ANALYSIS OF POWER LOSSES IN 0,4 kV DISTRIBUTION LINES LOCATED IN RURAL AREAS

ABSTRACT

The 0.4 kV transmission line is the longest transmission line in the existing power system. Also, this transmission line is the main power grid that provides low voltage to local consumers. This will lead to significant technical and economic advances in detecting power losses in the transmission network and reducing power losses that occur during the transmission process. This article analyzes the power losses created by 0.4 kV low-voltage power lines in rural areas of the Jizzakh region (Uzbekistan). The economic consequences of electricity losses were also calculated on the basis of technical analyses.

АННОТАЦИЯ

ЛЭП 0,4 кВ является самой протяженной ЛЭП в существующей энергосистеме. Также эта ЛЭП является основной энергосистемой, обеспечивающей низким напряжением местных потребителей. Это приведет к значительному техническому и экономическому прогрессу в обнаружении потерь мощности в сети передачи и уменьшении потерь мощности, возникающих в процессе передачи. В данной статье анализируются потери мощности, создаваемые низковольтными линиями электропередачи 0,4 кВ в сельской местности Джизакской области (Узбекистан). Экономические последствия потерь электроэнергии также рассчитывались на основе технического анализа.

Keywords: Transmission line, low-voltage power line, power losses, technical analysis, local consumers.

Ключевые слова: ЛЭП, низковольтная ЛЭП, потери мощности, технический анализ, местные потребители.

The limited fuel and energy resources of the Earth lead to an ever deeper awareness of the need for the strictest saving of resources, their careful spending. This the problem is of paramount importance for all countries, both developed and in transition economy. The development of key sectors of the economy is based primarily on outstripping growth production of electrical energy. However, in the process of transporting electrical energy along power grids, its losses are inevitable, which lead to additional combustion of fuel  in power plants and reduce network bandwidth. In connection with this, the tasks calculation and especially optimization of the level of electricity losses should be given the most close attention. The magnitude of losses in electrical networks can be significant (ten or more percent of useful supply), therefore, first of all, it is important to objectively determine the losses of electricity gee. It allows you to evaluate the amount of losses as one of the performance indicators networks, analyze their structure, identify foci, develop organizational and technical measures to reduce losses, to carry out their rationing in power systems[1].

At present, the share of the cost of energy resources is a determining component in the value of tariffs for housing and communal services.

Consider the components of actual electricity losses:

1) losses due to physical processes occurring during the transmission of electricity are technical (their values obtained by calculation on the basis of the laws of electrical engineering or with the help of measuring instruments);

2) losses associated with instrumental errors at measurement (calculated on the basis of data on metrological characteristics and modes of operation of devices);

3) electricity consumption for own needs of substations, necessary to ensure the operation of technological equipment and service personnel (registered by meters installed on auxiliary transformers)[2].

It is known that the power system consists of several components, in particular, electrical networks of different voltages. Low-voltage power networks are mainly used for power supply to the population. The highest power losses in the power system also fall on low-voltage 10 / 0.4 kV power grids. These power losses are estimated by the smallness of the voltage on these lines and the length of the distance. It is known that the power dissipated in a conductor is, of course, directly proportional to its length. The following table (table 1.) provides information on the length of existing low (10 / 0.4 kV) power lines in Jizzakh region[3].

Table 1.

Length of 10kV and 0.4 kV  power lines in Jizzakh region

As can be seen from the table above, the length of low-voltage transmission lines is so large that the power losses generated in these transmission lines are determined by the following expression:

                                                  (1)

Where:

I_i - is the equivalent current one phase of the network element between two branches

circuit lines and attached at the end of the section;

k_i - network execution factor;

k_dg - coefficient taking into account additional power losses caused by unequal

measured loading of phases;

r_i - active resistance.

The square of the equivalent current I_i define as follows:

=++                                                   (2)

where I_pi is the current uniformly distributed over the given i-th section of the network:

=                                                 (3)

As can be seen from equation 3, the uniform distribution of the current over the phases depends on the length of the line. Electricity losses for the scheme of one distribution line are determined by the expression:

 𝜂T                                                    (4)

Total power losses in all sections of the distribution line[4]:

=                                                    (5)

Voltage losses in sections of the line:

=                                                    (6)

References:

1. М.И. Фурсанов, Определение и анализ потерь электроэнергии в электрических сетях энергосистем, Минск 2006.
2. В.Н. Васильев, Определение потерь мощности и электроэнергии в городских электросетях на этапе проектирования, Известия ТулГУ. Технические науки. 2014.
3. Электронный ресурс: http://jizzaxhetk.uz
4. О. Г. Широков, Т. В. Алферова, А. А. Алферов, С. Л. Прусаков, оценка потерь электрической энергии, вызванных несинусоидальными режимами, при расчете небалансов системных подстанций 10 кв, Вестник ГГТУ им. П. О. Сухого №1, 2015.