Science topics: Power Engineering

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# Power Engineering - Science topic

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Questions related to Power Engineering

I am interested in a scientific research journal for publishing my academic work. Specifically, I am looking for a journal in the field of Electrical Power Engineering, such as SCOPE or any renowned international publication. It is important to me that the journal has a fast publication process, ideally within a timeframe of around two months.

Thank you for your assistance.

I am an electrical engineering student and starting my final year. I need ideas for Final Year Project related to Power Engineering. The ideas i am looking for are supposed to be new i.e., not implemented before in history or they are being done in rest of the world but not in Pakistan.

It will be a big help for me.

Thank you.

I am simulating a power converter circuit on Simulink platform. This also include a 400 V AC grid. I am not sure about a generic thumb rule to define the impedance of the cables for this 3ph 400V Grid system. Any suggestions?

Hello,

I have a question regarding the zero-sequence voltage injection in three-phase SSTs with bypassed modules in a failure case. I investigated some literature and it is clear that only the fundamental harmonic can shift power between the 3 arms (for power balance).

A 3rd harmonic is often used to reduce the peak arm voltages (-13.4%). However, I investigated asymmetrical fault cases and a 5th and 7th harmonic can help tofurther reduce the arm voltage by a small percentage like 5% (so less redundant modules are needed):

Conference Paper Adaptive Zero-Sequence Voltage Injection for Modular Solid-S...

My question is: Do you know other methods to handle asymmetrical fault conditions in cascaded H-bridges or SSTs? Can I handle grid-imbalances like module faults, since the modules in the phase with an over-voltage have to transmit more power (if no zero-voltage injection takes place)?

I thank you for your suggestions and ideas.

Hi,

I am working on tracing current unbalance in HV systems. All papers study unbalance based on simulations which may fail in practical conditions. I'd like to know whether there is any standard for CT/CVT accuracy class used for current/voltage unbalance measurement or not. I have read IEC60044-1 and IEC60044-5 for CT/CVT standards. There is also IEC 61000-4-30 which defines unbalance measurement classes and it is indicated that CT/CVT accuracy may affect measured current/voltage unbalance ratio in practice (which is obviously correct), but no numerical analysis is provided and here my problem arises. Let's say maximum accepted voltage unbalance in HV systems is 1%. A low-accuracy CVT (say 3% class) may cause a voltage unbalance of <1% be measured >1%. In other words a BALANCE system look UNBALANCE or vice versa. Is there any standard that provide unbalance limit + measurement instrument's accuracy class?

Something like:

If you are using a CVT of 3% accuracy class, maximum acceptable voltage unbalance is 2%.

If you are using a CVT of 1% accuracy class, maximum acceptable voltage unbalance is 1%.

(I know IEC61000-3-13 is another standard related to unbalance, but unfortunately I don't have access to it)

Regards

Dear All

Can you provide me with maximum allowable currents of branches in IEEE 33 bus distribution system?

Thank you

Ahmad

I'd like to know the common FACT devices in distribution systems.

I am designing a control for bi-directional LLC-SRC DC-DC converter. The converter charges a battery from the grid. But during reverse operation, i.e when the current flows from battery towards the grid, what may be the impacts of current on the resonant capacitor (Cs as attached)? Do I need to wait for the discharge of DC link capacitors (fast/slow anyhow) on both sides? I cannot see any abnormal change or fluctuations during simulations. For practical approach, I am not sure. Any suggestions?

I am currently designing a BMS for a 48 V Battery pack of an electric vehicle. One of the major challenges regarding the BMS is to equalize the voltages of the cells (as different cell have different ageing) of the battery pack. How can one address this issue??

Hi,

While learning about different algorithms such as Regression, Clustering, Classification, etc. in Machine Learning in different domains such as Medicine (Patient data analysis, etc.), Market analysis, etc. I wonder, how these algorithms could be implemented in Power Electronics or Grid Applications? Any ideas?? Are there any datasets available similar to the ones in UCI ML repositories??

Thanks in advance.

As a part of Industry 4.0, IoT also enjoys a vital position in smart technologies. However, with respect to power electronics, I have read that privacy over the internet could be a concern. Does this technology benefit us in power electronics /power systems domain? Are there any applications available?

I have seem active power ramp rates defined across 60 second intervals (or a minute), with the corresponding units reading as MW/min or kW/min.

I am working with original active power data that are recorded on average every 7 seconds, and am wondering if I can derive and calculate ramp rates over 7 seconds with units reading kW/7Sec ?

