Feature of Voltage Transformers Operation in the Direct Current Schemes of Ice Melting on Overhead Transmission Lines

2020 ◽  
Vol 63 (6) ◽  
pp. 83-90
Author(s):  
Alexander Zasypkin (jr.) ◽  
◽  
Artyom Shchurov ◽  
Alexander Zasypkin ◽  
◽  
...  
Keyword(s):  
Power System ◽  
Direct Current ◽  
Transmission Lines ◽  
Equivalent Circuits ◽  
Ice Melting ◽  
Electrical Networks ◽  
Accuracy Class ◽  
Dc Voltage ◽  
Overhead Transmission Lines ◽  
Parameters Calculation

It is well known that electromagnetic voltage transformers (VT), included in the direct current scheme of ice melting (SIM) on overhead transmission lines (OTL), must be switched off when the SIM is assembling and turned on during disassembling. This action increases the time of the power line output from work and reduces the reliability of the power system. It is noted that capacitance VTs used in the electrical networks of 110-500 kV are not subject to the dangerous influence of DC voltage. Three variants of capacitors installation for elec-tromagnetic VT protection from direct voltage at which it is not required to switch off VTs are considered. A conclusion was made on the conditions of applicability of each variant based on the analysis of basic SIM. The article includes the necessary for practical use equivalent circuits and the values of constant voltages on the VTs in the basic direct current schemes of ice melting on overhead transmission lines. The method and an exam-ple of parameters calculation of the capacitors' block and additional resistor, providing the required accuracy class of VT at its constant inclusion as in the normal scheme, and in the scheme of ice melting, are given.

scholarly journals Transient Temperature Calculation and Multi-Parameter Thermal Protection of Overhead Transmission Lines Based on an Equivalent Thermal Network

Energies ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 67 ◽  
Author(s):  
Jian Hu ◽  
Xiaofu Xiong ◽  
Jing Chen ◽  
Wei Wang ◽  
Jian Wang
Keyword(s):  
Power System ◽  
Transmission Line ◽  
Transmission Lines ◽  
Calculation Method ◽  
Thermal Protection ◽  
Transient Temperature ◽  
Accurate Analysis ◽  
Temperature Calculation ◽  
Overhead Transmission Lines ◽  
Thermal Network

The overload degree of a transmission line is represented by currents in traditional overload protection, which cannot reflect its safety condition accurately. The sudden rise in transmission line current may lead to cascading tripping under traditional protection during power flow transfer in a power system. Therefore, timely and accurate analysis of the transient temperature rise of overhead transmission lines, revealing their overload endurance capability under the premise of ensuring safety, and coordination with power system controls can effectively eliminate overloading. This paper presents a transient temperature calculation method for overhead transmission lines based on an equivalent thermal network. This method can fully consider the temperature-dependent characteristics with material properties, convective heat resistance, and radiation heat and can accurately calculate the gradient distribution and response of the conductor cross-section temperature. The validity and accuracy of the proposed calculation method are verified by a test platform. In addition, a multi-parameter thermal protection strategy is proposed on the basis of the abovementioned calculation method. The protection can adequately explore the maximum overload capability of the line, and prevent from unnecessary tripping to avoid the expansion of accidents. Finally, the validity of the proposed protection is verified by the modified 29-bus system.

scholarly journals Research on the decision of state maintenance for transmission line based on set pair analysis

2021 ◽  
Vol 71 (1&2) ◽  
pp. 17
Author(s):  
Shiyang Zhu ◽  
Le Wang
Keyword(s):  
Power System ◽  
Transmission Line ◽  
Transmission Lines ◽  
Power Grids ◽  
Financial Control ◽  
Set Pair Analysis ◽  
Overhead Transmission Lines ◽  
Maintenance Work ◽  
Maintenance Decision ◽  
Pair Analysis

Overhead transmission lines are important parts of a power system; their operation state directly affects the reliability level of the entire power system. With the in-depth development of state maintenance work for power grids, correctly evaluating the reliability of overhead transmission lines is the key to successful maintenance. A maintenance decision model for transmission lines is established in this study based on set pair analysis to achieve human financial control and low maintenance efficiency. Full consideration is provided to the influence of environmental factors, and a theoretical basis for transmission line maintenance decision is established.

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