Study of functioning of relay protection system under regular check conditions

2019 ◽  
Vol 12 (1) ◽  
pp. 36-44
Author(s):  
B. P. Zelentsov ◽  
A. S. Trofimov
Keyword(s):  
Markov Process ◽  
Power Systems ◽  
Power Transmission ◽  
Relay Protection ◽  
Point Of View ◽  
Distribution Law ◽  
Reliability Parameters ◽  
A Value ◽  
Semi Markov Process ◽  
Periodic Check

An analytical model of the operation of the relay protection of power systems is presented, which takes into account such types of failures as unwanted operation, failure to operate, as well as defects dangerous from the point of view of unwanted operation and failure to operate. Operability checks of relay protection of power systems are conducted with a constant period. The listed events can be divided into two groups: random and regular ones. The presence of random and regular components of events of recovery of relay protection of power systems can be correctly taken into account in the framework of the apparatus of the theory of Markov processes. The model is based on the description of the process of operation of relay protection of power transmission line by a semi-Markov process. The functioning of the system in time is presented in the form of cycles. The cycle of the functioning of the system consists of a subset, where the system is functioning and verifi ed, and a subset, in which it is restored. The model is implemented in a graph with 9 states. Probabilities of events describe the process of changing states on a discrete set of states of relay protection of the power system. The probability of a change of states is the initial characteristic of a semi-Markov process. This model has enabled to obtain the dependence of operation and reliability parameters on the frequency of regular checks. It is established that the frequency of regular checks with the exponential distribution law overstates the value of the unavailability factor, since the time of the onset of a periodic check is greater than the mathematical expectation of a given value of the periodic check under a random distribution law. With a signifi cant time between checks, or in absence of periodic checks, the unavailability factor tends to a value that does not depend on the way of setting the time between periodic checks.

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.

DYNAMIC RELIABILITY MEASURES AND LIFE DISTRIBUTION MODELS FOR MULTISTATE SYSTEMS

1995 ◽  
Vol 02 (01) ◽  
pp. 79-102 ◽  
Author(s):  
KAI YANG ◽  
JIANAN XUE
Keyword(s):  
Markov Process ◽  
Probability Models ◽  
Reliability Measures ◽  
Distribution Models ◽  
Dynamic Reliability ◽  
Reliability Models ◽  
Reliability Parameters ◽  
Multistate System ◽  
Binary State ◽  
Semi Markov Process

This paper generalizes the dynamic binary state reliability parameters R(t), F(t), λ(t) and MTBF to corresponding dynamic multistate reliability parameter vectors R(t), F(t), λ(t) and M. Then, probability models for system lifetime used on binary state reliability models, such as exponential, Weibull, and other distributions are generalized for multistate models. Continuous time Markov process and Semi-Markov process are used to model the lifetime distribution for multistate system. Multistate reliability measures, such as R(t), F(t), λ(t), M are derived for those multistate reliability models.

scholarly journals Analysis of the emergency control and relay protection structures approached from the point of view of EPS reliability and survivability by taking into account cybersecurity threats

2019 ◽  
Vol 139 ◽  
pp. 01029
Author(s):  
Alexey Osak ◽  
Daniil Panasetsky ◽  
Elena Buzina
Keyword(s):  
Power Systems ◽  
Control Systems ◽  
Relay Protection ◽  
Point Of View ◽  
Automated Control ◽  
Emergency Control ◽  
Automatic Control Systems ◽  
Cyber Threats ◽  
Methodical Approach ◽  
Protection Devices

Cyber threats pose an increasing threat to energy objects. It is essential to ensure the cybersecurity of automatic control systems, such as relay protection devices (RP), devices of regime control (RC) and emergency control (EC), automated control systems. At the same time, the issues of cybersecurity include not only the problem of hacker attacks, but also the whole complex of problems relating to adequate functioning of cybernetic systems in the power industry. The authors propose a methodical approach to the analysis of the structure of automatic means of regime and emergency control in terms of their impact on the reliability and survivability of power systems (EPS), taking into account the known threats to cybersecurity.

The Control of the Eye's Intrinsic Muscles: A Multivariable Optimum Performance Control System

1968 ◽  
Vol 1 (8) ◽  
pp. T.129-T.132 ◽  
Author(s):  
F. M. Toates
Keyword(s):  
Control System ◽  
Control Systems ◽  
Pupil Diameter ◽  
Control Model ◽  
Point Of View ◽  
Theoretical Point ◽  
Pupil Control ◽  
Performance Control ◽  
A Value ◽  
Intrinsic Muscles

The reciprocal interaction between the accommodation and pupil control systems of the human eye is examined from a theoretical point of view. The system, which is responsible for maintaining pupil diameter at a value which is a compromise between conflicting requirements, is represented by a control model, and is considered in terms of the concept of a performance index.

Partially observable semi-Markov reward processes

1993 ◽  
Vol 30 (3) ◽  
pp. 548-560 ◽  
Author(s):  
Yasushi Masuda
Keyword(s):  
Markov Process ◽  
Counting Process ◽  
Probabilistic Interpretation ◽  
Real Domain ◽  
Semi Markov Process ◽  
Reward Process ◽  
Markov Reward ◽  
Partially Observable ◽  
Joint Behavior

The main objective of this paper is to investigate the conditional behavior of the multivariate reward process given the number of certain signals where the underlying system is described by a semi-Markov process and the signal is defined by a counting process. To this end, we study the joint behavior of the multivariate reward process and the multivariate counting process in detail. We derive transform results as well as the corresponding real domain expressions, thus providing clear probabilistic interpretation.

