- Srete Nikolovski added an answer:5Is there any practical data or literature where the accelerating time from zero to nominal speed for turbo generators can be found?
Generators are rated power from 3-50 MW. In attachment is one test diagram for 5 MW generator
Dear Gabriel. Thank you
That is it. I have found answers on Fig 11 in the first and Fig 12 in the second paper which confirm our measurements for 5 MW steam generator which time was 40 min.
- Pouyan Asgharian added an answer:4How to make an interface between matlab and pscad?
Hello, everyone I'm working on optimization of coordinating overcurrent relay I wrote allocation codes and optimization code in matlab but I need to recall mfiles in PSCAD. I want o know is that possible to link between matlab and pscad wich I able to use matlab codes in Pscad?
i have this problem too!if you find your answer , please help me.
- Ravi Bhushan asked a question:OpenHow can I design h-infinity controller through state-space approach for the DFIG system?
I have already designed the LQR controller for DFIG system.
In LQR case
Here, I have already A, B, C and D matrices
In H-infinity case
How will I decide the variables z and y?Following
- Francisco Arrau added an answer:3What is the best winding configuration for a PMSG?
I'm designing a 5 kW and 115 rpm permanent magnet synchronous generator for a direct drive tidal turbine. I'm going to use concentrated winding.
I have seen that many authors prefer symmetrical configurations (like 10 poles and 12 slots) but by other side many commercial in-wheel motors (low speed applications) use 46 poles and 51 slots.
The disadvantage I already know is a lower torque compared to a machine with q=0.4 (the 10/12), but on the other hand the LCM is very high so the ripple torque is very low, and the THD is not so severe, so I think it could be a very good option to avoid vibrations problems and ensure a very long useful life that is something very important on this project.
I'm waiting for your comments, thanks a lot!
Mr. Yannis, the 46-poles/51-slots machine have a q=0.37.
My question is more about why I haven't seen any publication about this kind of motor used as a generator, and I only see advantages. I think the main problem is harmonic distortion, but I have no proves to discard it.Following
- Inno Davidson added an answer:15Do you have any good book/research article related to smart grid planning?
Demand Side Response and integration of renewable.
You are most welcome.Following
- Morteza Seddighighachkanloo added an answer:5How the insufficient damping of low frequency oscillations limits power transfer capability in power system?
Can someone please give me an example?
- Morteza Seddighighachkanloo added an answer:13Is it possible to model the line outage in MATPOWER ?
Specially when the network will be separated islands after line outage (radial distribution networks) .
- Kishore Bhaurao Khiradkar added an answer:11Can anyone recommend a PMU simulator to randomly generate data?
Please suggest software to randomly generate PMU data.
The data obtained should be as per IEEE format.
Even though it's not in the prescribed format(s) then also any PMU
generator which might be solving the purpose will do.
Thanks in anticipation.
Kishore B. Khiradkar
The paper is really helpful.Following
- Pisupati Sadasiva Subramanyam added an answer:16I have monthly load how can I extract daily or hourly load from it?
Hi all, I have monthly load how can I extract daily or hourly load from it?
You may also take a set of daily or hourly data and see whether this curve you have chosen fits fairly well with this data. If so you may use that curve for interpolation from your monthly data.
you can try curves with polynomials of a different degree.
This is a cumbersome Procedure and still we are not 100% confident of the Results we gt. It is a Rough Approximation.
- Mostafa Eidiani added an answer:2Which is the best power systems analysis software for small systems, ergum industrial systems?
You can see also this link
- Meera Karamta added an answer:7For a dynamic simualtion of a multi-m/c system with TCSC, what could be the ideal value of initial firing angle?
I want to perform EMTP based dynamic simulation of a multi-machine system having TCSC. One of the reference paper suggests using initial firing angle 8 degrees more than the TCSC's resonant point. The authors have justify this as based on engineering judgement..
Is there any specific limit?
Thank you Parekh Sir.. Will take into consideration.Following
- Sivanantham S added an answer:6How can we estimate power (RTL level) in RTL Compiler before performing actual synthesis?
Building RTL Power Models in RTL Compiler
It is always good to build power model before performing synthesisFollowing
- Muharem Mehmedovic added an answer:3In a synchronous machine modelling how do you derive the flux linkage equation in dq coordinate for a synchronous machine modelling?
