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POWER TRANSFORMERS

The manufacturing of power transformers in ELECTROPUTURE S.A. is done in accordance with international standarts (IEC, ANSI, etc.) and therefore, our transformers will most of the requirements existing on varios markets, moreover, we can manufacture transformers according to customers4 specific requirements.
The power transformers are designed to operate in temperate climate conditions (standard designed), in special climate condition such as: tropical dry-humid, tropical dry, highly polluted mining areas and in any other environmetal conditions.
Below you will find the main groups of standard trasformers manufactured and delivered by ELECTROPUTERE S.A.:

SMALL OIL IMMERSED DISTRIBUTION
These trasformers are rated up to 5000 KVA at voltages up to 36 kV. They are delivered with copper or aluminum windings. off load voltage control +/- 2x2.5%, hermetically sealed or conservator types and voltages’ terminals brought out thorough bushings or cable boxes.

LARGE OIL IMMERSED DISTRIBUTION
These transformers are up to 40 MVA at voltages up to 110 kV. They are delivered with copper or aluminum windings, dff circuit (OCTC) or on load tap changers (OLTC). ONAN and ONAF cooling and AVR panel.

MEDIUM POWER TRANSFORMERS
These transformers are rated up to 6.3 to 100 MVA at voltages up to 230 kV. They are delivered with off circuit (OCTC) or on load tap changers (OLTC), ONAN, ONAF and OFAF cooling and AVR panel.

LARGE POWER TRANSFORMERS
These trasformers are rated up to 440 MVA at voltages up to 420 kV. They are delivered with off circuit (OCTC) or on load tap changers (OLTC), ONAN, ONAF, OFAF and OFWF cooling, full winding or auto transformers and AVR panel. They can be network or generator trasformers.

INDUSTRIAL TRANSFORMERS
Transformers for Rectifiers and Converters, rated between 400 and 3600 KVA.
Transformers for electric-arc furnaces and induction heating plants, rated between 320KVA and 100MVA

TRANCTION TRANSFORMERS
Transformers for electric traction substations, rated between 630 and 16000 KVA

MINING TRANSFORMERS
Fire-damp transformers: They are rated up to 630 KVA at voltages up to 10 KV. They are fully fire-damp protected to operate in hazardous environments, containing highly explosive mineng gas.

DRY TYPE TRANSFORMERS
These transformers are rated up to 3150 KVA at voltages up to 20 KV. They are delivered with Class F or H.

GROUNDING AND AUXILIARY TRANSFORMERS
These transfonmers are rated from 100 to 1600 kVA with wye star connected primary winding and secondary winding of 0.4 kV. The ttransformers create artificially neutral for 6-36 kV networks.
Our Transformers are designed and produced to be used in all kinds of applications are to meet all customers’ requirements.
They can properly and safely used in:

Distribution networks and residential areas
Power transmission networks and substations
Generation Power Plats: Nuclear, thermal, combined cyco - generation, Hydro, renewable energy

Industry: Cement, Steel mills, Smelters, Oil and Gas, Chemicals and Petrochemicals, Mining, desalination plants and pumping stations and all other heavy and light industries.
Transportation: Traction Substations

Student record with linked list in C programing

#Ücretsiz Forex Kitabı Kazanmak için tıklayın

include<stdio.h>
    #include<stdlib.h>
    #include<malloc.h>


     struct student
      {
         char fname[29];
         char lname[29];
         int age;
         struct student *next;
      };

      int main()
      {
        int i,n,ch,ps,x,k;
        k=0;
      struct student *h,*t,*t1,*w,*q;
      h=NULL;

      printf("\n/* student data records*/");


    while(1)
     {
          printf("\n1.display\n2:add\n3.delete\n4.exit\n5.sort by first name\n");
            printf("\nenter your choice=");
          scanf("%d",&ch);
          switch(ch)
    {
    case 1:
      if(h==NULL)
       {
        printf("no records are available");
      }
      w=h;
      while(w!=NULL)
     {
        printf("\nfirst name of a student:%s\nlast name of a student:%s\nage of a student:%d\n",
      w->fname,w->lname,w->age);
      w=w->next;
     }
    break;

    case 2:
       printf("\nenter the new record=\t");
       if(h==NULL)
     {
      h=t=(struct student *)malloc(sizeof(struct student));
       printf("\nfirst Name of a student:\t");
        scanf("%s",&t->fname);
        printf("\nlast Name of a student:\t");
        scanf("%s",&t->lname);
        printf("\nage of a student:\t");
        scanf("%d",&t->age);
       t->next=NULL;
    break;
    }
    else
      {
        t1=(struct student *)malloc(sizeof(struct student));
        printf("\nFirst Name of a student:\t");
        scanf("%s",&t1->fname);
        printf("\nlast Name of a student:\t");
        scanf("%s",&t1->lname);
        printf("\nage of a student:\t");
        scanf("%d",&t1->age);
        t1->next=t->next;
        t->next=t1;
        t=t1;
    }
    break;

    case 3:
        printf("enter name of student whos record is to be deleted=\n");
        scanf("%d",&ps);
        t=h;
     while(t->fname!=ps-1)
       {
         t=t->next;
        }
         t1=t->next;
         t->next=t1->next;
         free(t1);
     break;

    case 4:
     exit(0);
     break;

    case 5:
    printf("not working yet");
    {
    void sort( student[],int n)
     { int i,j,comp=0,passes=0;
       student temp;
       for(i=1;i<n;i++)
        {
           passes++;
           for(j=0;j<n-i;j++)
        {      comp++;
               if(st[j].lname < st[j+1].lname)
               {  temp=st[j];
                  st[j]=st[j+1];
                  st[j+1]=temp;
               }
        }
        }
     }
    }
    break;
    }
    }
    }

Wind Energy Basics

Basic information on wind energy and wind power technology, resources, and issues of concern.

