Possibilities of applying time-classified tariffs in “ smooth ing” the loading graph of the electric energy system

. In this paper, the impact of the use of time-classified tariffs on the electricity system is considered. That is, the possibility of adjusting the loads on the existing substation in the morning and evening “ peak ” periods was assessed. In exchange for using the results of the energy audit and applying the system of time-classified tariffs, it will be possible to achieve smoothing of the load schedule of the electric power system during “ peak ” periods. Consumers ’ use of the time-classified tariff system will reduce the loading period of the electric power system and change its regimes.


Introduction
In order to ensure the stable development of Uzbekistan's electric power system, it is important to develop effective solutions for the use of tariffs, form and regulate the existing ones.Different methods are used to smooth the load graph in the electric power system.In particular, if some consumers are limited to a certain amount of electricity in "peak" periods, it will be possible to manage other consumers through different tariffs [1].The main goal of electricity suppliers and consumers in electricity consumption is mutual efficiency.Regulation of tariffs in the electric energy system is one of the methodological aspects of sustainable development of the energy industry.Due to the fact that the electricity consumption of consumers is different at different times of the day, rugged load graphs in the electric power system arise [2].For this reason, the ruggedness of load graphs in the electric power system in many countries is a specific problem and causes the use of various methods to solve it [2,3].Consumer demand for electricity varies daily, weekly, monthly, quarterly and annually.At the same time, one of the factors that negatively affect the performance of the system is the ruggedness of the daily "peak" period in electricity consumption [4,5,6].In addition, in the period from the beginning of 2020 to October 1, the indicator of electricity delivery to consumers was 44.9 billion.kWh, and it can be observed that the indicator was 1.3 billion kWh more than the corresponding period of 2019.According to forecasts, the demand for electricity is expected to increase by 70 percent by 2030 compared to 2020.In the near future, measures are being developed to introduce modern technologies that have been successfully tested in developed countries into practice in Uzbekistan [7].52.1 billion kWh of electricity was supplied to consumers in 2019, and the average daily consumption in the autumnwinter season was 149.4 mln.kWh (including 47.9 million kWh for the population).In summer, the daily consumption is 162.7 mln.kWh (from which it was 29.2 kWh for the population) (Fig. 1).It is important to determine the volume of delivered and consumed electricity, current technical condition of power transmission networks, and the amount of technical losses."Smart networks" aimed at automatic management of network work and quick elimination of detected faults in electrical equipment are being expanded.Research is being conducted on the implementation of the necessary measures to divide the consumed electricity into tariffs depending on the periods of the day [8].

Fig. 1. Average daily consumption in 2019
It is important to regulate the load schedules of the electric power system, that is, to reduce the load during the "peak" periods of the day.It is necessary for the electricity transmission organization to form a real daily electricity load schedule for all consumers in a prescribed manner.

Research Methods
If the power consumed in peak periods (∆P) is reduced by changing the operating mode of the enterprise, the annual consumption power (аΔР) of the enterprise is also reduced.However, this may lead to a decrease in the production volume of the product.In order to maintain the overall production plan, underproduction during periods of peak consumption can be compensated by more production during nighttime periods.
0  0 =  1 ( 0 −  3 ) +  3  3 =  0  1 ( 0 −  3 ) +  3  3  3 ; (1) where:  3duration of the enterprise's electricity consumption during the "peak" period of the electric power system, kWh; 1coefficient of electric energy used for the maximum product that is produced hourly in the maximum periods the electric power system;  3coefficient of electric energy consumed for the minimum hourly produced product in the maximum periods of the electric power system.Changing the operating mode of the enterprise leads to a change in the total annual costs.These costs can be expressed as follows: The annual economic effect of reducing the load at peak times of the electric power system is determined by the following expression: (3) If ΔЗ>0, it is appropriate for the enterprise to reduce the amount of electricity consumption during the maximum load of the electric power system.After a series of transformations, the appropriateness of the electric power system for the enterprise during periods of maximum load is expressed as follows: (4) The decrease in electricity consumption during the night or semi -peak periods ( 0 −  3 ) changes the electricity consumption: ∆Э 1,2 =  0  0 ( 0 −  3 )(1- 1  4 ); (5) During the period of maximum consumption (T 3) of the electric power system ) If ΔE>0, then the volume of the load in the operating mode, that is, the consumption of electricity, decreases, if ΔE<0, the consumption of electricity increases.After changing the periods of electricity consumption (due to the increase in electricity prices in "peak" periods), the period of maximum demand decreases: where:  1 ,  2 ,  3 -Т 1 , Т 2 and Т 3 a coefficient that takes into account production in hourly load periods; 1 ,  2 ,  3 -Т 1 , Т 2 and Т 3 the coefficient that takes into account the change in the consumption of raw materials and materials in production during the hourly load periods ;  4 ,  5 ,  6 -Т 1 , Т 2 and Т 3 a coefficient that takes into account the change in the consumption of certain energy when changing it in hourly load periods.If the consumption of 1 kW•h during the peak period (T3, T2) is transferred to the less valuable time (T1, T2), the annual economic effect is achieved, In this case, electricity consumption changes to the following value during the night, semi-peak and peak (T1, T2, T3) periods: The total change in electrical energy is expressed as: ) In any electricity consumers, there are certain minimum and maximum periods of consumption time.This, in turn, is directly related to time-classified tariffs.