For mutually coupled windings along d-axis and q-axis
The question could be more precise because there is no mutual couplings between d and q axis. The equations for flux linkages in d and q axis starts from their form in the stand still frame. After transformation from this to the rotor frame (this must be done for all quantities: inductances, resistances, voltages, currents and flux linkages) the final equations for flux linkages shall be derived. Also, the systematic approach can be found in: P. C. Krause, Analysis of Electric Machinery!Following
- Sándor F. Tóth added an answer:42How to measure the difficulty of a Mixed-Linear Integer Programming (MILP) problem?The intuitive answer is the number of binary variables, when solving the MILP through the branch-and-cut algorithm. But, is the number of binary variables really the main characteristic that increases the computational burden of an MILP?
In the case of the Unit Commitment problem (UC), it has been proven that including the startup and shutdown binary variables decreases its computational burden in comparison with a UC using only commitment binary variables (without the startup and shutdown ones).
So if the quantity of binary variables does not directly influence the computational burden of a UC, how to measure the computational burden of an MILP problem?
I think it is common in MIP optimization to have a few global constraints (e.g., enterprise-wide smooth workflows) whose number doesn't change with the size of operation (the number of decision variables) but at the same time it gets easier to satisfy them when more items are available. The number of "local" constraints can still explode in response to the higher number of variables but this will likely not have any impact on difficulty if the local regions are independent.Following
- Sheng Chen added an answer:2Inverter for Solar Power Systemhi , I am searching on "Inverters used in PV systems". I will be really grateful if someone can help me to get more details on the advancements in the fields.Also what are the project possiblities in this area which can be completed in maximum of 4 months. ?
Hi sir. For solar inverter research, I suggest you could login homepage of some solar inverter manufacturers, then download the datasheet and installation diagram.
Hope it can help for your work.Following
- Maksim Prudov added an answer:8What is the cause of oscillatory instability of power system?
I examine a simple two-machine model of the electrical system, which takes into account field circuit dynamics and excitation system (Kundur P. Power system stability and control, McGraw-Hill, New York, 1961).
When power generation reaches 1.3 p.u. appears a pair of complex eigenvalues with positive real part. This mode has a frequency of 1.4 Hz. Analysis of the participation matrix showed that this mode is related to the flux linkage of field winding and excitation system. I checked the voltage stability using the network dV/dQ curve (using the Jacobian). But the network dV/dQ curve change sign much later.
What is the cause of oscillatory instability of power system model?
You can see the angle-power curves for my model in attach. Green corresponds to the stability, blue - oscillatory instability, red - monotonic instability.
In my case, oscillatory instability is directly related to the action of ARV, coefficient K5 (see Kundur Power Systems Stability and Control p.759) changes its sign. Should be noted that the model was not included PSS.Following
- Bala Murugan s added an answer:3What software will help me accurately measure dynamic power dissipation of a circuit that is coded in verilog hdl?
I have worked in Cadence NCLaunch tool to measure power dissipation. However, presently I am unable to access Cadence and as there is no freeware available on the net, I am out of options. Please suggest me some other tool for my research purpose
You have to have either Cadence RTL compiler or Synopsys DC, without this if you are run the code to measure the dynamic power, you will receive many questions from the reviewer and at the end you are frustrated about your work. So, better use any one of the tool mentioned above and generate either VCD file or TCF file and calculate the dynamic power. Make sure that your VCD or TCF file covered 100% switching activity while tool read it.Following
- Jethro Betcke added an answer:4How can find data of a real microgrid for designing an MPC-based controller?
I want to design a EMS systems for a MicroGrid that determines real and reactive power set points for components of a real world MG, e.g. DGs, Compensators, Loads etc.
I need all of the information/data about this MicroGrid for design a MPC-based controller.
I prefer that this system includes a PV, a wind turbine, a diesel generator, and a battery storage device.
Let me help you on the way:
- Javad Modarresi added an answer:9How do you model the synchronous condenser in DIgSILENT?
I want to model the synchronous condenser in DIgSILENT. How can it be done?
Synchronous condenser consume little active power. Moreover, DigSILENT gives error in very low power factors (Simulation not converge). My network is IEEE 14 bus test system.
