scholarly journals Impact of impedance unbalance on the efficiency of electricity transmission and distribution - A case study

2017 ◽  
Vol 68 (6) ◽  
pp. 492-495 ◽  
Author(s):  
L’uboš Pavlov ◽  
L’uboš Skurčák ◽  
Juraj Chovanec ◽  
Juraj Altus
Keyword(s):  
Real System ◽  
Voltage Level ◽  
Electricity Transmission ◽  
Electricity System ◽  
Ohmic Losses ◽  
Transmission And Distribution

Abstract This article is devoted to the analysis of the possible influence of impedance asymmetry on the efficiency of electricity transmission and distribution in the electricity system in Slovakia, at a voltage level of 110 kV - 400 kV, using synchronic phasor monitoring results. For simplicity of calculations, in practice, the impedance imbalance from mutual interfacial inductive capacitances bonds is neglected. In this way, the 3-phase network is interpreted as symmetrical in the calculations. In this case, it is possible to determine only some components of losses (ohmic losses, corona loss, leakages, etc). The influence of impedance asymmetry can be quantified by calculation using the results of the monitoring of the synchronous phasors of selected electricity system elements (OHL, transformer, choke) or by 3-phase modelling of real system elements. frequency to test the transformer for induced over voltage test, and its characteristics is analysed.

scholarly journals Transmission Expansion Planning for the Optimization of Renewable Energy Integration in the Sulawesi Electricity System

2021 ◽  
Vol 13 (18) ◽  
pp. 10477
Author(s):  
Tumiran ◽  
Lesnanto Multa Putranto ◽  
Roni Irnawan ◽  
Sarjiya ◽  
Adi Priyanto ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Voltage Stability ◽  
Energy Integration ◽  
Voltage Level ◽  
Renewable Energy Integration ◽  
Expansion Planning ◽  
Transmission Expansion Planning ◽  
North Sulawesi ◽  
Electricity System ◽  
Transmission Expansion

In order to meet the growth in demand and the renewable energy integration target, the Sulawesi Electricity System (SES) should be expanded. Currently, the SES is divided into two systems, namely South and North Sulawesi. These two systems have different characteristics, such as the system size, reliability and operational cost. North Sulawesi is smaller, weaker and more expensive than the South System. In order to improve the system reliability, generation and transmission expansion planning should be executed simultaneously to meet the economical investment cost and satisfy the reliability standard. For this purpose, the necessity of a backbone system with a higher voltage level than the existing 150 kV system should be considered, including the interconnection option between the two existing systems in Sulawesi. A methodology based on economic and technical criteria was developed to determine the backbone voltage level. Two voltage level options were considered, namely 275 and 500 kV. Several criteria were considered in order to determine the backbone voltage level, including the economic voltage, the line-loading limit, N-1 contingency, short circuiting, transient stability, voltage stability and small signal stability. The backbone voltage candidates should fulfil all of the criteria. The simulation was conducted in base- and high-demand scenarios, considering the fluctuation of future economic growth. The load flow and the dynamic analysis were simulated in a DIgSILENT Power Factory environment. The results showed that the 275 kV backbone, which was built in 2022, would violate three criteria: the economic voltage, N-1 contingency and voltage stability. On the other hand, the 500 kV backbone voltage level fulfills all of the criteria. The result of this research was considered in the electricity planning documents in Sulawesi. From a technical and economical perspective, the 500 kV backbone was chosen for the SES.

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