HI all, I have been a very good reader of a lot of post here and would like to extend my appreciation and thanks.
I have been using IEEE 519 limits on the true PCC and we have always been compliant with it fortunately.
However, I have also been trying my best to understand and been looking for...
HI all,
I would like to obtain valuable inputs to my question and hope I am asking a generic one for my understanding.
A three winding transformer have primary delta, secondary delta and tertiary wye-solidly grounded connected. Primary and secondary winding terminals are connected to separate...
HI all,
I have been designing several industrial substations in the past and I always design the substation grounding mesh grid per IEEE 80 and as a "stand-alone" grounding grid. This means, I do not consider any bonding to the overall plant grid and design to be inherently safe and not rely to...
LionelHutz, can I compare to the total RMS Current (fundamental + harmonics) against derated cable ampacity (from temp, grouping plus 125% contingency) and breaker AT?
Gr8blu,
Will the specification of equipment or devices specify what or how much harmonic voltage and current they can...
Is it correct to make the following assumptions:
1. An 8.5% THD (volts) would mean 1.85% fundamental nominal voltage?
2. A 8.5% TDD (or THD (current) would mean 1.6% total maximum fundamental demand current
Will the distribution equipment(say the MCC) pass rated maximum voltage and continuous...
Hi Kiribanda, thank you for your prompt response.
I was referring to THD but will also consider TDD. ETAP have THD(I) which they have not changed by definition to TDD.
I agree with you on the reference PCC.
Based on my understanding, I am aligned with you on the premise that the TDD and THD...
Hi all,
I have 5 VFDs each with manufacturer test reported %THD content of 4.3% at 88% loading.
IEEE std 519 requires total harmonic distortion of 8% and I am getting 8.6% THD at 80% VFD loading and 11% at 100% loading at the 600V MCC bus where all these VFDs are connected and this is the...
Hi all,
We are extending an existing transformer yard which is going into the 3.0 PSIG blast radius from a nearby plant (200 ft).
We are looking into placing blast walls but am curious if the post insulators, disconnect switches, liquid immersed power transformers can withstand that pressure...
Hi all,
We have a strange condition wherein, our 600V switchgear power circuit breaker is tripping at no fault condition.
Here is the current case:
The switchgear is a main-tie-main with N.O. bus tie circuit breaker. The breaker is an 1600A K-Line breaker with solid state trip unit. The relay...
The design proposed to use 3 x ABB SSVT-350 (IPC) Voltage Station Transformers. A wye-neutral solidly grounded secondary winding is made by interconnecting the X2 terminals to ground and using the X1 terminals for the line conductors (see attached image). Each primary H1 terminals are connected...
I would like to know if I can operate the input of my VFD at 5~7.5% voltage drop. We have an electric dredge rated for 13.8 kV. The dredge has a small electrical room with 13.8 kV switchgear feeding a 13.8-4.16 kV VFD and a 13.8-0.6 kV stepdown auxiliary distribution transformer within the 13.8...
Hi all,
We have a Siemens Perfect Harmony VFD feeding three motors rated 3 x 4,000 HP, 6.9 kV. The VFD is having isolation transformer with 12.5 MVA primary wye winding and 13 MVA secondary delta winding (18 x windings connected to individual power cells (6 windings per phase).
The VFD...
Hi all,
I would like to obtain technical opinion from folks here about the fact of installing TECK 90 power cables in cable cones normally used for portable trailing cables (used in mines).
TECK 90 is an armored cable also suitable for direct burial and have sufficient strength to exposed...
