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...
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...
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...
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...
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...
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...
A damaged section of an existing cable is to be removed and replaced with a new cable.
- Existing Cable: 3c, Al, XLPE/Cu screen on each core/PVC, 3.8/6.6kV
- New Cable: 3c, Al, XLPE/Cu screen on each core/SWA/PVC , 3.8/6.6kV
Two cable joins are required.
Continuity of the copper screens of each...
I understand AIC Rating to be the interrupt rating of a breaker.
For low voltage breakers is AIC the initial symmetrical rms current ?
For medium/high voltage breakers is AIC the symmetrical rms current at the instant of contact parting ?
Does AIC include the d.c. offset ?
Is AIC...
SKM’s PTW Arc Flash IEEE 1584-2018 calculates additional:
- “Flash Boundaries” based on user defined incident energy, and
- “Incident Energy” based on user defined additional Working Distances.
As shown in attached file,my manual calculations agree with the PTW32 Ver 9003 results 2), 3), and...
When using software such as SKM / HIWAVE to calculate harmonic loadflows, what generator and motor reactances are used :
a) Generator direct axis saturated sub-transient reactance and motor starting reactance…or
b) Generator synchronous reactance and consider induction motors out-of-service.
The attached photo shows a Merlin Gerin - Automatic Changeover Breaker type C250H with an interrupt rating of 50kA at 380/415V a.c.
An integral trip unit is not evident in the photo.
Does anyone know if this device has an integral non-adjustable magnetic only trip unit and if so what is the...
thread238-292509
IEEE1584 does not specify a short-circuit current calculation method.
Pre version 8 of SKM PTW arc flash analysis software to IEEE 1584 used the PTW ‘comprehensive’ short-circuit current calculation method which is the classical impedance reduction method without the...
thread238-292509
IEEE1584 does not specify a short-circuit current calculation method.
Pre version 8 of SKM PTW arc flash analysis software to IEEE 1584 used the PTW ‘comprehensive’ short-circuit current calculation method which is the classical impedance reduction method without the...
