COMPUTER AIDED DESIGN OF ORGANIC FUEL POWER PLANT FOR DEVELOPING AFRICA

INTRODUCTION

The academic year thesis is based on computer aided design of an electric part of organic fuel power plant and substations has an object and a deep concern showing the construction of the main diagrams of stations and substations of a power plant, a choice of the basic units (generators and transformers), the high-voltage equipment and current carrying arrangements of a high pressure. 

The explanatory note of the sections is stated as follows:

1. A choice and the description of the main diagram of designed electrical installation.
2. A power supply circuit for the power plant.
3. Calculation of currents of short circuit
4. A choice of electric devices and current carrying parts.
5. The description of design of distributing block arrangements and estimate of its cost on the integrated parameters. 

The design output of the power plant is generated below:

– The Main diagram of an electrical installation.
– The Design distributing block arrangements.

          The project is carried out with consultation of different specialist, which upon termination of Designs signs an explanatory note and drawings and supposes the project to protection. Protection is made before the appointed faculty the commission including the project head. 

Essential design represents a choice of the best advantage from set of possible versions. From a mathematical point of view, it is a problem of integer optimization which decision usually make with the help of a method of the resulted expenses, a method being by a special case disconcertion.

       A number of possible variants can be large, that hampers a choice than even the best even at the use of COMPUTER. Therefore, planning worked out on the basis of experience is used in project organizations, exploitation and rules of device of electrical installation of norm of the technological planning, to shorten the number of subject to comparison of variants. Thus, theoretical knowledge, rules of device and technical and economic calculations, make a base for the educational planning of electric part of Electrical Station.

1 DEVELOPMENT OF THE PROGRAM OF COMPARISON OF VERSIONS DIAGRAM OF DELIVERY OF CAPACITY THERMAL POWER STATION BY CRITERION OF THE MINIMUM OF THE RESULTED EXPENSES OF THE ELECTRIC PARTS. 

         The electric part of power stations includes the power stations connected among them the main electric diagram (Hydro Power Station) and the diagram of own needs. Hydro Power Station substantially influences the quality indicators of an electric part, as well as all power stations (reliability, profitability, maintainability, convenience of operation, etc.). The diagram is indissolubly connected with a power supply system in which is networked through the transformers on Electric Power Transmission generators of power station giving out developed electric energy. Influence as power stations on progress of a power supply system, and a power supply system on choice Hydro Power Station is observed.

         Choice of Hydro Power Station represents a complex technological problem. The account of all factors at a choice of the diagram is possible only at use of the automated system of design. The problem of choice essentially becomes complicated if to consider and influence the diagram of a power station.

Requirements to the main electric diagram of power stations of various types are regulated by types of technological design of power stations.

         Design of Hydro Power Station is carried out in the following sequence: the diagram of accession of power station to a power supply system gets out, the diagram of delivery of capacity gets out, diagrams of the raised pressure get out, calculation of currents bridging is carried out, electric devices and current going out. 

         The design of the diagram of accession of power station solve problems of a choice of value and number of pressure on which capacity of station protrudes numbers, directions and put through Electric Power Transmission on each pressure, desirable distribution of generating capacity between different pressures.

         The diagram of delivery of capacity defines distribution of generators between different pressure, transformer (autotransformer) communication between different pressure, a way of connection of generators with block transformers and points of connection of transformers of Hydro Power Station.

         At design of the diagram of delivery of capacity of station at the first stage, versions of its execution are outlined. On the second stage for each version overflows of capacity through block transformers and autotransformers of communication are defined and their choices are carried out, losses of energy are calculated, the damage from unreliability of work of elements of the diagram is defined, there are capitals, operational and resulted expenses.

         The feasibility report on an accepted version maybe is carried out by comparison of versions of possible design decisions, the use of criteria of comparative economic efficiency Capital investments (a time of recovery of outlay, the specific efficiency, and the resulted expenses).

         Economic comparison of versions is made by definition of the rated resulted expenses. The economically attractive diagram is defined by the minimal resulted expenses.

         As a result of comparison of versions of the diagram of delivery of capacity thermal power station by criterion of a minimum of the resulted expenses, the rational version comes to light.
Figure 3 A typical design of thermal power plant.

Thermal Power Plant Construction

Thermal station (Thermal Power Plant) is a plant used in producing energy and can also be defined as a heat source in district heating supply source of the city (central heating, hot water).
( Кужеков С. Л. Проектирование электрической части электростанций и подстанций. Новочеркасск 1995, 7 - 10.)

Figure A. Typical diagram of a Power Plant System

The main building of the thermal power plant is a real huge city located on several tiers in a large iron box.

1.1 DEFINITION OF AN OVERFLOW OF CAPACITY FOR A CHOICE OF THE AUTOTRANSFER

              For this purpose it is necessary to enter vectors of capacity of generators Pg (МВА), factors of capacity Cos f, a vector, defining % of own needs of % _SN, the vectors defining  what generators does in a normal mode g_ru and in emergency operation g_rua are attached. Maximal load S.mn (MW) is specified.