The increase in the trend of distributed generation has led to the formation of community microgrids. What is the best possible solution to connect single-phase loads to a microgrid with 2 level voltage source converter?

I feel one possible solution to connect single-phase loads is to use a 3-phase 4 -wire transformer.

I mean devices which uses this effect

Hello everyone,

I have three questions about connecting onshore wind farms to substations:

1) I know, that larger onshore wind farms are connected to higher voltage levels (110 kV or 132 kV). But which voltage level would I choose, if I only have one wind turbine? does a rule of thumb exist depending of the wind turbine / farms capacity (MW)? A reference to cite would also be nice.

2) I have a wind farm which is already connected to a substation. Another wind farm is newly built and is nearer to the first wind farm than to the substation. Is it also possible to connect the wind farms, instead of the connecting line to the substation?

3) Do you have references for costs to connect wind farms to substations for UK? For example costs per km.

Thank you very much!

Jann

Hi

We want to build a quadcopter for a research project,but I have trouble choosing the battery,,,i'm looking for one with the lowest weight and highest capacity,and the price doesn't matter!

And i want this quadcopter to be able to work for an hour and it's weight be less than 3.5 kilograms and it's be able to ship(take) thing up to 1 kilograms

thanks for any help possible

I am using a 3 phase BLDC motor with current rating of 20 A and voltage rating of 18V. At the moment zero cross detection scheme has been employed in the floating phase for position detection of the rotor while two phases are energized at a time. In the start, motor is commutated for a predefined interval until a specific speed is reached. After that, the motor is commutated normally using BEMF detection method. The problem is sometimes commutation works fine and sometimes not. In other words it is not reliable. For example, i have to play a lot with the parameters so that commutation works fine until smooth BEMF signals are acquired. Still then, the results are not reliable.

How to proceed in this situation? any ideas or references would be appreciated!

Nominal power and frequency: 55 MVA, 50 Hz

Number of windings on left side: 1 (Nominal voltage: 230.94 kVA)

Number of windings on right side: 2 (Nominal voltages: 41.86 kVA, 20.25 kVA)

Considering thermal power plants, operational costs, start-up costs of units, are mainly due to the fuel consumption.

I would like to know what are some specific costs of daily operation of a hydroelectric power plant, specially regarding the hydro unit commitment model.

One specific question, is what is the cost of starting up a hydro unit ?

In some papers, an amount of water is related to the cost of starting a hydro unit, how one can specify that amount? Can we represent that cost in terms of discharge of water?

I guess, maybe the cost of starting up is said in terms of water, because, for starting up and connecting a synchronized generator, operator needs to wait till the generator reaches the plant frequency, and meanwhile, some amount of water needs to pass from the turbine which does not lead to power generation.

Is that correct ?

In the Unit Commitment Problem, for a hydropower system, trying to meet the forecasted demand.

If the scheduled generation ( solution of optimization)

have variations with the demand, say 0.01 MW, is it something practical?

Will it be accepted and operated by the operators? or is it too much?

I do place tolerance because It kind of helps the solver to reach feasible and optimal solution in MINLP problem. As you know, originally it should be an equality equation.

I am studying earthing system design for switchyard, substation, street lighting. I understand that fault current level for two earthing system is different. But I am not able to anticipate the effects if two are connected together.

N : Neutral of star point connection is earthed

PE: equipment cabinets, enclosures, and structural steel bonded together and earthed

What is the function of line traps other than communication?

How to calculate the value of the variables like stray capacitance etc? Is there any standard about measuring them and conducting such study?

I want to do a research in optimal sizing in hybrid power system, I want someone to suggest me anew point to do??

Hi all,

I am studying two Alfa Laval brazed plate heat exchangers (BPHEX) used in an ORC power engine (one CB30-40H for the recuperator, and one CH76-100E for the evaporator). More precisely, I am modelling these heat exchangers in the frame of an off-design performance analysis of the ORC engine, and to this end, I would like to know the chevrons angle of the BPHEX.

After reading the Alfa Laval documentation, I managed to find the plates shape and the chevrons angle of their L- , M- and H-type brazed plate heat exchangers. However, they do not mention anything about E-type BPHEX (case of my evaporator).

Anybody would have a hint for me?

Thanks in advance,

Rémi

I want to do switching overvoltage simulation in power system. What are the recommended practices to do the job? Can we do it without any commercial software (e.g build own algorithm in Python)? Thank you in advance.

