Hello everybody.
I’m from Portugal and we have many Electrical Engineering MSc degrees with different branches, like energy, telecommunications, automation and electronics.
In your own countries, can an Electrical Engineering MSc in branches, other than energy, be responsible for the project...
Good evening everybody.
I’m an electrical engineer and I have a safety question regarding a safety butterfly valve that closes automatically after an excess flow detection.
I’m familiar with these systems and, if the valve does close, I think it’s mandatory that the reset is always a manual...
Hello everybody.
I am looking for a lighting calculation software for a road tunnel project.
I have come across Relux Desktop which is free.
There is a Tunnel lighting add-on available to buy.
But it seems it’s included in the free downloadable Relux Desktop package.
Has anybody tried the...
Good afternoon everybody.
I am involved in a project and I want to calculate the fault currents on several locations to validate the short-circuit power needed for each panel and the upstream trip switches nominal currents and its types A, B, C or D.
I use the impedances method and determine...
Good morning everybody.
Some grid stability studies neglect the demand side inertial contribution. Only compute the synchronous generators inertial contribution.
Other studies refer that, on the demand side, there are synchronous motors that must be considered.
The majority of electrical...
Good afternoon
Suppose I have two synchronous generators. One rated 10 MVA with H=4s and the other 20 MVA with H=2s.
I understand that the SIRs of the generators don’t depend on their operating point.
But if both are working at, let’s say, 5 MVA, and there’s an outage of another generator in...
Good night experts.
I work for the utility in Madeira island. Our grid is small and not connected to Portugal mainland.
I want to validate our RoCoF figure. I have calculated all the synchronous generators (Si) inertia constants (Hi).
I´ve used Hi= (J*Wi^2)/(0.5*Si).
I´ve read somewhere...
Good evening everybody.
Can a diesel generator, connected to the grid, absorb reactive power while producing active power?
A small grid, with underground power cables and frequency converters everywhere, can have a surplus of capacitive reactive power. That raises the grid voltage, mainly...
Hello everybody.
I’m planning an IT earthing system to feed some emergency pumps within an existing building.
The existing electrical installation is on a TT scheme.
There will be, of course, a specific LV/LV transformer with a Permanent insulation monitor.
I will install an equipotential...
Good morning everybody.
I need your expert advices.
We are retrofitting an hydro power plants with three Pelton turbines that drive 8 MW alternators.
Historically, the turbines cannot be operated below 2 MW. But I cannot find any manufacturer documents that support this figure.
I know that...
Good morning everybody,
I want to measure the earth-resistance on a primary substation with separate N and PE grounds.
I have measured it with 3-wire connection earth resistance loop test on the LV panel. I am using a FLUKE 1653B tester. The result was over 40 Ohm.
I have also connected the...
Good morning everybody,
I have worked with SIEMENS PLCs for a long time, including solutions design, programming and commissioning.
Now I work as a consultant and I was asked an opinion about a new project.
In my projects I´ve always used third-party galvanic isolation modules to the analog...
Good evening everybody.
I want to calculate the inertia constant of a 1500 rpm synchronous generator with a 8304 rpm steam turbine prime-mover, both attached through a gear box.
I have the J figures for both. The generator has a J of 789 Kgm^2 and the turbine a J of 40 kgm^2.
I’ve come across...
Hello everybody,
I want to validate the inertia constant of a synchronous generator, stated by its supplier.
I have all the necessary instruments to study the behaviour of the generator including oscillo-perturbography recording devices.
I've read somewhere that one typical test is to perform...
Good morning everybody.
I am considering the acquisition of ETAP simulation software.
I want to use it to simulate and study the voltage recovery delay in our grid after a fault and its clearance.
The software must be able to model the synchronous generators with the reactances and time...