The full power of the generator (МW) pays off under the formula:

                                             

Capacity consumed for own needs (МW):
                                                                

Then the overflow of capacity through the block transformer (МW) will be:     
   
                                                                      

Capacity on ОРУ-1 is defined proceeding from a condition: if g_ru=1,                                         

                                                                          

In a similar way capacity ОРУ-2 is defined:  If g_ru=2,

                                                                        

In this case, the generator will be attached to winding НН of the autotransformer (g_rui=3) an overflow of capacity through winding НН (МW):

Overflow of capacity through winding CН:

                                                                  

Overflow of capacity through winding ВН:

                                                                      

In emergency operation at switching-off of one block ORU-1 total capacity on ОРУ-1 will be defined: if g_ruai=1

                                                                            

Overflow of capacity in emergency operation on winding СН:

                                                                   

 Overflow of capacity in emergency operation on winding ВН: 

                                                                

From two overflows on winding ВН (Satv, Satva) greater gets out, it and there will be a maximal overflow of capacity (S.m).
Then rated capacity of the autotransformer will be:                          
for the three-phase autotransformer:

                                                                     

For single phase of an autotransformer:

                                                                             
       On received design from [3] the autotransformer gets out and its parameters leave:

S – Rated power of the transformer (МW);
P.xx) – losses of idling (kw);
P.kz – losses of short circuit (kw).

Figure. 4: Thermal Power Plant Construction

1.2 CALCULATION OF LOSSES OF CAPACITY AND THE ELECTRIC POWER
Losses of power (kw) are defined under the formula:
                                                
Where

P.kz – a vector of loss of short circuit (kw); 
P.xx – a vector of loss of idling (kw);
S – a vector of capacity (МW);
S.per – a vector of overflows of capacities (МW).
Components of vectors are block transformers, alternate transformers, autotransformers. Elements of a vector of overflows of capacities are: 
S.tbi - for block transformers (МW); 
S.atn, S.ats, Satv - for the autotransformer (МW); 
S.per=0 - for alternate transformers.

Losses of the electric power (kw) are defined under the formula

                                         
Where - time of the greatest losses, is defined on curves for T.max and the typical chart on [3.] t =8760 h – an operating time of the transformer in a year.

Figure. 5: Design of Thermal Power Plant Construction.

1.3 DEFINITION OF THE FULL RESULTED EXPENSES

The full results are defined under the formula:   
 
                                                           

Where To – capital investments (NGN);
To – additional capital investments (NGN);
Р.н – normative effectiveness ratio (1/year), Р.н=0.12;
And – annual working costs (NGN/year).

Capital expenses on each version of the diagram of delivery of capacity are defined in view of rated cost of block transformers, autotransformers of communication, cost of switch/circuit broker raises pressure, cost of cells of switches in a circuit of generators and design costs РТСН.

                                                                       

Where
C – a vector of cost of the equipment (NGN.);

N – a vector of quantity of the equipment (pieces);

                                                                        

Where - cost of the installed capacity of 1 kw (NGN./кw);

                                                         

Where Иа – depreciation charges (NGN./year):

                                                                          

Ио – costs on service (NGN./year). At an assessment of economic efficiency of versions they can be neglected.
Ипот – the costs caused by losses of the electric power in designer of energy installation for year (NGN./year):

                                                                    

Where - an average net cost of the electric power in a power supply system (NGN/kw)
In this research we shall take Hydrogen fuel as a case study in other to comply with the green energy in the world.

Fig.1 The program for calculating the power design cost Continuation of Fig. 1 2. Automation of calculation of flow of hydro electric power station energy. In calculation we accept the method of node tensions in a matrix form. Which is the basic equalization?  =      ?                                                                                            (2.1) Where – A vector of tensions is in the basic calculation of chart  – The key is the square matrix     – Vector of currents Swiftness of a matrix can be shown as follows:  = P ?  ?                                                                                         (2.2) Where P – Matrix of connections of branches with knots  –Swiftness of branches with square matrix The matrix of Yv can be got as   = diag                                                                                   (2.3) Where  – Branches of vector resistances Vector of key currents at presence of in the knots of sources of current on the following expression =                                                                                               (2.4) Where  – Calculation of Power of node set  – Current value of node tension Where ОРУ1 = ODD 1 - Open distributive device ОРУ2 = ODD2 - Open distributive device ТГ 1 = TG 1 Step - up transformer ТГ 2 = TG 2 Sep - up transformer AT - it is Autotransformer Connection Г 1 = G1 - Generator Г 2 = G2 - Generator ТСН 1 = Transformer for the own need or supply ТСН 2 = Transformer for the own need or supply (Сивокобыленко В.Ф., Павлюков В.А. Расчет паpаметpов схем замещения и пусковых хаpактеpистик глубокопазных асинхpонных машин, "Электpичество", 1979) Fig. 4. Appropriate program for the chat On the algorithm given above MathCAD is worked out program of calculation of powers in Hydro Power Station. Illustration of this work we will show on the simplest example of chart of delivery of power (Fig. 2). Power of every generator, working transformers and local loading we will present the sources of current, as it is shown on a picture 3. Appropriate program for the chats on a fig. 4.

Literature Review

1. Кужеков С. Л. Проектирование электрической части электростанций и подстанций. Новочеркасск 1995, 7 - 10.
2. Сивокобыленко В.Ф., Павлюков В.А. Расчет паpаметpов схем замещения и пусковых хаpактеpистик глубокопазных асинхpонных машин, "Электpичество", 1979.
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