Could anyone kindly provide me a basic level of research paper which gives me an idea of how to integrate a battery or storage system in a simple series APF or in a STATCOM using the Simulink model?

Would you please explain a bit about infeasible solutions to a unit commitment (UC) problem and what dangers and consequences it may lead to ?

by solution to UC I mean a day-ahead schedule of course.

regarding UC I am studying different paradigms used to tackle this problem. Some conservative approaches like Robust Optimization(Ben-Tal) and Info-Gap ( Ben-Haim). Their conservatism can be justified due to risk averse nature of UC.

For me, as a water resources engineering student, this risk averse and avoiding infeasibility, needs to be explained in a general fashion,

thank you in advance.

Assume two wind generators are connected in parallel to a bus and supply power to a load demand. The rated power of the first generator is 2 MW, and the rated power of the second generator is 2.5 MW. You need to build the overall system model including the wind turbines, wind driven generators, and load demand. To maintain the power balance in the simulation, the load demand is the sum of the wind power outputs. Demonstrate the active power output curve with respect to the wind speed in the steady state. You can specify different wind speeds to get the curve.

good night , do research on broken bars in three phase motors, it was with a 1 HP motor and to generalize the application of the method 'm looking for a database with more powerful engines .

Any mathematical formulation for decide the limits of GRC and GDB in LFC.

A generation rate limitation of 0.1 p.u. per minute is considered here, i.e.,Δpg≤ 0.1 p. u ./ min=0.0017p. u ./ sec. In Saturation block +/- limits values for GRC.

The GDB width considered is 0.036 Hz. In dead Zone block +/- limits values for GDB.

Experts in nuclear power generation can reply

Now I study in the last year in mechanical power engineering department , I discover this field in this year and i like it , I want to work in this field but i don't know what I can do to be professional in this field,

advice me

I am working on partitioning problem and want to show a novel algorithm for network partitioning based on complex network theory. I need this system high quality figure. I don`t have access to this figure. Any advice? Can anyone send me this figure?

Dear all,

Generally, when we talk about the large scale of PV penetration in power grid, we associate the term stability. But, in case of roof top PV system to be connected extensively in the LOW VOLTAGE radial feeder, what are the factors to be focused on? Voltage Parameter violation, energy loss tracking, etc being the ones i pointed out. Others? We don't have to watch out for transient stability issues, do we?

Thanks in Advance.

Dear All

Practically, in Direct load control (DLC) demand response programs, the utility has full control over the registered loads? The consumer-side has no control at all?

Thank you

Sincerely,

Ahmad?

what's the main use of it other than making an analysis of the IEEE bus system

i had little doubt over the hybrid wave and wind energy turbine system. as when both are combined with common electric grid to transfer electricity. when turbine failure cause any problem to other turbine electric system or else can we operate even one fails. i am not deep into concept but need clarification in this point.

after removing some overloaded branches, power system is divided into some groups( each groups might contain generator or not), how can I calculate DC power flow in each single group by using matpower since running DC power flow on the whole system does not converge.

What are the methods for connecting and why?

I calculated PSD of my function, but the PSD output has too many oscillations; therefore, it's hard to find -10dB threshold. So, my question: Is there a correct way to smooth the PSD or do I just need to take the envelope into account?

Thanks.

I'm essentially trying to determine the power calculation for the following setup:

I would like to test the hypothesis that using different serum sample tubes have an effect on the test result. Imagine I would like to compare whether the two different sample tubes have an effect on the Troponin result - I would test the following:

1) patients who have a positive Troponin test, and obtain samples in the two different sample tubes, to be measured on the same analyser

2) serum from healthy volunteers, spiked with recombinant protein

The assay has a CV of 10%, so I would want to make sure I detect if the variance between the two samples exceeds this. How many patients do I need to recruit? Which test do I use to perform my power calc? Do I take 6 samples (3 of each sample tube) of each patient?

I have a 4 level signal that need to be power amplified with efficiency higher than 90%.

the levels of the signal are {-3A,-A,A,3A}. assuming in each level, the amplitude is constant until the next amplitude level is switched, what class of amplifier ( or customized power amplifier) can be used to amplify that type of signal with maximum switching rate with high power efficiency?

we know that when we have two level signal, class C amplifier can do this by applying an amplifier and limiter to the input signal and then non-linearly amplify the signal with out distorting the signal (because it is 2 level) .

so is there a generalization to that approach that can keep the (4-level) signal not distorted after amplification?

i am looking for a instrument to measure the efficiency of 1000 KW Inverter

No power analysis was applied given the study design and they produced statistically significant results. I'm just confused as to whether you can state that a type 2 error was avoided or not for this study design.