Results and Discussions
It is necessary to increase the efficiency of electric energy and reduce the consumption of electric energy during the "peak" periods of the day.As a result, it is possible to reduce the load on the electric power system and increase the efficiency of consumers.Research work was carried out in the following enterprises: -«O'z-HANWOO» LLC JV ("Uzavtosanoat" JSC and "HANWOO GLOBAL Co.Ltd" Republic of Korea); -«O'Z ERAE CLIMATE CONTROL» LLC JV ("Uzavtosanoat" JSC and "Erae cs Limited" Republic of Korea); -Research work was carried out at "UzAuto Austem" LLC JV (Uzavtosanoat and AUSTEM Co.Ltd, Republic of Korea).The months of the year with the least and most electricity consumption in the enterprises were conducted according to the periods of the day.As a result of this research, annual electricity savings and economic efficiency will be achieved due to the use of the tariff system in enterprises.Enterprises are the main part of consumers connected to the 220/35/10 kV "Babur" substation.In terms of electricity consumption, household (population) consumers also consume almost as much as enterprises (Fig. 2).The total number of consumers of the 220/35/10 kV "Babur" substation are 35, 5 of the cells are household consumers.The total consumption of consumers through the substation in 2020 was 182,225,314 kWh.-"Uz-HANWOO" LLC JV has the lowest in May (170,000 kWh), the highest in February (343,000 kWh); -"O'Z ERAE CLIMATE CONTROL" LLC JV is the least in January (262784.6 kW•h), the most in February (375300.7 kW•h); -"UzAuto Austem" LLC JV was observed to be the lowest in May (410,220 kWh), and the highest in February (548,940 kWh).Enterprises make payments according to the tariffs, i.e.I-tariff, classified tariffs specified in the contract concluded with the municipal electric network enterprise (MENE).In 2020, the following results will be obtained if enterprises make payments according to the periods of the day in the months of the lowest and highest electricity consumption (Table 1).For these consumers, it is economically efficient to consume during the night-time stimulated periods.For the electric energy system, this system of tariffs allows to eliminate morning and evening peak loads [9].In enterprises, it is recommended to increase the consumption during the night by reducing the consumption during the day-time and "peak" periods of the day.As a result: firstly, the price of the produced products will be reduced due to low tariff prices in the night periods; secondly, it is possible to reduce the load on the 220/35/10 kV "Babur" substation in the electric power system during the morning and evening "peak" periods.Table 2 shows the results of using the results of the energy audit in the months of the year with the least and most electricity consumption and the application of time-classified tariffs.The following results were obtained according to the use of the results of the energy audit of the energy consumption in the months of 2020 with the least electricity consumption of the enterprises and the tariff system stratified by time (Table 3).Difference between (sums) 9035700 8984999 9090000 According to the results of Table 6, based on the calculation of the months in which enterprises consumed the most electricity in 2020, 194400, 195600, 188640 kWh of electricity and 235620000, 116639928, 199908000 soums were saved per year.
It is necessary to use the results of energy audits in enterprises and to distribute electricity consumption in tariff periods classified by time.Increasing the consumption of enterprises during the stimulated periods of the night is beneficial to the "electricity supplier-consumer" system [10].
In recent years, the system of time-classified tariffs has been introduced in the republic only for consumers with an installed capacity of 750 kVA and above.The culture of using these tariffs has not yet been fully formed among consumers.But the research conducted in enterprises on this tariff system gave its results.
In enterprises, it is important to use the results of energy audits and apply time-classified tariffs.Shifting the consumption of electricity during the "peak" periods of the day to the stimulating periods of the night increases the possibility of obtaining significant results [11,12,13].
Table 7 shows the results of using the results of the energy audit and the use of tariffs classified by time in the months when the enterprises consume the least and the most electricity.It can be seen from Table 7 that the annual saved electricity of the enterprises was 442584 kWh.The annual money of electricity saved is 199,162,800 soums.Due to the use of the results of energy audits in enterprises and the use of timeclassified tariffs, the annual amount of total electricity saved was 11.3%.The total annual savings of the enterprises as a result of using the results of the energy audit and the indicators of using time-classified tariffs was as follows (Table 8).Using the results of the energy audit in the above enterprises, the effect on the 220/35/10 kV "Babur" substation was determined using time-classified tariffs.The total number of consumers is 35, and the results of which only the consumers with installed capacity of 750 kVA and above are currently received.Due to using the results of the energy audit and the payment according to the system of time-classified tariffs: "Uz-HANWOO" LLC JV (148464 kWh); "OZ ERAE CLIMATE CONTROL" LLC JV (147,600 kWh); "UzAuto Austem" LLC JV (146520 kWh) reduction was achieved.The annual peak period of enterprises was 442,584 kWh or 0.24% of the total electricity consumption (Fig. 3).

