scholarly journals Designing Predictive Diagnose Method for Insulation Resistance Degradation of the Electrical Power Cables from Neutral Insulated Power Networks

2017 ◽  
Vol 209 ◽  
pp. 012093
Author(s):  
R Dobra ◽  
D Pasculescu ◽  
M Risteiu ◽  
G Buica ◽  
V Jevremović
Keyword(s):  
Electrical Power ◽  
Power Cables ◽  
Insulation Resistance ◽  
Power Networks ◽  
Resistance Degradation

Examination of State of the Cable Insulation by the Return Voltage

2018 ◽  
Vol 19 (6) ◽  
Author(s):  
Dmitry Semenov ◽  
Anna Sidorova ◽  
Pavel Romanov ◽  
Aleksey Kuvshinov
Keyword(s):  
Residual Life ◽  
Technical Condition ◽  
Actual State ◽  
Power Cables ◽  
Insulation Resistance ◽  
Cable Lines ◽  
P Factor ◽  
Paper Insulation ◽  
New System

Abstract The relevance of the study is conditioned by the need to determine the state and residual life duration of high-voltage cable lines to identify faulty and maintainable cables. The aim of the article is to determine a reliable scientifically grounded criterion for assessment of insulation characteristics of the cables in use and to perform a comparative analysis of the results obtained by the traditional method of diagnosing insulation with the results of a new method of assessment by the return voltage. In this regard, the article deals with the issues related to the testing of cables having oil-impregnated paper insulation, as well as with the issue of switching from planned replacement of cables to assessment of their actual state and period of residual life. The authors propose to use the method of examining the cables by the return voltage using the device for testing electrical insulation “UDEI-1” developed at the department of Electrification and Automation of the Nizhny Novgorod State University of Engineering and Economics. The article presents the results of measuring the return voltage of three cables that operated under different conditions. The cables had different technical state. The analysis of the estimation of the residual life of cables by the return voltage was carried out using such criteria as the PIRV polarization index, the LIRV electrical conductivity index, and the P-factor. The P-factor is the physical criterion demonstrating the aging of paper-oil insulation by the shape of the return voltage curve. It represents such characteristics of insulation aging as moistening. To compare the results of testing the cables by the return voltage with the conventional methods of diagnostics and to determine the actual technical condition of power cables, the authors applied the method of spatiotemporal reflectometry and the method of measuring insulation resistance with the determination of such indicators of state as insulation resistance normalized per one kilometer, absorption coefficient, and polarization index. The results of this article confirm that the return voltage gives a qualitative assessment of the state and degree of aging of cables with impregnated paper insulation. The authors proposed a new system for evaluation of cable condition by weighting coefficients. In this approach, the determination of residual life of cables with impregnated paper insulation is based on the values of the return voltage. Application of the new system gives opportunity to improve reliability of the power lines. Recommendations for the further operation of the studied cables are given. The materials of the article are of practical value for carrying out complex assessment of the technical condition of power cables by the return voltage and can be useful for drawing up a schedule for replacement or repair of cable lines depending on their actual state.

Thermal analysis of underground electrical power cables buried in non-homogeneous soils

2011 ◽  
Vol 31 (5) ◽  
pp. 772-778 ◽  
Author(s):  
Roberto de Lieto Vollaro ◽  
Lucia Fontana ◽  
Andrea Vallati
Keyword(s):  
Thermal Analysis ◽  
Electrical Power ◽  
Power Cables

Testing of Underground Power Cables

2016 ◽  
pp. 288-317
Keyword(s):  
Power Systems ◽  
Electrical Power ◽  
Current Source ◽  
Electrical Equipment ◽  
Alternating Current ◽  
Power Cables ◽  
Test Procedures ◽  
Electrical Power Systems ◽  
Insulation Systems ◽  
Underground Power Cables