I am trying to model a CHP plant providing 175 MW electrical power 75 MW thermal power using steam. The CHP consists of a combined cycle power plant with CSP without storage providing thermal power. How does this plant fare compared with IGCC plant which uses coal as fuel source ?

Hello,

I am simulating a case of vanadium redox flow batteries with carbon felts of thickness3.8mm at 50 percent SOC.Now I am getting an overpotential across the thickness of negative electrode which increases near the membrane.Can anyone explain why this scenario happens?

Let's say I want to optimize a new generator location in an existing power system. I need to know how's the system efficiency, reliability, etc with the new generator. Can I use ETAP or PowerFactory to do this? I usually use Matlab but I don't want to build my own load flow or reliability evalutaion codes. Can I use those software to calculate it?

I am trying to maximize the generated energy form a certain power source (Irregular one), so I want to reach the maximum power transfer via defining an optimal load impedance. It happens that the optimal Load is not pure resistance (as the source itself has some reluctance/capacitance), is there a certain Power Electronic circuit such as Boost Converter that can be designed to "Emulate" that optimal LOAD.

Thanks

Dear All,

There has been numerous researches and studies related to optimization or economic dispatch algorithm used for the optimal power flow in various power grid ( standard IEEE as well as some other case studies as well.)

As i have understood, the problem is however still in the part of real world implementation.

**I am trying to indicate the challenges and problems while implementing those developed algorithm in real world power grid after successful simulation or modeling.****For example:**

To implement an optimization algorithm in a physical grid after successful modeling,

**1**. We would need a central control system in central load dispatch center to start with.

**2.**The central control unit is equipped with forecasted load demand for next hour or half an hour based on the nature of Grid load curve. and so on.

**3.**Based on the forecasted load demand, Central control unit dispatches the command to individual Governers of each generating stations to change the Power output accordingly.

**4.**The central control unit operate in closed loop system and thus capable of real time load sensing. Minor mismatch caused due to variation in forecasted load demand and actual load demand is covered by slack bus. For, exceptional major deviation, reiterations of load flow equations might be required.

**5.**The communication between the central unit and respective generating units could be facilitated via already existing OPGW system.

thus, in order to implement any optimization algorithm in a power grid, major additional requirement is of properly customized central control unit. Apart from that, other requirements like communication, Pg change and real time demand sensing could be done by utilizing the already existing setup like- OPGW, Governer, Power analysers, etc.

**This is the summary of my observation and understanding.**I would be grateful for any correction/ suggestions as i am planning to implement GA based optimization in a real world power grid. I have already done the simulations and now trying to get things together for real world implementation.

**Regards,**

**Bishal**

There is a confusion in defining repair rate. From Richard Brown's book, Power Distribution Reliability, it is said that repair rate is the inverse of repair duration, which is defined as the mean time needed to repair the system SINCE it fails (page 164). But in the Markov process example (page 204), he used repair rate as the rate of transition from switched state (1b to 0 and 2b to 0) to normal state, not from the fail state to normal state (1a to 0 and 2a to 0). I attached the screenshoot of his book.

What I am trying to signify here is, in case of power grid of NEPAL (My homeland), the load demand is always higher than the total generations from all Major generating stations (hydro power plants mostly).

**So, all power plants usually operate in their maximum possible capacity to meet the demand to whatever extends they could**(Total load demand is curtailed by load shedding through load dispatch center such that Pd=Pg-Pl).Now, the problem is, the transmission line loss is still very significant (around 8%) and I originally thought of following the

**CONCEPT OF OPTIMAL POWER FLOW**to minimize the transmission loss. However, under above mentioned condition of generators already being fully utilized, I am finding it hard to rationalize the whole concept of optimization for this case.**Is there still some way I could impose the concept of optimization or optimal power flow under these circumstances?**I hope I have explained the problem clear enough. Any help would be great.

For reference,

**Attached herewith**is the approximated ETAP model of grid itself.**Regards,**

**Bishal**

I'm planning to work on optimization of switch allocation in existing distribution network. I have no working on distribution system before. My question is, what are the considerations in moving a sectionalizer from a location to another? Can I just move sectionalizer near the substation to the end side of the network? Is a sectionalizer chosen to be placed in a specific location only?

