Urgency

Ukraine is provided own fuel - energetic resources on 40-45 %, therefore a question energetic saving is actual.

Compensation of jet power is necessary for decrease reduction in losses of the electric energy in an electric network, capital expenses for cables, section transformer substations, payments for jet energy

Indemnification of jet power to the full can be carried to энергосберегающим technologies. Increase cos (fi) allows to reduce consumption from a network of active and jet energy and to increase due to unloading on power service life of the equipment.

The great value has a correct choice of an installation site of the compensating device. The general rule: necessary jet power compensate in a place of its occurrence. If a source of jet power is the motor of the pump or the compressor it is expedient to put compensating condensers directly in a case of management of these devices. If jet power is formed on the side of a low voltage (LV) to compensate it is necessary also on side LV, not supposing passage of jet power through the transformer. Thus it is necessary to note, that service life of a significant share of the power transformers maintained at our enterprises, has stepped over a 15-years boundary. For prolongation of the remained service life it is necessary to unload a transformers on a current that will reduce temperature of an overheat of windings and, hence, will reduce speed of ageing of isolation. It is known, that reduction of temperature of an overheat of windings on 10оС allows to double the remained service life on the average. Considering significant cost of power transformers, at increase cos (fi) this aspect, alongside with reduction of a payment for jet energy, allows to improve economic parameters of the enterprise essentially.

For the branched out electric network of the industrial enterprise there is a question on an optimum place of connection of condenser batteries: to trunks 6-10 кВ main decrease substations (MDS) the industrial enterprise, to switch station (SS) or on the side 0,4 кV section transformer substations [1, 2]. From possible variants optimum can be chosen on the basis of technical -economic calculation.

The purposes and problems

The object of the work is development of the program for choice optimum accommodation condensation batteries in an electric network of the industrial enterprise.

Scientific novelty

The landing power of transformers of section transformer substations, section cable lines of electro transfer, waster electro energy in the lines and transformer, the cost of installed condenser batteries (on the voltage 0,4kV the condenser batteries of the same power are more expensive than on 10kV),the losses active electric energy on compensation jet energy influence on the choice of the rational place on accommodation of condenser batteries. Thus, at the choice of an optimum variant it is necessary to consider a plenty of factors. Calculation is carried out on the resulted expenses which are function of many variables: powers of the condenser batteries connected in all units of an electric network. The problem is reduced to search of the minimum of function of the resulted expenses. In addition the problem becomes complicated necessity on the account of step change of power transformers of the section transformer substations (TS), sections of cables that creates difficulties at definition private derivative of the resulted expenses on each variable.

The decision of the problem in view with use of package Mathcad . Auxiliary functions to the composed choice of owe the transformer shop ТS, sections of a cable electric main (CLM) on economic density of a current with check on the admissible current in normal and after emergency modes, definitions of the resulted expenses for complete transformer substations (CTS), cable, condenser batteries on a voltage 0,4 and 10 кV (dependence of cost of condenser batteries on cost is approximated by a polynom of the first degree on a method of the least squares) are made

The program allows executing the choice of the optimum installation site of condenser batteries in a network of any configuration. For this purpose the plan of a network is set by the special matrix consisting for two columns which can contain the enclosed files. For thea designation elements of the network codes are used: 0-MDS, of 1 to 99 - ТS, more than 100-SS. Codes all elements of a network are unique. The information on sites of the electric network in a matrix describing the plan of connections enters the name построчно. For radial cable, feeding ТS, is number ТS, in the first column in the second - 0 enters the name. For the main line feeding some ТS is the vector which elements are codes ТП which has been written down by way of their connection in a highway in the first column, in the second column for a highway, as well as for ТS is located, enters the name 0. For SS in the first column is code SS, in the second - a matrix describing a site of a network enters the name, connected to SS and having structure of the matrix similar described, as to SS consumers with rated voltage 10 кВ, main and radial cabel, feeding ТS can be connected. Special function analyses the plan of internal electrosupply and carries out a call of one of three functions intended for calculation of characteristic sites of an electric network: radial line, main line or SS.

The information on loadings separate ТS and SS, length cable line, powers of the established condenser batteries, the quantity of power supplies demanded for maintenance of reliable electro supply of electro receivers, and also results of the choice transformers, cables, losses of power in transformers, annual losses of energy in transformers,cabel, etc. are kept in a special matrix which is transmitted as parameter and comes back each of auxiliary functions. Thus, in this matrix all necessary information for definition of the resulted expenses contains.

The basic function realizing calculation, can return the received matrix - for the analysis the results of the choice of transformers, cables, power of condenser batteries or the resulted expenses at the set way of accommodation of condenser batteries.

For search the minimum of the resulted expenses from power of condenser batteries in Mathcad the block of the decision with function Minimize intended for search of a minimum of function of many variables, especially is used when the capture of individual derivatives represents difficulties. The additional limiting condition set in the block of the decision, conformity of total power of installed condenser batteries of demanded power of condenser batteries is.

The developed algorithm is supposed to be improved in addition as follows:

- To add function of a choice of power of complete condenser installations (CCI) and to consider their actual cost (in the program approximation of dependence of cost CCI from power is used);

- To consider an opportunity of indemnification of jet power synchronous engines, thus to carry out a choice of optimum indemnification of jet power synchronous engines and condenser batteries.

Final part

Thus, the made program provides a choice of optimum accommodation of condenser batteries in a network of the industrial enterprise on a minimum of the resulted expenses. Programs for definition of accommodation of condenser batteries by other criteria, for example, to a minimum of losses of the electric power in a network [2] can be similarly made. For the accepted algorithm of calculation, change of criterion will demand entering of only insignificant updating. Except for a choice of an installation site of the condenser batteries, the developed program can be used for performance of calculations of internal electro supply of the industrial enterprise, performance of technical and economic comparison of a plenty of variants of plans of internal electro supply.