Adjacent Power Systems Research Articles

ВИЗНАЧЕННЯ ЗАРЯДНОЇ ЄМНОСТІ ПОВІТРЯНИХ ЛІНІЙ ЕЛЕКТРОПЕРЕДАЧІ З УРАХУВАННЯМ ПРОВИСАННЯ ПРОВОДУ

The paper presents the results of studying the effect of wire sagging on the charging capacity of an overhead power line. A refined mathematical model of the overhead line charging capacity is obtained. The results of the study of the error of neglect of wire sagging for typical structures of overhead power lines with voltage from 35 to 750 kV with the arrangement of wires in 2-3 tiers and horizontal arrangement are presented. The influence of changes in the wire sagging boom on the value of the power line charging capacity due to changes in the operating temperature of the wire and due to ice deposits is investigated. It is shown that for 750 kV power lines, such a change can reach 1-1.5%, which, in combination with the long length of the main power lines, can cause a change in the balance of reactive power in the line itself and in adjacent power systems. The possibility of monitoring the wire sagging boom in a run is investigated and the requirements for the accuracy of such measurements are determined. Bibl. 14, fig. 3, table.

Climatic Extremes: a New Challenge for Russian Power Systems

Changes in temperature extremes in Russia after 1945 are examined, and their effect on power system performance is analyzed. It is indicated that the Unified Power System (UPS) of Russia and all integrated power systems (IPS) presently have a considerable amount of installed and available spare capacities. However, a quarter of the regional power systems suffer a power shortage, and three of seven integrated regional power systems of Russia (Northwest, Center, and South) feature a deficit in the power control range, which is covered by power flows from adjacent power systems (Middle Volga, Urals, and Siberia). Based on the meteorological monitoring results and power industry statistic, the observed change in the extremal climatic characteristics over the past 70 years was calculated. Its effect on the power balance and power system modes was assessed. It has been established that climatic changes that occurred in Russia and manifested themselves in an increase in the air temperature in all seasons in all regions of the country reduce the maximum load increase rate in the winter and raise it in the summer in almost all power systems, thereby contributing to an increase in the reliability of electricity supply. For the summer, a continuous increase in the power demand maxima in combination with an enhancement in the nonuniformity of the daily demand, and, as a result, a greater need for the control range mean an increase in the risk of massive power supply failures. It has been demonstrated that, against this background, a decrease in the output of generating facilities (such as thermal power plants (TPP), hydroelectric power plants (HPP), and nuclear power plants (NPP)) in hot weather and accidents at power facilities lead to the depletion of the available spare power and substantiate the fact that many consumers can be disconnected in the power systems of the South and the Center.

Машинное обучение как инструмент повышения эффективности управления жизненным циклом высоковольтного электрооборудования

The purpose of the study is to analyze the practical implementation of high-voltage electrical equipment technical state estimation subsystems as a part of solving the lifecycle management problem based on machine learning methods and taking into account the effect of the adjacent power system operation modes. To deal with the problem of power equipment technical state analysis, i.e. power equipment state pattern recognition, XGBoost based on gradient boosting decision tree algorithm is used. Its main advantages are the ability to process gapped data and efficient operation with tabular data for solving classification and regression problems. The author suggests the formation procedure of correct and sufficient initial database for high-voltage equipment state pattern recognition based on its technical diagnostic data and the algorithm for training and testing sets creation in order to improve the identification accuracy of power equipment actual state. The description and justification of the machine learning method and corresponding error metrics are also provided. Based on the actual states of power transformers and circuit breakers the sets of technical diagnostic parameters that have the greatest impact on the accuracy of state identification are formed. The effectiveness of using power systems operation parameters as additional features is also confirmed. It is determined that the consideration of operation parameters obtained by calculation as a part of the training set for high-voltage equipment technical state identification makes it possible to improve the tuning accuracy. The developed structure and approaches to power equipment technical state analysis supplemented by power system operation mode data and diagnostic results provide an information link between the tasks of technological and dispatch control. This allows us to consider the task of power system operation mode planning from the standpoint of power equipment technical state and identify the priorities in repair and maintenance to eliminate power network “bottlenecks”.

An electromechanical moving load fixed node position and fixed node number railway power supply systems optimization model

This paper presents an optimization model for simulations of railway power supply systems. It includes detailed power systems modeling, train movements in discretized time considering running resistance and other mechanical constraints, and the voltage-drop-induced reduction of possible train tractive forces. The model has a fixed number of stationary power system nodes, which alleviates optimized operation over time. The proposed model uses SOS2 (Special Ordered Sets of type 2) variables to distribute the train loads to the two most adjacent power system nodes available.The impacts of the number of power system nodes along the contact line and the discretized time step length on model accuracy and computation times are investigated.The program is implemented in GAMS. Experiences from various solver choices are also discussed. The train traveling times are minimized in the example. Other studies could e.g. consider energy consumption minimization. The numerical example is representative for a Swedish decentralized, rotary-converter fed railway power supply system. The proposed concept is however generalizable and could be applied for all kinds of moving load power system studies.

Manitoba's Hydroelectric Resources and Interconnections

In many parts of the world, and particularly in North America, the development of remote renewable energy resources has resulted in an improved standard of clean living for the population and an enhanced quality of life. As each stage of development was accomplished in the planning of the reliability of the system, the authors looked at the possibilities of interconnecting with adjacent power systems. In the early 1950s, the interconnection of two power companies in Manitoba was accomplished, followed with a very low capacity interconnection with the Ontario Hydro Northwest region. The capacity of interconnections from Manitoba are in excess of 60 percent of the peak load of the Manitoba system and are expected to increase in the future. The authors want to generalize here by saying that the reliability of any system would be improved if it has interconnections of capacity equal to the connected load of the system as each new interconnection was added, the security of the system was improved. When the 500 kV interconnection was added, the security of the system was greatly enhanced.

A Decentralized Load Frequency Control Method by Means of Frequency Measurement of Adjacent Power Systems

The presently used TBC and FFC methods have satisfactorily maintained power system frequency within a prescribed tolerance. With steady increase in power system capacity, however, undue fluctuations in tie-line power flow has become prominent; This fact suggests the sheer necessity of establishing a more sophisticated LFC system. Intensive research efforts have been concentrated on applications of modern control theory, above all the linear optimal control (LOC) using the state regulator theory. This paper presents a decentralized suboptimal LFC method which makes use of the frequencies of adjacent areas in addition to local information to calculate the control variables of each area. This artifice has made it possible to realize a practical yet almost optimal control scheme. Simulation studies on a A area system have demonstrated the effectiveness of the proposed method.

A case of inductive co-ordination

The co-ordination of the expansion of both power and communication networks, to avoid the problem of excessive longitudinally induced voltage on communication and signal circuits, is a matter of increasing importance. This paper deals with the design and installation of railway signal and communication cables in a case where elaborate shielding from the influence of a proposed new adjacent power system was required.

Interconnection of electric power systems

Companies with adjacent power systems are showing an ever increasing tendency to interconnect their properties. Supplementing previously published information, the following (our articles classify and discuss the various interconnection services available.