Conclusions
Summarizing the research results, we can draw the following conclusions: -Annual electricity saving of "Uz-HANWOO" LLC JV is 148,464 kWh, i.e. 4.6% per year, and due to the use of the results of the energy audit for the consumed electricity and the use of time-classified tariffs, the enterprise has achieved savings of 238,833,000 sums per year .
-Annual electricity saving of "O'Z ERAE CLIMATE CONTROL" LLC JV is 147,600 kWh, i.e. 4%, and due to the use of energy audit results and the use of time-classified tariffs for consumed electricity, the enterprise saved 178,649,952 sums per year.
-Annual electricity saving of "UzAuto Austem" LLC JV is 146,520 kWh, i.e. 2.7%, and due to the use of the energy audit results and the use of time-classified tariffs for the consumed electricity, the enterprise saved 220,428,000 sums per year.

З 1 = 4 -
∆( + ) + ∆Ф + Х 0 +  0  0 × [ 1  1 ( 0 −  3 ) +  3  3  3 ] + +( 0 − ∆)a+ 0  0 [ 1  4 ( 0 −  3 ) +  3  6  3 ];(2) where: ∆additional capital values after the change in the mode of operation; Еefficiency ratio of capital investments, taking into account the payments; pdepreciation rate; ∆Фchange of work mode;  1coefficient that takes into account the volume of consumption of raw materials and materials in the production unit during the changed working hours;  3the coefficient that takes into account the volume of consumption of raw materials and materials in the production unit at the time of maximum load; Coefficient that takes into account the change in electricity consumption when production is changed in the interval T0-T3;  6 -Coefficient that takes into account the change in electricity consumption when production is changed at time T3;

Fig. 2 .
Fig. 2. 220/35/10 kV "Babur" substation's share of population and enterprises in electricity consumption (%)Research was conducted on the lowest and highest electricity consumption months of 2020 in enterprises, i.e.:-"Uz-HANWOO" LLC JV has the lowest in May (170,000 kWh), the highest in February (343,000 kWh); -"O'Z ERAE CLIMATE CONTROL" LLC JV is the least in January (262784.6 kW•h), the most in February (375300.7 kW•h);-"UzAuto Austem" LLC JV was observed to be the lowest in May (410,220 kWh), and the highest in February (548,940 kWh).Enterprises make payments according to the tariffs, i.e.I-tariff, classified tariffs specified in the contract concluded with the municipal electric network enterprise (MENE).In 2020, the following results will be obtained if enterprises make payments according to the periods of the day in the months of the lowest and highest electricity consumption (Table1).

Table 1 .
Payment indicators of enterprises by periods of the day in the months of the lowest and highest electricity consumption in 2020

Table 2 .
Indicators of using energy audit results and application of tariffs classified by time in the months of the year when enterprises consume the least and most electricity

Table 3 .
Months of 2020 with the least electricity consumption in periods of the day kWh

Table 7 .
Performance indicators of using energy audit results in enterprises and the application of time-classified tariffs in 2020

Table 8 .
Total annual savings of enterprises