Dear all,

I am trying to run a load flow analysis of relatively unknown power grid. However, one of many problem i am facing is that the network consists of 132 kV branch or line and 66 kV lines as well. I could opt for using the lumped representation of the 66 kV segment but it would make the analysis more unrealistic. Also, if i try to consider two different voltage level for the load flow analysis, i might face the problem of Per unit representation.

How could i proceed? I would highly appreciate any help in this topic.

Regards,

Bishal

Any ideas on features/factors that could make cooperative transactive control more attractive to smartgrid an local community energy markets ?

I am trying to design a model in MATLAB which takes lesser computation time. I have seen how it is possible to design averaged switch models for unidirectional buck, boost and buck-boost converters. I was wondering how the same could be done for bi-directional DC-DC converters.

Can anyone please share an experiment based on the PM800MG Power meter with 18Amps contactor with overload relay.

i am working on project in which we will be converting a gasoline powered engine to E100.To increase the compression ratio we have decided to change the piston as we have decided to increase the diameter of the cylinder.So what changes should we make to the connecting rod so that it withstands the increase in force,torque etc.We don 't want to change the diameter of the pin as it would require us to make changes in the crankshaft as well.

In RF sputtering system, there is control panel in build with the system, which is used to control and adjust the cathode power, here my question is that what is Reverse Power (RP)...? while we are applying the power (for example 100 watts) means, reverse power is showed that 20 watts. I thought that the target power of 100 watts should not be there in the cathode,

Kindly give your valuable ideas and suggestions for this above-mentioned questions, which may be useful for me.

I am planning to use timing belt for the power transmission. In my application shock loading is exist. So I wanted to know which belt having more shock resistance, made from carbon-fiber or from Kevlar? (If both belts having same power transmission capacity)

while doing power flow analysis of a radial distribution systems using backward forward method,how to apply DG with bidirection

i am working on project in which we will be converting a gasoline powered engine to E100. I want to know maximum compression ratio that can be achieved within the safety limits (using bajaj discover 100cc dts-si engine for the same).

There are some SKF type high pressure feed pumps that work under conditions: P

_{out}= 200 bar, T_{out}= 247^{o}C.I want to know that when this pumps should go under repairs.

I need a reliable failure rate and mtbf database of different power supplies, but I can not find any database with this information.

If we have a rectangular function for voltage for a certain waveguide,and we have the rise and fall time of that, is the power output change by changing the rise time ?why?

I am designing much better ferrite-core high frequency transformers than I can buy. The core is wound with two layers over it's entire magnetic path length, The winding is coherent, i.e.: all parts of all windings have the same lay, and the same lead. I will attempt to measure the time lag between a sudden increase in load current, and the reflected current in the source. Are there parameters of the transformer, that should allow me to predict the delay?

One of our generators output current has unbalanced current.

What is cause of generator unbalanced current?

What is its cause possibly?

Six similar Genset connected to one bus. One of those Gensets have unbalanced current.

Is it possible its because of air gap of the failed phase?

What is solution for this problem?

What are the strengths and weaknesses of Simulink to simulate power systems?

If the positive terminal of 12 volt battery is connected to the +6 volt and the negative terminal is connected to the -6 volt supply, Does it leaves any side effect on the battery? if yes please discuss the effect.

Suppose the main power supply is down. The standby generator now supplies power to loads in its bus. Is it possible to make a standby generator supply power via the distribution feeder to another load points as well? If it is possible, what are the requirements (beside enough capacity)?

Hello,

This question is about the dimensioning of the fuse to be placed in my application of inverter. I have calculated the current rating considering various derating factors.

Now, I want to dimension the fuse as per its I2t rating. I amaware that Fuse I2t should be less than the Semiconductor I2t etc. I am looking for some document which has some steps to calculate and co-ordinate I2t of fuse with that of the application.

I will be grateful for your help.

Regards

Aalok

Would like to know how to model a constant power load in SImulink/Simpowersystems. I'd like to be able to simply change the power requirement of the load which is being powered by two boost converters. Any help would be great, thanks.

is there anyone who can help me to explain if do not consider line impedance effect only consider effect of load , so how to design droop parameters to get more accurate power sharing concept among parallel inverter?what are the parameters will be effected ?

its quite diffcult for me to understand the power sharing and droop concept anyone will try to expalin it .

Please provide me help and related literatures for designing a coupled inductor with coupling coefficient about 0.4 to 0.5 in laboratory.

How does it affects the accuracy and convergence of a load flow study? Why is it typically 1.6? Does it have something to do with the golden ratio?

Can someone kindly introduce some references (new references will be better) and new lines of research about chaos and its applications in electrical power engineering?