Probably 80% of all testing performed in electrical power systems is related to the verification of insulation quality. This chapter briefly describes the fundamental concepts of insulation testing including – insulation behavior, types of tests, and some test procedures. Most electrical equipment in utility, industrial, and commercial power systems uses either 50 or 60 Hz alternating current. Because of this, the use of an alternating current source to test insulation would appear to be the logical choice. However, as will be described a little later, insulation systems are extremely capacitive. For this and other reasons, DC has found a large niche in the technology. Before we can really evaluate the value of one system as opposed to the other (e.g. AC vs DC), let us examine how each type of voltage affects insulation. Testing of underground power cables are reported by NS161. (2014). IEC 6038. (1979). IEC Standard 60228. (1979). IEC60229. (2007). IEC60230. (1974). IEC60233. (1981). IEC 60332 (1974). IEC 6071 (2008). IEC 60270. (2000), IEC 60287. (2002).

Operating Modes Optimization of Bulk Electrical Power Networks: Structural and Parametrical Methods

2021 ◽  
pp. 99-119
Author(s):  
Vladislav Kuchanskyy ◽  
Denys Malakhatka ◽  
Artur Zaporozhets
Keyword(s):  
Electrical Power ◽  
Power Networks ◽  
Operating Modes

Effect of La doping on the suppression of insulation resistance degradation in multi-layer ceramic capacitors

2019 ◽  
Vol 58 (SL) ◽  
pp. SLLC02 ◽  
Author(s):  
Takashi Tateishi ◽  
Shoichiro Suzuki ◽  
Koichi Banno ◽  
Akira Ando
Keyword(s):  
Insulation Resistance ◽  
La Doping ◽  
Resistance Degradation ◽  
Ceramic Capacitors

Conversaziones, 1973

1974 ◽  
Vol 28 (2) ◽  
pp. 157-166
Keyword(s):  
Diagnostic Testing ◽  
Electrical Power ◽  
Standard Technique ◽  
Power Cables ◽  
Combustion Chambers ◽  
Insulating Layer ◽  
Double Decker ◽  
Creep Characteristics ◽  
Boiler Tubes ◽  
Conductor Surface

Conversaziones were held this year on 10 May and 28 June. At the first conversazione twenty-six exhibits and a film were shown. Two exhibits were arranged by the Central Electricity Research Laboratories, Leatherhead. The effect on very large boilers of very small traces of impurities was demonstrated by Mr G. M. W. Mann, Dr K. Torrance and Professor J. M. Ward. Modern power station boilers are enormous structures— they cost £10m each, contain 300 miles of metal tubing and have combustion chambers large enough to house 100 double-decker buses. For their trouble-free operation demineralized water has to be used; this is so pure that commonly occurring substances such as iron, copper, sodium and chloride are present only to the extent of a few parts per 1000 million. If the levels of impurities are not carefully controlled, corrosion of the boiler tubes can occur and one faulty tube will put the whole boiler out of action at a cost of £30 000 per day. Recent advances in potentiometry have led to the use of selective ion electrodes for the on-steam monitoring of water quality and these electrodes were demonstrated to show their sensitivity. In addition mechanisms of corrosion were illustrated and typical examples of corrosion displayed. Mr H. K. Beale, Mr C. F. Price and Mr C. N. Reed arranged an exhibit on compression terminations for aluminium conductors. Although aluminium conductors for the electrical power industry are being increasingly used for power cables because of cheapness and lightness compared with copper, they have the disadvantage of being difficult to terminate. This is due to the electrically insulating layer of oxide on the conductor surface, and the creep characteristics of the metal. As a result, terminating aluminium cables by means of the standard technique of lugs compressed on the end of the conductor poses problems not encountered with copper. An outline was given of research now in progress to overcome these problems. A working display of a prototype cartridge-operated tool illustrated the developments that are taking place in compression jointing equipment for speedy field use. A new CERL measuring set for the diagnostic testing of joints in service was demonstrated.

Sign in / Sign up

Export Citation Format

Share Document