Coal Mine Power System Research Articles

Application of FACTS Devices in Power Supply Systems of Coal Mines

In this article, the authors discuss the use of FACTS devices in coal mine power systems. The problems of reactive power compensation and the disadvantages of regulatory and technical documentation regarding the use of modern reactive power compensation devices are considered. The main types of FACTS devices that can be used in coal mines are identified. The scientific publications in the field of application of FACTS devices in power supply systems of industrial enterprises are analyzed. The cost indicators of FACTS devices are considered and conclusions are drawn on the theoretical technical and economic efficiency of using FACTS devices in mine conditions.

Research on Visualized Protective Relaying Setting Software for Coal Mine Power System

According to the special requirement of protective relaying setting in coal mine power system, the research and development of a visualized protective relaying setting software is described in this paper. Firstly, software architectural and its functional module is defined to meet special needs, then a novel setting method based on ‘triggered by setting condition’ and action simulation method based on setting value are proposed. Object-oriented and visualized programming means ensure its users can easily and directly carry out the setting calculation of protective relaying and simulate the protective action. The application and the achievements of good effects at last ensure its rationality.

The Solution for Malfunction of the Leakage Protection System Caused by Mine-Used Converter

The leakage protection system usually trends to make a misjudgment and tripping in normal operation after applying the converter in the coal mine power system. This seriously affects the safety in coal production. Based on the research of the structure and working principle of the converter, it has obtained the definite reason for the converter interfere the leakage protection system. It is the higher harmonics and pulses that generate the zero sequence current through the ground capacitance. Combined with the actual situation in coal mine, it has proposed two corresponding solutions: one is adding the isolation transformer in the output lines of the converter; another is modifying criterion of the leakage protection system. Both methods have their own characteristics, and have verified the feasibility of the methods through the MATLAB simulation.

Application of Smart Grid Technology in the Coalmine Power System

According to the problems emerged in the coalmine power system, such as poor reliability and lagging protection technology principles, this paper proposed some advices about the construction of the intelligent coalmine power system. Using SCADA system and GIS to locate the fault and recovery it; using Differential protection and intelligent monitoring terminal to guarantee the reliability of the coalmine power system; using Panoramic Data Platform to monitor the coalmine power system; using a series of auxiliary equipment to realize the automatic regulation and control of the coalmine power system.

Research of Integrated Distribution Scheme of Reactive Power Compensation Based on SVG for Coal Mine Power System

Aiming at the situation of the low power factor of coal mine power system, this paper puts forward an integrated distribution scheme of reactive power compensation based on SVG. In this paper, not only the disadvantageous influences of reactive power of coal mine power network are analyzed, but also the working principle and advantages of SVG are introduced. This paper proposes a distribution scheme of three-level reactive power compensation, which is to compensate in the sides of high voltage, high-low voltage power distribution and the long-distance high-power loads. According to the results of theoretical calculation and MATLAB simulation, the scheme can reduce the power loss and increase the power factor, so the power quality of coal mine can be improved.

The Research of wxWidgets Applied to Power System Graphics Software Development

This article discusses the problems existing in power system graphics software, and analyze wxWidgetss characteristics like cross-platform, local perception, face to objects and other features. The validation based on the wxWidgets development can make up for the graphics software shortcomings, providing new ideas for the development of future coal mine power system graphics software.

Based on OMAP Platform to Build the Distribution System Network of Relay Protection Devices in Coal Power

This article has carried on the analysis in view of the coal mine old communication network and the relay protection installment existence's question, Proposed based on the OMAP platform to build a coal mine power system relay protection program, elaborated the OMAP platform coal mine relay protection principle, To design this equipment's schematic diagram, and has carried on the performance introduction to this equipment's main hardware constitution, this paper has developed the data acquisition function software flow chart, it provided the basis for the development new coal mine distribution network relay protection installment.