BASIN CONFIGURATION OF A SIX-DIMENSIONAL MODEL OF AN ELECTRIC POWER SYSTEM

2002 ◽  
Vol 12 (06) ◽  
pp. 1333-1356 ◽  
Author(s):  
YOSHISUKE UEDA ◽  
HIROYUKI AMANO ◽  
RALPH H. ABRAHAM ◽  
H. BRUCE STEWART
Keyword(s):  
Power Systems ◽  
Power System ◽  
Initial Conditions ◽  
Electrical Power ◽  
Practical Importance ◽  
Intervention Strategy ◽  
Basins Of Attraction ◽  
Electric Power System ◽  
Point Of View ◽  
Electrical Power System

As part of an ongoing project on the stability of massively complex electrical power systems, we discuss the global geometric structure of contacts among the basins of attraction of a six-dimensional dynamical system. This system represents a simple model of an electrical power system involving three machines and an infinite bus. Apart from the possible occurrence of attractors representing pathological states, the contacts between the basins have a practical importance, from the point of view of the operation of a real electrical power system. With the aid of a global map of basins, one could hope to design an intervention strategy to boot the power system back into its normal state. Our method involves taking two-dimensional sections of the six-dimensional state space, and then determining the basins directly by numerical simulation from a dense grid of initial conditions. The relations among all the basins are given for a specific numerical example, that is, choosing particular values for the parameters in our model.

scholarly journals Dynamic Integrated Model for Assessing Fisheries: Discard Bans as an Implicit Value-Added Tax

2021 ◽  
Author(s):  
Jose Maria Da Rocha ◽  
Javier García-Cutrín ◽  
Maria-Jose Gutiérrez ◽  
Raul Prellezo ◽  
Eduardo Sanchez
Keyword(s):  
Value Added ◽  
Point Of View ◽  
Value Added Tax ◽  
Biological Variables ◽  
A Value ◽  
Long Run ◽  
The Social ◽  
Negative Effect ◽  
Short Run ◽  
The Impact

AbstractIntegrated economic models have become popular for assessing climate change. In this paper we show how these methods can be used to assess the impact of a discard ban in a fishery. We state that a discard ban can be understood as a confiscatory tax equivalent to a value-added tax. Under this framework, we show that a discard ban improves the sustainability of the fishery in the short run and increases economic welfare in the long run. In particular, we show that consumption, capital and wages show an initial decrease just after the implementation of the discard ban then recover after some periods to reach their steady-sate values, which are 16–20% higher than the initial values, depending on the valuation of the landed discards. The discard ban also improves biological variables, increasing landings by 14% and reducing discards by 29% on the initial figures. These patterns highlight the two channels through which discard bans affect a fishery: the tax channel, which shows that the confiscation of landed discards reduces the incentive to invest in the fishery; and the productivity channel, which increases the abundance of the stock. Thus, during the first few years after the implementation of a discard ban, the negative effect from the tax channel dominates the positive effect from the productivity channel, because the stock needs time to recover. Once stock abundance improves, the productivity channel dominates the tax channel and the economic variables rise above their initial levels. Our results also show that a landed discards valorisation policy is optimal from the social welfare point of view provided that incentives to increase discards are not created.

Assessment of technical condition of high-voltage overhead power transmission lines at the stage of their ageing

2021 ◽  
Vol 14 (2) ◽  
pp. 100-107
Author(s):  
E. M. Farhadzadeh ◽  
A. Z. Muradalyiev ◽  
S. A. Muradalyiev ◽  
A. A. Nazarov
Keyword(s):  
Power Systems ◽  
Electric Power ◽  
Transmission Lines ◽  
Power Transmission ◽  
Operational Reliability ◽  
Technical Condition ◽  
Weak Links ◽  
Power Transmission Lines ◽  
Nonlinear Growth ◽  
Overhead Power Transmission Lines

The organization of operation, maintenance and repair of the basic technological facilities of electric power systems (EPS), which are beyond their designed service life (hereinafter referred to as ageing facilities, or AFs) is one of the problems that determine the energy security of many countries, including economically developed nations. The principal cause of insufficient overall performance of AFs is the traditional focus of the EPS management on economic efficiency and the insufficient attention to reliability and safety of AFs. The tendency to nonlinear growth in the frequency of occurrence of unacceptable consequences in the EPS requires ensuring the operational reliability and safety of AFs. The averaged estimates of reliability and safety used at designing power facilities are not suitable for characterization of overall operational performance. Among the basic and the least investigated (in terms of operational reliability and safety) EPS facilities are overhead power transmission lines (OPL) with a voltage of 110 кV and above. This is for a reason. OPL are electric power facilities with elements distributed along a multi-kilometer line (supports, insulators, wires, accessories, etc.). That is what makes the organization of continuous monitoring of the technical condition of each of these elements, and, consequently, the assessment of operational reliability and safety, so problematic. A method is suggested for assessment of “weak links” among the operated OPL on operative intervals of time along with a method for assessment of the technical condition of OPL at examination of a representative sample.

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