Veliyeva T.D.
CALCULATION OF THE ECONOMIC EFFECT OF VOLTAGE LEVEL OPTIMIZATION IN ELECTRICAL NETWORKS BY METHODS OF NONLINEAR PROGRAMMING *
Аннотация:
the problems of the influence of voltage deviation on the operation of electrical networks and electricity consumers are considered. The influence of the voltage level on the efficiency of the modes of electrical networks, the occurrence of additional energy losses in the network elements and electrical receivers is investigated
Ключевые слова:
electricity quality, electrical grid, voltage deviation, frequency, jet power, asynchronous motor, power loss, electric receiver
DOI: 10.24412/2712-8849-2023-259-198-202
УДК 624.07:534.1
Veliyeva T.D.
Associate professor of the Department Power Industry
Azerbaijan State Oil and Industry University
(Baku, Azerbaijan)
CALCULATION OF THE ECONOMIC EFFECT
OF VOLTAGE LEVEL OPTIMIZATION IN ELECTRICAL
NETWORKS BY METHODS OF NONLINEAR PROGRAMMING
Abstract: the problems of the influence of voltage deviation on the operation of electrical networks and electricity consumers are considered. The influence of the voltage level on the efficiency of the modes of electrical networks, the occurrence of additional energy losses in the network elements and electrical receivers is investigated.
Keywords: electricity quality, electrical grid, voltage deviation, frequency, jet power, asynchronous motor, power loss, electric receiver.
Introduction. The levels of pressure to ensure the normal economical and reliable operation of electrical receivers of all branches of the national economy very often do not meet the requirements of state standards. At the same time, a regular increase in yarns in most networks at night (up to 10%) leads to an annual overconsumption of more than 30 million pieces of street, staircase and yard lighting lamps and, accordingly, more than 250 million kWh of electricity. A regular reduction in the voltage of lighting loads during the hours of the evening maximum by 10% and below leads to a forced overconsumption of more than 150 million kWh of electricity for more powerful and annual lamps. That is, insignificant deviations of voltage on the scale of the republic lead to significant damage, most of which falls on electricity consumers [1].
Approach method. The technical and economic consequences of voltage deviation are manifested depending on the nature of the technological process.
The economic effect of improving the quality of the voltage is defined as the difference between the two costs determined for the current and nominal value of the voltage, that is,
Determination of the economic effect of improving the voltage level can be carried out by analytical or experimental-analytical method [2,3].
With the analytical method, there is a dependence of the target function C on the deviation of the voltage U
C (1)
under the specified technical restrictions (I will comply with the condition of reliability, stability and other parameters)
(2)
Usually, the total costs are expressed in their components.
C (3)
The task of control in accordance with the expressions (1) - (3) is to determine the extreme values of voltage deviation, at which the function (1) or (3) under the restrictions (2) acquires a minimal value. Expressions (1) and (3) include components due to a decrease in the deviation of tension, namely:
C1 — from increasing the productivity of mechanisms; C2 — from the reduction of active energy losses; C3 - from the reduction of reactive losses, power; C4 — from increasing the reliability of operation (increasing the service life) of the object.
Reduction of voltage deviation U is achieved by installation in the electrical system and in consumers with the appropriate regulating and compensating devices (reactive power source, transformers, etc.). All these devices require certain capital C5 and operating C6 costs, which must be taken into account in the expression (3). It is obvious that the costs of C5 and C6 will be absent if the improvement in the voltage level is achieved by efficient use of the regulating devices available in the network and in the load unit.
All components of C1- C6 are generally complex and often nonlinear functions of voltage deviation. The specific analytical forms of these dependencies are determined by the features of the objects. Thus, having analytical expressions (1) – (3), it is possible to solve the optimization problem in a general form and divide the economic effect of optimization by known analytical methods of nonlinear programming.
The analytical method in the most simplified voltage is well developed only for the indicator of voltage output U. At the same time, it is believed that all other indicators of energy quality are fixed at a given level, that is, they are not regulated and are at a level that meets state standards. Further simplification is achieved by the fact that the tension is regulated within the limits permissible by state standards for this object and therefore the impact of such regulation on C4 can be neglected. If the regulation of the yarn is made even within a wider range (in post-accident modes) or if the limits of voltage variation are small, but it is still necessary to take into account the reliability and durability of the object, then these factors are transferred to the limitation area and C4 is excluded from (1) due to the uncertainty in the obvious form of the composition of the C4 (U).
where Sk is the power of the compensating and regulating devices, kvar, Kv*A; Ck - unit cost of these devices, man/kvar, man/(Kv*A); ЕH - is the regulatory coefficient of the investment efficiency of these devices, EH = 0.125; Pk - loss of active power in these devices, kW; Kp - unit cost of installed capacity in the power supply system, man/kW; Ea is the norm of the coefficient of depreciation deductions for the re-installation and maintenance of devices: τ, τ1 - the number of hours of the device and the number of hours of maximum losses per year; β-unit cost of electricity losses, man/(kWh); - an increase in the net power of the object caused by a change in voltage deviation; K0 - unit cost of production of the facility per 1 kWh of consumed useful energy; - reduction of losses of active and reactive power in the facility and in networks caused by a change in U; KQ is the unit cost of reactive power.
The analytical form of the dependencies Sk(U), Kp(U),,, is determined for given types of objects (network, energy consumer). As a limitation to equations (4), conditions are added to the preservation of other indicators of power quality, as well as on the validity, stability and durability of the object within the specified limits when the indicator U changes. Thus, a mathematical model of the object is formed to find the extreme value of one of the main indicators of power quality U. With the analytical method, a graph of the function C(U) is plotted and the optimal value of the voltage UH or its deviation from the memorial U corresponding to Cm/n is determined from it.
Such a curve is called the economic characteristic of an object (by energy requirement) and is widely used to determine U0. For complex objects, economic characteristics are usually built by the experimental-analytical method, since the analytical method becomes difficult. In this case, the experiments are organized and conducted so that the influencing factor on the entire composition of C1 remains the voltage of the object, which is registered discretely in the permissible region. Many of them cannot be directly measured (or determined) experimentally and are determined by calculation.
Conclusion. The above method of constructing economic characteristics and determining the optimal voltage deflection can be used for all other indicators of power quality. At the same time, it is necessary to note some difficulties of the analytical method for determining the economic effect of improving the quality of electricity, which include:
REFERENCES:
Номер журнала Вестник науки №2 (59) том 2
Ссылка для цитирования:
Veliyeva T.D. CALCULATION OF THE ECONOMIC EFFECT OF VOLTAGE LEVEL OPTIMIZATION IN ELECTRICAL NETWORKS BY METHODS OF NONLINEAR PROGRAMMING // Вестник науки №2 (59) том 2. С. 198 - 202. 2023 г. ISSN 2712-8849 // Электронный ресурс: https://www.вестник-науки.рф/article/7264 (дата обращения: 26.04.2024 г.)
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