In DigSILENT, the setting of power flow tap is only applied to the power flow analysis and synchronous machine exchanges the active power with network in the time domain simulation even in the P=0 condition.Following
- Albert Juhasz added an answer:7What is the physical interpretation of the energy conversion factor for power generation from steam turbines?
I am using a model for power generation from steam turbines to be the difference between the superheated steam enthalpy and the outlet saturated low pressure steam enthalpy multiplied by the efficiency of the turbine. The power calculated is smaller than the actual power that is generated by real power plant data. However, I figured out that if I multiplied the enthalpy difference with a certain factor it will reproduce the actual plant data, and the model worked for data for many different power plants. I cannot find a physical interpretation for this factor. I only found one paper that explicitly shows this factor and called it " energy conversion factor" with no physical interpretation.
Natalia and Maddali essentiall y answeredyour question.Following
- Abdulla Rahil added an answer:1To input measured variable wind speeds for mathematical modelling in simulink?How to input variable wind velocity to the simulink model correspondingly to get the output for variable speed, using the lookup table in simulink is giving an error. I want to give wind speed measured for every 10mins and to dump/interface those in simulink model.
sorry this is exactly is my question if you got any answer plz let me nowFollowing
- Salah Eldeen Gasim added an answer:9Who can help in application of neural networks (NN) in load flow analysis?
Supply me by any documents, examples, and MATLAB codes.
Your efforts are highly appreciated Mr. Chathura Senanayake,
I will do that, and get back to you later on.
Thank you so much.Following
- Morteza Shabanzadeh added an answer:4Microgrid test system in Digsilent or matlab simpower?I want work on my project in the field of "Microgrid." I need a test system of microgrid in digsilent or matlab simulink. If anyone here has this file, please give me.
Just read and collect the case studies of academic papers concerning Smart Grid and Microgrid issues.
- Okan Ozgonenel added an answer:10Has anyone used matpower for simulation?Am having some doubts related to switching off of generators.
I also recommend you to use PSCAD software, which is more powerful than matpower. Please contact to me if you have any questions. Prof. Dr. Okan OzgonenelFollowing
- Michael Hainzl added an answer:17In a pipe electrode used for earthing, will the current flow both inside and outside of the cylindrical surface area?I was just going through BS 7430, where a formula was given in Page No. 29 for calculation of current density of one electrode. Now in order to calculate the number of electrodes required to take the short circuit current of the system, I need to divide "J" with the surface area. However, when calculating the surface area of the cylinder do we have to calculate only "2 x 3.14 x r x h" or "2 x 3.14 x h x (r +R)" where "r" is the inside diameter and "R" outside diameter of the pipe electrode.
The inner surface of a hollow grounding electrode (a pipe) isn't going to help dissipate current into the surrounding ground, no matter how you connect it. If you assume the grounding electrode can be filled with earth, it could, in theory, conduct a tiny amount of energy out the ends of the pipe. But in a practical application, the fraction of current out the ends of the pipe from the inner surface would be so small, it's not even worth your time to try and calculate the result.
All that being said, I went back to the original post and it appears this is a textbook question, so making practical approximations for real applications might cost you in this case. Perhaps the objective of the problem is to demonstrate how little current would flow from the inner surface of the pipe?Following
- Mahesh S. Illindala added an answer:1Inverter based microgridWhen stability analysis has to be performed in an inverter based microgrid, is there a need to convert the load flow variables from network frame to the machine (inverter) frame?
All the system dynamic equations have to be on the same reference frame.Following
- Salah Eldeen Gasim added an answer:3Which loss has to be considered for transformer losses?The technical specification of our project has specified both fixed and capitalization factor-based losses. Now our vendor is asking for which losses need to be considered.Transformer iron-loss (the power lost in a transformer's core) is also a considerable part of transformer no load losses. The iron which is meant here represents the transformer core. Transformer iron loss is divided to two: Hysteresis loss and eddy current loss. Both depend on type of the core material, the current frequency, the maximum value of the magnetic field and thickness of core sheets. The main cause of hysteresis loss is the magnetic field reversal. Eddy currents are the currents that flow in the core. They are due to the emf which is generated in the core (as the flux cuts it) by the same principle of the induced voltage in the secondary winding of the transformer.Following
About Power Systems Modelling
Simulation of Power Systems as a whole and of each separate component