High-voltage electrical equipment in electrical power systems: diagnostics, defects, damage, monitoring

2019 ◽  
Author(s):  
Александр Хренников ◽  
Alexander Khrennikov
Keyword(s):  
Power Systems ◽  
Short Circuit ◽  
Electrical Power ◽  
Electrical Equipment ◽  
Diagnostic Methods ◽  
Power Transformers ◽  
Electrical Power Systems ◽  
The Impact ◽  
Short Circuit Currents ◽  
Detection Of Defects

The analysis of the main methods of diagnostics of electrical equipment for detection of defects and damages in the course of operation is presented. Analysis of the effectiveness of the main diagnostic methods is accompanied by examples of detection of defects and damage to specific equipment: power transformers, reactors, current and voltage transformers, disconnectors, turbogenerators, OPN, etc. Examples of damage and investigation of technological violations of oil-filled transformer-reactor equipment during operation, associated with the loss of electrodynamic resistance of the windings during the flow of through short-circuit currents (short-circuit). The analysis of efficiency of application of methods of diagnostics at detection of defects and damages of power transformers because of the impact of fault current. The questions of electrodynamic tests of power transformers (reactors) for resistance to short-circuit currents, which serve as a tool to improve the reliability of their design, are considered.

scholarly journals Assessment of the Impact of the Rigidity of Nodes on the Operating Reliability of EPSs

2019 ◽  
Vol 139 ◽  
pp. 01070
Author(s):  
Nailya Chemborisova
Keyword(s):  
Power Systems ◽  
Short Circuit ◽  
Electrical Power ◽  
Operating Conditions ◽  
Electrical Power Systems ◽  
Operating Reliability ◽  
The Matrix ◽  
Active Power Losses ◽  
The Impact ◽  
Short Circuit Currents

The operating reliability of electrical power systems is mostly based on the topology and parameters of the schemes considered in this article. The preliminary (before the calculation of operating conditions) analysis of the rigidity or sensitivity of nodes, based on the matrix of node conductivity, allows for evaluating and increasing the controllability of conditions by voltages and limiting short-circuit currents, making the reduction of active power losses in the grid more efficient. A conclusion was made regarding the consistent effects of changes in the node rigidity on increasing the EPS operating reliability.

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).

scholarly journals Determine the Optimum Efficiency of Transformer Cores Using Comparative Study Method

2021 ◽  
Vol 12 (1) ◽  
pp. 35
Author(s):  
Nabeel Zahoor ◽  
Abid Ali Dogar ◽  
Akhtar Hussain
Keyword(s):  
Power Systems ◽  
Short Circuit ◽  
Electrical Power ◽  
Operating Cost ◽  
Open Circuit ◽  
Core Material ◽  
Local Market ◽  
Electrical Power Systems ◽  
Research Perspective ◽  
Core Losses

The transformer is one of the most discussed and important components of electrical power systems because of its reliability, durability and energy conversion capability. It is also useful in load sharing, which reduces system burden, but is also responsible for a sufficient number of losses, as it is used in different types of electric appliances that require voltage conversion. The no-load losses of transformers have gained much attention from research perspective because of its operating cost throughout its lifetime. Many studies were carried out to achieve the highest possible efficiency, decreasing certain losses by using different methods and materials. However, the local market in Pakistan is far behind in the field of efficient core material manufacturing of transformers, which is why consumers are unable to obtain efficient electric appliances. Due to these loss-making appliances, the overall residential load increases and the consumers are charged with heavy electricity bills. This proposed study discusses core losses, different core comparisons, T/F efficiency and advancement in the core material. To accomplish a core comparison, two locally available core materials are used to fabricate two different T/F, and some tests such as open-circuit and short-circuit tests are performed to discover their losses, thermal degradation, and output efficiencies.

scholarly journals Mechanical-Stress Analytical Modeling for the Design of Coils in Power Applications

2014 ◽  
Vol 63 (4) ◽  
pp. 579-590
Author(s):  
D. Bellan
Keyword(s):  
Power Systems ◽  
Mechanical Stress ◽  
Short Circuit ◽  
Electrical Power ◽  
Short Circuit Current ◽  
Geometrical Parameters ◽  
Electrical Power Systems ◽  
Inrush Currents ◽  
Current Flows ◽  
The Relationship

