DonNTU 
Master's portal
Faculty: Electrotechnical
Speciality: Electric power stations
One of the primary goals of electric power industry is increase of reliability of electro supply of the country. The component of this problem consists in maintenance of reliable work of systems of own needs, defining stability of work of generating units of power supply systems. For maintenance of trouble-free operation of the named systems carrying out of an experimental research-settlement of transitive modes of their work arising at short circuit, switching of power supplies, start-up and switching of electric motors, etc. Therefore settlement methods should provide accuracy of calculations and an opportunity of modelling of designing demanded by practice and operation of power stations of complex cascade modes.
The further perfection of methods of mathematical modelling of transients in systems thermal power station needs.
For achievement of an object in view in work solve following problems:
1. Development of an information-calculating complex for calculations electromechanical transitive processes in system thermal stations own needs, allowed to model complex kinds commutation the equipment of these systems.
2.Creation of the information database containing parameters of these systems’ equipment.
3.Mathematical models of the equipment of systems’ own needs.
4. Research of transients in systems’ own needs of some thermal power stations and development on its basis of recommendations on increase of reliability of their work.
Ways of modelling of basic elements of system thermal power station of one of gas thermal power station Russia and methods of reception of deep-phase asynchronous engine parameters, electromechanical transients used in calculations are considered.
As an example for asynchronous engine DAZO-19-10-12 (PH = 1700 kW, UH = 6 kV, cosH = 0.8, H = 0.9435, SH = 0.008, Ki = 4.5, mï = 0.8, mm = 2.25) rotor resistance dependences on fig. 1 have been received.
Figure 1 - Dependence of parameters of an equivalent circuit for DAZO -19-10-12
The numerous calculations performed have shown, that satisfactory results of approximation of deep-phase asynchronous engine the characteristics of various types turn out at a two-planimetric equivalent circuit of a rotor. To increase the accuracy on occassion the quantity of contours increased up to 3, 4, that however, does not result in complication of algorithm of calculation of transients.
Development of structure of an information-calculating complex and its separate components is executed. With this purpose the analysis of existing methods, algorithms and programs of calculation on the PC of transients in systems thermal power station’s needs has been made.
Machine methods allow to carry out calculations of various transients in multimachine, multinodal systems of electrosupply with use of the differential equations describing processes in separate elements of the settlement scheme, and also the equations of the communication, separate groups of elements leading regime parameters to uniform system of coordinates.
The basic distinctive feature of a complex is the realization of a dissociation principle of calculation process of transient on two independent stages’: calculation of parameters of mathematical asynchronous engine models and gear mechanisms and calculation of transients. It allows to spend gathering separately, processing and ordering of the initial information and after reception of parameters of mathematical models bring them in specially created databases located on machine data carriers. In this case the information on the basic types of asynchronous engines is stored in databases gas thermal power station by voltage 10 êV and 0.4 êV gear mechanisms of own needs.
The basic program of a regime part of a complex is the program of calculation of modes of calculation of transient on two an independent. For modelling complex cascade modes its algorithm provides a partition of an analyzed mode on separate submodes, differing a various condition of the settlement scheme due to executed commutations its elements or shunts short circuit.
Change of structure of the settlement scheme used in separate submodes, is made by ways of exclusion of separate branches and units. It results in rearrangement of branches conduction and setting currents.
For calculations of dynamic modes parameters of two-planimetric equivalent equivalent circuits the asynchronous engine from their databases are used. The algorithm of the program is based on the decision of systems of the full differential equations describing transients in the asynchronous engine, shunts of loading and short circuit, and also branches of system. The structure of a complex allows to supplement it with other programs and data sets, and also to make changes in existing.
Results of application of the developed complex for the analysis of transients in systems thermal power station needs are considered.
As an example of use of a complex the analysis of reliability of work of systems of own needs gas thermal power station is resulted. For the given station six various variants of change of works has been considered.
Results of calculation in the form of dependences on time of frequencies of rotation of units of own needs, pressure and currents section with impellent loadings, change of resistance section are given in figures 2- 5.
Figure 2 - Change of frequency of rotation 0.4 kV gas thermal power station during self-start the asynchronous engine after a break of supply in 1 with
Figure 3 - Change of a voltage in units of the settlement scheme 0.4 kV gas thermal power station during self-start the asynchronous engine after a break of supply in 1 with
Figure 4 - Change of currents sections of own needs (kA) during self-start the asynchronous engines after a break of supply in 1 with (animation: 7 frames, 7 frames, 38.2 Kb)
Figure 5 - Change of resistance of own needs (Ohm) during their self-start after a break of a supply in 1 with
Is the developed technique, algorithm and the program of calculation of parameters of equivalent circuits and starting characteristics the deep-phases asynchronous engine. Calculations of parameters and starting characteristics of engines of own needs by a 10 and 0.4 êV gas thermal power station are made. The technique, algorithm and the program of self-start of engines after their individual or group running with reference to multinodal power supply circuits of systems of own needs of power stations is developed. Modes of self-start of engines of own needs gas thermal power station are calculated.
1. With use of existing methods of calculation of parameters and starting characteristics cannot be the received satisfactory results, especially the asynchronous engine with great values of critical sliding.
2. The Developed technique, algorithm and the program of calculation of starting characteristics which are based on correction of formula Klossa by means of a step polynom, and differs from previous full concurrence of settlement data for points of sliding Sn, Sk and S=1.
3. The Developed technique, algorithm and the program of calculation of parameters of an equivalent circuit the deep-phase asynchronous engine which differs from previous by full concurrence of settlement values of the reference moment and a current stator with their catalogue values for points of sliding Sn, Sk and S=1.
4. The Developed technique, algorithm and the program of calculation of modes of self-start the asynchronous engine after individual and group running concerning complex, many central power supply circuits of own needs of power stations.
5. By means of the developed program the executed calculations of modes of self-start of mechanisms of own needs gas thermal power station which have allowed to choose the optimum operating modes operation for this power station.