Short LV Phases by Cu/Al plate which could withstand short circuit current and connect these short circuited terminals to Neutral 4] Energise HV side by LV supply (440 3ph Supply) with OLTC tap position on Normal. 5] Measure Current in Neutral, LV line voltages, HV Volatage and HV Line Currents on various OLTC Tap position. Analysis: If Neutral current is near to zero transformer windings are OK If Neutral current is higher or equal to Line current between LV Phase one of the winding is Open.
What is difference between ICT and Transformers in power system?
A CT is a measuring device but does not step up or step down voltage like a transformer will.
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 output voltage of a transformer if the turns ratio is 0.5?
It is a Step-Up Transformer which has 2 times voltage in secondary(HV) than primary(LV)
