Overvoltage Analysis Considering Transmission Tower Models Based on Impedances and Inductances

2015 ◽  
Vol 775 ◽  
pp. 373-377
Author(s):  
John Morales ◽  
Julio Montesdeoca ◽  
Guillermo Guidi
Keyword(s):  
Power Systems ◽  
Comparative Study ◽  
Electric Power ◽  
Transmission Lines ◽  
Short Circuit ◽  
Electric Power Systems ◽  
Transmission Tower ◽  
Impedance Model ◽  
Distributed Parameters ◽  
Transmission Towers

It is clear that lightning strokes produce overvoltages on Transmission Lines (TLs), which can be higher that the Basic Insulator Level (BIL), generating a fault or short circuit. Thus, in order to adequately analyze when a lightning hits on a TL, it is necessary to simulate different elements corresponding to Electric Power Systems (EPSs) as real as possible. In this context, transmission towers are considered crucial parameters in lightning studies, which must be correctly selected and simulated in order to consider reflected voltage waveforms from cross arms. Based on the above said, this paper presents a comparative study corresponding to the transmission tower simulation using two models. The first uses inductances, and the second uses distributed parameters impedances characterized by their impedance and travel time. This paper presents voltage variations that exist in each phase, using different lightning features. Alternative Transients Program (ATP) is used to simulate the TL model considering different lightning currents and the two tower models. Results show that the impedance model analyze reflected waveforms, while that the inductance model does not analyze this issue.

Relay protection and automation of electric power systems

2021 ◽  
Author(s):  
Sergey Goremykin
Keyword(s):  
Power Systems ◽  
Electric Power ◽  
Transmission Lines ◽  
Power Supply ◽  
Power Transmission ◽  
Relay Protection ◽  
Electrical Equipment ◽  
Electric Power Systems ◽  
Federal State ◽  
Advantages And Disadvantages

The textbook describes the main issues of the theory of relay protection and automation of electric power systems. The structure and functional purpose of protection devices and automation of power transmission lines of various configurations, synchronous generators, power transformers, electric motors and individual electrical installations are considered. For each of the types of protection of the above objects, the structure, the principle of operation, the order of selection of settings are given, the advantages and disadvantages are evaluated, indicating the scope of application. The manual includes material on complete devices based on semiconductor and microprocessor element bases. The progressive use of such devices (protection of the third and fourth generations) is appropriate and effective due to their significant advantages. Meets the requirements of the federal state educational standards of higher education of the latest generation. It is intended for students in the areas of training 13.03.02 "Electric power and electrical engineering" (profile "Power supply", discipline "Relay protection and automation of electric power systems") and 35.03.06 "Agroengineering" (profile "Power supply and electrical equipment of agricultural enterprises", discipline "Relay protection of electrical equipment of agricultural objects"), as well as for graduate students and specialists engaged in the field of electrification and automation of industrial and agrotechnical objects.

Analisis Gangguan Pada Sistem Tenaga Listrik Jawa Bali 500 kV Menggunakan Power World Simulator

2019 ◽  
Vol 10 (1) ◽  
pp. 35-41
Author(s):  
Dwi Ajiatmo ◽  
Imam Robandi ◽  
Machrus Ali ◽  
Betta Aidya Suroya
Keyword(s):  
Power Systems ◽  
Power System ◽  
Electric Power ◽  
Power Distribution ◽  
Short Circuit ◽  
Electric Power Systems ◽  
Electric Power System ◽  
Positive Sequence ◽  
Simulation Design ◽  
Component System

