Investigation and optimization of the energy efficiency of the Tajik energy system

Publication date
2020-02
Document type
PhD thesis (dissertation)
Author
Halimjanova, Munira
Advisor
Referee
Becker, Christian
Granting institution
Helmut-Schmidt-Universität / Universität der Bundeswehr Hamburg
Exam date
2019-10-02
Organisational unit
DDC Class
620 Ingenieurwissenschaften
Keyword
Efficiency
Reliability
Power
Quality
DIgSILENT PowerFactory 2018
Thermoelectric plant (CHP)
Hydro Power Plant (HPP)
Central Asia and South Asia project (CASA-1000)
Energy security
Transmission lines
Abstract
This thesis is devoted to the system instability due to load variability and inadmissible voltage changes and also provided the technical decision for increasing electrical power stability in the whole Tajik energy system. The issue of providing high-quality and reliable electrical power regularly appears in the energy systems of different countries of the world, and this issue became a case to investigate the Tajik real electrical transmission system. It is considered to put the all extra-high and high-voltage Tajik grid in the analyzation, namely: four extra-high substations with 490 km overhead lines and one hydropower plant at the 500 kV level; as well as 26 substations with 1327 km overhead lines, and seven power plants at the 220 kV level; moreover 29.997 km overhead lines, 156 substations and 3 power plants at the 110 kV level and one decentralised zone with voltage level of 10/0.4 kV. The Tajik energy system is in detail considered, and essential suggestions for improving the whole energy system and increasing power stability are provided. Considering that the primary energy resource in Tajikistan is water and the large hydropower stations are often located far away from the loads, the system voltage instability occurs periodically. Lack of compensation equipment like reactors makes this situation with voltage stability and power reliability more difficult. This problem becomes more significant because of the new “CASA-1000” project which aims to connect four Asia countries through high voltage lines. According to the World Bank and Tajik government, suggestions consider three different connection scenarios. To find a negative and positive impact of these connections, after connecting CASA-1000 to the Tajik grid, load flow calculation for the whole energy system is modelled. For solving voltage instability, a possibility to transmit the maximum power under given line impedance and load power factor were considered. Due to simulation was proven the efficiency of using reactive power compensation equipment, instead of using loads for voltage stabilization. Specifically, installation of the Static Var Compensators at the line between substation-Datka in the Republik of Kyrgyzstan and the substation-Sugd in the Republic of Tajikistan is proposed, through this solution the maximum power transmission with minimal power losses has been achieved.
Version
Not applicable (or unknown)
Access right on openHSU
Open access