What would be a practical approach for assessing actual arc flash hazard risk level when one is just walking inside a 230kV switchyard (N. American case)? It does not seem to me that empirical formulas in NFPA 70E and IEEE 1584 would be adequate to use since, given the typical fault level of say...
Please ignore my post just below this one, it is a duplicate - accidently pressed submit before finishing Subject line.
A small wind farm of five units connects to a 44kV utility line. The facility is operating for about 1 year and experiences high level of gasses at turbine step up...
A small wind farm of five units connects to a 44kV utility line. The facility is operating for about 1 year and experiences high level of gasses at turbine step up transformers 34.5kV/690V. Turbines are 2.2MW operate at 690V, step up transformers are 2.5MVA, while the main 44/34.5kV transformer...
A small wind farm of five units connects to a 44kV utility line. The facility is operating for about 1 year and experiences high level of gasses at turbine step up transformers 34.5kV/690V. Turbines are 2.2MW operate at 690V, step up transformers are 2.5MVA, while the main 44/34.5kV...
System:
The facility is a larger wind farm with two 35kV collector feeders each having about twenty 1.5MW turbines. There is one step up 230/35kV transformer in the substation serving both feeders, connected as WYE/DELTA (230/35).
The turbine step up transforms use DELTA on the 35kV side, so...
Even though wind farms are becoming common almost everywhere, they are mostly large scale connecting to HV transmission lines and appear much less common as imbedded distributed generation (DG) connecting to medium voltage distribution lines. Such distribution scenarios appear not to be well...
Small 9 MW wind farm is connecting to a 44kV distribution line. The power utility requires that at the point of interconnection, the wind facility maintains a fixed power factor of 0.97 at all times (inductive, the wind facility imports reactive power from the utility grid).
There are 4...
I'm working on a project in Canada where an European GIS medium voltage switchgear is provided (voltage class 36kV-38kV) requiring a tee elbow pluggable cable connectors, Elastimold M400TB or equivalent. The maximum system voltage is 29kV (27.6kV nominal).
However, the Elastimold M400TB tee...
Has anyone dealt with optimization of number and size of inverters for large scale solar projects. For example, if a 10MW solar park is located on a land parcel with regular dimensions, is it more economical to use 20 500kW inverters each covering 5% of the area, or 10 1MW units each covering...
I’m tasked to compare two 1MW PV inverters. One of the items which seems to be rather difficult to compare is the efficiency. One unit is specified with CEC (California) weighted efficiency, while for the other one European weighted efficiency is provided.
I know that inverter efficiency...
A fairly large PV solar plant, 10MW, is now in the feasibility phase. The proposed configuration consists of 10 inverters 1MW each 240V output coupled with a high ratio transformers stepping up to 46kV. All transformers would be connected in a “daisy chain” arrangement on the HV side (DELTA)...
A while ago, I started a thread http://eng-tips.com/viewthread.cfm?qid=235885&page=1 which many of you contributed to, but that story has not ended yet...
So the issue is that a 3.5 MW motor driving a large fan has problems starting. The starting method is the soft starter. Rotational inertia...
The SSM series 6kV ABB soft starter is used to drive a 3.5MW asynchronous motor, which drives a large fan. The vendor seems to be unable to provide commissioning assistance in a timely manner, so the Client may have to commission this using its own resources.
The primary soft starter...
A 30 MVA oil filled transformer (115 kV) will be put onto the temporary pad with oil contentment for about 2 years, de-energized, in Canada. What considerations (re moisture, etc) should be given? Thank you.
A 140 MW diesel plant will consist of 14 units, 10 MW each (or a similar combination). It will operate off grid and will be feeding a large industrial facility. Among many problems still be solved, one of them appear to be very severe – the load will mainly consist of various large motors...
Looking for typical parameters, a small hydro machine, 5000 kVA, 450 rpm, 4.16 kV, pf 0.9, specifically some rough range for unsaturated reactances (pu): Xd, X'd, X"d, Xq, X1, X2 and X0 and open circuit time constants T'do, T"do, T'qo and T"qo. Thank you for any help.
An 8 x 15 MW diesel plant is proposed as the only power source for a large industrial facility (no grid). The proposed generation voltage level is 11 kV which may be used to feed some large motors directly, or will be stepped down to other medim and low voltage levels to feed other loads, as...
A power measurement device (transducer) used to be connected to the open delta (2 PTs) scheme, using 2 current elements (A, C) 3 voltage wires scheme (A-B, B-C). The PT configuration, however, is going to change from an open delta to 3 PTs wye-wye, whereas the secondary L-L voltage will remain...
Case:
Twenty diesel generators are connected through step up transformers to a common MV bus, off grid. Generators are similar but not exactly the same, with power output ranging 1000 – 1200 kVA. Governors and AVR are also different on some units. All units have PM pilot exciters. After all...
This LM6000 project, with a gearbox (50 Hz). Suppose the following scenario:
The turbine shuts down for some reason other than electrical fault on the generator side. The GT control system will then trip the generator protection and the generator breaker. However, generator breaker fails to...