Ücretsiz Forex Kitabı Kazanmak için tıklayın

Wind Energy and Wind Power

Wind is a form of solar energy. Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth's surface, and rotation of the earth. Wind flow patterns are modified by the earth's terrain, bodies of water, and vegetative cover. This wind flow, or motion energy, when "harvested" by modernwind turbines, can be used to generate electricity.

How Wind Power Is Generated

The terms "wind energy" or "wind power" describe the process by which the wind is used to generate mechanical power or electricity. Wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical power can be used for specific tasks (such as grinding grain or pumping water) or a generator can convert this mechanical power into electricity to power homes, businesses, schools, and the like.

Wind Turbines

Wind turbines, like aircraft propeller blades, turn in the moving air and power anelectric generator that supplies an electric current. Simply stated, a wind turbine is the opposite of a fan. Instead of using electricity to make wind, like a fan, wind turbines use wind to make electricity. The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity.

Wind Turbine Types

Modern wind turbines fall into two basic groups; the horizontal-axis variety, like the traditional farm windmills used for pumping water, and the vertical-axis design, like the eggbeater-style Darrieus model, named after its French inventor. Most large modern wind turbines are horizontal-axis turbines.

Turbine Components

Horizontal turbine components include:

• blade or rotor, which converts the energy in the wind to rotational shaft energy;
• a drive train, usually including a gearbox and a generator;
• a tower that supports the rotor and drive train; and
• other equipment, including controls, electrical cables, ground support equipment, and interconnection equipment.

Wind turbine diagram - click for enlarged image.

Turbine Configurations

Wind turbines are often grouped together into a single wind power plant, also known as a wind farm, and generate bulk electrical power. Electricity from these turbines is fed into a utility grid and distributed to customers, just as with conventional power plants.

See Wind Energy Photos page for wind farm photographs.

Wind Turbine Size and Power Ratings

Wind turbines are available in a variety of sizes, and therefore power ratings. The largest machine has blades that span more than the length of a football field, stands 20 building stories high, and produces enough electricity to power 1,400 homes. A small home-sized wind machine has rotors between 8 and 25 feet in diameter and stands upwards of 30 feet and can supply the power needs of an all-electric home or small business. Utility-scale turbines range in size from 50 to 750 kilowatts. Single small turbines, below 50 kilowatts, are used for homes, telecommunications dishes, or water pumping.

See Wind Energy Photos page for wind turbine photographs.

Wind Energy Resources in the United States

Wind energy is very abundant in many parts of the United States. Wind resources are characterized by wind-power density classes, ranging from class 1 (the lowest) to class 7 (the highest). Good wind resources (e.g., class 3 and above, which have an average annual wind speed of at least 13 miles per hour) are found in many locations (see United States Wind Energy Resource Map). Wind speed is a critical feature of wind resources, because the energy in wind is proportional to thecube of the wind speed. In other words, a stronger wind means a lot more power.

Advantages and Disadvantages of Wind-Generated Electricity

A Renewable Non-Polluting Resource

Wind energy is a free, renewable resource, so no matter how much is used today, there will still be the same supply in the future. Wind energy is also a source ofclean, non-polluting, electricity. Unlike conventional power plants, wind plants emit no air pollutants or greenhouse gases. According to the U.S. Department of Energy, in 1990, California's wind power plants offset the emission of more than 2.5 billion pounds of carbon dioxide, and 15 million pounds of other pollutants that would have otherwise been produced. It would take a forest of 90 million to 175 million trees to provide the same air quality.

Cost Issues

Even though the cost of wind power has decreased dramatically in the past 10 years, the technology requires a higher initial investment than fossil-fueled generators. Roughly 80% of the cost is the machinery, with the balance being site preparation and installation. If wind generating systems are compared with fossil-fueled systems on a "life-cycle" cost basis (counting fuel and operating expenses for the life of the generator), however, wind costs are much more competitive with other generating technologies because there is no fuel to purchase and minimal operating expenses.

Environmental Concerns

Although wind power plants have relatively little impact on the environment compared to fossil fuel power plants, there is some concern over the noiseproduced by the rotor blades, aesthetic (visual) impacts, and birds and bats having been killed (avian/bat mortality) by flying into the rotors. Most of these problems have been resolved or greatly reduced through technological development or by properly siting wind plants.

Supply and Transport Issues

The major challenge to using wind as a source of power is that it is intermittentand does not always blow when electricity is needed. Wind cannot be stored (although wind-generated electricity can be stored, if batteries are used), and not all winds can be harnessed to meet the timing of electricity demands. Further, good wind sites are often located in remote locations far from areas of electric power demand (such as cities). Finally, wind resource development may compete with other uses for the land, and those alternative uses may be more highly valued than electricity generation. However, wind turbines can be located on land that is also used for grazing or even farming.