Chicha Andrey

Abstract on the final work

Contents

1. Introduction. Rationale for the relevance of the them

2. Content of work

3. Method of calculating the multi- scheme with MRI

4. Machine calculation of short circuit currents using the CBM

5. Check circuit breakers and cables RU Zuevskaya NTV and sections s.n.3B

6. Conclusions

7. bibliography

Introduction. Rationale for the relevance of the them

 

      The object of research is the system power supply block and life of general stress auxiliary power station, which has a large dispersion across the station and at a considerable distance from it.
The aim of research is to identify opportunities to connect to sections auxiliary power more dispersed load. Applied to study the station consists of the pumping process water and Dredge pumping the second lift, which now receive power from the substations of the city, which will improve reliability and efficiency of thermal power plants[1].
Calculations of short circuit currents, modes of self-engines were performed by mathematical modeling using matrix methods to calculate the nodal multi-node schemes for solving differential equations of electric motors in the simulation group of rundown and solving systems of nonlinear algebraic equations in the synthesis parameters glubokopaznyh induction motors of their own needs.
At this time Master's work is not finished. TES is applied to study the reverse process water system with cooling towers tower. To refill the significant loss of service water recharge scheme implemented circuit tehvody from the reservoir. According to the project, pumping the water pump industrial water is supplied from a network of substations. The scheme has insufficient power supply pumping reliability.
A similar situation was and Dredge the second lift pump, pumping ash slurry ash-disposal area at the plant. Pump is powered by two cable lines from the power substation. Due to the damage of cables laid on the rocky ground, power supply circuit of the pump has a low reliability.
In order to improve reliability and efficiency of these pumping stations in the studied power plant is designed to execute transfer of power from the auxiliary power system voltage of 6 kV. The objective of this study is to determine the technical conditions specified transfer power. To this end, we have studied the loading sections auxiliary power units, changes in the quantities of short-circuit conditions the self-electric auxiliary power unit under different conditions of their work, as well as the guidelines for building the relay protections[2].

IContent of work

       Connecting to the sections auxiliary power units additional load should lead to a deterioration of the terms self-critical auxiliary mechanisms. To quantify the operating parameters for the self-electric motors, we calculated these modes on a PC program designed to package MathCAD[6].

Figure 1 - Phase Power Pumping Station

 

Method of calculating the multi- scheme with MR

 

In this paper we propose to review software products with open construction algorithms, whose implementation is made in the automation package MathCad.Kak mathematical calculations and hand calculations of short circuit currents at the first stage of works Domashin formed electrical circuit design and the corresponding equivalent circuit of the substitution. For its elements from reference books or other sources are selected the required input data[4].
On an equivalent replacement scheme is carried out numbering schemes for small or symbolic identification of nodes. Also marked in the direction of the currents in the branches.
The program of calculating short circuit currents calculation scheme is the input matrix description of the branches of V. This matrix has the number of rows equals the number of branches of a design scheme, and several columns. In the first two of them are numbers or symbols of nodes from which the current branch out and in which this current is included. In the next column are the resistance branches. If necessary (in case of different values) in another column are the branches of the EMF. For example, in the schemes of the main electrical power connections emf generators may be about 1.2, while the EMF motors - 0.9.
Algorithms programs for calculating short circuit currents based on the method of nodal stresses in the matrix form (1)

 

 

where Uu - vector of nodal voltages, Yu - a square matrix of nodal conductivities, Iu - vector of nodal currents.
Yu matrix is as follows (2)

where P - the matrix of connections of nodes with branches, Yv-diagonal matrix conductivities of branches, Zv - vector resistance, branches, which must be obtained from a member of the matrix V.
Iu vector of EMF can be found as (3)

 

 

where Ev - vector EMF branches.

Machine calculation of short circuit currents using the CBM

 

For operativnoї otsіnki values strumіv circuit in whether yakіy tochtsі elektrichnoї Chasteen ZUTES bula rozroblena programa rozrahunku on PEVM. Її listing i result rozrahunkіv for rіznih vuzlіv Circuits ZuTES. For vikonannya rozrahunkіv on programі spochatku boule stvorenі rozrahunkovі elektrichnі scheme. shown in Figure 2. Danі ekvіvalentnih schemes zamіschennya potіm boule vvedenі in the program rozrahunku on PEOM i on them boule Realized works bagatovarіantnі rozrahunki for rіznih tochok SYSTEM OF is the pumping stantsіy.In yakostі porіvnyannya in tablitsі 1 privedenі results of machine is the machine without rozrahunkіv strumіv fault.

 

       Table 1 Results of the comparison of machine and without machine computation circuit currents

 

 

       As seen from the above data discrepancies in the calculation of values ??resulting circuit currents do not exceed 10%, which proves the correctness of their implementation[5].

 

      Table 2 Test Results of switches and cables cells PKK 6 kV pp Section 4A Check value calculation conditions acceptable value

      Similar checks do switches and cables for cell PKK BN2 6 kV AC.  According to the settlement will take longer (6.15 kA) of the current circuit of the desktop and back inputs (4.32 and 6.15 kA, respectively). The results are given in Table 3

       Table 3 Test Results of switches and cables cells PKK 6 kV AC BN2

 As seen from the results of cell switches PKK as 6 kV sections v.p.4A and 6 kV AC BN2 satisfy all of our choices and checking.

Check circuit breakers and cables RU Zuevskaya NTV

 

      Verification was performed for switches used pp 3B, which receives power from Zuevskaya NTV. According to the settlement will take longer (18.5 kA) with the current circuit of the working and backup transformers (18.5 and 10.2 kA respectively). The results of calculations and check switches and cables 6 kV PKK cells are forming in Table 4

      Table 4 Test Results of switches and cables cells PKK 6 kV pp Section 3B

      Similar checks will perform for circuit cells PKK 6 kV AC Zuevskaya NTV. According to the settlement will take longer (11.2 kA) with the current circuit of the desktop and back inputs (3,0 and 11,2 kA ).

Conclusions

       As a result of this workmay bemade the following conclusions Based on methods developed computer calculation circuit currents upgraded calculation program on a PC in the medium mathematical package MathCad, which has the following advantages over similar products: - The possibility of settlement of symmetrical and asymmetrical short circuit currents - The introduction of the index numbering the branches. Calculations performed by comparing short circuit currents of the developed program with the best world analogues have yielded positive results. Under this program were made calculations of short circuit currents for some stations in the Donetsk region . The program incorporated in the educational process of the Department of ES when the course and diploma design.

bibliography

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2.       Сивокобыленко В.Ф., Лебедев В.К. Переходные процессы в системах электроснабжения собственных нужд электростанций. – ДонНТУ, 2002. – 136 с.
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9          Голубев М.Л. Расчет токов короткого замыкания в электросетях 0,4-35кВ. - 2-е издание переработанное и дополненное. - М.: Энергия, 1980.

10          Мельников Н. А. Матричный метод анализа электрических цепей. Изд. 2-е, перераб. и доп., М., "Энергия", 1972.