The work is devoted to the analysis of the efficiency of the radial power supply system. The scheme of the radial power supply system includes three substations of the Kamensky district of the Penza region, the load of transformers is taken on the basis of data from the interactive map of the load of power centers.
Energy efficiency is a set of characteristics that reflect the ratio of the useful effect from the use of energy resources to the costs of energy resources produced in order to obtain such an effect, in relation to a product or technological process.
The main criterion for evaluating the efficiency of the functioning of power supply systems (SES), including measures to reduce the loss of electrical energy (EE), is a reliable and economical supply of EE consumers of the required quality. And significant losses of EE in power supply systems are caused, as a rule, by the following reasons:
- operation of SES elements in suboptimal modes;
- unsatisfactory condition of electrical networks due to a decrease in the volume of major repairs, reconstruction and replacement of technically outdated and worn-out equipment;
- the presence of significant overflows of reactive power in electrical networks, which lead to a decrease in their throughput, an increase in voltage losses, and a violation of the power balance;
- operation of irrational power supply schemes.
The considered power supply system consists of three electrical substations 1-3, connected by power lines L1, L2, L3.
The first and second lines are double-stranded and are made of AC-120/19 and AC-95/16 wires, respectively. The third line is single-chain, made with AC-120/19 wire. The line lengths are 46, 48 and 44 km, respectively.
Substations 1 and 2 have two transformers each, and substation 3 has one transformer.
For the considered variant of the radial power supply system, a model of the radial power supply system in the Matlab environment is compiled. The power substation is represented in the model as an ideal electromotive force source. Electricity is transmitted to the substations by three power lines. Each substation is represented by a step-down transformer, a load of substations in the form of resistances, measuring devices and capacitors connected in parallel to the loads.
Studies were conducted on the radial power supply system operating in normal mode, minimum load mode, and weighted mode.
Simulation of a radial power supply system has yielded the following results.
The efficiency of the system is most important when the system is operating in the minimum load mode. This is due to the fact that the current of lines and transformers is determined practically by the resistance of consumers. Since the losses in lines and transformers are proportional to the square of the current, the percentage of total losses in lines and transformers is much less than the percentage of total losses of the system operating in normal mode.
A comparative analysis of the performance of the system in normal mode and weighted mode indicates that the efficiency of the system operating in weighted mode is much lower than the efficiency of the system operating in normal mode. This is due to the fact that disconnecting the second circuits of two-chain lines and second transformers at two-transformer substations leads to an increase in the equivalent active resistances of electric power transmission elements. An increase in resistances leads to an increase in losses for the transmission of electrical energy.