Abstract Modern electrical-power systems are often exploited for transmitting high-frequency carrier signals for communications purposes. Series-connected air-core coils represent the fundamental component allowing such applications by providing a proper filtering in the frequency domain. They must be designed, however, to withstand also the line short-circuit current. When a high-magnitude current flows through a coil, strong mechanical stresses are produced within the conductor, leading to possible damage of the coil. In this paper, an approximate analytical model is derived for the relationship between the maximum mechanical stress and the electrical/geometrical parameters of the coil. Such a model provides the guidelines for a fast and safe coil design, whereas numerical simulations are only needed for the design refinement. The presented approach can be extended to other applications such as, for example, the mechanical stress resulting from the inrush currents in the coils of power transformers.

scholarly journals ASSESS THE RISK LEVEL OF POWER TRANSFORMER DUE SHORT-CIRCUIT FAULTS BASED ON ANFIS

SINERGI ◽  
2019 ◽  
Vol 23 (2) ◽  
pp. 99
Author(s):  
Azriyenni Azhari Zakri ◽  
Mohd Wazir Mustafa ◽  
Hari Firdaus ◽  
Ibim Sofimieari
Keyword(s):  
Power Systems ◽  
Power Distribution ◽  
Fuzzy Inference ◽  
Power Transformer ◽  
Short Circuit ◽  
Electrical Power ◽  
Power Transformers ◽  
Risk Level ◽  
Electrical Machine ◽  
Intelligent Technique

A power transformer is an electrical machine that converts electrical power at different voltage levels. Faults, occur in power transformers, inhibit electrical power distribution to the consumer. Protection, therefore, of the power transformers is essential in power systems reliability. The power system can be reliable if the protection devices work well when there is a fault. A hybrid intelligent technique, which is a combination of Artificial Neural Network (ANN) and Fuzzy known as Adaptive Neuro-Fuzzy Inference Systems (ANFIS), was used in this research. The objective of this paper is the simulation of differential relays as a protection device on power transformers using Matlab/Simulink. Performance of differential relays for power transformers protection is carried out with internal and external fault scenarios. The input data were classified into three different input for ANFIS such as internal and external 1, internal and external 2, internal, external 1, and external 2, respectively. The error results of ANFIS training for the type of fault internal and external 1 is 9.46*10-7, and types of fault internal and external 2 is 1.09*10-6 internal, external 1 and external 2 are 8.59*10-7. The results obtained from the simulation were accurate and shows that the ANFIS technique is an efficient method that gives less error and a great value. Finally, the technique can minimize faults with power transformers. Finally, to prove this method can reduce faults in the power transformer, the assess of this model has been carried out through the RMSE that has been generated which is zero.

The Effect of Dynamic Out-of-Phase Operation of Synchronous Generators on the Short-Circuit Currents in Electric Power Systems

2021 ◽  
Vol 3 (3) ◽  
pp. 26-32
Author(s):  
Yury P. GUSEV ◽  
◽  
Alisher G. KAYUMOV ◽  
Keyword(s):  
Power Systems ◽  
Electric Power ◽  
Initial Phase ◽  
Short Circuit ◽  
Electrical Equipment ◽  
Electric Power Systems ◽  
Current Phase ◽  
Analysis Model ◽  
Synchronous Generators ◽  
Short Circuit Currents

The growing levels of short-circuit currents (SCC) in electric power systems (EPS) generate the need of improving the SCC calculation methods. Factors causing the occurrence of dynamic out-of-phase operation of synchronous generators (SGs) and its effect on the SCC are studied. To analyze the effect the out-of-phase operation of SGs has on the SCC, an analysis model was developed in the EMTP-RV software package (Powersys, France), and variant calculations were carried out. The study was carried out for an SG operating in parallel with the EPS. The parameters of electrical equipment installed in the EPS of Russia and CIS countries were used as initial data. The effects the mechanical inertia and electromagnetic parameters of the rotor and stator windings have on the occurrence of out-of-phase operation of generators was considered. It is shown that the analysis of SCC carried out without taking into account the dynamic out-of-phase operation of SGs yields SCC values significantly overestimated in comparison with those calculated according to the standards that are currently in force. By the short-circuit clearing time, the initial phase of the SCC component from the SG may differ from the initial phase of the SCC component from the network source by 90 degrees or more; i.e., the total SCC obtained taking into account the SG current phase becomes less than the current from the network source. It is recommended to take into account the dynamic out-of-phase operation of SGs in solving matters concerned with coordinating the SCC levels and to improve methods for calculating SCC in the EPS.

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