Abstract:
In this paper, the object of the research
is 110 kV power grids of three regions of
the Republic of Kazakhstan: Astana city,
Turkestan region and Shymkent city, as
well as West Kazakhstan region.
Operators of the studied power grids
have no idea about the real levels of voltage
and current sinusoidality distortion coefficients, as well as about their relationship
with other regime and system parameters
of power grids. Similar problems may be
faced by other grid companies that do
not have the appropriate information and
measurement infrastructure to monitor the
modes of power grids in terms of voltage
and current sinusoidality distortion.
In the course of the present study,
using portable three-phase power quantity and quality analyzers, it was possible
to make daily measurements of mode parameters in 41 110 kV transmission lines with
a length of 5 to 120 km.
The results of measurements showed
that in Astana city, the voltage quality is at
a satisfactory level, but the distortion coefficient of sinusoidality of current reaches
39 % (the average level for 15 studied lines
is 13.3 %) due to the high concentration of
non-linear load of consumers. In the South
of Kazakhstan, the voltage and current
sinusoidality distortion coefficients are relatively moderate, but voltage drops are
frequent (sometimes up to 10 % or more)
due to the large distance between load centers and relatively high population density.
In the power grids of Western Kazakhstan,
voltage and current sinusoidality distortion coefficients have high levels (reach
14 % and 70 %, respectively) due to low
network load with a large length of transmission lines.
The analysis makes it possible to trace
the relationship of voltage and current
sinusoidality distortion coefficients with
such regional characteristics as population
density, nature of loads, power losses, voltage and current levels
