Two off Single Phase Auto Transformers Connected in Open Delta to Supply 3 Phase Load
Single Phase Auto Transformer Data
From Fig 4 of attached file.
Cooper Power Systems Single Phase Step Voltage Regulator
kVA 220 / 246kVA
Load Amps 200 / 224 A
Rated Volts: 11000 V
Load Volts 5500V to 11600V (...
When calculating voltage imbalance, what is the positive to negative sequence coupling ( Z12 ) and negative to positive sequence coupling ( Z21 ) at the point of common coupling, in relation to unbalanced voltage ? How is it determined ?
The utility has only provided positive ( Z1 ) , negative...
Thank you Kiribanda
Assuming:
1) Symmetrical sub-transient short-circuit current (I"k) is 1.25 * symmetrical synchronous short-circuit current (Ik).
2) IG X/R ratio of 30 ( IEEE Std 399-1997 )
PrG = 6300000 W
VrG = 11000 V
pf running = 0.87 pu
FLC = 382 A
Symmetrical Synchronous...
Thank you Kirbanda, I assume that the LRC of 1720.6 A is synchronous short-circuit current.
Short-circuit current of 1720.6 A divided by rated current of 380 A is 4.51 FLA, or an IG impedance of 1 / 4.51 = 0.22 per-unit.
Although a typical induction motor locked rotor current is approx. 6 x FLA...
How is the short-circuit current contribution from the induction generator in attached datasheet calculated ?https://files.engineering.com/getfile.aspx?folder=7dda6281-b439-4ad3-b19b-5d933b717b2f&file=Generator_Datasheet_1.pdf
The steel structure of a conveyor extends 400m beyond a substation which supplies the conveyor motors.
The conveyor steel structure is bonded to the substation earth grid.
The conveyor steel structure has concrete footings.
Does anyone know how to use SKM’s Ground Mat to calculate the ‘transfer...
It is required to model a three phase, three limb, core type transformer with connection YN d11 d11 in the software PTW32.
Measured impedance values are shown shaded in green in the attached excel spreadsheet.
Question:
How are the following transformer zero sequence impedances modelled :
zo...
Does anybody out there in IEC land have experience in specifying MV breakers to IEC 62271.100 ?
The breakers are ‘near’ to large generators.
The IEC 60909.0 calculated values for Ib sym, Ib asym, i p and i dc are high.
I need to determine if a 11kV, breaker with following short-circuit...
The attached spreadsheet SKM-PTW and IEC 60909-0 Manual Calc.xlsx includes data for a ABB VD4 1212-40 circuit-breaker.
The calculations on Tab ABB VD4 of attached spreadsheet confirms that the breaker has following IEC 62271.100 short-circuit withstand ratings:
Rated short-circuit breaking...
A balanced 240V a.c. phase-to-phase three phase ( A-B-C ) star connected source of equal negligible positive and negative sequence impedance and no connection to earth (ground) supplies single phase 240V a.c. incandescent lamps.
Each lamp is connected between 240V phase-to-phase at 5 m intervals...
What synchronous generator reactance should be used in a harmonic study ?
Saturated sub-transient x"d, saturated transient x'd, saturated synchronous xd ?
A Dyn transformer with solidly earthed star point supplies an induction motor with either delta or unearthed star windings.
Attached Fig. 1 shows PTW32 Ver 9014 Comprehensive results for an earth fault on BUS_0003 with earth fault current contribution from both transformer and motor as expected...
An 11kV Utility with a 10 amp neutral earth resistor supplies an 11kV bus ( M1C-Pole1 ).
The 11kV bus supplies a 5 MVA, 11/66kV, YNzn11, 3 limb core transformer ( XF2-0023 ) with a positive sequence impedance voltage of 7.18%.
The transformer dataplate does not include zero sequence impedance...
My earlier post incorrectly stated that the ABB DriveSize 5.9 reported triplen and even harmonics.
The attached DriveSize 5.9 report for a 315kW VSD shows insignificant triplen and even...
ABB variable speed drives type ACS580 with front-end uncontrolled 6 pulse rectifier are supplied via Delta-Wye Ground transformers.
The ABB DriveSize Ver 5.9 software reports triplen and even order harmonic currents injected into the system impedance, on both sides of the Delta-Wye Ground...
I found by trial and error:
1) Select ‘General purpose drives’
2) Go to the last item (motor) in the configuration tree
3) Enter motor rated shaft output power, or the next standard size below
4) Click on the select unit icon ( a 315kW motor appears after 250kW chosen in step 3) )
5) Select the...
ABB VFD Drive Software
I need to determine the harmonic currents injected into system impedance by ABB ACS580 VFDs where the following has already been installed:
- Transformer: 33000/415V, 2500kVA, urz = 6.25%,Dyn11
- ABB ACS580 VFDs
The ABB DriveSize software does not allow entry of above...
Thanks RedSnake, the Tmax XT_IEC_TECHNICAL CHARACTERISTICS_2021 manual has the information I need to confirm my Tmax XT tcc's.
"Mit Logik kommt man von A nach Z; mit Phantasie kommt man überall hin." Albert Einstein
ABB SACE TMax XT Series
Does anyone out there in IEC land know:
1) The threshold current at which TMax XT series MCCBs start to current limit.
2) Look-up table for selectivity limit and backup protection for TMax XT breaker combinations.
The ABB e-Design software only includes TMax XT breakers...