Short circuit is one type of interference that often occurs in electric power systems. The interference if it lasts a long time will affect the quality and continity of electrical power distribution as well as the reliability and safety of the equipment on the system. To minimize the possibility of interference and to minimize the consequences caused by interference, an analysis of disturbances in the electric power system is needed. This study discusses the classification and analysis of disturbances in the electric power system. The type of interference in the electric power system is classified into two, namely symmetry and non-symmetrical interference. Symmetry disturbances are three phase disturbances which are described by the equation of the sequence of the symmetry component system. Sequence equations from the symmetry component system are positive sequence equations, negative sequence equations, and zero sequence equations. Non-symmetrical interference is a disorder that often occurs in electric power systems, namely the interference of one network to the ground, network interference to the network and interference of two networks to the ground. This research is to classify and to analyze the types of disturbances in the Java-Bali electric power system 500 kV 20 buses in the form of a single line diagram, using Power World Simulator and ETAP Software applications. The simulation results are calculated and display the simulation design of the power system with the tools contained in the program.

scholarly journals Generation adequacy of electric power systems in market price setting

2019 ◽  
Vol 114 ◽  
pp. 03006
Author(s):  
Natalia Aizenberg ◽  
Sergey Perzhabinsky
Keyword(s):  
Power Systems ◽  
Social Welfare ◽  
Electric Power ◽  
Transmission Lines ◽  
Electricity Market ◽  
Market Price ◽  
Consumer Surplus ◽  
Electric Power Systems ◽  
Electric Power System ◽  
Electricity Shortage

We propose the new model of generation adequacy optimization. Optimization criterion is a maximum of social welfare. Social welfare consists of profits of generating companies, consumer surplus, costs for development and servicing of electrical grids. In the article we present a review of existed methods of adequacy level management in liberalized electric power systems. Optimization of adequacy level is based on analysis of variants of development of the electric power system. For adequacy analysis of the variants of development we multiple estimate the electricity shortage in random hours of the system work. Analysis of the system work in every random hour is realized in two stages. At first we define values of equilibrium electricity demand in every system node and equilibrium price of electricity according to Cournot model. We consider only electricity market in the model. At the next stage we simulate failures of power generating equipment and transmission lines. The electricity shortage in a current hour is estimated on the second stage. After a whole cycle of analysis, we compute reliability indexes and profits of generating companies. Profits of generating companies are depended on the reliability of the electricity supply. The simulations of random values are based on Monte Carlo method.

Research of Parameters of Electric Power Systems Affecting Core Saturation of Current Transformers with a Closed Magnetic Circuit in Transitional Short Circuit Modes

2021 ◽  
Vol 64 (1) ◽  
pp. 92-100
Author(s):  
Viliya Ivanova ◽  
◽  
Igor Ivanov ◽  
Keyword(s):  
Power Systems ◽  
Electric Power ◽  
Magnetic Circuit ◽  
Short Circuit ◽  
Relay Protection ◽  
Electric Power Systems ◽  
Current Transformers ◽  
Core Saturation ◽  
Protection Devices ◽  
Closed Magnetic Circuit

The relevance of the study is due to the excess of the permissible errors of current transformers in transient short-circuit modes associated with saturation of the cores of current transformers. The latter leads to improper operation of relay protection devices, which can negatively affect the stability of electric power systems and the efficiency of industrial enterprises with a continuous technological cycle, the power failure of which leads to significant economic damage. The aim of this work is to study the parameters of electric power systems that affect the saturation of the cores of current transformers with a closed magnetic circuit in transient short-circuit modes. The object of research is electromagnetic current transformers of accuracy class 10P in electric power systems. The study was carried out using numerical methods for solving algebraic and differential equations, methods of computer modeling of electromagnetic transient processes and functional programming. As a result, the main parameters influencing the nature and intensity of electromagnetic transients in current transformers during a short circuit are noted; it is shown that in transient short-circuit modes, significant errors in the operation of current transformers associated with core saturation are possible; recommended for assessing the compliance of current transformers of accuracy classes 5P, 10P with the conditions for the correct functioning of relay protection devices in transient short-circuit modes, to calculate the time to saturation of current transformers, taking into account the real parameters of the electric power system at the place where current transformers are installed, in addition to the traditional design checking of current transformers by permissible er-rors for the steady state short circuit.

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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