Distinguishing motor starts from short circuits through phase-angle measurements

The National Institute for Occupational Safety and Health investigated how the starting of induction motors may cause nuisance tripping of short-circuit protection on coal mine power systems. This research had a dual purpose: (1) to identify how motor-start waveforms differ from those for short circuits and (2) to devise a method to provide short-circuit protection without intentional time delays to account for motor starts. This technology will help ensure that surface temperatures of energized electrical apparatus will not exceed gas or dust ignition thresholds when short circuits occur.

New insight into the detection of high-impedance arcing faults on DC trolley systems

High-impedance arcing faults are difficult to detect with conventional switchgear, and the presence of these faults in coal mine power systems represents a significant fire hazard. Research was performed to identify plausible techniques that would discriminate between the high-impedance arcing faults and legitimate load currents on the DC trolley system. This paper briefly summarizes that effort, and focuses on the frequency characteristics of the arc current. After the arc was modelled as a stochastic process, good agreement was obtained between experimental observations and mathematical predictions.

Technological innovations in deep coal mine power systems

Various innovations and changes have occurred to underground coal mine power systems during the past ten years. Some of these are the use of higher utilization and distribution voltages and associated switchgear, the use of programmable logic controllers for control, monitoring and diagnostic applications, improved protective relaying with built-in test circuitry, power-factor correction near loads for improved voltage regulation and modifications to power system component arrangements. Many of the innovations were necessitated by significant increases in power requirements of face equipment, particularly longwall equipment, while others are the result of improved technology. In either case, improved power system operating characteristics, as well as enhanced levels of safety, have resulted. This paper describes many of the major innovations that have evolved during recent years.

A detailed R-L fed bridge converter model for power flow studies in industrial AC/DC power systems

Because of lower voltage levels and smaller power ratings, the R/X ratio of commutation impedance in industrial AC/DC distribution systems is usually higher than that in HVDC transmission systems. Considerable discrepancies may therefore occur in industrial AC/DC power flow results, especially the reactive power consumption of converters, if the commutation resistances of the converters are neglected. To describe the effects of commutation impedance on converter operations and to precisely relate the fundamental line current and DC output current of the converter, a detailed model of the bridge converter with commutation impedance for use of Newton-Raphson power flow studies in industrial AC/DC power systems is derived in this paper. A coal mine power system and a DC electrified transit railway system with regenerative braking function, a part of Taipei Rapid Transit Systems under planning, have been analyzed to show the improved accuracy and good convergence characteristics of the developed Newton-Raphson power flow formulation with the proposed converter model.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Safety evaluation of coal mine power systems : Elmer W. Collins. Proc. a. Reliab. Maintainab. Symp., 51 (1987)

Safety evaluation of coal mine power systems : Elmer W. Collins. Proc. a. Reliab. Maintainab. Symp., 51 (1987)

Analysis Techniques in AC/DC Power Systems

Many present-day industrial power systems have combined ac/dc power distribution systems. A typical example is a coal mine power system, where ac is used for running the mining equipment and dc is used for track haulage, etc. Also, the topology of the dc network is constantly changing due to the movement of locomotives along the track. Methods are described that can be used to carry out load-flow and short-circuit analyses of such a system.

A Technique for Optimal Sequential Maintenance Scheduling

This paper presents the mathematical development of, and a simple solution technique for, an optimal sequential maintenance scheduling problem. The model is shown to satisfy the Kuhn-Tucker conditions, the necessary and sufficient conditions for the existence of an optimal solution. Real-world systems consisting of mixtures of constant and increasing failure rate devices are considered in the model. Sequential preventive maintenance schedules are developed for groups of identical items with increasing failure rates. Provision is made for the corrective maintenance of these groups if failures occur in between the preventive maintenance schedules. Also, constant failure rate devices are accorded corrective maintenance when failures occur. Optimality is achieved by minimizing the total annual maintenance cost, subject to constraints on the system availability, number of maintenance personnel and intervals of preventive maintenance. The model is applied to a coal mine power system example.